Many pregnant women complain of “pregnancy brain”.  They describe that they feel less sharp than usual and often complain of bouts of forgetfulness.  Is it because they are distracted by thinking about and planning for the arrival of the new baby?  Is it the hormones? Is it sleep deprivation? A new study suggests that depression may be a factor.

Researchers hypothesized that reports of poor concentration and memory lapses might reflect difficulties in working memory (WM). In addition, they hypothesized that antenatal depression (depression arising during pregnancy) may play a role here, either on its own or due to secondary changes in endocrine function or sleep.

They compared healthy pregnant women at 34-36 weeks of gestation (n=28) with age- and education-matched non-pregnant controls (n=26).

Deficits in working memory were observed only among pregnant women with depressive symptoms. In contrast, pregnant women who were not depressed showed working memory performance that equalled, or even exceeded, non-pregnant controls. No significant differences were observed on tests of other cognitive functions.

Consistent with other studies of estradiol and WM in other populations, higher levels of estradiol was associated with better WM, whereas higher levels of depressive symptoms predicted poorer WM.  Somewhat surprising is the finding that sleep disturbance did not appear to correlate with variation in the WM scores.

While memory disturbance might not be as common as some believe, this study indicates it may be more prominent among women experiencing depression during pregnancy.

Ruta Nonacs, MD PhD

Hampson E, Phillips SD, Duff-Canning SJ, Evans KL, Merrill M, Pinsonneault JK, Sadée W, Soares CN, Steiner M.  Working memory in pregnant women: Relation to estrogen and antepartum depression.  Horm Behav. 2015 Jul 15. p

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