(Reuters Health) - Women who experience sleep disorders like insomnia and apnea during pregnancy may be more likely to deliver premature babies than pregnant women who don’t have trouble sleeping, a U.S. study suggests.

Compared with women who didn’t have sleep problems, women with insomnia were 30 percent more likely to have a preemie and the odds for women with sleep apnea, a breathing disorder, were 50 percent higher, the study found.

“It is normal to experience sleep changes during pregnancy - often due to discomfort, pain or frequent trips to the bathroom,” said lead study author Jennifer Felder, of the University of California, San Francisco.

“The current study focused on more impairing sleep problems that were severe enough to result in a sleep disorder diagnosis,” Felder said by email.

Apnea, a potentially serious sleep disorder that involves repeated stops and starts in breathing, has been linked to high blood pressure during pregnancy, which is an independent risk factor for preterm births. Obesity and advanced age can make apnea more likely.

Even though many pregnant women have insomnia at some point, previous studies haven’t offered a clear picture of how this type of sleep deprivation influences the odds of preterm births.

Worldwide, preterm birth is the leading cause of death for children under 5 years old, the researchers note in the journal Obstetrics and Gynecology.

Pregnancy normally lasts about 40 weeks, and babies born after 37 weeks are considered full term. The new study focused on preterm infants, delivered at 34 to 36 weeks’ gestation, and extremely premature babies delivered before 34 weeks.

In the weeks immediately after birth, preemies often have difficulty breathing and digesting food. They can also encounter longer-term challenges such as impaired vision, hearing, and cognitive skills as well as social and behavioral problems.

The study team examined data on more than 3 million births in California from 2007 to 2012. They focused on 2,172 women who had a sleep disorder diagnosis and compared their birth outcomes to a randomly selected group of 2,172 mothers who were similar in many ways but had no sleep issues.

Women with sleep disorders were more likely to be black, age 35 or older, obese, and to have other medical issues like high blood pressure, diabetes and infections as well as higher odds of smoking or using drugs and alcohol while pregnant. They were also more likely to have a history of preterm birth.

Overall, almost 15 percent of women with sleep disorders had a preterm birth, compared with 11 percent of women without sleep issues.

The study wasn’t a controlled experiment designed to prove how or even whether sleep disorders directly cause preterm births.

Even so, the results offer fresh evidence of the link between sleep disorders and early arrivals, said Dr. Ghada Bourjeily, a researcher at Warren Alpert Medical School of Brown University in Providence, Rhode Island, who wasn’t involved in the study.

“Sleep appears to get worse in pregnancy in many, even women who do not have a preexisting sleep disorder,” Bourjeily said by email. “Unfortunately, we do not know yet whether improving sleep quality before or during pregnancy would prevent development of negative outcomes such as preterm birth.”

Starting pregnancy at a healthy weight, however, may make sleep disorders less likely, said Dr. Amos Grunebaum, director of obstetrics at NewYork-Presbyterian Hospital/Weill Cornell Medical Center in New York.

“Being overweight or obese increases your risk of having a sleep disorder,” Grunebaum, who wasn’t involved in the study, said by email. “It also increases pregnancy complications.”

When sleep disorders do surface during pregnancy, women should discuss symptoms in detail with their doctors, said Dr. Milena Pavlova, a researcher at Brigham and Women’s Hospital in Boston who wasn’t involved in the study. This includes any issues with breathing, gasping or choking at night or any uncomfortable leg or body sensations that prevent sleep.

Expectant mothers should also make sleep a priority in their schedules, Pavlova, who wasn’t involved in the study, said by email.

“Allow enough time for sleep - the life you save may be your baby’s,” Pavlova said.

SOURCE: bit.ly/2j2fR06 Obstetrics and Gynecology, online August 8, 2017.