Chronic hypertension through pregnancy to superimposed pre-eclampsia — case discussion

Presentation

Practice case (not a real patient). A 36-year-old woman with chronic hypertension, diagnosed three years ago, takes ramipril. Her BP is well controlled, her kidney function and urinalysis are normal, and she has no other medical conditions. She plans her first pregnancy and asks what needs to change. ESC 2025 lists chronic hypertension among the high risk factors for pre-eclampsia.^[1]

Step 1 — Before conception

Discussion:

• Stop the ramipril: ESC 2025 says ACE inhibitors can cause foetal malformations, IUGR and death and are contraindicated in pregnancy, and its hypertension text calls ACE inhibitors, ARBs and direct renin inhibitors strictly contraindicated.^[1]
• AHA/ACC 2025: individuals with hypertension who are planning a pregnancy should not be treated with atenolol, ACEi, ARB, direct renin inhibitors, nitroprusside or MRA, to avoid fetal harm (COR 3: Harm, LOE C-LD); ESC 2024 hypertension said RAS blockers are not recommended during pregnancy (Class III, Level B).^[5][4]
• Replacement: AHA/ACC 2025 names labetalol and extended-release nifedipine as preferred agents for individuals with hypertension planning a pregnancy (COR 1, LOE A); ESC 2025 recommends methyldopa (Class I, Level B) and labetalol, metoprolol and dihydropyridine CCBs (Class I, Level C) for hypertension in pregnancy.^[5][1]
• Aspirin: chronic hypertension is a high-risk factor for pre-eclampsia, so ESC 2025 recommends low-dose aspirin 75–150 mg daily from weeks 12 to 36/37 (Class I, Level A); AHA/ACC 2025 says she should be counseled about the benefits of low-dose (81 mg/day) aspirin to reduce the risk of preeclampsia and its sequelae (COR 1, LOE B-R).^[1][5]
• Exercise: ESC 2025 text says that, unless contraindicated, aerobic exercise should be recommended in pregnant women with hypertension to maintain ideal body weight and reduce adverse pregnancy outcomes; the earlier ESC 2024 row recommends low- to moderate-intensity exercise, in consultation with an obstetrician, in all pregnant women without contraindications, to reduce the risk of gestational hypertension and pre-eclampsia (Class I, Level B).^[1][4]

Step 2 — Early pregnancy

She switches from ramipril to labetalol and then conceives. At 12 weeks her office BP is 136/86 mmHg, and she starts aspirin.^[1]

Discussion:

• ESC 2025 recommends aiming for systolic BP below 140 mmHg and diastolic BP below 90 mmHg in pregnant women (Class I, Level B); the earlier ESC 2024 row said to lower BP below 140/90 mmHg but not below 80 mmHg diastolic in chronic and gestational hypertension (Class I, Level C).^[1][4]
• For chronic hypertension, the starting threshold is in ESC 2024 (confirmed office systolic BP of 140 mmHg or more or diastolic BP of 90 mmHg or more, Class I, Level B), and AHA/ACC 2025 says pregnant individuals with chronic hypertension should receive therapy to achieve BP below 140/90 mm Hg, to prevent maternal and perinatal morbidity and mortality (COR 1, LOE B-R).^[4][5]
• ESC 2025: ambulatory or home BP monitoring should be considered to exclude white-coat and masked hypertension (Class IIa, Level C), and home monitoring may be considered as an adjunct to office readings to detect new-onset hypertension or monitor BP control (Class IIb, Level B).^[1]
• ESC 2025: calcium supplements are recommended to prevent pre-eclampsia in women with low dietary calcium intake (below 600 mg/day); ask about her intake.^[1]

Step 3 — At 35 weeks

At 35 weeks she has a headache. Her BP is 164/112 mmHg, confirmed on a repeat reading 15 minutes later. Urine albumin–creatinine ratio is 45 mg/mmol (new), platelets and liver and kidney tests are normal, and she has no breathlessness or signs of pulmonary oedema.^[1]

Discussion:

• This is pre-existing hypertension with superimposed pre-eclampsia: a further rise in BP with new proteinuria (ESC 2025 Table 14).^[1]
• Systolic BP of 160 mmHg or more or diastolic BP of 110 mmHg or more in pregnancy is an emergency, and treatment in hospital is recommended (ESC 2025, Class I, Level C); AHA/ACC 2025 says that with SBP of 160 mm Hg or more or DBP of 110 mm Hg or more confirmed within 15 minutes, antihypertensive medication should lower BP below 160/110 mm Hg within 30 to 60 minutes, to prevent adverse events (COR 1, LOE B-R).^[1][5]
• Drugs: in severe hypertension, i.v. labetalol, urapidil or nicardipine, or oral short-acting nifedipine or methyldopa, is recommended, with i.v. hydralazine second line (ESC 2025, Class I, Level C); in pre-eclampsia or eclampsia with hypertensive crisis, ESC 2024 recommended i.v. labetalol or nicardipine and magnesium (Class I, Level C).^[1][4]
• Severe hypertension makes this pre-eclampsia with severe features, which should be managed with a magnesium sulfate infusion to prevent eclampsia, in addition to early delivery (ESC 2025).^[1]
• On magnesium, watch for toxicity: it can present with PR, QRS and QT prolongation at 2.5–5 mmol/L and can progress to AV nodal conduction block, bradycardia, hypotension and cardiac arrest at 6–10 mmol/L; if toxicity is suspected, stop the infusion and give 30 mL i.v. calcium gluconate.^[1]
• Timing: the 37-week delivery row applies to pre-eclampsia without severe features, so it does not fit her; ESC 2025 also recommends expediting delivery in pre-eclampsia associated with adverse markers such as haemostatic disorders (Class I, Level C), and that list of markers is open.^[1]
• ESC 2025 reports a UK randomised trial in late preterm pre-eclampsia (34–37 weeks) in which planned delivery within 48 h lowered maternal morbidity and severe maternal hypertension, but more neonates were admitted to neonatal intensive care; ESC 2025 says timing decisions should be individualised, considering both maternal and foetal well-being.^[1]

Step 4 — Delivery and after

Discussion:

• Women with severe pre-eclampsia benefit from neuraxial anaesthesia to reduce the hypertensive response to pain.^[1]
• After birth, monitor BP in hospital (or with equivalent outpatient surveillance) for 72 h and check again at 7–10 days post-partum.^[1]
• Nifedipine and labetalol (metoprolol if labetalol is unavailable) are recommended for uncomplicated post-partum hypertension in the first 6 weeks (ESC 2025, Class I, Level C); if methyldopa had been used, it should be avoided after delivery because of the risk of post-partum depression.^[1]
• If post-partum hypertension persists beyond 6 weeks to 3 months, starting antihypertensive therapy with reference to lactating status, following current guidelines, is recommended (ESC 2025, Class I, Level B).^[1]
• Long term: a cardiovascular risk assessment, with counselling on healthy lifestyle choices that optimise cardiovascular health, is recommended after an adverse pregnancy outcome (Class I, Level B) and should be considered at 3 months post-partum, with repeat assessment at 6–12 months after implementation of appropriate lifestyle interventions and regular long-term follow-up thereafter (Class IIa, Level C); breastfeeding may be considered to lower future cardiovascular risk (Class IIb, Level C).^[1]

Learning points

• Change ACE inhibitors before conception; ESC 2025 and AHA/ACC 2025 both rule them out in pregnancy.^[1][5]
• Chronic hypertension alone is a high-risk factor for pre-eclampsia, so low-dose aspirin 75–150 mg daily from weeks 12 to 36/37 is recommended (ESC 2025, Class I, Level A).^[1]
• Systolic BP of 160 mmHg or more or diastolic BP of 110 mmHg or more is an emergency in pregnancy, and treatment in hospital is recommended; pre-eclampsia with severe features should be managed with magnesium sulfate and early delivery.^[1]
• After this adverse pregnancy outcome, a cardiovascular risk assessment is recommended (ESC 2025, Class I, Level B).^[1]