Poor sleep quality in first, third trimesters linked to preterm births

Poor sleep quality in both early and late pregnancy has been linked to an increased risk of delivering preterm.

A study published in the Nov. 1 issue of the journal Sleep shows a significant risk for preterm birth in women reporting sleep disruptions during their first and third trimesters. The connection remained even after medical risk factors and income levels were taken into account.

"This supports the growing evidence that poor sleep is an important risk factor for preterm birth," said Michele Okun, PhD, assistant professor of psychiatry and psychology at the University of Pittsburgh School of Medicine.

"It likely occurs in the presence of other risk factors, but sleep can be measured easily and quickly during prenatal visits. Simply by assessing a woman's sleep quality, we may be able to identify a risk early in the pregnancy, when there is time to intervene. The data suggest that beneficial outcomes may be possible through modifications in behavior," Okun said.

Sleep quality in the second trimester did not correlate with increased risk. Okun said sleep often improves modestly during this part of pregnancy, although it is unclear why. One explanation might be hormones or other biological pathways playing a role, but there is no data.

Similarly, Okun and her co-authors suggest a biological cause for the increase in preterm births with disrupted sleep. Poor sleep quality has been shown to initiate inflammation, possibly activating the processes associated with childbirth prematurely. Sleep disruption also might do this in combination with stress, a known activator of inflammation.

Okun said more research is needed, but the early results are encouraging – and important.

"The need to reduce adverse pregnancy outcomes remains high," she said. "Despite our advanced society and medical knowledge, we still find a growing number of women having a preterm baby or other adverse outcome."