Hypertension in pregnancy by Dr. Vaibhav Yawalkar MD DM Cardiology, Consultant Interventional Cardiologist, Nagpur, MH, India

1. Hypertension in Pregnancy

2. • Types of Hypertension in Pregnancy
• Pre-eclampsia
• Prevention of HTN & Pre-eclampsia
• Management of Hypertension
• Emergent treatment for severe hypertension

3. Hemodynamic changes in Pregnancy
• Cardiac output increases by 30-50%
• Most of the increase due to an increase in stroke volume.
• Heart rate increases by ~10 beats/min (20% above
baseline) during the third trimester.
• In the second trimester SVR decreases
• Blood pressure falls
• Venous pressure in lower limbs rises (Pedal edema)

4. Hypertension in Pregnancy
• Hypertension is most common medical problem in
pregnancy
• Chronic Hypertension
• Gestational Hypertension
• Preeclampsia (de novo or superimposed on chronic
hypertension)
• Antenatally unclassifiable hypertension

5. Chronic Hypertension
• Hypertension (SBP ≥140 mm Hg or ≥ 90 mm Hg diastolic)
• Predating pregnancy or diagnosed before 20 weeks of
gestation
• May have associated family history of hypertension or
overweight or obesity
• Secondary causes of hypertension need to be excluded
• Usually persists beyond post-partum period

6. Gestational Hypertension
• New hypertension (SBP ≥140 mm Hg or ≥ 90 mm Hg
diastolic)
• Arising after the 20th week of pregnancy and without any of
the abnormalities that define preeclampsia
• Progresses to preeclampsia in about 25% of cases
• Blood pressure often normalizes by 12 weeks post-partum

7. Preeclampsia
• SBP ≥140 mm Hg or ≥ 90 mm Hg diastolic measured on
two occasions at least 4 hours apart
OR
SBP ≥160 mm Hg or ≥ 110 mm Hg diastolic
• Arising after the 20th week of gestation
AND
• Proteinuria : 300 mg per 24-hour urine collection or
albumin/creatinine ratio ≥ 30 (mg/mmol) [or ≥ 0.3 mg/dL]

8. Preeclampsia (In absence of Proteinuria)
New-onset hypertension with new onset of any of the
following:
• Thrombocytopenia: Platelet count <100,000/mL
• Renal insufficiency:
– Serum creatinine >1.1 mg/dL or doubling of serum creatinine in the absence
of other renal disease
• Impaired liver function:
– Serum liver transaminases elevated twice normal
• Pulmonary edema
• Cerebral or visual symptoms

9. Preeclampsia
• Cause is not entirely known
• Endothelial dysfunction with abnormal remodeling of spiral
arteries of placenta
• Placental production of antagonists to both VEGF and
TGF-beta
More commonly in:
• Nulliparous women
• BMI of more than 30 kg/m2
• Age younger than 20 years or older than 35 years
• Preexisting medical conditions (HTN,CKD,DM,SLE,APLA)
• History of preeclampsia, fetal growth restriction, or placental
abruption
• Multifetal pregnancies.

10. Antenatally unclassifiable hypertension
• When BP is first recorded after 20 weeks of gestation and it
is unclear if hypertension was pre-existing.
• Reassessment 6 weeks post-partum will help distinguish
pre-existing from gestational hypertension.

11. Classification as per Severity
• Mild (140 –159 / 90 –109 mmHg)
• Severe (≥ 160/110 mmHg)

12. • Maternal risks:
– Placental abruption, stroke, multiple organ failure, and DIC
• Foetus:
– High risk of IUGR (25% of cases of pre-eclampsia),
– Prematurity (27% of cases of preeclampsia)
– Intrauterine death (4% of cases of pre-eclampsia)
• Preeclampsia cause about 15% of maternal deaths
• Preeclampsia constitutes an important major CV risk factor
for later life.
• 10-fold increased risk for CV disease in later life
Effect of hypertension on Pregnancy

13. Diagnosis
• ABPM is superior to office BP measurement & predicts
outcome
• BP measured in the sitting position (or the left lateral
recumbent position during labour)
• All HTN cases should be tested for proteinuria, A dipstick
test of ≥ 1+ should prompt evaluation of ACR in a single
spot urine sample and a value <30 mg/mmol can reliably
rule out proteinuria.
• Serum uric acid: Hyperuricaemia indicates increased risk of
adverse maternal and foetal outcomes

14. Diagnosis
• Doppler ultrasound of uterine arteries (after 20 weeks of
gestation):
– Detects those at higher risk of gestational hypertension, pre-
eclampsia, and intrauterine growth retardation.
• A soluble fms-like tyrosine kinase 1:placental growth factor
ratio of ≤ 38
– excludes the development of preeclampsia in the next week when
suspected clinically.

15. Prevention of HTN & Preeclampsia

16. Prevention of HTN & Preeclampsia
• ESC guidelines:
High or moderate-risk of pre-eclampsia should be advised
to take 100–150 mg of aspirin daily from weeks 12–36
• ACOG guidelines:
Low-dose (81 mg/ day) aspirin initiated between 12 weeks
and 28 weeks of gestation (optimally before 16 weeks of
gestation) and continuing until delivery
• Investigational drugs for Prophylaxis:
– Metformin
– Statins
– Addition of Heparin to Aspirin
– Sildenafil
– Calcium suppliments

17. Management of Hypertension
• All cases with BP ≥ 150/95 mm Hg should receive
treatment
• Start treatment if BP ≥ 140/90 mm Hg
AND
– Women with gestational hypertension (with or without
proteinuria)
– Pre-existing hypertension with the superimposition of
gestational hypertension
– Hypertension with subclinical HMOD
*ESC HTN Guidelines 2018

18. Management of Hypertension
• Women with pre-existing hypertension may continue their
current antihypertensive medications
• ACE inhibitors, ARBs, and direct renin inhibitors should be
discontinued
• Beta-blockers should be used cautiously (foetal
bradycardia, IUGR), with atenolol best avoided
• Diuretics: generally avoided as plasma volume is reduced
in women with pre-eclampsia
• Labetalol , Nifedipine & Methyl Dopa are the drugs of
choice.

19. Management of Hypertension
• In mild HTN (140-159 / 90-109 mm Hg) target should be <
140 / 90 mm Hg.
• Initial regimen of Labetalol at 200 mg orally every 12 hours
and increase the dose up to 800 mg orally every 8–12
hours as needed (maximum total 2,400 mg/ day [ACOG],
max 800 mg /Day [ESC])
• If the maximum dose is inadequate to achieve the desired
blood pressure goal, or the dosage is limited by adverse
effect, then sustained release oral nifedipine or methyl
dopa can be added

20. Management of Hypertension
• Methyldopa (0.5–3 g/day PO in 2 divided doses)
• Long-acting Nifedipine can be given as a sustained release
tablet in doses of 30–90 mg once daily. (maximum dose of
120 mg a day)
• Methyldopa has largest data regarding safety & efficacy,
but mild antihypertensive effect & slower onset (also post-
partum depression)
• Short acting Nifedipine may cause severe hypotension, is
an option for emergent treatment of severe HTN

21. Management of Severe Hypertension
HTN ≥ 160/110 mm Hg
persisting for > 15 mins
First Line
• IV Labetalol
• IV Hydralazine
• Oral Nifedipine (Immediate
release)
Second Line
• IV Nicardipine
• IV Esmolol
 IV Glyceryl trinitrate (if Pulmonary Edema)
 IV Sodium Nitroprusside (for extreme emergencies as
last measure)

22. Management of Severe Hypertension
If IV access can not be obtained OR as first line approach
• Oral immediate release Nifedipine Capsule 10 mg stat
• Repeat 20 mg after 20 mins if BP > 160/105
• Repeat 20 mg after 20 mins if BP > 160/105
• Switch to IV Labetalol if Target not achieved
• If Oral Nifedipine is not available Oral Labetalol 200 mg stat
• Repeat after 30 mins if BP > 160/105
*Updated ACOG Guidelines 2019

23. Management of Severe Hypertension
If IV Labetalol as first line approach
• IV Labetalol 20 mg over 2 min
• If target not achieved after 10 mins,
IV Labetalol 40 mg over 2 min
• If target not achieved after 10 mins,
IV Labetalol 80 mg over 2 min
Switch to IV Hydralazine if Target is not achieved

24. Management of Severe Hypertension
IV Hydralazine
• IV Hydralazine 5 mg or 10 mg over 2 min
• If target not achieved after 20 mins,
IV Hydralazine 20 mg over 2 min
Switch to IV Labetalol if Target is not achieved

25. Management of Severe Hypertension
• Drug of choice when pre-eclampsia is associated with
pulmonary edema is nitroglycerin (glyceryl trinitrate)
• Given as an i.v. infusion of 5 microgram/min, and gradually
increased every 3–5 min to a maximum dose of 100
microgram/min

26. Management of Severe Hypertension
• Intravenous sodium nitroprusside is contraindicated in
pregnancy because of an increased risk of foetal cyanide
poisoning.
• Can still be used in extreme situations for resistant HTN
• Dose of IV Esmolol :
Load 0.25-0.5 mg/kg IV over 1 min, THEN
0.05-0.1 mg/kg/min IV for 4 min

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