Chapter 19. Fetal Therapy
BS. Nguyễn Hồng Anh
Innovative treatments developed during the past three decades have dramatically altered the course o selected etal anomalies and conditions. Over time, etal interventions have become less invasive, and the number o etal centers has expanded. Te North American Fetal Terapy Network now includes 36 medical centers in the United States and Canada. Some o the etal abnormalities and conditions amenable to either medical or surgical treatment are presented here. Te management o etal anemia and thrombocytopenia is reviewed in Chapter 18, and treatment o some etal inections is discussed in Chapters 67 and 68.
MEDICAL THERAPY
Selected medications administered to the pregnant woman are transported across the placenta in concentrations high enough to treat etal conditions. Pregnancy physiology aects drug concentration, and transer depends on maternal and placental metabolism (Chap. 8, p. 145).
■ Arrhythmias
Abnormal etal cardiac rhythms are grouped into three categories: tachyarrhythmias, heart rates >180 beats per minute (bpm); bradyarrhythmias, heart rates <110 bpm; and ectopy, typically premature atrial contractions. I a etal arrhythmia is suspected, M-mode ultrasound, described in Chapter 15 (p. 294), is used to measure the atrial and ventricular rates and to clariy the relationship between atrial and ventricular beats, thereby diagnosing the type o rhythm disturbance.
Premature Atrial Contractions
I the etal heart rate is normal but the rhythm is irregular, the most common etiology is premature atrial contractions (PACs). Tese atrial ectopic beats are ound in 1 to 2 percent o uncomplicated pregnancies (Hahurij, 2011; Strasburger, 2010). PACs represent immaturity o the cardiac conduction system. Tey typically resolve later in gestation or in the neonatal period. PACs are usually an isolated nding but may be associated with redundancy o the oramen ovale ap—ormerly termed a oramen ovale aneurysm. When a PAC is conducted, an extra beat is heard with handheld Doppler. However, the premature contraction more commonly arrives at the atrioventricular node during the reractory period. Tis results in a compensatory pause, which sounds like a dropped beat. M-mode evaluation conrms the diagnosis (Fig. 15-46, p. 295).
PACs may occur as requently as every other beat, which means that the auscultated etal heart rate may be as low as 60 to 80 bpm. Known as blocked atrial bigeminy, this condition is benign and does not require treatment (Strasburger, 2010). However, monitoring the etus in labor may be challenging and necessitate cesarean delivery. M-mode ultrasound will dierentiate atrial bigeminy rom other causes o bradycardia, such as third-degree atrioventricular block. Up to 2 percent o etuses with PACs are later ound to have supraventricular tachycardia (Copel, 2000; Srinivasan, 2008). Given the importance o prompt identication and treatment o supraventricular tachyarrhythmias, pregnancies with PACs are oten monitored with etal heart rate assessment every 1 to 2 weeks until the ectopy resolves. At Parkland Hospital, we nd that auscultation with handheld Doppler is sucient or surveillance.
Tachyarrhythmias
Te two most common tachyarrhythmias are supraventricular tachycardia (SV) and atrial utter. SV is characterized by an abrupt increase in the etal heart rate to 180 to 300 bpm with 1:1 atrioventricular concordance (Fig. 19-1). Te typical range is 200 to 240 bpm. SV may develop secondary to an ectopic ocus or to an accessory atrioventricular pathway leading to a reentrant tachycardia. Atrial utter is characterized by a much higher atrial rate, generally 300 to 500 bpm, with varying degrees o atrioventricular block. As a result, the ventricular rate in a etus with atrial utter may range rom below normal to approximately 250 bpm (Fig. 19-2). In contrast, etal sinus tachycardia typically presents with a gradual heart rate rise to a rate that is only slightly above normal. With this, readily discernible causes may be maternal ever or hyperthyroidism, or rarely, etal anemia or inection.
I a etal tachyarrhythmia is identied, it is important to determine whether it is sustained—dened as present or at least
50 percent o the time. It may be necessary to monitor the
etal heart rate or 12 to 24 hours upon initial detection, and
then periodically to reassess (Srinivasan, 2008). Unsustained
or intermittent tachyarrhythmias may become sustained over
time. Although intermittent tachyarrhythmias do not generally
require treatment, close etal surveillance is warranted.
Sustained etal tachyarrhythmias with ventricular rates
exceeding 200 bpm impair ventricular lling to a degree that
the risks or developing cardiomyopathy and hydrops are signicant. With atrial utter, lack o coordinated atrioventricular contractions may urther compound this risk. Maternal
administration o antiarrhythmic agents that cross the placenta
may convert the rhythm to normal or may lower the baseline
heart rate to orestall heart ailure. Terapy can require dosages
at the upper end o the therapeutic adult range. Tereore, a
maternal electrocardiogram is obtained beore and during therapy. Monitoring o the maternal serum level may be necessary,
particularly i the dosage requires titration. I medical therapy is
successul, the medication is generally continued until delivery.
Antiarrhythmic medications most commonly used include
digoxin, ecainide, and sotalol. Teir selection depends on the
type o tachyarrhythmia and provider experience with the drug.
raditionally, digoxin was the initial preerred treatment, but
its placental transer may be poor in the setting o hydrops.
Many centers now use ecainide or sotalol as rst-line therapy
(Ekiz, 2018; van der Heijden, 2013). A second agent is needed
in more than 50 percent o cases (Jaeggi, 2011; O’Leary, 2020;
Shah, 2012). With treatment, conversion to a normal rhythm
or reduction in heart rate to a normal range occurs in 90 percent, including 80 percent o those with hydrops (Miyoshi,
2019; Ueda, 2018). SV is more likely than atrial utter to
convert to a normal rhythm. Te neonatal survival rate exceeds
90 percent (Ekman-Joelsson, 2015; Miyoshi, 2019; O’Leary,
2020; van der Heijden, 2013).
Bradyarrhythmia
Te most common etiology o etal bradycardia is congenital
heart block. Approximately 50 percent o cases occur in the setting o a structural cardiac abnormality involving the conduction system. Tese include heterotaxy, in particular left-atrial
isomerism; endocardial cushion defect; and less commonly corrected transposition of the great vessels (Srinivasan, 2008). Te
prognosis o heart block rom a structural cardiac anomaly is
extremely poor, and etal loss rates exceed 80 percent (Glatz,
2008; Strasburger, 2010).
In a structurally normal heart, 85 percent o atrioventricular block cases are caused by transplacental passage o maternal
FIGURE 19-1 Supraventricular tachycardia (SVT). This M-mode
image at 20 weeks’ gestation demonstrates an initially normal fetal
heartrate of 150 bpm. Midway through the image (arrow), the fetal
heart rate suddenly increases to 240 bpm. With SVT, there is one
atrial beat (A) for each ventricular beat (V).
FIGURE 19-2 Atrial flutter. In this M-mode image at 32 weeks’
gestation, calipers mark the ventricular rate, which is approximately
220 bpm. There are two atrial beats (A) for each ventricular beat (V),
such that the atrial rate is approximately 440 bpm with 2:1 atrioventricular block.
anti-SSA/Ro or anti-SSB/La antibodies (Buyon, 2009). Many
o these women have, or subsequently develop, systemic lupus
erythematosus or other autoimmune disease (Chap. 62, p.
1113). Te risk o third-degree heart block with Ro antibodies
is small—only approximately 2 percent. However, the risk may
reach 20 percent i a prior inant has been aected. Immunemediated congenital heart block coners a mortality rate o
nearly 20 percent, requires permanent pacing in two thirds o
surviving children, and also poses a risk or cardiomyopathy
(Brito-Zeron, 2015; Izmirly, 2011). I associated with eusions, bradyarrhythmias, or endocardial broelastosis, neonatal
status may progressively worsen ater birth.
Research has ocused on maternal corticosteroid therapy
to potentially reverse etal heart block or to orestall it. In the
PR Interval and Dexamethasone (PRIDE) study, a multicenter
trial o pregnancies with anti-SSA/Ro antibodies, Friedman
and colleagues (2008, 2009) perormed weekly etal echocardiography to assess or development o heart block. Fetal heart
block was treated with maternal oral dexamethasone, 4 mg
daily. Unortunately, therapy did not prevent progression
rom second- to third-degree block, and third-degree atrioventricular block was irreversible. In rare cases, there was a potential
benet in reversing rst-degree atrioventricular block. However, rst-degree block did not generally progress even without treatment. Similarly, a subsequent review o pregnancies
with isolated second- or third-degree etal heart block ound
that dexamethasone therapy did not aect disease progression,
need or pacemaker in the neonatal period, or overall survival
rates (Izmirly, 2016). Despite considerable enthusiasm or corticosteroid treatment, a systematic review o more than 700
pregnancies with treated etal heart block demonstrated no
improvement in etal or neonatal morbidity or mortality rates
(Michael, 2019). Tus, we do not recommend dexamethasone
use or this indication.
More recent eorts have turned to potential therapy with
hydroxychloroquine (Plaquenil), a mainstay o treatment
or systemic lupus erythematosus (Chap. 62, p. 1112). In a
review o more than 250 women with prior aected children,
early treatment with hydroxychloroquine was associated with
a signicant decrease in recurrence o congenital heart block
(Izmirly, 2012). A subsequent clinical trial ound that treatment with hydroxychloroquine was associated with a greater
than 50-percent reduction in the rate o etal heart block
(Izmirly, 2020). In each o these series, ewer than 8 percent
o children rom pregnancies treated with hydroxychloroquine
experienced heart block. Research in this area is ongoing.
Maternal terbutaline has also been given in small cohorts
with either alloimmune- or heterotaxy-mediated etal heart
block in which the etal heart rate is persistently below 56 bpm.
Te terbutaline dosage is titrated to a maternal heart rate o 95
to 115 bpm. Fetal heart rate increases o 5 to 10 bpm have been
reported, but resolution o hydrops has not been consistently
demonstrated (Cuneo, 2007, 2010).
■ Congenital Adrenal Hyperplasia
Several autosomal recessive enzyme deciencies impair etal
synthesis o cortisol rom cholesterol by the adrenal cortex,
leading to congenital adrenal hyperplasia (CAH). CAH is
the most common etiology o androgen excess in those with
46,XX disorders o sex development (Chap. 3, p. 38). Lack
o cortisol stimulates adrenocorticotrophic hormone (ACH)
secretion by the anterior pituitary, overproduction o androstenedione and testosterone, and subsequent virilization o
emale etuses. Sequelae may include ormation o labioscrotal
olds, persistence o a urogenital sinus, or even creation o a
penile urethra and scrotal sac (Fig. 15-55, p. 299).
More than 90 percent o CAH cases are caused by
21-hydroxylase deciency. Tere are two types: classic and
nonclassic. Te incidence o classic CAH approximates 1 in
15,000 births worldwide but is higher in selected populations.
Among Yupik Eskimos, the reported incidence is 1 in 300
births (Nimkarn, 2016). O those with classic CAH, 75 percent require postnatal treatment with mineralocorticoids and
glucocorticoids to prevent a salt-wasting adrenal crisis, which is
characterized by hyponatremia, dehydration, hypotension, and
even cardiovascular collapse. Te remaining 25 percent with
classic CAH have the simple virilizing type and also require
glucocorticoid supplementation. Nonclassic CAH may present
with precocious pubarche, hirsutism, or inertility. However,
aected individuals also may be asymptomatic. Te prevalence
o nonclassic CAH approximates 1 case per 200 Caucasians and
Ashkenazi Jews in the United States (Hannah-Shmouni, 2017).
As discussed in Chapter 32 (p.594), all states mandate newborn
screening or CAH.
For more than three decades, dexamethasone has been administered to the pregnant woman to suppress etal androgen overproduction and either obviate or ameliorate virilization o emale
etuses (David, 1984; New, 2012). Prenatal corticosteroid therapy is successul in most cases i initiated early and taken consistently. One metaanalysis ound that dexamethasone treatment
was associated with reduced virilization. Specically, the Prader
score, which grades genital masculinization on a scale 1 to 5,
improved by 2.3 grades (Fernandez-Balselis, 2010). Te alternative is consideration o postnatal genitoplasty, which may include
clitoroplasty, urogenital sinus surgery, and additional vaginoplasty
procedures. In a recent review, 18 percent o children treated with
eminizing genitoplasty experienced postoperative complications,
and 12 percent required urther surgery (Baskin, 2020).
Te typical preventive regimen is oral dexamethasone given
to the mother at a dosage o 20 μg/kg/d—up to 1.5 mg per
day, divided in three doses. Te critical period or external genitalia development is 7 to 12 weeks’ gestation, and treatment to
prevent virilization should be initiated by 9 weeks—before it is
known whether the fetus is aected. Because this is an autosomal
recessive condition, aected emales make up only 1 in 8 at-risk
conceptions.
Carrier parents are typically identied ater the birth o an
aected child. Molecular genetic testing is clinically available in
such cases and initially uses sequence analysis o the CYP21A2
gene, which encodes the 21-hydroxylase enzyme (Nimkarn,
2016). I this is uninormative, gene-targeted deletion/duplication analysis is perormed, and additional testing such as whole
exome sequencing may be considered (Chap. 16, p. 327).
A goal o prenatal diagnosis is to limit dexamethasone
exposure in males and in unaected emales. I both parents
are determined to be carriers, prenatal molecular genetic testing may be perormed on chorionic villi—at 10 to 12 weeks’
gestation—or on amniocytes ater 15 weeks. Determination o etal gender using cell-ree DNA (cDNA) may aid
in avoiding dexamethasone treatment. CDNA sensitivity to
detect Y-chromosome sequences is at least 95 percent when
perormed at or beyond 7 weeks (Devaney, 2011; Hill, 2011).
In the research setting, eective cDNA testing using hybridization probes anking the CYP21A2 gene has been reported as
early as 56/7 weeks’ gestation (New, 2014).
Maternal treatment with dexamethasone has become controversial. Te Endocrine Society recommends that treatment be
given only in the context o research protocols (Speiser, 2018).
It urther recommends that such protocols incorporate cDNA
screening or the Y-chromosome to avoid treatment o male
etuses. O note, i therapy is initiated shortly beore 9 weeks’
gestation, the dose o dexamethasone used is not considered
to have signicant teratogenic potential because organogenesis
o major organs has already taken place (McCullough, 2010).
Ongoing concerns ocus on the potential eects o either excess
endogenous androgens or excess exogenous dexamethasone on the
developing brain. Although maternal dexamethasone has been
used or many years to prevent virilization o emale etuses
with CAH, long-term saety data are relatively limited.
■ Congenital Cystic Adenomatoid
Malformation
Tis well-circumscribed lung mass may appear solid and echogenic or may have one or multiple variably sized cysts (Fig.
15-33, p. 288). Lesions with one or more cysts ≥5 mm are
termed macrocystic, whereas solid lesions and those with
smaller cysts are microcystic (Adzick, 1985). A small subset
o microcystic congenital cystic adenomatoid malormations
(CCAMs) may demonstrate rapid growth, generally between
18 and 26 weeks’ gestation. Te mass may become so large that
it causes mediastinal shit, which may compromise cardiac output and venous return, leading to hydrops (Cavoretto, 2008).
A CCAM-volume ratio (CVR) has been used to quantiy
size and risk or hydrops in these severe cases (Crombleholme,
2002). Tis ratio is an estimate o the CCAM volume using the
ormula or a prolate ellipse (length × width × height × π/6)
divided by the head circumerence. In a series o 40 pregnancies
with microcystic CCAM, the mean CVR was 0.5 at 20 weeks’
gestation, peaked at 1.0 by 26 weeks, and then declined sharply
beore delivery (Macardle, 2016). With a CVR exceeding 1.6,
the risk or hydrops is as high as 60 percent. However, i the
initial CVR is below 1.6, CCAM growth resulting in hydrops
develops in ewer than 2 percent o cases (Ehrenberg-Buchner,
2013; Peranteau, 2016).
A CVR threshold o 1.0 also may assist counseling. In a
series o 62 pregnancies with etal lung masses, a maximal CVR
>1.0 was associated with a 75-percent likelihood that the neonate would be symptomatic (Ehrenberg-Buchner, 2013). However, no etus with a CVR ≤1.0 subsequently required surgery
in the newborn period.
I the CVR exceeds 1.6 or i signs o hydrops develop,
corticosteroid treatment may be benecial. Regimens include
dexamethasone—6.25 mg every 12 hours or our doses, or
betamethasone—12.5 mg intramuscularly every 24 hours or
two doses. A single course o corticosteroids has been associated
with resolution o hydrops in approximately 80 percent o cases,
and 90 percent o treated etuses survived (Loh, 2012; Peranteau, 2016). Multiple courses o corticosteroids— generally
two—have been advocated or etuses with large CCAM lesions
and with persistent or worsening hydrops or ascites despite a single course o medication (Derderian, 2015; Peranteau, 2016).
Terapy or macrocystic CCAM is discussed later.
■ Thyroid Disease
Identication o etal thyroid disease is rare and is usually
prompted by sonographic detection o a etal goiter. I a goiter
is identied, determination o etal hyper- or hypothyroidism
is essential, and thyroid hormone levels should be measured in
amnionic uid or etal blood. raditionally, etal blood sampling was preerred to amniocentesis or guiding treatment,
but data are limited (Abuhamad, 1995; Ribault, 2009). Perormance o these procedures is discussed in Chapter 17 (p. 347).
Goals o therapy are correction o the physiological abnormality and diminished goiter size. Te goiter may compress the
trachea and esophagus, leading to hydramnios rom impaired
swallowing. Despite this, case reports attest to lack o airway
compromise and avorable outcomes (Blumeneld, 2013;
Machado, 2019).
Thyrotoxicosis
Maternal Graves disease may result in transplacental passage
o immunoglobulin G (IgG) thyroid-stimulating antibodies.
Untreated etal thyrotoxicosis can present with goiter, tachycardia, growth restriction, hydramnios, accelerated bone maturation, and even heart ailure and hydrops (Huel, 2009; Kieer,
2017; Peleg, 2002; van Dijk, 2018). Fetal blood sampling may
be considered to conrm the diagnosis (Duncombe, 2001;
Srisupundit, 2008). Maternal administration o antithyroid
medication may be needed, even i the woman has had prior
surgery or ablation and no longer has hyperthyroidism. I the
pregnant women develops hypothyroidism, she is treated with
supplemental levothyroxine (Hui, 2011).
Hypothyroidism
In a woman receiving medication or Graves disease, transplacental passage o methimazole or propylthiouracil may cause
fetal hypothyroidism (Bliddal, 2011). Other potential causes o
etal hypothyroidism resulting in goiter include transplacental
passage o thyroid peroxidase antibodies, etal thyroid dyshormonogenesis, and maternal consumption o iodine supplements (Agrawal, 2002; Hardley, 2018; Overcash, 2016).
Goitrous hypothyroidism may lead to hydramnios, neck
hyperextension, and delayed bone maturation. reatment
with intraamnionic levothyroxine should be considered.
Optimal dosage and requency have not been established
but have typically ranged rom 150 to 500 μg every 1 to
4 weeks (Machado, 2019; Nemescu, 2020; Ribault, 2009). I
the pregnant woman is receiving antithyroid medication, it is
generally discontinued.
SURGICAL THERAPY
Fetal surgery, also called maternal-fetal surgery, is oered or
selected congenital abnormalities in which the likelihood o
deterioration during gestation is so great that delaying treatment until ater delivery would risk etal death or substantially
greater postnatal morbidity. Fetal surgical procedures are highly
specialized interventions perormed at relatively ew centers to
treat a small number o etal conditions. Tey require extensive
preoperative counseling and multidisciplinary care. Principles
or guiding case selection are listed in Table 19-1. When considering etal surgery, the overriding concern is the saety o the
mother and etus. Accomplishing the etal goals o the procedure is secondary (Walsh, 2011).
Selected abnormalities amenable to etal surgical treatment
are shown in Table 19-2. An overview o some o these procedures, their indications, and complications is provided here to
assist with initial patient evaluation and counseling. Additional
content is also ound in Cunningham and Gilstrap’s Operative
Obstetrics, 3rd edition.
■ Open Fetal Surgery
Fetal procedures are considered open i they are accomplished
though a hysterotomy that is not perormed or the purpose o
delivery. Open procedures are perormed under general endotracheal anesthesia to suppress uterine contractions and etal
responses. Te hysterotomy is made with a stapling device, and
intraoperative ultrasound is used to avoid the placental edge and
to veriy etal position. Te stapler seals the edges o the myometrium and membranes to achieve hemostasis and avoid chorioamnion separation. Warmed uid is continuously inused into
the uterus thorough a rapid inusion device to limit cord compression. Te etus is gently manipulated to acilitate exposure,
to permit pulse oximetry monitoring, and to establish venous
access in case uids or blood are emergently needed. Te surgical procedure is then perormed, and the hysterotomy is closed.
Prophylactic antibiotics are generally administered or 24 hours.
ocolysis typically includes intravenous magnesium sulate or
24 hours and oral indomethacin or 48 hours. Cesarean delivery
is needed later in gestation and or all uture deliveries.
Risks
Open etal surgery entails signicant maternal and etal risks.
Te most recent data are rom studies o etal myelomeningocele
TABLE 19-1. Guiding Principles for Fetal Surgical Procedures
Accurate prenatal diagnosis for the defect is available, with staging if applicable
The defect appears isolated, with no evidence of other abnormality or underlying genetic syndrome that would
significantly worsen survival or quality of life
The defect results in a high likelihood of death or irreversible organ destruction, and postnatal therapy is inadequate
The procedure is technically feasible, and a multidisciplinary team is in agreement regarding the treatment plan
Maternal risks from the procedure are well documented and considered acceptable
There is comprehensive parental counseling
It is recommended that there be an animal model for the defect and procedure
Data from Deprest, 2010; Harrison, 1982; Vrecenak, 2013; Walsh, 2011.
TABLE 19-2. Selected Fetal and Placental Abnormalities
Amenable to In-Utero Procedures
Open Fetal Surgery
Congenital cystic adenomatoid malformation (CCAM)
Myelomeningocele
Pulmonary sequestration
Sacrococcygeal teratoma
Fetoscopic Surgery
Amnionic band sequence: band release
Congenital diaphragmatic hernia (CDH): fetal endoscopic
tracheal occlusion (FETO)
Congenital high airway obstruction sequence (CHAOS):
vocal cord laser
Myelomeningocele
Posterior urethral valves: cystoscopic laser
Twin-twin transfusion: laser of placental anastomoses
Percutaneous Procedures
Cardiac catheter procedures
Aortic or pulmonic valvuloplasty for stenosis
Atrial septoplasty for hypoplastic left heart with
restrictive atrial septum
Radiofrequency ablation
Twin reversed arterial perfusion (TRAP) sequence
Monochorionic twins with severe anomaly in one twin
Chorioangioma
Shunt therapy
Dominant cyst in CCAM
Thoracoamnionic shunt for pleural effusion
Vesicoamnionic shunt for bladder outlet obstruction
ExUtero Intrapartum Treatment (EXIT) Procedures
CDH after FETO
CHAOS
EXIT-to-extracorporeal membrane oxygenation (ECMO):
CDH
EXIT-to-resection: resection of fetal thoracic or mediastinal
mass
Micrognathia
Neck or airway tumors
Procedures are listed alphabetically within groupings.372 The Fetal Patient
Section 6
repair, which is the most commonly perormed procedure.
Morbidities identied in the Management o Myelomeningocele Study (MOMS) are shown in Table 19-3 (Adzick, 2011).
In a review o 26 open etal myelomeningocele cases, 15 percent experienced preterm rupture o membranes, and the mean
gestational age at delivery was 35 weeks (Pruthi, 2021). Other
potential risks include maternal sepsis and etal death during
or ollowing the procedure, particularly i hydrops is present.
Wilson and associates (2010) reviewed subsequent pregnancy
outcomes ollowing open etal surgery and reported that 14
percent o women experienced uterine rupture and 14 percent
had uterine dehiscence.
Myelomeningocele Surgery
Fetal myelomeningocele is the rst nonlethal birth deect or
which in-utero repair has been oered (Fig. 19-3). Following standard postnatal myelomeningocele repair, aected
children experience varying degrees o paralysis, bladder and
bowel dysunction, developmental delays, and brainstem dys-
unction rom the Arnold-Chiari II malormation (Chap. 15,
p. 277). Damage is postulated to result rom abnormal embryonic neurulation ollowed by exposure o neural elements to
amnionic uid throughout pregnancy (Adzick, 2010; Meuli,
1995, 1997).
In the landmark MOMS trial, Adzick and colleagues (2011)
randomized 183 pregnancies to prenatal or standard postnatal myelomeningocele repair at three centers. Criteria or trial
participation included: (1) a singleton etus at 19.0 to 25.9
weeks’ gestation; (2) an upper myelomeningocele boundary
between 1 and S1 conrmed by magnetic resonance imaging;
(3) evidence o hindbrain herniation; and (4) a normal karyotype and no evidence o a etal anomaly unrelated to the myelomeningocele. Women at risk or preterm birth or placental
abruption, those with a contraindication to etal surgery, and
women with body mass index (BMI) >35 kg/m2 were excluded.
Te MOMS trial demonstrated improved early childhood
outcomes in the prenatal surgery cohort (see able 19-3). Children who had undergone etal surgery were twice as likely to
walk independently by 30 months. Tey had signicantly less
hindbrain herniation and were only hal as likely to undergo
ventriculoperitoneal shunting by age 1 year. A primary outcome was a composite score that was derived rom the Bayley
Mental Development Index and rom the dierence between
the unctional and anatomical level o the lesion at 30 months.
Tis primary outcome was also signicantly better in the prenatal surgery group.
Despite these benets, most children who received etal
surgery were not able to ambulate independently, and nearly
30 percent were not able to ambulate at all. Prenatal surgery did not coner improvements in etal or neonatal death
rates or in the Bayley Mental Development Index score at
age 30 months. Prenatal surgery was also associated with a
small risk or placental abruption and maternal pulmonary
edema. Moreover, nearly hal were delivered beore 34 weeks,
TABLE 19-3. Benefits and Risks of Fetal Myelomeningocele Surgery versus Postnatal
Repair
Fetal Surgery
(n = 78)
Postnatal Surgery
(n = 80) p value
Benefits (Primary Outcomes)
Perinatal death or shunt by 12 monthsa 68% 98% <0.001
Shunt placement by 12 months 40% 82% <0.001
Composite developmental scorea,b 149 ± 58 123 ± 57 0.007
Hindbrain herniation (any) 64% 96% <0.001
Brainstem kinking (any) 20% 48% <0.001
Independent walking (30 months) 42% 21% 0.01
Risks
Maternal pulmonary edema 6% 0 0.03
Placental abruption 6% 0 0.03
Maternal transfusion at delivery 9% 1% 0.03
Oligohydramnios 21% 4% 0.001
Gestational age at delivery 34 ± 3 37 ± 1 <0.001
Preterm birth
<37 weeks 79% 15% <0.001
<35 weeks 46% 5%
<30 weeks 13% 0
aEach primary outcome had two components. The perinatal death components of the
primary outcomes as well as the Bayley Mental Development Index at 30 months did
not differ between the two study cohorts.
bScore derived from Bayley Mental Development Index and difference between
functional and anatomical level of lesion (30 months).
Data from Adzick, 2011.
which signicantly increased the risk or respiratory distress
syndrome (Adzick, 2011).
It is the position o the American College o Obstetricians
and Gynecologists (2017) that nondirective counseling include
the option o etal surgery or all pregnancies that meet MOMS
trial criteria. Study o etal myelomeningocele repair in women
with BMI up to 40 kg/m2 has demonstrated outcomes similar
to those in women o lower BMI (Hilton, 2019; Moldenhauer,
2020). Otherwise, MOMS trial criteria are strictly ollowed.
Outcomes o children aged 6 to 10 years who previously participated in the MOMs trial are now available (Houtrow, 2020).
Fetal surgery conerred a sustained benet in the likelihood o
independent ambulation. Nearly 30 percent o children were
able to ambulate independently, and approximately 50 percent
required ventriculoperitoneal shunt placement. Overall cognitive unction was similar between cohorts (Houtrow, 2020).
Thoracic Masses
Open etal surgery is rarely perormed or thoracic masses.
Most are small, and these have a good prognosis. Large CCAMs
are oten treated medically with a course o corticosteroids
(p. 370). A dominant cyst in a CCAM may be amenable to
drainage or shunt placement (p. 376). Similarly, an isolated
pleural eusion surrounding a pulmonary sequestration may be
amenable to drainage or shunt placement.
Fetal surgery is generally reserved or pregnancies prior to
32 weeks’ gestation in which there is a large, solid-appearing
or microcystic mass and hydrops is developing. In careully
selected cases, the survival rate ollowing open lobectomy
approximates 60 percent (Vrecenak, 2013). Use o the ex-utero
intrapartum treatment procedure in the treatment o etal lung
masses at delivery is discussed later.
Sacrococcygeal Teratoma
Te perinatal mortality rate or cases o sacrococcygeal teratoma diagnosed prenatally is 20 to 40 percent (Hedrick, 2004; Shue, 2013, Simonini, 2021). Poor prognostic actors include a solid component constituting more than 50 percent o the tumor mass and a tumor volume-to-etal weight ratio exceeding 12 percent prior to 24 weeks’ gestation (Akinkuotu, 2015).
Hydramnios is common, and hydrops may develop rom highoutput cardiac ailure, either as a consequence o tumor vascularity or secondary to bleeding within the tumor and resulting
anemia. Fetal loss rates approach 100 percent in such cases.
Mirror syndrome—maternal preeclampsia developing along
with etal hydrops—may occur in this setting (Chap. 18, p.
364).
Open etal surgery is considered only i the tumor is completely external and high cardiac output with early hydrops has developed in the second trimester (Vrecenak, 2013). However, given the poor prognosis, rapid growth beyond 27 weeks oten prompts early delivery and postnatal resection rather than open etal surgery (Baumgarten, 2019).
■ Fetoscopic Surgery
As with open etal surgeries, these procedures are perormed at highly specialized centers. Fetoscopy is perormed with beroptic endoscopes that measure 1 to 2 mm in diameter. Instruments such as lasers t through a 3- to 5-mm cannula
A B
FIGURE 19-3 Fetal myelomeningocele surgery. A. With the edges of both the laparotomy and hysterotomy incisions retracted, the skin
around the defect is incised. Subsequently, the neural placode is sharply dissected from the arachnoid membrane. B. The dural membrane
is reflected to the midline to cover the neural placode and is reapproximated using suture. In some cases a patch is needed (not shown).
The fetal skin incision is subsequently sutured. Last, hysterotomy and laparotomy are then closed. (Figures 19-3, 19-4, 19-6, and 19-8:
Reproduced with permission from Shamshirsaz AA, Ramin, SM, Belfort MA: Fetal therapy. In Yeomans ER, Hoffman BL, Gilstrap LC III, et al:
Cunningham and Gilstrap’s Operative Obstetrics, 3rd ed. New York, McGraw Hill Education, 2017.)374 The Fetal Patient
Section 6
that surrounds the endoscope. Not all etoscopic procedures
involve placing the instruments through the maternal anterior
abdominal wall. In some cases, laparotomy acilitates optimal
placement and maneuvering o the instruments or positioning
o the etus. Examples o conditions treated by etoscopy are
listed in able 19-2.
Twin-Twin Transfusion Syndrome
As discussed in Chapter 48 (p. 849), etoscopic laser ablation o placental anastomoses is the preerred management
or severe twin-twin transusion syndrome (S). It is
generally perormed between 16 and 26 weeks’ gestation or
monochorionic-diamnionic twin pregnancies with stage II to
stage IV S (Quintero, 1999; Society or Maternal-Fetal
Medicine, 2013).
A etoscope inserted into the sac o the recipient twin
is used to image the vascular equator. Te vascular equator separates the placental cotyledons that supply each twin
(Fig. 19-4). Selective laser photocoagulation involves individually
coagulating anastomoses that cross between the twins (Ville,
1995). Arteriovenous anastomoses along the placental sur-
ace o the equator are visualized with the etoscope and then
photocoagulated using a 600-μm diameter diode laser or a
400-μm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser
(Fig. 19-5). Te procedure is typically perormed under epidural analgesia. At the end, amnioreduction is perormed to
decrease the single deepest pocket o amnionic uid to below
5 cm, and antibiotics are injected into the amnionic cavity.
Unortunately, residual anastomoses remain in up to a third
o cases and may lead to S recurrence or to the development o twin anemia-polycythemia sequence (APS). Te latter is a eto-etal transusion characterized by large dierences
in hemoglobin concentrations between a pair o monochorionic
twins. With the Solomon technique, immediately ater selective photocoagulation, the laser is used to coagulate the entire
vascular equator rom one edge o the placenta to the other
(Slaghekke, 2014a). Placental dye-injection studies conrm a
signicant reduction in the number o residual anastomoses
ollowing this procedure (Ruano, 2013; Slaghekke, 2014b).
Families should have reasonable expectations o procedural
success and potential complications. Without treatment, the
perinatal mortality rate or severe S is 70 to 100 percent.
Following laser therapy, the perinatal mortality rate approximates 30 to 50 percent, and the risk or long-term neurological
handicap is 5 to 20 percent (Society or Maternal-Fetal Medicine, 2013). One series reported a double-twin survival rate
o nearly 70 percent and survival o at least one twin in more
than 90 percent o cases (Diehl, 2017). Ischemic etal brain
lesions have been identied in 2 percent o those treated by
laser and include cystic periventricular leukomalacia and grade
III or IV interventricular hemorrhage (Stirnemann, 2018).
FIGURE 19-4 Selective laser photocoagulation for twin-twin
transfusion syndrome. The fetoscope is inserted into the recipienttwin sac and positioned over the vascular equator, which lies in
between the two placental cord insertion sites. Arteriovenous
anastomoses along the placental surface are individually photocoagulated using the laser. (Reproduced with permission from Shamshirsaz AA, Ramin, SM, Belfort MA: Fetal therapy. In Yeomans ER,
Hoffman BL, Gilstrap LC III, et al: Cunningham and Gilstrap’s Operative Obstetrics, 3rd ed. New York, NY: McGraw Hill; 2017.)
A B
FIGURE 19-5 Fetoscopic photograph of laser photocoagulation for twin-twin transfusion syndrome. A. Vascular anastomoses (arrows) are shown before photocoagulation is performed. B. The ablation sites appear as blanched yellow-white areas (arrows). (Reproduced with permission from Dr. Timothy M. Crombleholme.)
Cerebral palsy has been reported in 5 percent o surviving children (Schou, 2019). Procedure-related complications include preterm prelabor rup tured membranes in up to 25 percent, placental abruption in 8 percent, vascular laceration in 3 percent, and amnionic band syndrome resulting rom laser laceration o the membranes in 3 percent. Additionally, APS complicates 16 percent o pregnancies treated with selective laser photocoagulation and 3 percent treated with the Solomon technique (Habli, 2009; Robyr, 2006; Slaghekke, 2014b). Te majority o laser-treated S pregnancies deliver beore 34 weeks’ gestation (Akkermans, 2015).
Congenital Diaphragmatic Hernia
Early attempts to treat congenital diaphragmatic hernia (CDH) used open etal surgery to reposition the liver into the abdomen. Tis unortunately kinked the umbilical vein and led to etal demise (Harrison, 1993). Knowledge that lungs normally produce uid and that etuses with upper airway obstruction develop pulmonary hyperplasia ormed the rationale or tracheal occlusion. Te idea was to “plug the lung until it grows” (Hedrick, 1994). Initial eorts ocused on occluding the trachea with an external clip (Harrison, 1993). Subsequently, a detachable silicone or latex balloon was placed within the trachea endoscopically and inated with normal saline (Fig. 19-6). Tis procedure, fetoscopic tracheal occlusion (FETO), is oered to selected pregnancies with isolated CDH in which the prognosis is otherwise poor based on the degree o etal liver herniation.
FEO uses a 3-mm operating sheath and etoscopes as small as 1 mm (Van der Veeken, 2018). Te procedure is generally perormed between 26 and 30 weeks’ gestation. Te balloon is removed ater 6 weeks or at approximately 34 weeks, either through a second etoscopic procedure or by ultrasound-guided puncture (Baschat, 2020). Fetal lamb research demonstrated that without balloon removal, the number o type II pneumocytes was markedly reduced, but that balloon removal normalized type II pneumocyte density (Flageole, 1998). Because the procedure is perormed etoscopically, vaginal delivery is not contraindicated.
In 2003, a randomized trial o the FEO procedure in pregnancies with isolated CDH, liver herniation, and lung-to-head ratio <1.4 did not identiy a benet rom etal therapy (Harrison, 2003). Survival rates 90 days ater birth were unexpectedly high—75 percent—in both groups. Tereore, the lung-tohead threshold was lowered and adjusted or gestational age in an eort to improve prediction. In a metaanalysis o more than 200 pregnancies, treatment with FEO was associated with a 13-old improvement in survival rates (Al-Maary, 2016).
FEO has also been associated with improved survival rates in right-sided CDH (Russo, 2021). Although study outcomes are promising, this procedure is currently available in the United States only through a research protocol.
Lung-to-Head Ratio. Tis imaging index was developed to improve prediction o survival in etuses with isolated let-sided CDH diagnosed beore 25 weeks’ gestation (Metkus, 1996). Te lung-to-head ratio (LHR) is a semi-quantitative estimate o the right lung area divided by the head circumerence. Investigators ound that the neonatal survival rate was 100 percent i the LHR was >1.35 and that there were no survivors i the LHR was <0.6 (Metkus, 1996). Nearly three ourths o pregnancies had values between 0.6 and 1.35, and prediction was dicult in this group because the overall survival rate approximated 60 percent. Modications to the LHR have been developed in an eort to improve prediction. Jani and colleagues (2007) derived an observed-to-expected (O/E) LHR nomogram to account or dierential growth o the head and torso across gestation.
Lung area has been measured in 3 dierent ways: (1) by tracing the lung circumerence, (2) by multiplying the longest diameter o the lung with its longest perpendicular diameter, and (3) by multiplying the anterior-posterior diameter o the at the mid-clavicular line by the perpendicular diameter at its midpoint (Jani, 2012). Te North American Fetal Terapy Network ound that reproducibility o the O/E LHR was highest when the lung circumerence was traced, but that overall interrater agreement was lower than anticipated (Abbasi, 2019).
Fetoscopic Myelomeningocele Repair
Ater publication o the MOMS trial ndings, research eorts ocused on whether maternal morbidities associated with open etal myelomeningocele repair might be mitigated i the procedure were accomplished etoscopically. Araujo Junior and associates (2016) conducted a systematic review that included 456 open cases and 84 etoscopic surgeries. Te endoscopic procedures were generally perormed by inserting instruments through the maternal abdominal wall and then through the uterine wall, with partial carbon dioxide insufation o the
FIGURE 19-6 Fetoscopic tracheal occlusion (FETO). The endoscope enters the fetal oropharynx and advances down the trachea. Inset: The balloon is inflated to occlude the trachea, and then the endoscope is removed. (Reproduced with permission from Shamshirsaz AA, Ramin, SM, Belfort MA: Fetal therapy. In Yeomans ER, Hoffman BL, Gilstrap LC III, et al: Cunningham and Gilstrap’s Operative Obstetrics, 3rd ed. New York, NY: McGraw Hill; 2017.)
Chylothorax is diagnosed i a cell count perormed on the pleural uid demonstrates that more than 80 percent o the cells are lymphocytes, and there is no evidence o inection. Pleural eusions may also orm secondary to congenital viral inection or aneuploidy, or they may be associated with a malormation such as a pulmonary sequestration. Yinon and associates (2010) reported aneuploidy in approximately 5 percent and associated anomalies in 10 percent o cases.
ypically, the eusion is rst drained using a 22-gauge needle. Te uid may be sent or chromosomal microarray analysis, inection studies, and a cell count. I the eusion recurs, a double-pigtail shunt is placed through the etal chest wall using a trocar and cannula. For a right-sided eusion, the shunt is placed in the lower third o the chest to permit maximum expansion o the lung. I let-sided, the shunt is placed along the upper axillary line to allow the heart to return to normal position. Te overall survival rate is 70 percent, and that or hydropic etuses approximates 50 percent (Mann, 2010; Yinon, 2010). We recommend weekly surveillance ollowing shunt placement because displacement into the amnionic cavity is common. At time o delivery, the shunt must be clamped immediately to avoid neonatal pneumothorax.
A shunt may also be used drain a dominant cyst in a etus with macrocystic CCAM (Fig. 15-33, p. 288). Only rarely are such cysts large enough to coner risk or hydrops or pulmonary hypoplasia. Shunt placement may improve the survival rate to 90 percent in those without hydrops and to at least 75 percent i hydrops has developed (Litwinska, 2017).
Urinary Shunts
Vesicoamnionic shunts are oered in selected cases o etal bladder-outlet obstruction in which the amnionic uid volume is severely diminished. Lower urinary tract obstruction uterus. Te rate o maternal myometrial dehiscence or attenuation was only 1 percent ollowing endoscopy compared with 26 percent ollowing open procedures. However, etoscopy was associated with signicantly higher rates o preterm delivery beore 34 weeks—80 versus 45 percent, and o perinatal mortality—14 versus 5 percent. More recently, investigators have perormed etoscopic myelomeningocele repair but used laparotomy and exteriorization o the uterus (Belort 2017). Te proportion o inants requiring ventriculoperitoneal shunts beore age 1 year— approximately 40 percent—was similar to that with open etal surgery in the MOMS trial (Adzick, 2011; Belort, 2017).
In one series o 34 pregnancies treated with open etoscopic myelomeningocele repair, the median gestational age at delivery was 38 weeks, and 50 percent delivered vaginally (Kohn, 2018). Research is ongoing in this area.
■ Percutaneous Procedures
Tese procedures are perormed using a shunt, angioplasty catheter, radiorequency ablation needle, or bipolar cautery. Under ultrasound guidance, instruments are inserted through the maternal abdominal wall, uterine wall, and membranes to reach the amnionic cavity and etus. Risks may include preterm labor, preterm prelabor ruptured membranes, placental abruption, maternal inection, and etal injury or loss.
Thoracic Shunts
Tese shunts drain etal pleural uid into the amnionic cavity (Fig. 19-7). A large eusion may result in pulmonary hypoplasia or may cause mediastinal shit that is severe enough to result in hydrops. Te most common etiology o a primary eusion is chylothorax, which is caused by lymphatic obstruction.
FIGURE 19-7 Thoracoamnionic shunt placement. A. A large, right-sided fetal pleural effusion (asterisks) and ascites were identified at 18 weeks’ gestation. The effusion was drained but rapidly reaccumulated. The xanthochromic fluid contained 95-percent lymphocytes, consistent with chylothorax. B. A double-pigtail shunt (arrow) was inserted under ultrasound guidance. Following shunt placement, the effusion and ascites resolved
(LUO) occurs more oten in male etuses. It is most commonly caused by posterior urethral valves but may be due to anterior urethral valves, urethral atresia or stenosis, or prune belly syndrome, which is also called Eagle-Barrett syndrome. Cases in emales may be associated with complex cloacal abnormalities or the megacystis-microcolon syndrome. Ultrasound ndings include dilation o the bladder and proximal urethra, termed the “keyhole” sign, along with bladder wall thickening (Fig. 15-61, p. 301). Associated oligohydramnios beore midpregnancy leads to pulmonary hypoplasia. Unortunately, postnatal renal unction may be poor even when amnionic uid volume is normal.
Evaluation includes a careul search or associated anomalies, which may occur in 40 percent o cases, and or aneuploidy, which has been reported in 5 to 8 percent (Hayden, 1988; Hobbins, 1984; Mann, 2010). Potential candidates or therapy are etuses without other severe anomalies or genetic syndromes. Terapy is generally oered only i the etus is male because the underlying anomaly tends to be even more severe in emales. Serial bladder drainage—vesicocentesis—perormed under ultrasound guidance at approximately 48-hour intervals is used to evaluate etal urine electrolyte and protein content.
Fetal urine is normally hypotonic due to tubular resorption o sodium and chloride, whereas isotonic urine in the setting o obstruction suggests renal tubular damage. Serial assessment has been used to guide candidate selection or therapy (Table 19-4). Chromosomal microarray analysis also may be perormed on etal urine.
Vesicoamnionic shunt placement allows urine to drain rom the bladder into the amnionic cavity (Fig. 19-8). While this may prevent pulmonary hypoplasia, it does not reliably preserve renal unction, particularly i cortical cysts are visible s onographically (Ruano, 2017). Warmed lactated Ringer solution is rst inused into the amniotic cavity. Amnioinusion improves ultrasound visualization, thereby acilitating evaluation o etal anatomy and shunt placement. A small trocar and cannula are then inserted into the etal bladder. A doublepigtail catheter is used, and the shunt is placed as caudal as possible within the bladder to avoid dislodgement ater bladder decompression.
Complications include displacement o the shunt out o
the etal bladder in up to 40 percent o cases, urinary ascites
in approximately 20 percent, and even development o bowel
herniation through the abdominal wall deect—gastroschisis—
in up to 10 percent (Freedman, 2000; Mann, 2010). Preterm
delivery is common, and reported neonatal survival rates range
rom 50 to 90 percent (Biard, 2005; Walsh, 2011). A third o
A
B
FIGURE 19-8 Vesicoamnionic shunt placement. A. After amnioinfusion is performed, a trocar is inserted into the distended fetal bladder under sonographic guidance. The pigtail catheter is threaded into the trocar. B. The double-pigtail shunt has been deployed down the trocar, and the trocar has been removed. The distal end of the shunt is coiled within the fetal bladder, and the proximal end is draining into the amnionic cavity. (Reproduced with permission from Shamshirsaz AA, Ramin, SM, Belfort MA: Fetal therapy. In Yeomans ER, Hoffman BL, Gilstrap LC III, et al: Cunningham and Gilstrap’s Operative Obstetrics, 3rd ed. New York, NY: McGraw Hill; 2017.)
TABLE 19-4. Fetal Urinary Analyte Values with Bladder Outlet Obstruction
surviving children have required dialysis or renal transplantation, and almost hal have respiratory problems (Biard, 2005). In a randomized trial comparing vesicoamnionic shunt with conservative management in 31 cases, those receiving shunts
had higher survival rates. However, only two children had normal renal unction at age 2 years (Morris, 2013). Similarly, a
metaanalysis o LUO studies perormed between 1990 and
2015 ound that vesicoamnionic shunt conerred perinatal survival benet but no improvement in renal unction or survival
at age 2 years (Nassr, 2017).
Radiofrequency Ablation
With this procedure, high-requency alternating current is
used to coagulate and desiccate tissue. Radiorequency ablation
(RFA) is the avored modality or treatment o twin reversed
arterial perfusion (TRAP) sequence, also known as acardiac twin
(Chap. 48, p. 850). Without treatment, the mortality rate or
the normal or pump twin in severe RAP sequence exceeds 50
percent. Te procedure is also used or selective termination
with other monochorionic twin complications.
Under ultrasound guidance, a 17- to 19-gauge RFA needle
is directed into the base o the umbilical cord within the abdomen o the acardiac twin, and a 2-cm area o coagulation is
achieved. Color Doppler is used to veriy absent ow into the
acardius. Te procedure is generally perormed at 20 weeks’ gestation. Te neonatal survival rate o the normal or pump twin
approximates 85 percent (Cabassa, 2013; Lee, 2013; Wagata,
2016). Risks are higher or monoamnionic twin pregnancies, in
whom the survival rate is only 67 percent (Sugibayashi, 2016).
Te most common complications are preterm prelabor ruptured membranes and preterm birth.
RFA has generally been oered or RAP sequence when
the volume o the acardiac twin is large. In a series rom the
North American Fetal Terapy Network, the median size o the
acardius relative to the pump twin was 90 percent (Lee, 2013).
Considering procedure-related risks, expectant management
with close etal surveillance is oten considered i the estimated
weight o the acardius is below 50 percent o the estimated
weight o the pump twin (Jelin, 2010).
Intracardiac Catheter Procedures
Selected etal cardiac lesions may worsen during gestation,
urther complicating and even limiting options or postnatal repair. Severe narrowing o a cardiac outow tract may
result in progressive myocardial damage in utero, and a goal
o etal intervention is to permit muscle growth and preserve
ventricular unction. Tese innovative procedures include aortic valvuloplasty or critical aortic stenosis; atrial septoplasty or
hypoplastic let heart syndrome with intact interatrial septum;
and pulmonary valvuloplasty or pulmonary atresia with intact
interventricular septum.
Fetal aortic valvuloplasty is the most commonly perormed
cardiac procedure, accounting or 75 percent o cases reported
by the International Fetal Cardiac Intervention Registry
(Moon-Grady, 2015). It is oered or selected cases o critical aortic stenosis in which the let ventricle is either normal
sized or dilated. Te goal is to prevent progression to hypoplastic let heart and to permit postnatal biventricular repair.
Under sonographic guidance, an 18-gauge cannula is inserted
through uterus and etal chest wall and into the let ventricle.
Although the procedure is ideally perormed percutaneously—
through the maternal abdominal wall—laparotomy may be
needed i the etal position is unavorable. Te cannula tip is
positioned in ront o the stenotic aortic valve, and a 2.5- to
4.5-mm balloon catheter is guided into the aortic annulus and
then inated. Fetal bradycardia requiring treatment may complicate a third o cases, and hemopericardium requiring drainage aects approximately 20 percent (Patel, 2020).
In a review o 108 etuses treated with aortic valvuloplasty
rom 15 international centers, 75 percent survived until delivery, and biventricular repair was achieved in 32 percent (Patel,
2020). Friedman and coworkers (2018) rom Boston Children’s Hospital have reported improved outcomes with the
procedure in recent years. O 52 aortic valvuloplasty procedures
perormed between 2009 and 2015, nearly 90 percent resulted
in a live birth, and more than 50 percent achieved biventricular
repair. Guseh and colleagues (2020) emphasize that most children with biventricular unction still require postnatal cardiac
procedures. Te risk or neurodevelopmental impairment in
childhood appears similar to cases treated with postnatal repair
(Laraja, 2017; Moon-Grady, 2015).
Te subset o etuses with hypoplastic let heart syndrome
who also have an intact or restrictive interatrial septum have
postnatal mortality rates o nearly 80 percent (Glantz, 2007;
Jantzen, 2017). o help improve survival, etal atrial septoplasty using a percutaneous balloon catheter has been oered.
Atrial septal stent placement is oten attempted at the time o
septoplasty to ensure patency. O 47 such procedures reported
by the International Fetal Cardiac Intervention Registry, 35
percent o inants survived to hospital discharge (Jantzen,
2017). However, the 1-year survival rate was higher in those
that had successul etal cardiac intervention compared with
those that had not undergone intervention.
Fetal pulmonary valvuloplasty has been oered in cases o
pulmonary atresia with intact interventricular septum to prevent development o hypoplastic right heart syndrome and
subsequent single ventricle palliation. Te International Fetal
Cardiac Intervention Registry reported that o 58 cases o
attempted pulmonary valvuloplasty, the procedure was technically successul in 70 percent (Hogan, 2020). Tose with
successul in-utero procedures were twice as likely to achieve
biventricular repair. However, when procedure-related losses
were considered, survival to hospital discharge was similar to
those who had not received etal intervention, approximating
75 percent. Long-term benets o the procedure have yet to be
demonstrated.
■ ExUtero Intrapartum Treatment
Tis procedure allows the etus to remain perused by the placenta ater being partially delivered, so that liesaving treatment can be perormed beore completing the delivery. Te technique was rst developed to obtain an airway with etal tumors involving the oropharynx and neck and is still used or this indication (Catalano, 1992; Kelly, 1990; Langer, 1992; Shamshirsaz, 2021). An ex-utero intrapartum treatment (EXI)
procedure is perormed by a multidisciplinary team, which may include an obstetrician, maternal-etal medicine specialist, pediatric surgeon(s), pediatric otolaryngologist, pediatric cardiologist, anesthesiologists or the mother and etus, neonatologists, and specially trained nursing personnel. Components o the procedure are shown in Table 19-5 (Moldenhauer, 2013). Selected indications are listed in able 19-2. EXI is the preerred procedure or intrapartum management o large venolymphatic malormations o the neck such as the one shown in
Figure 19-9. Criteria or EXI with a cervical venolymphatic malormation include compression, deviation, or obstruction o the airway by the mass, and also involvement o the oor o the mouth (Laje, 2015). However, a review o 112 pregnancies with etal cervical venolymphatic malormations ound that only about 10 percent met these criteria. Other indications or EXI include severe micrognathia and congenital high airway obstruction sequence (CHAOS), which are discussed in Chapter 15 (Figs. 15-27 and 15-35, p. 285).
Criteria or an EXI procedure or micrognathia include a etal jaw measurement below the 5th percentile along with indirect evidence o obstruction, such as hydramnios, an absent stomach bubble, or glossoptosis (Morris, 2009b). Case selection or EXI procedures is generally based on etal magnetic resonance imaging ndings.
In some cases, an EXI procedure has been used as a bridge to other procedures. For example, resection o large thoracic masses may be accomplished by etal thoracotomy perormed with intact placental circulation. In a series o 16 etuses with CCAM volume ratios >1.6 or hydrops, all o whom had mediastinal compression, Cass and colleagues (2013) reported that nine inants undergoing EXIT-to-resection survived. In contrast, there were no survivors with urgent postnatal surgery alone. Similarly, Moldenhauer (2013) reported that 20 o 22 newborns treated with EXI-to-resection or lung masses survived. Te EXI procedure has also been used as a bridge to extracorporeal membrane oxygenation—EXI-to-ECMO—in pregnancies with severe congenital diaphragmatic hernia. However,
TABLE 19-5. Components of the Ex-Utero Intrapartum Treatment (EXIT) Procedure Comprehensive preoperative evaluation: specialized fetal sonography, fetal echocardiography, magnetic resonance imaging, fetal karyotype if possible
Uterine relaxation with deep general anesthesia and tocolysis
Intraoperative sonography to confirm placental margin and fetal position and to visualize vessels at planned hysterotomy site
Placement of stay-sutures followed by use of uterine stapling device to decrease hysterotomy-site bleeding
Maintenance of uterine volume during the procedure via continuous amnioinfusion of warmed physiological solution to help prevent placental separation
Delivery of the fetal head, neck, and upper torso to permit access as needed
Fetal injection of intramuscular vecuronium, fentanyl, and atropine
Fetal peripheral intravenous access, pulse oximeter, and cardiac ultrasound
Following procedure, umbilical lines placed prior to cord clamping
Uterotonic agents administered as needed
FIGURE 19-9 Ex-utero intrapartum treatment (EXIT) procedure for a venolymphatic malformation. A. Upon delivery of the head, placental circulation was maintained, and an airway was established over the course of 20 minutes by a team of pediatric subspecialists that included a surgeon, anesthesiologist, and otolaryngologist. B. Following a controlled intubation, the fetus was ready for delivery and transfer to the neonatal intensive care unit team. (Reproduced with permission from Drs. Stacey Thomas and Patricia Santiago-Muñoz.)
it has not been ound to clearly coner survival benet in such cases (Morris, 2009a; Shieh, 2017; Stoan, 2012). Counseling prior to an EXI procedure includes procedurerelated risks such as hemorrhage rom placental abruption or uterine atony, need or cesarean delivery in uture pregnancies, higher risk or subsequent uterine rupture or dehiscence, possible need or hysterectomy, and etal death or permanent neonatal disability. Compared with cesarean delivery, the EXI procedure is associated with greater blood loss, a higher incidence o wound complications, and a longer operating time (Noah, 2002; Shamshirsaz, 2019).
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