Depression and PTSD together dramatically increase risk of premature birth

Pregnant women who suffer from both post traumatic stress disorder and major depression are four times more likely to deliver prematurely than women without those conditions, a new Yale University School of Medicine study shows.

The combination of PTSD and a major depressive episodes rank as high as a prior preterm birth as risk factors for early delivery, study authors report in the 11 June issue of the journal JAMA Psychiatry.

''These really should be considered high-risk pregnancies,'' said Kimberly Yonkers, professor of psychiatry and of obstetrics, gynecology, and reproductive sciences and lead author of the study.

Yonkers and the late Kathleen Belanger of Yale had studied effects of depression and antidepressant use on pregnancy but at the advice of clinicians decided to analyse the impact of PTSD as well.

Among 2654 women in the study, they found little increased risk of premature birth (before 37 completed weeks of pregnancy) in women suffering from depression alone.

Initially PTSD appeared to be a potent risk factor, but they found risk was only elevated for those individuals who had both PTSD and depression.  All analyses controlled for use of harmful substances and for antidepressants.   

Previous studies by Yonkers and Belanger had found an increased risk of late term premature birth - after 34 weeks but prior to 37 weeks gestation - in women taking antidepressants.

The research was funded by the National Institute for Child Health and Human Development.