BACKGROUND AND PURPOSE:

• Chronic hypertension in pregnancy is approximately 3% and rising due to obesity epidemic and increasing maternal age
• In nonpregnant setting, ethnicity helps to determine first line antihypertensive medication
  • For example, calcium channel blockers are first line in those with African/Caribbean family origin
• RCT data on antihypertensive medications for women with chronic hypertension in pregnancy is limited
• Webster et al. (Hypertension, 2017) sought to compare labetalol and nifedipine for chronic hypertension in pregnancy, additionally assessing the impact of ethnicity on treatment efficacy

METHODS:

• PANDA study (Pregnancy and Chronic Hypertension: Nifedipine Versus Labetalol as Antihypertensive Treatment)
• Randomized Controlled Trial (RCT)
• Pregnant women with chronic hypertension were enrolled at 4 UK centers
• Eligibility criteria
  • Prenatal diagnosis of chronic hypertension (treated or untreated) or blood pressure (BP) readings ≥140 mm Hg systolic or ≥ 90 mm Hg diastolic before 20 weeks’ gestation, requiring antihypertensive treatment before 27w6d
• Open-label first-line antihypertensive treatment was randomly assigned
  • Labetalol (200-1800 mg/d)
  • Nifedipine-modified release (20-80 mg/d)
• Outcomes were maximum blood pressure, mean blood pressure, and central aortic pressure

RESULTS:

• 56 women were randomized to labetalol and 58 to nifedipine
• Both medications were effective in controlling BP
  • Mean BP: labetalol 134/84 mm Hg versus nifedipine 134/85 mm Hg
  • No difference in days out of target range (≥160 mm Hg systolic, ≥150 mm Hg systolic, and <80 mm Hg diastolic)
• There was a mean 7.4 mm Hg decrease (-0.4 to -14.4 mm Hg) in central aortic pressure in the nifedipine arm but not seen in peripheral BP measurements
• No difference in treatment effect was observed in black women, but a mean 4 mm Hg reduction (-6.6 to -0.8 mm Hg; p= 0.015) in brachial diastolic blood pressure was observed with labetalol compared with nifedipine in non-black women
• Secondary maternal and perinatal outcomes
  • More women receiving nifedipine developed superimposed preeclampsia but difference was not significant
  • 6 women (11%) in each group developed superimposed preeclampsia < 34 weeks
  • No difference noted in requirement for additional oral antihypertensive agents
  • A greater proportion of nifedipine group (14% versus 4%) required IV antihypertensive agents
  • Rates of induction of labor and cesarean section were comparable as were median gestation at delivery and adverse maternal outcomes (11% labetalol vs 14% nifedipine)

CONCLUSION:

• First head-to-head RCT trial comparing labetalol to nifedipine for chronic hypertension in pregnancy, and results show both maximum and mean BP were comparable
• Study was not sufficiently powered to make conclusions regarding secondary perinatal and maternal outcomes
• In non-white women, labetalol has a greater effect in reducing diastolic BP but more research needed to determine whether this finding is of any clinical significance

Learn More – Primary Sources:

Labetalol Versus Nifedipine as Antihypertensive Treatment for Chronic Hypertension in Pregnancy: A Randomized Controlled Trial

Related ObG Topics:

ACOG Guidance: Emergency Treatment for Severe Hypertension in Pregnancy

Diagnosing Preeclampsia – Key Definitions and ACOG Guidelines

Eclampsia and Role of Magnesium Sulfate

HYPITAT-II: Immediate Delivery or Expectant Management for Non-Severe Hypertension at 34 – 37 weeks?