Biomarker that may predict depression in pregnancy identified

Scientists have identified a blood biomarker that can predict women who are likely to suffer from depression during pregnancy, or give birth to low-weight babies. Depression is very common during pregnancy, with as many as one in seven women suffering from the illness and more than a half million women impacted by postpartum depression in the US alone.

The disorder not only affects the mother's mood, but has also been linked to influencing the newborn's development, researchers said. Lower blood levels of a biomarker called brain-derived neurotrophic factor (BDNF) have been associated with depression in multiple studies, mainly in non-pregnant adults. Research from The Ohio State University Wexner Medical Centre in the US found that BDNF levels change during pregnancy, and can cause depression in the mother and low birth weight in the baby.

"Our research shows BDNF levels change considerably across pregnancy and provide predictive value for depressive symptoms in women, as well as poor foetal growth," said Lisa M Christian, an associate professor Wexner Medical Centre. Researchers took blood serum samples during and after pregnancy from 139 women and observed that BDNF levels dropped considerably from the first through the third trimesters and subsequently increased at postpartum.

Overall, black women exhibited significantly higher BDNF than white women during the perinatal period. Controlling for race, lower BDNF levels at both the second and third trimesters predicted greater depressive symptoms in the third trimester. In addition, women delivering low versus healthy weight infants showed significantly lower BDNF in the third trimester, but did not differ in depressive symptoms at any point during pregnancy, which suggests separate effects.

"The good news is there are some good ways to address the issue," Christian said. "Antidepressant medications have been shown to increase BDNF levels. This may be appropriate for some pregnant women, but is not without potential risks and side effects," she said. "Another very effective way to increase BDNF levels is through exercise," she said. "Staying physically active during pregnancy can help maintain BDNF levels, which has benefits for a woman's mood, as well as for her baby's development," she added. The study appears in the journal Psychoneuroendocrinology.