1. A Patient with Hypertension in Pregnancy
Max Brinsmead MB BS PhD
March 2017

2. Carol is a 36-year old Intensive Care Nurse who has been trying to have a baby for 5 years. She conceives spontaneously and commences antenatal care in Sydney. During a “weekend away” in Coffs Harbour she comes to Maternity feeling a little unwell and asks to have her BP checked. It is 160/105. The midwife starts a CTG and asks that you come to see this patient.

3. Carol is pregnant with a BP of 160/105
Is this preeclampsia or pregnancy-induced hypertension
How urgent is this review
What further history do you require
Preeclampsia is sustained hypertension in the 2nd half of pregnancy accompanied by evidence of some other organ involvement. Returns to normal after 3m
Not urgent, but symptoms are worrying…
This pregnancy. Other pregnancies. Personal and Family medical history. Social circumstances. Symptoms.
Preeclampsia is sustained hypertension in the 2nd half of pregnancy accompanied by evidence of some other organ involvement. Returns to normal after 3m
Not urgent, but symptoms are worrying…
This pregnancy. Other pregnancies. Personal and Family medical history. Social circumstances. Symptoms.

4. Carol with a BP of 160/105
Gestation is 33 weeks by dates and early scans
Never pregnant before
All tests thus far, including PAPP-A for triploidy, are normal
Had “nephritis” aged 6 years but recovered after 6 weeks
Mother is hypertensive on medication
Married to another nurse. Non smoker. Usually fit and healthy but just “feels unwell and thought her BP might be up”
BP in the first trimester was 105–115/60–75 and was 130/80 one week ago

5. Carol G1P0 at 33 weeks with a BP of 160/105
What examination would you do
What tests are desirable
Would you admit this patient to the antenatal ward
Repeat BP after resting. Cardiovascular and pregnancy examination. Test urine for protein
FBC, UEC, LFTs, Urate, Proteinuria quantification, UMCS
Pregnancy ultrasound
YES
Repeat BP after resting. Cardiovascular and pregnancy examination. Test urine for protein
FBC, UEC, LFTs, Urate, Proteinuria quantification, UMCS
Pregnancy ultrasound
YES

6. Carol G1P0 at 33 weeks BP 160/105
Cardiovascular exam is normal apart from accentuated 2nd heart sound. Mild generalized oedema noted
Symphysis-fundal height 29 cm
Knee jerks are active but there is no sustained clonus
Oedema is no longer regarded as a sign of preeclampsia
Because oedema is a “good sign” in pregnancy
This uterus is small for dates
It is normal to have 1-2 beats of clonus but sustained clonus is a sign of imminent eclampsia

8. Carol G1P0 at 33 weeks BP 160/105 Test results
Ward test proteinuria +
HB 128 Hct 0.36 Platelets 231
UEC and LFT’s normal. S Creat normal. Urate 0.38
24-hr urine protein 0.25G (normal <0.3G)
UMCS – no red/white cells or casts. Culture negative
Estimated Fetal Weight (EFW) by ultrasound <10th centile with evidence of head-sparing IUGR. Reduced amniotic fluid index. Umbilical Art. (UA) Dopplers on 95th centile

9. Estimated Fetal Weight by Ultrasound
Is made by ultrasonic measurements of head biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and Femur Length (FL)
Has an error of not less than ± 20%
Fetal growth restriction is either generalised (symmetrical) or head-sparing (asymmetrical)
Asymmetrical IUGR arises from a redirection of cardiac output by the fetus to support its vital brain growth

10. Is largely composed of fetal urine
Amniotic Fluid
Is largely composed of fetal urine
It’s volume is a reflection of fetal urine output
Which, in turn, is a reflection of fetal cardiac output/function, fetal oxygenation and welfare
Will be absent if there is renal agenesis or urine output obstruction
Is often expressed as the Amniotic Fluid Index (AFI)

11. Umbilical Artery Doppler Study
Upper panel represents peak (systolic) and trough (diastolic) flow often expressed as S/D ratio
Lower panel is constant flow through a uterine vein
UA Doppler reflects downstream placental resistance
It is the first change to occur with placental disease

12. Umbilical Artery Doppler changes with Gestation

13. Abnormal UA Doppler Flows
When flow ceases in the diastolic phase (AEDF) the S/D ratio is very high (∞)
Flow may even reverse in the diastolic phase (RDF) as shown opposite

14. Pathophysiology of Pre eclampsia
Placental tissue
In healthy pregnancies cytotrophoblast infiltrates the decidual portion of the uterine spiral arteries
In order to increase maternal blood flow to the placenta
In patients destined to develop pre eclampsia this fails to occur
This results in placental hypoperfusion
These changes occur at <16 weeks gestation but the pre eclampsia may not be manifest until much later in the pregnancy

15. Pathophysiology of Pre eclampsia
Hypoperfusion of the Placenta
Becomes worse as pregnancy progresses
The abnormal uterine vasculature is unable to accommodate the normal rise in blood flow to the fetus/placenta that occurs with increasing gestational age.
Late placental changes consistent with ischemia include atherosis (lipid-laden cells in the wall arterioles), fibrinoid necrosis, thrombosis, sclerotic narrowing of arterioles, and placental infarction

16. Pathophysiology Effects
Contracted intravascular volume of mother
In reality, a failure of the normal increase plasma volume associated with pregnancy
↑Sensitivity to pressure agents
Leaky capillaries
Reduced oncotic pressure
In part due to low serum albumen
Poor placental reserve
A fetus at risk of hypoxia and death

17. Why is that an important diagnosis
Carol G1P0 33 weeks BP of 160/105 but no significant proteinuria. Clinical and scan evidence of IUGR
Is this preeclampsia
Why is that an important diagnosis
YES
Preeclampsia is an unpredictable disease with significant maternal and fetal morbidity and risk of mortality
YES
Preeclampsia is an unpredictable disease with significant maternal and fetal morbidity and risk of mortality

18. Systems involved in Preeclampsia
Renal
Significant proteinuria
Renal failure biochemistry
Oliguria
Hepatic
Elevated transaminases
Epigastric or RUQ pain
Haematological
Thrombocytopenia
Haemolysis
DIC
CNS
Eclampsia or stroke
Hyperreflexia with sustained clonus
Severe headache or visual disturbance
Cardiovascular
Pulmonary oedema
Placental
IUGR
Abruption

19. Carol 33 weeks with preeclampsia in hospital
Carol 33 weeks with preeclampsia in hospital. BP rises to 180/110 at 6 pm with dull headache. No sustained clonus
Does this hypertension require treatment
Why
What drug will you use
What BP would you aim to achieve
Yes
Risk of eclampsia, cerebral haemorrhage and pulmonary oedema
Aldomet or Labetalol with a loading dose
Reduce BP to / so as not to further compromise uterine blood flow
Yes
Risk of eclampsia, cerebral haemorrhage and pulmonary oedema
Aldomet or Labetalol with a loading dose
Reduce BP to / so as not to further compromise uterine blood flow

20. Carol 33 weeks with preeclampsia
Carol 33 weeks with preeclampsia. Over the next 2 days her BP continues to rise, especially at night
What measures can you use to control the BP
How will you monitor fetal wellbeing on a daily basis
Use drugs to maximum possible doses. Then add in other drugs from a different class
For example, Aldomet + Labetalol + Nifedipine + Prazosin
Fetal movement charts and non stress cardiotocography (CTG)
Use drugs to maximum possible doses. Then add in other drugs from a different class
For example, Aldomet + Labetalol + Nifedipine + Prazosin
Fetal movement charts and non stress cardiotocography (CTG)

21. Antenatal (Non stress) CTG
10–40 min of continuous FHR
Tocograph for fetal movements + maternal trigger
Is an assessment of fetal CNS and cardiac oxygenation
High negative predictive value when “reactive"

22. Carol now 34 weeks. BP difficult to control
Carol now 34 weeks. BP difficult to control. She develops severe epigastric pain and vomiting.
Deteriorating preeclampsia with a significant risk of fits
Acute liver swelling stretches its capsule. Maybe subcapsular haematoma
AST 240, ALT 115 (NR <70)
What is the most likely diagnosis
What causes the pain
What tests may be useful
Deteriorating preeclampsia with a significant risk of fits
Acute liver swelling stretches its capsule. Maybe subcapsular haematoma
AST 240, ALT 115 (NR <70)

23. A course of steroids to promote fetal lung maturation
Carol 34 weeks with uncontrolled hypertension and epigastric pain. Ultrasound shows no further fetal growth and AEDF with Doppler of the umbilical arteries.
DELIVERY
A course of steroids to promote fetal lung maturation
How will you CURE this patient
What steps may be desirable on behalf of the baby
DELIVERY
A course of steroids to promote fetal lung maturation

24. How can you deliver this patient
Carol 34 weeks with severe preeclampsia and fetal compromise requires delivery
Induction of labour best for mother but baby may not tolerate the hypoxic stress of contractions. Cervix may be unfavourable.
Caesarean quick and best for baby but riskier for mother and may compromise her future deliveries
How can you deliver this patient
Describe the pros and cons of each method
DELIVERY
A course of steroids to promote fetal lung maturation

25. First aid is more important than drugs
As preparations are being made for a Caesarean Carol has a grand mal seizure. You are present as it commences…
First aid is more important than drugs
Protect from injury
Secure an airway
Administer oxygen
Then secure IV access
IV MgSO4 loading dose and maintain by infusion
What do you do
First aid is more important than drugs
Protect from injury
Secure an airway
Administer oxygen
Then secure IV access
IV MgSO4 loading dose and maintain by infusion

26. IV Hydrallazine or Diazoxide used most in Australian practice
Carol 34 weeks has had an eclamptic fit. MgSO4 continues by infusion. Her BP is 180/120.
IV Hydrallazine or Diazoxide used most in Australian practice
Risk of respiratory and cardiac arrest. Monitor urine output, respirations, O2 saturation, knee jerks and serum Mg levels
What drugs are useful now to lower BP
What are the risks from the MgSO4 and how is that avoided
IV Hydrallazine or Diazoxide used most in Australian practice
Risk of respiratory and cardiac arrest. Monitor urine output, respirations, O2 saturation, knee jerks and serum Mg levels

27. Not less than 24 hours after delivery
Carol undergoes urgent Caesarean section and is transferred to Intensive Care for postoperative care
Not less than 24 hours after delivery
Separation of mother and infant interferes with bonding and lactation
Insomnia and stress to Carol and her relatives
May increase the risk of thromboembolism
How long should the MgSO4 infusion continue
What are the problems that may arise from intensive care
Not less than 24 hours after delivery
Separation of mother and infant interferes with bonding and lactation
Insomnia and stress to Carol and her relatives
May increase the risk of thromboembolism

28. The baby weighs 1800g and has signs of IUGR.
Hypoglycaemia due to depleted glycogen liver stores
Monitor blood glucose levels. Early feeding by suckling or D-tube or IV glucose may be required
What is the most common neonatal problem for this baby
How is it avoided
Hypoglycaemia due to depleted glycogen liver stores
Monitor blood glucose levels. Early feeding by suckling or D-tube or IV glucose may be required

29. The baby does well. Carol’s BP still requires treatment postpartum.
24-72 hours but renal/hepatic function may get worse before it gets better
Keep BP <150/100, drugs may be required for 6-12 weeks
Any antihypertensive drug can be used (but some patients don’t respond to ACE inhibitors)
When would expect recovery of renal or hepatic dysfunction
How about the hypertension
What drugs are used in the control of hypertension
24-72 hours but renal/hepatic function may get worse before it gets better
Keep BP <150/100, drugs may be required for 6-12 weeks
Any antihypertensive drug can be used (but some patients don’t respond to ACE inhibitors)

30. Also use Ca supplements 1.5G/day
Carol’s BP is normal off all medication by 6 weeks. Tests for autoimmune disease and thrombophilia are negative
50 – 66%
Low dose aspirin (100 mg daily preferably commencing in the 1st trimester) reduces risk by >17%
Also use Ca supplements 1.5G/day
YES
What is the risk that she will develop preeclampsia in a subsequent pregnancy
How could that risk be reduced
Is Carol at risk of hypertension in the future
50 – 66%
Low dose aspirin (100 mg daily preferably commencing in the 1st trimester) reduces risk by >17%
Also use Ca supplements 1.5G/day
YES

31. Any Questions or Comments?
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