Insomnia, sleep apnea, and other sleep disorders may be linked to preterm birth, according to new research. A large study of more than 4,000 pregnant women — half of whom had been diagnosed with severe sleep disorders — found that new mothers with these conditions were twice as likely to deliver preterm. Given the dangers of preterm birth, the findings could help physicians identify and provide interventions for women at high risk of delivering early.
“Strangely, this study has not been done before,” coauthor on the study Laura Jelliffe-Pawlowski of the University of California, San Francisco told Nature. “Seeing this relationship is important because we are just starved for interventions that can make a difference.”
Preterm birth — when a baby is born before 36 weeks (full gestation is 40) — is the number one cause of death for children under the age of five. Babies born before 34 weeks can suffer from respiratory, digestive, and neurological problems. Naturally, any risk factor for preterm birth is cause for concern, so the notion that poor sleep is linked to early delivery raises eyebrows.
At the same time, almost every pregnant woman gets at least a little less sleep as a tiny human grows inside her and fidgets on top of her bladder. Jelliffe-Pawlowski and colleagues controlled for that by focusing solely on sleep changes that rise to clinical significance — diagnosed, severe sleep disorders like insomnia and sleep apnea. “It is normal to experience sleep changes during pregnancy, often due to discomfort, pain or frequent trips to the bathroom,” coauthor Jennifer Felder, also of UCSF, told Reuters. “The current study focused on more impairing sleep problems that were severe enough to result in a sleep disorder diagnosis.”
For the study, the researchers examined data on more than three million births in California and discovered a large sample of 2,172 women who had sleep disorder diagnosis during pregnancy. They then compared those birth outcomes with 2,172 women who had many of the same risk factors for preterm birth (smoking during pregnancy, high blood pressure) but no diagnosed sleep disorders. Fifteen percent of the women with sleep disorders delivered before 36 weeks. Only 11 percent of women without sleep problems delivered preterm.
For some healthcare providers, the findings are a red flag. “I counsel women on how to have the best pregnancy outcome,” Louis Muglia of the Center for Prevention of Preterm Birth at Cincinnati Children’s Hospital Medical Center in Ohio (who was not involved in the study) told Nature. “Now I might start asking, ‘Do you get a good night’s sleep?’.” But since the findings are preliminary, others are more cautious about drawing clinical conclusions. “Unfortunately, we do not know yet whether improving sleep quality before or during pregnancy would prevent the development of negative outcomes such as preterm birth,” Ghada Bourjeily of Warren Alpert Medical School of Brown University (who was not involved in the study) told Reuters.
Regardless, the study authors stress that pregnant women who are having trouble sleeping should not assume sleep is just a casualty of carrying a child, and fail to inform their doctors. “More severe sleep disorders are often under-diagnosed, because poor sleep is common during pregnancy,” Felder told The New York Times. “But for women having sleep problems that are severe, impairing and distressing, it’s important to talk to their health care providers.”