Almost two-thirds of women complain of memory impairment during menopause and after childbirth, when hormones are in flux. This "brain fog" is common and likely is influenced by estrogen. We do have estrogen receptors on the brain and estrogen stimulates neurotransmitters which are involved in processing information. Estrogen also stimulates blood vessels that increase blood flow to the brain. Given that estrogen has been shown to have beneficial effects on brain function, researchers hypothesize that the fluctuations in estrogen that occur during perimenopause might compromise memory and other brain functions.
A study published in Neurology showed that women do not learn as well during early and late perimenopause, when periods are irregular but have not disappeared altogether. The changes were quite subtle, however and the good news is that the deficits were temporary and women bounced back after menopause. The study showed that after menopause, a woman's cognitive function was back to the pre-menopause level.