Researchers have found a connection between depression in pregnant women and physical effects on infants. The effects noted include reduced muscle tone, increased stress hormones and neurological / behavioral problems.

Study participants included more than 150 women over 20 years of age. Symptoms of depression were recorded at 28 weeks, 32 weeks, 37 weeks and at birth. Blood samples were taken from the umbilical cord. The samples were used to test for stress hormones. Infants were asked to return for testing at two weeks of age. Tests included behavioral tests – specifically to test infant response to stress and motor skills.

Researchers have no idea why depression causes physical reactions in infants, but theories include the infant being sensitive to stress and sensitization to stress with the inability to prevent stress-based reactions.

Depression is common during pregnancy with about 20% of women reporting depression related symptoms. Post-partum depression is also common in many pregnancies. Researcher noted women should feel comfortable seeking help from therapists or other mental professionals during pregnancy if they feel depressed at any time.

Source: News Release. University of Michigan Health System. 9 December, 2010.