Behavioral Health Gives Clues to Risk of Preterm Birth

Pregnant women with post-traumatic stress disorder and a major depressive episode have a 4-fold increased risk of preterm delivery, according to a study published online in JAMA Psychiatry.

Post-traumatic stress disorder (PTSD) occurs in about 8% of pregnant women. Stress-related conditions, including PTSD, have been linked to preterm birth, although evidence to support this link has been inconsistent, the study authors explained. In addition, medications to treat PTSD and depression have also been linked with preterm birth. Considering this, the study authors began to wonder: If there is an independent association with preterm birth, is it the condition itself or its treatment?

Pertinent Points

- Women with both PTSD and a major depressive episode are four times more likely to give birth prior to 37 weeks’ gestation.

- The risk of preterm labor when both disorders are present is independent of antidepressant or benzodiazepine use, the authors found.

The authors recruited 2,654 pregnant women prior to 17 weeks’ gestation and looked for a likely diagnosis of PTSD, major depressive episode, and the use of antidepressant or anxiolytic medications. The women were recruited from any of 137 obstetrical practices in Connecticut and Western Massachusetts.

While PTSD and a major depressive episode were associated with preterm birth, which was defined as births occurring before 37 weeks’ gestation, the authors found that the risk appeared to be independent of antidepressant and benzodiazepine use. In addition, the authors found that while women using serotonin reuptake inhibitors (SRIs) or a benzo were also at increased risk for preterm birth, the risk was less than that of those with both PTSD and a major depressive episode.

The odds ratio of preterm birth was 1.55 [95% CI, 1.02-2.36] for women who used an SRI and 1.99 [95% CI, 0.98-4.03] for those taking a benzo. However, the odds ratio for women with PTSD and a major depressive episode was 4.08 (95% CI, 1.27-13.15).

Of the women included in the study, just 129 (4.9%) had symptoms consistent with PTSD, which is below the estimated average of 8% of pregnant women with PTSD. The authors also found that each 1-point increase on the Modified PTSD Symptom Scale measuring PTSD symptoms increased the risk of preterm birth by 1% to 2%, meaning those with the most severe cases were at even greater risk for preterm delivery.

The authors, led by Kimberly Ann Yonkers, MD, of the Yale School of Medicine, New Haven, Ct, suggested that further research is needed to explore the biological and genetic factors that could help identify the pathways leading to the increased risk, as well as risk-stratify patients.

Although the odds of risk of preterm birth are high for women who take an SRI or a benzo, the odds of risk of preterm birth are even higher for women with PTSD and a major depressive episode. The data reveal that this risk is independent of antidepressant and benzo use and not simply a function of mood or anxiety symptoms, the authors concluded.