Case 16 A 16-year-old woman with high blood
pressure at 32 weeks gestation
Miss Jones is a 16-year-old primigravida who is 32 weeks’
pregnant. At a routine antenatal check with her midwife her
blood pressure is found to be 160/100mmHg (mean arterial
pressure [MAP] 120mmHg).
Her midwife sends her to the maternity day assessment
unit for review.
What differential diagnosis should you
consider?
• Essential hypertension
• Secondary hypertension
• Pregnancy - induced hypertension
• Pre - eclampsia (Box 16.1 ).
What information do you need from
the history?
• Does she have any symptoms that may be related to
high blood pressure? Specifically, headache, visual disturbance, epigastric pain, nausea and vomiting.
• Does she have lots of swelling? Do her rings still fit?
Does she feel her face is swollen?
• Is the baby moving? Has there been any abdominal
pain or vaginal bleeding?
• Has she had any problems with the pregnancy to this
point?
• What was her blood pressure at her booking
appointment?
• Does she have any significant past medical history,
especially renal disease or diabetes?
• Have any of her close family members had high blood
pressure in their pregnancies?
Miss Jones tells you she is feeling absolutely fine, although
she has had to take off her engagement ring and her fiancé
says her face looks puffy. She has been very well in the
pregnancy to this point. There has been no bleeding or
abdominal pain and baby is moving well.
She has no past medical history or family history of note.
She cannot remember her booking blood pressure but you
can see from her notes it was 100/60mmHg.
What are the risk factors for
pre-eclampsia
• First pregnancy, or first pregnancy with new partner
• Multiparous with:
pre - eclampsia in any previous pregnancy
10 years or more since last baby
• Pregnancy at extremes of maternal age
• Body mass index (BMI) of 35 or more
• Family history of pre - eclampsia (in mother or sister)
• Booking diastolic blood pressure of 80 mmHg or more
• Booking proteinuria (of one or more, on more than
one occasion or quantified at 0.3 g/24 hours or greater)
• Multiple pregnancy
• Certain underlying medical conditions:
pre - existing hypertension
pre - existing renal disease
pre - existing diabetes
antiphospholipid antibodies
What features will you look for
on examination?
General examination
• Is she obviously oedematous? Remember 50% of pregnant women will have some peripheral oedema
• What are her pulse and blood pressure now?
Neurological examination
• Does she have normal upper and lower limb reflexes?
• Is there clonus? More than two beats is significant
• On fundoscopy, is there any evidence of papilloedema?
Obstetrics and Gynaecology: Clinical Cases Uncovered.
By M. Cruickshank and A. Shetty. Published 2009 by Blackwell
Publishing. ISBN 978-1-4051-8671-1.110 Part 2: Cases
PART 2: CASES
Abdominal examination
On abdominal palpation:
• Is there tenderness in the right hypochondrium (over
the liver)?
• Does the baby seem well grown?
• Lie and presentation of the baby
• Doppler fetal heart check
Which initial investigation do
you request?
Urinalysis for protein.
Miss Jones looks well. Her BMI is 36 and she has moderate
pitting oedema of her lower legs to mid calf. Her pulse is
86beats/minute and her mean blood pressure over three
readings using an appropriate-sized BP cuff is 155/95mmHg
(MAP 115; Box 16.2). She has normal reflexes and
fundoscopy and no clonus. The baby seems a little small for
gestational age with a symphysiofundal height of 29cm. It
has a longitudinal lie and cephalic presentation, the fetal
heart is heard clearly. Her urinalysis shows ++ protein.
What is the most likely diagnosis based
on the history and examination?
Pre - eclampsia.
Box 16.1 Definitions
Pre-existing hypertension: defined as a systolic blood
pressure of ≥140mmHg, and/or a diastolic blood pressure
of ≥90mmHg, either pre-pregnancy or at booking (before
20 weeks)
Pregnancy-induced hypertension: develops after 20 weeks’
gestation. May reflect a familial disposition to chronic
hypertension or be an early manifestation of pre-eclampsia
Pre-eclampsia: pregnancy-induced hypertension in
association with proteinuria ≥0.3g in 24hours with or
without oedema
Box 16.2 Mean arterial pressure
• The average pressure within an artery over a complete
cycle of one heartbeat:
MAP s = + 1 3 2 3 / / ystolic pressure diastolic pressure
• An MAP of at least 60mmHg is necessary to perfuse
coronary arteries, brain, kidneys, etc.
• Usual range of MAP is 70–110mmHg
What would you do next?
• Admit her to the antenatal ward
• Carry out 4 - hourly BP monitoring
• Fluid intake – output balance chart
• 24 - hour urine collection for quantification of
proteinuria
• Check full blood count (FBC), serum urea and electrolytes (U & E), liver function tests and urate (Box 16.3 )
• Arrange an ultrasound scan for fetal size and well -
being (Box 16.4 ; Figs 16.1 & 16.2 )
• Administer corticosteroids for fetal lung maturity in
case of worsening condition and need for delivery before
36 weeks (Box 16.5 )
Miss Jones consistently has blood pressures below
160/100mmHg so no treatment is required. Her urine
output is good and all blood tests are normal. Ultrasound
confirms that the baby is just above the 5th centile and has
normal liquor volume. A first dose of steroids is given.
Box 16.3 Blood tests in pre-eclampsia
Pre-eclampsia can affect any organ system but some
investigations are especially helpful in suggesting an end
organ effect
Urate
An increase in serum urate levels is often considered the
‘early warning’ blood test in pre-eclampsia and can
indicate renal impairment before U&E becomes deranged
Urea and electrolytes
Indicates renal impairment. Note normal ranges for urea
and creatinine are lower in pregnancy – get reference
ranges from local laboratory
Liver function tests
Become abnormal in variants of pre-eclampsia with liver
involvement especially in HELLP syndrome (haemolytic
anaemia, elevated liver enzymes and low platelet count)
Full blood count
Can indicate HELLP with drop in haemoglobin secondary
to haemolysis and low platelet count
Coagulation screen
Not routinely required but should be included in severe
pre-eclampsia and if platelets are found to be abnormalCase 16 111
PART 2: CASES
x
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20 22 24 26 28 30 32 34 36 38 40
20 22 24 26 28 30 32 34 36 38 40
Gestational age (weeks)
Circumference (cm)
Circumference (cm)
Gestational age (weeks)
Estimated date of delivery
Abdominal circumference
Head circumference
Figure 16.1 Example of fetal growth chart.
Normal flow Reduced end diastolic flow
Absent end diastolic flow Reversed end diastolic flow
Figure 16.2 Umbilical artery Doppler waveforms.
Figure 16.3 Normal umbilical artery Doppler.112 Part 2: Cases
PART 2: CASES
Box 16.4 Intrauterine growth restriction
In pre-eclampsia, a combination of abnormal placentation
and hypertension can result in reduced placental blood
flow and fetal nutrition leading to intrauterine growth
restriction (IUGR). IUGR is a term used to describe a baby
that is smaller than expected for gestation; the usual
cut-off is <5th centile for gestation. In addition to
pre-eclampsia there are a variety of other problems that
can result in IUGR.
Maternal factors
• High blood pressure
• Chronic kidney disease
• Advanced diabetes
• Heart or respiratory disease
• Malnutrition, anaemia
• Infection
• Substance abuse (alcohol, drugs)
• Cigarette smoking
Factors involving the uterus and placenta
• Decreased blood flow in the uterus and placenta
• Placental abruption (placenta detaches from the
uterus)
• Placenta previa (placenta attaches low in the uterus)
• Infection in the tissues around the fetus
Factors related to the developing fetus
• Multiple gestation (twins, triplets, etc.)
• Infection
• Birth defects
• Chromosomal abnormality
It is important to identify these fetuses as babies with
IUGR are at an increased risk of problems at birth
including:
• Hypoxia/hypoxaemia
• Low Apgar scores
• Meconium aspiration
• Hypoglycaemia
• Hypothermia
• Polycythaemia
In addition, severe IUGR may result in stillbirth. It may
also lead to long-term growth problems in babies and
children.
If a fetus is found to be <5th centile for gestation, further
ultrasound assessment including liquor volume, umbilical
artery Doppler studies (umbilical arterial blood flow becomes
abnormal when there is placental insufficiency) and
biophysical profiles can help to distinguish those babies who
are small but coping, from those babies who are struggling
and will benefit from early delivery despite being premature
(Figs 16.2 and 16.3).
Box 16.5 Drug choices for high blood pressure
It remains unclear whether antihypertensive drug therapy
for mild to moderate hypertension during pregnancy is
worthwhile. Antihypertensive treatment should be
started in women with a systolic blood pressure
>160mmHg or a diastolic blood pressure >110mmHg;
MAP 125mmHg.
In women with other markers of potentially severe
disease, treatment can be considered at lower degrees of
hypertension.
Labetalol (orally or intravenously), oral nifedipine or
intravenous hydralazine can be used for the acute
management of severe hypertension. Both labetolol and
hydralazine can be given as IV boluses with or with out
infusions.
ACE inhibitors, angiotensin receptor-blockers and
diuretics should be avoided.
What will you tell Miss Jones about
her condition?
She has a condition called pre - eclampsia. This is a combination of high blood pressure and protein in the urine.
It is important because it can affect both the mother ’ s
and the baby ’ s health. About 25% of women will get high
blood pressure in their first pregnancy and 5/1000
women will develop severe pre - eclampsia. The only
‘ cure ’ for the condition is delivery of the baby and
placenta.
However, as the baby is preterm and she is feeling well,
as long as her blood pressure is satisfactory, all her blood
tests are normal and baby is coping well (normal scans
and cardiotocography [CTG]) the plan is to wait and
monitor her and the baby until it is mature (≥37 weeks).
At 02.00 the next night Miss Jones calls the midwife to say
she has a mild headache and could she have some
paracetamol. The midwife checks her blood pressure and
finds it to be 170/110mmHg (MAP 130). She calls the doctor.Case 16 113
PART 2: CASES
What will you do?
Attend as soon as possible. One per cent of women with
severe pre - eclampsia will develop an eclamptic seizure
which has a mortality rate of 1.8%, with 35% suffering
severe morbidity.
Site IV access, check bloods as above plus urgent group
and save and coagulation screen in case delivery is
necessary.
Inform your senior and arrange transfer as soon as
possible to a high dependency area (usually the labour
ward).
Miss Jones’ headache is now severe with a pain score of
9/10. She has no visual disturbance or epigastric pain but is
hyper-reflexic and has marked clonus. Her blood pressure
remains 170/110mmHg (MAP 130) and she now has ++++
protein in her urine.
What are your priorities?
• Reduce her blood pressure
• Seizure prophylaxis (Box 16.6 )
• Recheck blood pressure, re - examine and site catheter
for urinalysis and hourly urine volumes
• Maintain strict fluid balance restricted to 80 mL/hour
(Box 16.7 )
Once the mother is stabilized perform CTG and
arrange urgent delivery (Box 16.8 ).
Box 16.6 Seizure prophylaxis
Magnesium sulphate should be considered when there is
concern about the risk of eclampsia. In women with less
severe disease, the decision is less clear and will depend
on the individual case.
Magnesium sulphate is the therapy of choice to control
seizures. A loading dose of 4g is given by infusion pump
over 5–10minutes, followed by a further infusion of 1g/
hour maintained for 24hours after the last seizure.
Recurrent seizures should be treated with either a
further bolus of 2g magnesium sulphate or an increase in
the infusion rate to 1.5g or 2.0g/hour.
During administration it can cause flushing and
palpitations and cause the woman to feel quite unwell so
it is important to warn her about this before commencing
the treatment.
Box 16.7 Fluid balance
Fluid restriction is advisable to reduce the risk of fluid
overload in the intrapartum and postpartum periods. Total
fluids should usually be limited to 80mL/hour or 1ml/kg/
hour.
Urine volumes of ≥0.5mL/kg/hour are desirable. Usually,
30mL/hour is acceptable.
Oliguria is common initially but if persistent its
management should involve senior anaesthetic and
obstetric staff and invasive monitoring of central venous
pressure because of a significant risk of fluid overload and
problems with pulmonary and cerebral oedema.
Box 16.8 Choice of mode of delivery
The decision to deliver should be made once the woman is
stable and with appropriate senior personnel present.
If the fetus is less than 34 weeks’ gestation and delivery
can be deferred, corticosteroids should be given, although
after 24hours the benefits of conservative management
should be reassessed. Conservative management at very
early gestations may improve the perinatal outcome but
must be carefully balanced with maternal well-being.
The mode of delivery should be determined after
considering the presentation of the fetus and the fetal
condition, together with the likelihood of success of
induction of labour after assessment of the cervix.
The third stage should be managed with 5units
Syntocinon IM or slow IV. Ergometrine and Syntometrine
should not be given for prevention of haemorrhage, as
this can further increase the blood pressure.
KEY POINT
Magnesium toxicity is important as it can ultimately cause
respiratory and cardiac depression and death. One of the
earliest signs of toxicity is loss of deep tendon reflexes,
and patellar tendon reflexes (or bicep tendon in the case
of a woman with epidural or spinal anaesthetic) should be
performed hourly during treatment.
Respiratory rate should also be monitored and, as
magnesium is excreted in urine, if hourly urine volumes fall
considerably it is sensible to halve the rate of infusion.
Magnesium levels are not routinely monitored but if there
was any clinical concern regarding toxicity stopping the
infusion and taking a serum level may help with
decision-making.
The antidote is calcium gluconate and this should be
used immediately in cases of respiratory or cardiac
depression.114 Part 2: Cases
PART 2: CASES
Miss Jones’ blood pressure improves following 5mg
hydralazine IV to 145/90mmHg. Her headache resolves with
this treatment. She is commenced on magnesium sulphate
for seizure prophylaxis. The CTG is satisfactory. Her cervix is
unfavourable for induction of labour (Bishop score 3; see
Case 1) and as her platelets and coagulation are normal a
decision is made for emergency caesarean section.
An uncomplicated section is performed and a healthy
male baby is delivered. As 44% of eclamptic seizures occur
postnatally it is vital to remain vigilant so Miss Jones is
transferred back to the high dependency unit.
What will be your plan for
postnatal care?
Intensive monitoring of pulse, blood pressure and oxygen
saturation every 15 minutes initially, reducing to hourly
once she is completely stable. Also take hourly urine
volume measurements. Administer magnesium sulphate
for 24 hours following delivery and take hourly reflexes
while she is on magnesium sulphate. Repeat blood tests
at least daily until she is well. Use thromboembolic
disease (TED) stockings and low molecular weight
heparin for deep venous thrombosis prophylaxis if coagulation and/or platelet count is normal.
Miss Jones improves significantly over her first 24hours
postnatally. Her blood pressure remains stable and daily
blood tests are normal. She is observed for a further 4 days
on the postnatal ward before discharge. On day 2 her blood
pressure is noted to be slightly elevated, she is commenced
on oral antihypertensive therapy and her blood pressure
improves. Her baby is doing well in the neonatal unit. She
asks the midwife if she will always need tablets for her
blood pressure now and if she will develop pre-eclampsia in
her next pregnancy. The midwife calls you to talk to her
before discharge.
What will you tell her?
Most women who develop pre - eclampsia become completely better over a period of days to weeks but some
women will require treatment for longer. Her GP will
check her blood pressure regularly and stop her tablets
when she no longer needs them. If her blood pressure is
high at 6 weeks they will refer her for investigation of this.
More women who have pre - eclampsia will develop
high blood pressure in later life compared with the whole
female population. Women who have pre - eclampsia in a
first pregnancy are at an increased risk (7 – 10%) of developing it in a subsequent pregnancy.
Miss Jones is happy with your explanation and is discharged
to the care of her GP. An appointment for a postnatal check
is made with her consultant for 6 weeks’ time in view of her
severe pre-eclampsia.
CASE REVIEW
Miss Jones, in view of her age of 16 years and being in her
first pregnancy, had risk factors for developing pre -
eclampsia. As in most cases, pre - eclampsia was first picked
up on routine antenatal screening with BP and urine
protein checks which are performed at every antenatal
visit. She demonstrated some of the complications of pre -
eclampsia including a small baby and signs of impending
eclampsia with a significant increase in her blood pressure.
Prophylaxis for eclampsia was with magnesium sulphate
and the blood pressure was controlled rapidly with hydralazine IV. The only treatment for pre - eclampsia is delivery
of the baby and once maternal condition was stabilized
delivery was planned. As her cervix was unfavourable with
a low Bishop ’ s score, an emergency caesarean section was
performed. Her monitoring continued postpartum as the
risks of severe pre - eclampsia remain for some time
postnatally.
Pre - eclampsia is a common and serious complication of
pregnancy. There are specific factors that put women at
increased risk of pre - eclampsia but it can occur in anyone.
Severe pre - eclampsia can affect any maternal organ system
and can cause fetal intrauterine growth restriction (IUGR)
and placental abruption.
Five in 1000 women will develop severe pre - eclampsia
and 5 in 10,000 will have an eclamptic seizure. Of these,
38% of seizures occur antenatally, 18% intrapartum and
44% postnatally.
Low dose aspirin prophylaxis may be beneficial in preventing recurrence of pre - eclampsia when there has been
early onset of severe disease with or without IUGR.
Appropriate management of blood pressure can sometimes prolong pregnancy but the only cure for pre - eclampsia is delivery of baby and sometimes this will have to be
at an early gestation despite the risks to the fetus.Case 16 115
PART 2: CASES
KEY POINTS
• Extremes of maternal age, first pregnancy (or first
pregnancy with a new partner) and multiple pregnancy
are some of the risk factors for pre-eclampsia
• Maternal complications of pre-eclampsia include HELLP,
renal failure, disseminated intravascular coagulopathy,
pulmonary odema, intracerebral haemorrhage and
eclampsia. Over 40% of eclamptic fits occur postpartum
• Fetal complications include IUGR, increased perinatal and
neonatal morbidity and mortality, mostly due to IUGR and
prematurity (which is very likely to be iatrogenic)
• Headaches, visual disturbances, epigastric and/or right
hypochondrial tenderness and hyper-reflexia suggest
worsening of pre-eclampsia and/or impending eclampsia.
Magnesium sulphate is the treatment of choice for
eclampsia and prophylaxis of eclampsia
• Antihypertensives are indicated with MAP readings of 125
or above (or with systolic readings ≥160mmHg and
diastole ≥110mmHg)
• Close monitoring of blood pressure, fluid intake and
output, and blood investigations (including haemoglobin
and platelet counts, U&E, liver function tests) is indicated
with severe pre-eclampsia
• In the presence of oliguria, central venous pressure
monitoring should be considered before fluid challenges
to avoid the risks of fluid overload and pulmonary and
cerebral odema
Further reading
The management of severe pre - eclampsia/eclampsia. RCOG
Green topped Guideline No 10 (A), March 2006.
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