Case 19 A 29-year-old woman with leaking fluid per vaginum at 31 weeks’ gestation

 Case 19 A 29-year-old woman with leaking

fluid per vaginum at 31 weeks’

gestation

Ms McRoberts, a 29-year-old para 3 + 0, presented to the

labour ward at 31 weeks’ gestation with a history of a gush

of fluid per vaginum in the early hours of the morning. She

had been on her way to the toilet when she noticed fluid

running down her legs. She had undergone a routine check

with her midwife 2 days ago, when she was told that all

was well with the pregnancy.

What would be the differential

diagnosis here?

• Preterm premature rupture of membranes (PPROM)

• Urinary incontinence

• Vaginal discharge

Past obstetric history

Details of her previous pregnancies and labours:

• Gestation at delivery (term or preterm)

• History of PPROM

• Spontaneous or induced labour

• Mode of delivery (vaginal or by caesarean section)

• Any complications

Past medical history including allergies

Is there anything of relevance in her past medical history

and does she have any allegies?

Ms McRoberts has had an uneventful pregnancy until

tonight. She denies any abdominal pain or contractions and

reports normal fetal movements. She experienced a sudden

gush of clear fluid on her way to the toilet. The fluid ran

down her legs and wet the bathroom floor. She gives no

history of dysuria but reports increased urinary frequency for

the past week or two. Apart from that she had been feeling

well and denies any major medical problems or allergies. She

admits to smoking up to 20 cigarettes per day.

She has had three previous pregnancies. In her first two

pregnancies she laboured spontaneously and had uneventful

vaginal deliveries at term, while in the third pregnancy she

had a preterm vaginal birth at 33 weeks’ gestation following

PPROM and then preterm labour. She gives no history of

postnatal problems.

What key features would you look for

on physical examination?

General examination

Signs of labour – does she appear to be in pain? Check

her pulse, blood pressure and temperature recordings:

tachycardia and pyrexia may indicate an infection.

Abdominal examination

• Uterine contractions

• Lie and presentation of the baby and symphysiofundal

height

Obstetrics and Gynaecology: Clinical Cases Uncovered.

By M. Cruickshank and A. Shetty. Published 2009 by Blackwell

Publishing. ISBN 978-1-4051-8671-1.

KEY POINT

PPROM is defined as prelabour rupture of membranes

prior to 37 completed weeks of gestation. It complicates

2% of pregnancies but is associated with 40% of preterm

deliveries.

What specific information would you

need from her history to help you

formulate a diagnosis?

Presenting complaints

• Colour and amount of the fluid

• Any associated abdominal pain/contractions?

• Has she felt the baby move?

• Any urinary symptoms (e.g. dysuria and frequency)?

• Any flu - like symptoms?

• Any problems in the present pregnancy?Case 19 127

PART 2: CASES

• Tenderness on palpation (sign of infection)

• Fetal heart check with Doppler and cardiotocograph

(CTG)

• Pad check for colour of fluid

Ms McRoberts appears anxious but not in any pain. Her

pulse is 90 beats/minute, her BP is 110/70mmHg and her

temperature is 36.8°C. On palpation, the uterus is relaxed

and non-tender with the fetus presenting as cephalic. The

fundal height is appropriate to her gestation. The CTG

appears reassuring with a normal reactive baseline of

approximately 140 beats/minute, with accelerations.

What would you do next?

Speculum examination

The next step would be a sterile speculum examination

looking for pooling of fluid in the posterior vaginal

fornix to confirm spontaneous rupture of membranes. A

convincing history followed by demonstration of presence of fluid in the posterior vaginal fornix is highly

suggestive if not conclusive of rupture of membranes and

further diagnostic tests are unnecessary. A high vaginal

swab is obtained for culture and sensitivity at this time.

However, in case of equivocal findings it may be necessary to proceed to further diagnostic tests to confirm or

refute the diagnosis of PPROM.

What additional diagnostic tests could

you use?

1 The nitrazine test. A series of tests have been used to

confirm membrane rupture; the most widely used has

been the nitrazine test:

 Detects pH change

 Has a sensitivity of 90% and false positive rate of

17%

 Normal vaginal pH is 4.5 – 6.0 (nitrazine paper does

not change colour). With ruptured membranes, vaginal

pH is 7.1 – 7.3 (colour of paper changes to blue)

 A false positive test (nitrazine positive, pH >7) indicates blood, semen, antiseptic solutions or bacterial

vaginosis

More recently, other tests (e.g. fetal fibronectin and

raised insulin - like growth factor binding protein - 1 in

cervical or vaginal secretions) have reported sensitivities

of 94% and 75%, and specificities of 97%, respectively.

2 Ultrasound for liquor volume. Ultrasound is useful in

some cases to help confirm the diagnosis of PPROM,

by demonstrating oligohydramnios (reduced liquor

volume).

3 Mid - stream sample of urine (MSSU). MSSU should be

obtained at this stage if other tests are negative to exclude

a urinary tract infection.

A sterile speculum examination was performed which

revealed obvious pools of clear fluid in the posterior vaginal

fornix.

In view of the convincing history of rupture of membranes at 31 weeks ’ gestation and the presence of pools

of liquor on speculum examination, the diagnosis was

that of PPROM.

!RED FLAG

Digital examination should be avoided where PPROM is

suspected.

Box 19.1 Preterm premature rupture of

membranes

• PPROM leads to significant neonatal morbidity and

mortality

• The three causes of increased neonatal morbidity and

mortality are prematurity, sepsis and pulmonary

hypoplasia

• Maternal risks are associated with chorioamnionitis

• Women with intrauterine infection deliver earlier than

non-infected women and infants born with sepsis have

a mortality rate four times higher than those without

sepsis

Risk factors associated with PPROM

• History of PPROM in previous pregnancy

• Tobacco use

• Amniocentesis or cervical cerclage in present pregnancy

• History of cone biopsy of cervix

• Uterine distension resulting from polyhydramnios and

multiple pregnancy

• Cervical or vaginal infection (e.g. bacterial vaginosis,

group B streptococci, ureaplasma, Chlamydia)

Course prior to delivery

• Term PROM: labour starts within 24 hours in 70% of

cases

• PPROM between 28 and 34 weeks: labour starts within

24 hours in 50% of cases; labour starts within 1 week

in 80% of cases

• PPROM between weeks 24 and 26: labour starts within

1 week in >50%; labour delayed 4 weeks in 22%128 Part 2: Cases

PART 2: CASES

The ultrasound scan shows that Ms McRoberts’ baby is

presenting as cephalic, is well grown and in good condition,

with reduced amniotic fluid volume. She is apyrexial with a

normal white cell count and has a CRP of <10. An high

vaginal swab has been reported as negative.

What would you do next?

Prophylactic antibiotics

The use of antibiotics following PPROM was associated

with a statistically significant reduction in chorioamnionitis. There was a significant reduction in the numbers of

babies born within 48 hours and 7 days. Neonatal infection was significantly reduced in the babies whose

mothers received antibiotics. Erythromycin (250 mg

orally 6 - hourly) should be given for 10 days following the

diagnosis of PPROM. Co - amoxiclav is not recommended

for women with PPROM because of concerns about necrotizing enterocolitis.

Corticosteroids

Antenatal corticosteroids should be administered in

women with PPROM as steroids reduce the risks of respiratory distress syndrome, intraventricular haemorrhage

and necrotizing enterocolitis. They do not appear to

increase the risk of infection in either the mother or the

fetus.

Digital vaginal examination is best avoided unless

there is a strong suspicion that the woman may be

in labour. This is because microorganisms may be

transported from the vagina into the cervix, leading to

intrauterine infection, prostaglandin release and preterm

labour.

What would be your plan

of management?

1. Assess fetal well - being. Use fetal CTG and ultrasound

to assess fetal well - being. Use ultrasound to establish the

fetal growth and lie, and amniotic fluid volume.

2. Exclude maternal infection by:

 Regular observations – pulse, temperature, uterine

activity and tenderness

 Blood tests – full blood count, C - reactive protein

(CRP)

 High vaginal swab – chorioamnionitis is an ascending infection

KEY POINT

The criteria for the diagnosis of clinical chorioamnionitis

include maternal pyrexia (>37.8°C), tachycardia,

leucocytosis, uterine tenderness, offensive vaginal

discharge and fetal tachycardia (>160 beats/minute).

During inpatient observation, the woman should

be regularly examined for such signs of intrauterine

infection as an abnormal parameter or a combination

can indicate intrauterine infection (Box 19.2 ).

Box 19.2 Royal College of Obstetricians and

Gynaecologists (RCOG) recommendations for

monitoring for intrauterine infection

• Women should be observed for signs of clinical

chorioamnionitis at least 12-hourly

• A weekly high vaginal swab and at least a weekly

maternal full blood count should be considered

• Fetal monitoring using CTG should be considered where

regular fetal surveillance is required

• Biophysical profile scoring or Doppler velocimetry should

not be considered as first-line surveillance or diagnostic

tests for fetal infection

KEY POINT

Betamethasone is the steroid of choice to enhance lung

maturation. Recommended therapy involves two doses of

12mg betamethasone, given intramuscularly 24 hours

apart.

The optimal treatment – delivery interval for administration of antenatal corticosteroids is more than 24 hours

but fewer than 7 days after the start of treatment.

Ms McRoberts wonders whether she should receive drugs to

prevent onset of labour to enable her to complete the

course of corticosteroids.

Could tocolytic agents be used?

Evidence suggests that prophylactic tocolysis in women

with PPROM without uterine activity is not recommended. The only indication for the short - term use of

tocolytics could be to complete the course of steroids for

fetal lung maturity or to allow for in utero transfer of theCase 19 129

PART 2: CASES

mother to a unit with neonatal facilities to manage a

preterm neonate.

Ms McRoberts enquires about when she

might be delivered?

Delivery should be considered at 34 weeks ’ gestation.

Where expectant management is considered beyond

34 weeks ’ gestation, women should be counselled about

the increased risk of chorioamnionitis and its consequences versus the decreased risk of serious respiratory

problems in the neonate, admission for neonatal

intensive care and caesarean section. Therefore, it is

standard practice to manage expectantly until 34 weeks ’

gestation.

Ms McRoberts is commenced on erythromycin as per

protocol and also receives the first betamethasone injection.

The neonatal unit is informed of her admission to ensure

there is an available neonatal bed. The plan is for expectant

management and induction of labour at 34 weeks’

gestation. She feels well and wonders if she could be

managed as an outpatient as she lives near the hospital

and is willing to come for regular check ups and blood

tests.

Can Ms McRoberts be managed as

an outpatient?

In a randomized study of home versus hospital management outcomes, the two groups were comparable with a

similar latency period and gestational age at delivery.

There were no significant differences in the frequencies

of chorioamnionitis, respiratory distress syndrome or

neonatal sepsis (Box 19.3 ).

A management plan is made for Ms McRoberts to be

monitored as an inpatient for 72 hours and then for

discharge home, if all remains well. However, later that day

she experiences abdominal discomfort and reports irregular

uterine activity. Her observations are normal and the CTG is

reassuring. On palpation she is noted to have one to two

mild contractions every 15 minutes. The registrar on duty

performs a sterile vaginal examination, which shows the

cervix to be 1–2cm dilated and shortened. The diagnosis is

that of threatened preterm labour.

Ms McRoberts is extremely worried about her baby’s

health as she has not completed her steroid course and asks

the registrar if anything could be done to stop her from

labouring?

There is no clear evidence that tocolysis improves

pregnancy outcome. Tocolysis should be considered if the

few days gained would be put to good use, such as completing a course of corticosteroids or in utero transfer.

Once a decision is made to use a

tocolytic drug, which is the best choice?

Atosiban or nifedipine appear preferable to ritodrine, a

beta - agonist, as they have fewer adverse effects and seem

to have comparable effectiveness (Box 19.4 ). Atosiban (an

oxytocin antagonist) is licensed for tocolysis in the UK

but nifedipine (a calcium - channel blocker) is not. Ritodrine has been the most thoroughly evaluated but, like

all beta - agonists, has a high frequency of unpleasant and

sometimes severe adverse effects (Box 19.5 ).

Box 19.3 RCOG recommendations for

outpatient management in PPROM

• Women should be considered for outpatient monitoring

of PPROM only after rigorous individual selection

• Outpatient monitoring should be considered only after a

period of 48–72 hours of inpatient observation

• Women being monitored at home for PPROM should

take their temperature twice daily and should be advised

of the symptoms associated with chorioamnionitis (e.g.

abdominal pain, pyrexia, change in the colour, smell of

the fluid leaking per vaginum), and when they should

seek specialist advice

• There should be clearly described local arrangements for

the frequency of outpatient visits and what should be

carried out at these visits

Box 19.4 Tocolytic agents

A variety of preparations are available of comparative

efficacy but different side-effect profiles

• Atosiban: oxytocin antagonist

• Nifedipine: calcium-channel antagonist

• Ritodrine (beta-agonist): not preferred because of

maternal side-effects

• Indometacin (antiprostaglandin): concerns about safety

in fetus and neonate

• Nitric oxide donors mainly glyceryl trinitrate: under trial,

comparative effectiveness to beta-agonist but fewer

maternal side-effects

• Magnesium sulphate: popular in the USA, comparative

effectiveness to ritodrine but better tolerated130 Part 2: Cases

PART 2: CASES

After discussion, Ms McRoberts is commenced on the

tocolytic drug atosiban and monitored in accordance with

the departmental guideline in the high dependency area.

Over the next few hours she feels more comfortable, her

contractions settle and she manages some sleep overnight.

Her observations remain stable on the infusion. She receives

the second dose of betamethasone IM the following

morning, and is transferred to the antenatal ward for

observation after the ward round. The management plans

remain as before: if she does not labour for outpatient

management and induction of labour around 34 weeks’

gestation.

Ms McRoberts is discharged from hospital 72 hours later

with follow-up planned at the day assessment unit, with

advice regarding monitoring for the warning signs of

chorioamnionitis. She starts to labour spontaneously 1 week

later, comes into hospital and is delivered of a baby boy in

good condition weighing 1956g. The baby is transferred to

neonatal unit in view of his prematurity. Her postnatal

period is uneventful and she is discharged home 2 days

later. Over the next few weeks her baby makes good

progress in the neonatal unit requiring minimal ventilatory

support and is discharged home 4 weeks later.

CASE REVIEW

Ms McRoberts presented with a convincing history of

PPROM with no evidence of labour. She was a heavy

smoker with a past obstetric history of preterm delivery

and PPROM, thus putting her at a high risk of these recurring again in this pregnancy.

The diagnosis was confirmed by a speculum examination. Normal recordings and relevant investigations confirmed maternal and fetal well - being. She was commenced

on prophylactic antibiotics and prescribed steroids for fetal

lung maturity, with a plan for conservative management

until 34 weeks ’ gestation in the absence of chorioamniotis.

However, before the course of steroids was complete she

developed signs of labour. Tocolysis in the form of atosiban

infusion was started to enable her to complete the course

of steroids. Thereafter she was managed as an outpatient

as the uterine contractions settled down and there was no

evidence of chorioamnionitis.

Premature labour set in within a week and she had a

spontaneous vaginal delivery. Prior to discharge she was

counselled about her increased risk of PPROM and

preterm labour in subsequent pregnancies. This woman

would be a candidate for detection and treatment of

asymptomatic infections (e.g. bacterial vaginosis) by

means of high vaginal swab in the second and early third

trimesters along with prophylactic steroids (at around

28 – 29 weeks) for fetal lung maturity.

Box 19.5 Side-effects of tocolytic drugs

Maternal side-effects

Common: nausea, headache, dizziness, tachycardia,

palpitations, chest pain

Rare: hypotension, hyperglycemia, pulmonary oedema

(beta-agonists)

Atosiban is associated with fewer maternal side-effects

than beta-agonists

Fetal side-effects

• Fetal and neonatal tachycardia

• Premature closure of ductus arteriosis, renal and cerebral

vasoconstriction, necrotizing enterocolitis (indometacin)Case 19 131

PART 2: CASES

Further reading

Royal College of Obstetricians and Gynaecologists . Tocolytic

drugs for women in preterm labour. Green - top Guideline No.1

(B). RCOG , London , 2002 .

Royal College of Obstetricians and Gynaecologists . Antenatal

corticosteroids to prevent respiratory distress syndrome. Green -

top Guideline No. 7. RCOG , London , 2004 .

KEY POINTS

• Preterm labour is the single most important determinant

of adverse infant outcome, most morbidity and mortality

being experienced by babies born before 34 weeks

• Definition: onset of labour prior to 37 completed weeks

of gestation

• Incidence: 6–15% of deliveries

• Risk factors for preterm labour include:

 low socioeconomic status

 extremes of maternal age

 tobacco use or substance abuse

 prior preterm delivery or second trimester miscarriage

 African-American race

 uterine anomaly (e.g. unicornuate or bicornuate uterus)

 genitourinary infection

 uterine distension caused by twins, polyhydramnios

 history of cervical cone biopsy

• Prediction of PTL: various scoring systems exist,

incorporating:

 history of preterm delivery

 assessment of cervical length: transvaginal ultrasound is

the most sensitive test

 fetal fibronectin: high negative predictive value

 research tools: salivary oestriol, home monitoring

• Prevention:

 prophylactic cervical cerclage if cervical incompetence is

suspected

 detection and treatment of asymptomatic infections in

high risk women (e.g. bacterial vaginosis, asymptomatic

bacteriuria)

• Treatment:

 emergency cerclage/rescue cervical suture (limited

evidence)

 tocolysis: no clear evidence that it improves outcome.

Should be considered if the few days gained would be

put to good use, such as completing a course of

corticosteroids or in utero transfer. Evidence suggests

no benefit of antibiotic use in women with intact

membranes.

Royal College of Obstetricians and Gynaecologists . Preterm

prelabour rupture of membranes. Green - top Guideline No. 44.

RCOG , London , 2006 .