Hypertensive disorders in pregnancy and intellectual abilities in the offspring in young adulthood: the Helsinki Birth Cohort Study.

BACKGROUND: Hypertensive disorders may affect the fetal developmental milieu and thus hint at mechanisms by which prenatal adversity associates with poorer intellectual ability in subsequent life. AIM: We tested if hypertensive disorders in pregnancy are associated with intellectual ability in the offspring in young adulthood and if any potential associations between hypertensive disorders and intellectual abilities differ according to length of gestation, birth-weight, parity, and childhood socio-economic background.
METHODS: Using mothers' blood pressure and urinary protein measurements at maternity clinics and birth hospitals, we defined normotensive or hypertensive pregnancies in mothers of 1,196 men who participated in the Helsinki Birth Cohort 1934-1944 Study. At age 20 years the men completed a test on intellectual abilities during compulsory military service.
RESULTS: Participants born after pregnancies complicated by hypertensive disorders scored lower on intellectual abilities compared to those born after normotensive pregnancies. The effects of hypertensive disorders were most obvious in men born preterm or after a primiparous pregnancy and in men of higher childhood socio-economic background.
CONCLUSION: Hypertensive disorders in pregnancy are, albeit weakly, associated with lower intellectual abilities in the offspring. These findings are compatible with the concept of adverse fetal 'programming' by a suboptimal prenatal environment.