Heightened Amygdala Activity Tied to Postpartum Depression

MILAN — Pregnant women with heightened amygdala activity have a reduced capacity to regulate emotions and report more symptoms of depression than those with lower activity in this brain region, a new imaging study suggested.

If validated, these findings could pave the way for identifying women at higher risk for postpartum depression, said lead researcher Franziska Weinmar, MSc, from the University of Tübingen, Tübingen, Germany.

The study was presented here at the 37th European College of Neuropsychopharmacology (ECNP) Congress.

Differences in Brain Activity

During pregnancy and the peripartum period, rising hormone levels create a “psychoneuroendocrinological window of vulnerability” for mental health in which 80% of women can develop transitory “baby blues,” and about one in seven develop more serious postpartum depression, Weinmar told Medscape Medical News.

The study included 47 women — 15 pregnant women and 32 nonpregnant controls. The nonpregnant women had normal menstrual cycles; 16 were in the early follicular phase with low estradiol levels (231.7 pmol/L), and 16 had high estradiol levels (516.6 pmol/L) after administration of estradiol.

To examine brain activity, participants were asked to view negative emotional images while undergoing functional MRI. They were then asked to use cognitive reappraisal to regulate their emotional response to the images.

The findings showed that both pregnant and nonpregnant women were equally successful at emotional regulation, but this process involved different brain activity in pregnant vs their nonpregnant counterpart.

All women had increased left middle frontal gyrus activity when regulating their emotions, but there was a difference in the amygdala between the pregnancy group and controls, Weinmar noted.

This suggests that pregnant women may have to exert more neural effort in emotional regulation, she said. “And pregnant women with higher amygdala activity were less able to regulate their emotions successfully compared to those with less amygdala activity,” she added.

Linear regression analyses were performed to assess the relation of brain activity during downregulation, regulation success, and self-reported depression scores, and this showed that higher amygdala activity was also associated with higher depression scores.

“We need to be cautious in interpreting this,” said Weinmar. “This is a small sample, and we are the first to undertake this work.”

Nonetheless, she said that if the findings are confirmed by larger studies, pregnant women could be assessed “in the waiting room” using existing questionnaires that evaluate emotional regulation.

If a woman has difficulties with emotion regulation, “there are adaptive strategies, like cognitive reappraisal that a counseling psychotherapist can help with,” said Weinmar.

“I could also imagine group sessions, for example, or online courses,” she said, adding that obstetricians could also be trained to identify these women.

Commenting on the findings in a press release, Susana Carmona, PhD, from Gregorio Marañón Hospital in Madrid, Spain, said research like this is crucial for gaining insight into one of the most intense physiological processes a human can undergo: Pregnancy. It’s remarkable how much remains unknown.

“Recently, the FDA approved the first treatment for postpartum depression. However, we still have a long way to go in characterizing what happens in the brain during pregnancy, identifying biomarkers that can indicate the risk of developing perinatal mental disorders, and designing strategies to prevent mother and infant suffering during the delicate and critical peripartum period,” Carmona added.

The study was supported by the Center for Integrative Neuroscience, Tübingen, Germany (CIN; EXC307, MRTG Pregnancy & the Brain); International Research Training Group “Women’s Mental Health Across the Reproductive Years” (IRTG 2804).

Weinmar and Carmona reported no relevant disclosures.