Sleep disorders during pregnancy up risk of preterm delivery
Pregnant women with insomnia or sleep apnoea appear to be at higher risk of preterm birth, according to an observational study.
“Although sleep disturbances are common during pregnancy, some women experience clinical [sleep] disorders with serious implications,” the authors said, adding that their findings highlight the importance of screening for severe presentations of insomnia and sleep apnoea during pregnancy.
The study population comprised 2,265 women with singleton neonates liveborn between 20 and 44 weeks of gestation and who had a recorded sleep disorder diagnosis. None had chromosomal abnormalities or major structural birth defects and mental illness during pregnancy. Propensity score matching at 1:1 ratio was performed to establish a referent population of women without a sleep disorder diagnosis (n=2,172).
Compared with the referent group, significantly more women in the sleep disorder group delivered before 37 weeks of gestation (10.9 vs 14.6 percent; odds ratio [OR], 1.4; 95 percent CI, 1.2 to 1.7; p<0.001). [Obstet Gynecol 2017;doi:10.1097/AOG.0000000000002132]
In particular, insomnia and sleep apnoea during pregnancy were respectively associated with a 1.3- (1.0 to 1.7; p=0.023) and 1.5-fold (1.2 to 1.8; p<0.001) higher risk of preterm delivery. This increased risk was not observed for sleep-related movement disorders or other sleep disorders.
The authors noted that the risk of preterm birth differed by gestational age and preterm birth type. For example, women with a recorded insomnia diagnosis were nearly twice as likely as those without a sleep disorder diagnosis to deliver before 34 weeks of gestation (OR, 1.7; 1.1 to 2.6), and the highest risk was seen for preterm prelabour rupture of the membranes at <34 weeks of gestation (OR, 4.1; 2.0 to 8.3).
Although the exact pathways by which sleep disorders increase risk of preterm birth are unknown, inflammation and high levels of inflammatory cytokines in amniotic fluid have been implicated in the said association. [Obstet Gynecol Surv 2009;64:273–80; Psychosom Med 2013;75:670–81; Obstet Gynecol 2010;116:393–401]
Notwithstanding the presence of limitations, the study addresses a critical gap in literature by examining insomnia diagnosis, the authors said. The present data may be of considerable significance in light of previous studies reporting that >50 percent of pregnant women experience clinically significant insomnia. [Behav Sleep Med 2012;10:152–66]
“More work is urgently needed to test whether this is a causal relationship, identify biological mechanisms, and [evaluate] the efficacy of interventions for sleep disorders during pregnancy and the effect on preterm birth,” they added.