A new pilot study finds that pregnant women with a history of depression or bipolar disorder may interpret babies’ facial expressions and emotions differently, compared to healthy controls. This occurs even when the women are not currently experiencing depressive or manic symptoms.

The findings may represent an early risk factor for the children, but the authors stress that more research is needed to confirm any long-term effects.

For the study, the researchers compared 29 pregnant women with a history of mental illness — 22 with a history of depression and 7 with bipolar disorder — to 28 pregnant women with no mental health history and 18 non-pregnant women (controls). All of the women were currently well with no symptoms.

Between the 27th and 39th weeks of pregnancy, all of the women were tested to see how they respond to a series of happy or sad faces, and to laughter and crying, of both babies and adults.

Specifically, the participants were asked to rate how happy or distressed the infants were based on their facial and vocal displays of emotion (including smiles, laughter and cries). They were also asked to identify adult facial expressions of emotion (including happiness, sadness, fear and disgust) across varying intensity levels.

“In this study, we found that pregnant women with depression or bipolar disorder process infants’ facial and vocal signals of emotion differently even when they are not currently experiencing a depressive or manic episode,” said lead researcher Dr. Anne Bjertrup from Rigshospitalet, a specialized hospital in Copenhagen, Denmark.

“These differences may impair these women’s ability to recognize, interpret and respond appropriately to their future infants’ emotional signals.”

The researchers found that, compared to healthy pregnant women, expecting women with bipolar disorder had difficulty recognizing all facial expressions and showed a “positive face-processing bias,” where they showed better recognition of happy adult faces and more positive ratings of happy infant faces.

In contrast, pregnant women with previous depression showed a negative bias in the recognition of adult facial expressions and rated infant cries more negatively.

“This is a pilot study, so we need to replicate the findings within a larger sample. We know that depression and bipolar disorder are highly heritable, with up to 60 percent of children of parents with these affective disorders more likely to develop a mental disorder themselves,” Bjertrup said.

“Genes play a role, but it is also likely that the quality of the early interaction with the mother is important. The different cognitive response to emotional infant signals in pregnant women with a history of mania and/or depression may make it more difficult for them to relate to their child and could thus confer an early environmental risk for the child.”

“It’s worth emphasizing that this work does not say that the affected women are ‘bad mothers,’” she said. “It simply means that because of their health history, they may experience difficulties interpreting and responding appropriately to their infants’ emotional needs and that we as clinicians need to be more aware of these possible difficulties.”

Bjertrup said the findings are still early and more research is needed. Ultimately the researchers would like to develop and test early screening and intervention programs to help train mothers to interpret the signals from their children better.

This findings were presented recently at the ECNP Congress in Barcelona.

Source: European College of Neuropsychopharmacology