Treatment of Hypertension in Pregnancy
The first-line medications for hypertension in pregnancy are methyldopa, labetalol, and extended-release nifedipine, with the choice among these three being equivalent in efficacy and safety. 1, 2, 3
First-Line Pharmacological Options
All three recommended agents have comparable safety profiles and can be selected based on availability and dosing convenience:
Methyldopa has the longest safety track record with documented long-term infant follow-up data extending to 7.5 years, making it a particularly reassuring choice 2, 4
Labetalol demonstrates efficacy comparable to methyldopa and is widely used as an alpha/beta-blocker option 2, 5, 6
Extended-release nifedipine (a dihydropyridine calcium channel blocker) offers once-daily dosing that improves adherence and has a strong safety profile 2, 5
Blood Pressure Thresholds and Targets
Initiate antihypertensive medication when BP is persistently ≥140/90 mmHg in pregnant women with: 2
- Gestational hypertension (with or without proteinuria)
- Pre-existing hypertension with superimposed gestational hypertension
- Any hypertension with organ dysfunction or symptoms
- Pre-eclampsia
Target BP should be <140/90 mmHg but keep diastolic BP ≥80 mmHg to optimize maternal health without compromising fetal perfusion 1, 2, 5
For uncomplicated chronic hypertension without the above features, treatment threshold is BP persistently ≥150/95 mmHg 2
Severe Hypertension/Hypertensive Emergency
Severe hypertension (SBP ≥160 mmHg or DBP ≥110 mmHg) requires immediate hospitalization and urgent treatment to prevent maternal stroke, heart failure, and adverse fetal outcomes 1, 2, 5
Intravenous labetalol is the preferred option for acute management of severe hypertension in pregnancy 2
Alternative parenteral options include IV hydralazine and oral nifedipine, though hydralazine may carry higher risk of maternal hypotension 1, 7
Sodium nitroprusside should only be used when all other treatments fail due to risk of fetal cyanide poisoning with prolonged use 2, 5
Absolutely Contraindicated Medications
ACE inhibitors, angiotensin receptor blockers (ARBs), and direct renin inhibitors are absolutely contraindicated throughout pregnancy due to severe fetotoxicity, particularly in the second and third trimesters 1, 2, 3
These agents cause fetal renal dysfunction, oligohydramnios, intrauterine growth restriction, and neonatal death 1
Women taking these medications who are planning pregnancy must be transitioned to safe alternatives before conception 1, 8
Common Pitfalls to Avoid
Do not use atenolol during pregnancy as it has been associated with impaired fetal growth, despite other beta-blockers being acceptable 7, 9
Avoid NSAIDs for postpartum analgesia in women with pre-eclampsia, especially if they have renal disease, placental abruption, or acute kidney injury 2
Do not abruptly discontinue antihypertensive medications postpartum—withdraw slowly over days, as eclamptic seizures may develop in the early postpartum period 2, 3
Diuretics are not recommended for blood pressure control in pregnancy but may be used during late-stage pregnancy if needed for volume control 1
Adjunctive Preventive Measures
Low-dose aspirin (75-100 mg daily) should be started before 16 weeks gestation in women with history of early-onset pre-eclampsia (<28 weeks) 2
Calcium supplementation of at least 1 gram daily reduces pre-eclampsia risk, particularly in high-risk women 2
Low to moderate-intensity exercise is recommended for all pregnant women without contraindications to reduce risk of gestational hypertension and pre-eclampsia 2, 5
Postpartum and Long-term Management
All women should be reviewed at 3 months postpartum to ensure BP, urinalysis, and laboratory abnormalities have normalized 2
Annual medical review is advised lifelong, as women with gestational hypertension or pre-eclampsia have significantly increased long-term cardiovascular risk and should be counseled about maintaining healthy lifestyle, exercise, proper nutrition, and ideal body weight 2, 3, 9, 10