Low levels of a brain protein during pregnancy can cause depression in the mother and low birth weight in the baby, a study has found. The findings showed that brain-derived neurotrophic factor (BDNF) commonly known to regulate moods, is also vital for the placenta and a baby’s brain development. It constantly changes during pregnancy. A dip in this protein’s levels is behind the depression, which is a common condition during pregnancy. “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, Associate Professor at Ohio State University. For the study, 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. The results showed that the lower BDNF levels at both the second and third trimesters predicted greater depressive symptoms in the third trimester. Some antidepressant medications have been shown to increase BDNF levels. However, “this may be appropriate for some pregnant women, but is not without potential risks and side effects,” Christian said. Another effective way to increase BDNF levels is through exercise, the researchers stated.