Nicola M. Parry, DVM
August 08, 2017
Pregnant women who are diagnosed with sleep disorders are more likely to have a preterm birth than those without sleep disorders, researchers report in a study published online today in Obstetrics & Gynecology.
"Women with an insomnia diagnosis had nearly twofold higher risk for an early preterm birth (less than 34 weeks of gestation) compared with women without a recorded sleep disorder diagnosis," write Jennifer N. Felder, PhD, from the University of California, San Francisco, and colleagues. "The importance of these findings may be considerable given studies showing that more than 50% of pregnant women experience clinically significant insomnia."
According to the authors, recent data highlight a rising trend in preterm birth rates in the United States; preterm birth is the world's number one killer of young children.
Although multiple factors play a role in the etiology of preterm birth, previous studies have suggested disturbed sleep may be a novel risk factor for preterm birth.
Dr Felder and colleagues therefore conducted a retrospective study of women with singleton live births between 20 and 44 weeks of gestation without chromosomal abnormalities or major structural birth defects.
They used a case-control study design in which 2172 women with a diagnostic code for a sleep disorder during pregnancy were matched to 2172 women without a sleep disorder diagnosis, but with similar maternal risk factors for preterm birth, such as a previous preterm birth, diabetes, or hypertension.
Among the women with a sleep disorder diagnosis, more than 30% had insomnia, and 56.9% had sleep apnea. Sleep-related movement disorders (7.5%) and other sleep disorders (5.4%) were less common.
Overall, 14.6% of the women with a sleep disorder diagnosis delivered before 37 weeks of gestation compared with 10.9% of those without such a diagnosis (odds ratio, [OR] 1.4; 95% confidence interval [CI], 1.2 - 1.7).
This seemed to be associated with preterm prelabor rupture of the membranes and spontaneous preterm birth, the authors note.
Compared with women without a sleep disorder, those with a sleep disorder diagnosis had a greater incidence of preterm prelabor rupture of the membranes (at <34 weeks of gestation, 0.6% vs 1.7%; at 34 - 36 weeks of gestation, 1.4% vs 2%), spontaneous (at <34 weeks of gestation, 1.6% vs 2.7%; at 34 - 36 weeks of gestation, 4.4% vs 4.7%), and indicated (at <34 weeks of gestation, 0.6% vs 0.9%; at 34 - 36 weeks of gestation, 1.8% vs 2.4%) preterm birth.
When analyzed by individual diagnoses, the odds of preterm birth before 37 weeks of gestation was 1.3 (95% CI, 1.0 - 1.7; 14.1%; P = .023) for women with insomnia and 1.5 (95% CI, 1.2 - 1.8; 15.5%; P < .001) for those with sleep apnea. The rate of preterm birth before 37 weeks was 10.9% among those without a sleep disorder diagnosis.
The odds of early preterm birth before 34 weeks was also more than double for women with sleep apnea (OR, 2.2; 95% CI, 1.5 - 3.1), and almost double for those with insomnia (OR, 1.7; 95% CI, 1.1 - 2.6).
However, the odds of preterm birth were not significantly greater for women with sleep-related movement disorders or other sleep disorders.
In contrast, sleep-related movement disorders (OR, 3.9; 95% CI, 1.3 - 11.9) and other sleep disorders (OR, 4.0; 95% CI, 1.1 - 14.2) were associated with increased risk for preterm prelabor rupture of the membranes at less than 34 weeks of gestation.
Overall, the results of this study reinforce those of previous studies that have suggested a link between sleep apnea and preterm birth, the authors say.
Although the results of this study reveal an association between sleep disorders during pregnancy and preterm birth, the authors stress that "[m]ore work is urgently needed to test whether this is a causal relationship, identify biological mechanisms, and test the efficacy of interventions for sleep disorders during pregnancy and the effect on preterm birth."
The study was supported by the California Preterm Birth Initiative at the University of California, San Francisco, funded by Marc and Lynne Benioff. One author has reported being a paid consultant for Posit Science on an unrelated project. The remaining authors have reported no financial conflicts of interest.