A pregnant woman may pass depression onto her unborn child, according to a new study. Doctors have long suspected a connection between maternal depression and mood disorders in offspring; this research helps medical scientists understand how and when this occurs.
Environmental and genetic factors combine to increase the risk for depression in children whose parents suffer from the condition. Scientific testing shows actual changes in the brains of these children, especially in the area of the brain known as the amygdala, responsible for regulating emotions and stress. However, these previous tests did not take place until several years after the children were born – researchers were not certain when these changes to the amygdala actually occurred. This new study suggests the changes are apparent almost immediately after birth.
Maternal depression is common. The New York State Department of Health estimates 10 to 20 percent of women experience symptoms of prenatal depression, such as crying or weepiness, fatigues, irritability, along with sleep and appetite disturbances.
For this newest study, Dr. Anqi Qiu from the National University of Singapore and a team of researchers recruited 157 pregnant women. During their 26th week of pregnancy, study participants filled out a depression questionnaire. Within two weeks after delivery, the women brought their babies in for MRI brain scans that looked at the structure and “wiring” of the babies’ amygdalas.
The researchers found that there was no difference in the size of amygdalas between the babies but they did find a difference in the structural connectivity of the microstructures within this area of the brain. This means there is a difference in the wiring of the brains of babies whose mothers were depressed during pregnancy. This poor structural connectivity could cause lifelong symptoms of depression in the offspring.
The word amygdala means ‘almond,’ named because the area of the brain is about the size and shape of an almond. The amygdala evaluates the emotional significance of stimuli to determine if a particular stimulus is a threat or a reward. People with depression tend have an overly active amygdala when confronted with sad stimulus and an underactive amygdala when faced with a happy situation.
This study results, published in Biological Psychiatry, suggest anxiety and depression could transmit from mother to child while the baby is still in the womb. It also supports early detection of and treatment for maternal depression.