the observational study followed live singleton births (a single child born after at least 20 weeks of gestation) in sweden and finland searching for signs of ischemic heart disease and stroke over the course of decades. hypertensive pregnancy disorders (high blood pressure) and preeclampsia (high blood pressure with evidence of organ damage) were flagged ahead of time.
with the hypothesis that ischemic heart disease and stroke were associated with high blood pressure during pregnancy, researchers controlled for a host of other factors that might influence this relationship, including the year the child was born, sex, congenital anomalies, mother’s age, marital status, education level and family history. they also performed a sibling analysis to control for any unmeasured genetic or environmental familial factors.
from the pool of more than 5.8 million singletons, researchers found 218,322 (or 3.76 per cent) had mothers who had hypertensive disorders during pregnancy. over a follow-up period of close to 41 years, 2,340 (0.4 per cent) were found to have ischemic heart disease and 5,360 (0.09 per cent) had experienced a stroke.
the findings mean children from mothers with hypertension during pregnancy had a 29 per cent increased risk of heart disease and 33 per cent increased risk of stroke during the course of observation. when researchers factored in the sibling analysis, the associations held for stroke but not heart disease, a sign that other factors might be at play here.