The new study by Dr Maddalena Ardissino of National Heart and Lung Institute, Imperial College London, and Dr Eric A. W. Slob of Nuffield Department of Population Health, University of Oxford, focused on antihypertensive drugs that are commonly used in pregnancy, beta-blockers (BB) and calcium channel blockers (CCB) . However, a limited number of studies have been conducted on their relative effects on maternal and fetal outcomes. By using a Mendelian randomization paradigm, researchers examined the effects of genetic variants mimicking BB and CCB antihypertensive drugs on pre-eclampsia, gestational diabetes, and birthweight.
Study methods: A genome-wide association study (GWAS) on 757,601 participants was used to estimate genetic associations for systolic blood pressure (SBP). A genetic association estimate was derived from GWASs of 4743 cases and 136,325 controls (women without hypertensive disorders during pregnancy) with pre-eclampsia or eclampsia, 7676 cases and 130,424 controls (women without pregnancy-related morbidity) with gestational diabetes, and 155,202 women (who have given birth to at least eleven children) with birthweights.
Study results: While not reaching conventional statistical significance, genetically-proxied BB was associated with reduced preeclampsia risk and increased gestational diabetes risk, and significantly associated with lower birthweight in the first child. The genetically-proxied CCB was associated with pre-eclampsia and eclampsia, but not with gestational diabetes or changes in birth weight of the first child.
Study conclusions: BB use may lower birthweight compared to CCB use, but both antihypertensive drugs are effective at lowering blood pressure in pregnancy. Conversely, CCB use may reduce preeclampsia and eclampsia risk without affecting gestational diabetes risk or birthweight. These data support the need for further study on the effects of BBs on birthweight.
