Launched on 6th of October 2026

Cardio.toolsby Mohamed Ghazy, MD CardiologyAin Shams University, Egypt · Cardiology Consultant, Saudi ArabiaScopus ID: 55257919100
Cardiovascular disease in pregnancy

Antihypertensives and magnesium sulphate in pregnancy

The oral drugs used in pregnancy with their doses: methyldopa (Aldomet), labetalol and extended-release nifedipine first line, then hydralazine, metoprolol, amlodipine and thiazides, and the drugs to avoid (ACE inhibitors, ARBs, sacubitril/valsartan, atenolol, MRAs). The emergency order sets of ACOG Committee Opinion 767 for severe hypertension, starting with IV labetalol, IV hydralazine or oral immediate-release nifedipine, with the BP checks between doses and the maximum doses. Magnesium sulphate: indications, the IV (Zuspan) and IM (Pritchard) regimens, the maintenance pump rate from the bag, dose reduction in kidney impairment, monitoring, toxic levels and calcium gluconate. Postpartum and breastfeeding choices close the list.

Upload a report, lab sheet or echo picture to fill this calculator automatically.
Show
First drug
All three are first line (ACOG, ISSHP, NICE, ESC); use the one your unit knows best
Patient
Hypertension in pregnancy · drugs
Severe hypertension
BP ≥ 160/110 confirmed after 15 min: first dose within 30–60 min
Decision guide
Labetalol first (ACOG Committee Opinion 767)
  1. 1
    Labetalol 20 mg IV over 2 min
    Repeat BP in 10 min; continue if ≥ 160 systolic or ≥ 110 diastolic
  2. 2
    Still severe: labetalol 40 mg IV over 2 min
    10 min; continue if ≥ 160 systolic or ≥ 110 diastolic
  3. 3
    Still severe: labetalol 80 mg IV over 2 min
    10 min; continue if ≥ 160 systolic or ≥ 110 diastolic
  4. 4
    Still severe: hydralazine 10 mg IV over 2 min
    20 min; continue if ≥ 160 systolic or ≥ 110 diastolic
  5. 5
    Still severe: emergency consultation (MFM, anaesthesia, critical care) for an infusion: labetalol 1–2 mg/min or nicardipine
  • Once below the threshold
    ACOG CO 767
    BP every 10 min for 1 h, every 15 min for 1 h, every 30 min for 1 h, then hourly for 4 h. Aim for 140–150/90–100 mmHg; start or adjust oral drugs.
  • Maximum doses
    ACOG · NICE NG133
    Labetalol cumulative 300 mg IV (infusion 1–2 mg/min). Hydralazine 20 mg IV per episode (infusion 0.5–10 mg/h); give 250–500 mL crystalloid with the first dose if no pulmonary oedema. Nifedipine IR 50 mg in the first hour.
  • Pulmonary oedema: IV nitroglycerin
    IESC 2018 pregnancy
    5 µg/min, increasing every 3–5 min to 100 µg/min, with furosemide and oxygen.
  • Urapidil (ESC alternative) and nicardipine infusions are used in intensive care
    ESC 2024
Infusion rates in mL/h: IV antihypertensive dosing.
References
  1. American College of Obstetricians and Gynecologists. Clinical management guidelines: Emergent therapy for acute-onset, severe hypertension during pregnancy and the postpartum period. ACOG Committee Opinion No. 767. Obstet Gynecol 2019;133:e174-e180.
  2. American College of Obstetricians and Gynecologists. Gestational hypertension and preeclampsia: ACOG Practice Bulletin No. 222. Obstet Gynecol 2020;135:e237-e260.
  3. American College of Obstetricians and Gynecologists. Chronic hypertension in pregnancy. ACOG Practice Bulletin No. 203. Obstet Gynecol 2019;133:e26-e50.
  4. De Backer J, Haugaa KH, et al. 2025 ESC Guidelines for the management of cardiovascular disease and pregnancy. Eur Heart J 2025.
  5. McEvoy JW, McCarthy CP, et al. 2024 ESC Guidelines for the management of elevated blood pressure and hypertension. Eur Heart J 2024;45:3912-4018.
  6. National Institute for Health and Care Excellence. Hypertension in pregnancy: diagnosis and management. NICE guideline NG133, 2019 (updated 2023).
  7. Magee LA, Brown MA, et al. The 2021 International Society for the Study of Hypertension in Pregnancy classification, diagnosis & management recommendations for international practice. Pregnancy Hypertens 2022;27:148-169.
  8. World Health Organization. WHO recommendations for prevention and treatment of pre-eclampsia and eclampsia. Geneva: WHO, 2011.
  9. Magpie Trial Collaborative Group. Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial. Lancet 2002;359:1877-1890.
More in Cardiovascular disease in pregnancy