Cognition in pregnancy and motherhood: prospective cohort study.

BACKGROUND Research has reported that pregnant women and mothers become forgetful. However, in these studies, women are not recruited prior to pregnancy, samples are not representative and studies are underpowered. AIMS The current study sought to determine whether pregnancy and motherhood are associated with brief or long-term cognitive deterioration using a representative sample and measuring cognition during and before the onset of pregnancy and motherhood. METHOD Women aged 20-24 years were recruited prospectively and assessed in 1999, 2003 and 2007. Seventy-six women were pregnant at follow-up assessments, 188 became mothers between study waves and 542 remained nulliparous. RESULTS No significant differences in cognitive change were found as a function of pregnancy or motherhood, although late pregnancy was associated with deterioration on one of four tests of memory and cognition. CONCLUSIONS The hypothesis that pregnancy and motherhood are associated with persistent cognitive deterioration was not supported. Previous negative findings may be a result of biased sampling.