A joint British and Swedish study has found that babies who were born before reaching the thirty second week of gestation may be at a higher risk for a number of mental health disorders once they reach their teen years. That study, led by Chiara Nosarti from the Institute of Psychiatry at Kings College in London found that a number of premature babies were at a higher risk for those issues at a higher rate than babies who were born at full term. That study is published in the Archives of General Psychiatry.

In the study, Nosarti and her team found that babies, regardless of gender, who were born before reaching week 32 were more than three times more likely to have a mental health disorder at the age of sixteen than other babies. Those children were also at a much higher risk to be hospitalized for their psychiatric condition at one point as well. The risk for developing psychosis was nearly two and a half times higher and severe depression risk was slightly higher at three times more than for full term babies. The highest risk though, came for bipolar depression at a risk that was just over seven times higher for preemies than for the full term babies.

The study found that there was a smaller but still significant risk for babies that were born between thirty two and thirty six weeks of gestation. The average pregnancy lasts roughly thirty nine to forty weeks, with a baby born before thirty six weeks being described as premature. In recent years, babies born earlier and earlier in gestation are not only surviving but thriving.

According to a report co-published by Save the Children, the March of Dimes and the World Health Organization. there are more than fifteen million premature babies born in the world every year, accounting for one in every ten live births. Just over one million of those babies will die before reaching one year of age and those who survive for longer may have a number of long term disabilities to deal with. Prematurity is the leading cause of death for newborns and the second leading cause of death for children under the age of five. In the US, prematurity accounts for nearly twelve percent of all live births, equal to the numbers in Thailand, Turkey and Somalia. The rate for Japan and Sweden is nearly half that figure at 5.9 %