O65. Is there evidence to inform antihypertensive prescribing in pregnancy complicated by chronic hypertension: A systematic review

Abstract

Introduction Chronic hypertension (CHT) complicates 1–5% of all pregnancies. The importance of optimising blood pressure control has been highlighted by the results of the Control of hypertension in pregnancy study. The frequency of severe hypertension in pregnancy directly affects maternal morbidity and mortality. Effective anti-hypertensive treatments (AHTs) for CHT in pregnancy that reduce this risk need to be identified. Objectives To perform a systematic review of randomised controlled trials (RCTs) in women with CHT in pregnancy to determine the incidence of severe hypertension with AHT use (vs. none) and by drug class, together with incidence of adverse maternal and fetal/neonatal outcomes. Method Medline (via OVID), Embase (via OVID) and the Cochrane Trials Register were searched from their earliest entries until 30.4.15. All RCTs evaluating AHTs for CHT in pregnancy were included. Additional data were found from references of papers identified from the original searches. Two review authors (LW and FCR) extracted and tabulated relevant data. Data were analysed in Stata 13.1 (StataCorp, College Station, Texas), using the metan suite of commands (Higgins et al. 2003). Where there was significant evidence of heterogeneity, the DerSimonian & Laird (1986) method was used. Results 10 RCTs of AHT vs other AHT or placebo/no AHT were identified for a pre-defined CHT cohort and an additional 5 RCTs reported outcomes for a CHT subgroup; all data were from studies completed prior to 2000. A clinically important reduction in the incidence of severe hypertension was seen with AHT use vs no AHT (4 studies, 244 women; risk ratio (RR) 0.37; 95% confidence interval (CI) 0.22 to 0.64; I 2 0.0%). Additionally two small studies reported incidence of severe hypertension when comparing β -blockers with methyldopa, but results are ambiguous (86 women; RR 0.85, CI 0.5 to 1.37; I 2 66.1%). There was no clear difference in the incidence of superimposed pre-eclampsia for women on AHTs vs no AHTs (6 studies, 525 women; RR 0.77, CI 0.50 to 1.18; I 2 37.3%). No significant difference in birthweight (g) was demonstrated with AHT treatment of CHT in pregnancy ( 7 studies, 731 women; weighted mean difference − 78.23; CI − 164.59 to 8.13; I 2 59.9%). Conclusion A considerable paucity of data exists from RCTs to guide AHT prescribing for CHT in pregnancy. Given the increasing incidence of CHT in pregnancy and that AHTs reduce the incidence of severe hypertension, head-to-head RCTs of the commonly used AHTs are urgently required to inform prescribing.