Fall in mean arterial pressure and fetal growth restriction in pregnancy hypertension: a meta-analysis

Background We investigated the relation between fetoplacental growth and th e use of oral antihypertensive medication to treat mild-to-moderate pregnan cy hypertension. Methods The study design was a metaregression analysis of published data fr om randomised controlled trials. Data from a paper that was regarded as an extreme statistical outliner were excluded from primary analyses. The chang e in (group) mean arterial pressure (MAP) from enrolment to delivery was co mpared with indicators of fetoplacental growth. Findings Greater mean difference in MAP with antihypertensive therapy was a ssociated with the birth of a higher proportion of small-for-gestational-ag e (SGA) infants (slope: 0.09 [SD 0.03], r(2)=0.48, p=0.006, 14 trials) and lower mean birthweight significant after exclusion of data from another pap er regarded as an extreme statistical outliner (slope: -14.49 [6.98] r(2)=0 .16, p=0.049, 27). No relation with mean placental weight was seen (slope - 2.01 [1.62], r(2)=0.15, p=0.25, 11 trials). Interpretation Treatment-induced falls in maternal blood pressure may adver sely affect fetal growth. Given the small maternal benefits that are likely to be derived from therapy, new data are urgently needed to elucidate the relative maternal and fetal benefits and risks of oral antihypertensive dru g treatment of mild-to-moderate pregnancy hypertension.