9 Pregnancy and chronic hypertension: Nifedipine vs labetalol as antihypertensive treatment (the panda study)

Introduction Chronic hypertension complicates around 3% of all pregnancies and is associated with adverse maternal and perinatal outcome. The optimal antihypertensive treatment(s) for pregnancy complicated by chronic hypertension is uncertain. Choice of antihypertensive outside pregnancy depends on ethnicity. It is unclear if ethnicity impacts on the efficacy of antihypertensive treatment during pregnancy. Objectives To perform a feasibility study to inform a randomised controlled trial in women with chronic hypertension in pregnancy, comparing nifedipine and labetalol for control of chronic hypertension in pregnancy, with additional assessment of the impact of ethnicity on efficacy of each treatment. Method Pregnant women with chronic hypertension were enrolled between August 2014 and October 2015 at four UK centres, with the last woman delivering in April 2016. Participants were randomised to nifedipine or labetalol as antihypertensive treatment between 12+0 and 27+6 weeks' gestation using a minimisation protocol. Demographic, serial longitudinal antenatal blood pressure readings, and maternal/perinatal outcome data were collected and analysed. Results 114 women were randomised to antihypertensive treatment (67% of those screened and eligible). Average monthly recruitment varied from 1.2 to 3.7 participants per centre. 54% ( n =62) of those recruited were of black ethnicity. 98% ( n =112) completed the study (1 withdrawal, 1 lost to follow-up). 12 participants (10.5%) (five in the nifedipine arm and seven in the labetalol arm) discontinued their assigned intervention due to side effects of the treatment and switched to alternative medication. Four women (3.6%) had a second trimester miscarriage and two women (1.8%) underwent termination of pregnancy (one with superimposed pre-eclampsia at 16 weeks' gestation and one with a fetus with sickle cell disease on amniocentesis). Of the women whose pregnancies continued beyond 24 weeks' gestation, 25% ( n =27) were diagnosed with superimposed pre-eclampsia; 27% ( n =29) of babies were delivered before 37 weeks' gestation, 35% ( n =38) of birthweights were less than the 10th percentile, 17% ( n =20) of birthweights were less than the 3rd percentile and there were two stillbirths (1.9%). Conclusion This study confirms good recruitment to a trial comparing commonly used antihypertensive agents for the treatment of chronic hypertension in pregnancy. In addition, the high incidence of adverse maternal and perinatal outcomes is highlighted within this cohort. Further exploration of the antenatal blood pressure profiles and maternal/perinatal outcomes within each treatment group is planned to assess efficacy.