Perinatal mortality and birth-weight in relation to aspirin taken during pregnancy.

In a cohort of 41 337 gravidas and their offspring in the U.S.A. there was no evidence that aspirin taken in pregnancy is a cause of stillbirth, neonatal death, or reduced birth-weight. The women were divided into those who were not exposed to aspirin (14 956), those with intermediate exposure (24 866), and those who were heavily exposed (1515). Stillbirth-rates were similar for all three groups. Differences in neonatal death-rates and mean birth-weights were slight and none were statistically significant. Trends were opposite among approximately equal numbers of White and Black children.