In some girls, the seeds of depression could be planted before they know how to shake a rattle, let alone know what it feels like to be sad.
A new study shows that being born underweight puts girls more at risk for depression as teenagers. Duke University researchers found that one-quarter of teenage girls born weighing under five-and-a-half pounds struggle with depression every year. Only three percent of their normal-weight peers do.
Researchers don’t know what causes this, but they think conditions in the womb may play a role. The study cites a concept called fetal programming. According to this theory, the environment inside the womb affects how a fetus develops. For example, if a woman is malnourished, the body may send signals that restrict the baby’s growth, preparing her for life with less food. Placenta growth and hormone levels can have an effect too. Adjusting to these challenges helps babies survive but may put some at risk for later problems, which could emerge as they cope with stress or changing hormone levels during puberty.
Duke researchers did not find a link between low birthweight and depression in boys, but this could be because boys are more apt to struggle as babies while girls tend to thrive at birth and exhibit problems later.
More studies are needed to determine why puberty increases depression in these girls. For now, researchers say doctors and parents should watch for signs of depression, which can hurt the mind and body if left untreated.