A new study in the November issue of the journal SLEEP linked poor sleep in early and late pregnancy with an increased risk of preterm birth.

Researchers found that women who reported sleep disruptions during the first and third trimesters faced significant risks of delivering prematurely. Even after income levels and medical risks were factored in, the connection still remained. There was no association between quality of sleep in the second trimester and preterm births. Sleep appears to improve in the second trimester but there is no clear reason why.

The study’s authors suggested that inflammation may be the culprit. Growing evidence points to inflammation having a role in triggering the childbirth process early. Sleep disturbances are associated with exaggerated inflammatory responses. The authors also said a combination of sleep disruption and stress could lead to premature delivery.

The good news is that sleep disorders during pregnancy are easily diagnosed. An assessment of a woman’s sleep quality may help identify risk earlier, giving doctors time to step in. If sleep disruptions are occurring, they could be reduced through behavioral modification.