pregnant woman sleeping
RESEARCH FEATURE

Pregnant women with sleep problems could face a lifetime of cardiovascular woes


Poor sleep may seem like a normal fallout of pregnancy, but research shows it can be a pernicious problem, with long-term ill effects on a woman’s cardiovascular health.

Pregnant women who suffer from sleep-disordered breathing, particularly sleep apnea, are at higher risk for both gestational diabetes and hypertensive disorders of pregnancy, the leading cause of maternal illness and death worldwide. For many, the negative cardiovascular effects may linger for decades, sometimes a lifetime.   

Pregnant woman sleeping peacefully
Poor sleep may seem like a normal fallout of pregnancy, but research shows it can have long-term ill effects on a woman’s cardiovascular health.
CREDIT: Ruslan Dashinsky, istockphoto

Yet, pregnant women often are told, even from their doctors, not to get too hot and bothered about poor sleep. Of course, you can’t sleep well—you’re uncomfortable. It’s just nature prepping you for when your baby arrives.

Francesca Facco, M.D., assistant professor at the University of Pittsburgh Medical Center thinks that while those doctors may seem dismissive, the truth is they don’t have the proven, evidence-based tools to change their medical practice, and offer different advice to their patients. 

“It is one thing to say that poor sleep is a risk factor for adverse pregnancy outcomes,” Facco said. “But to change clinical practice, doctors need the tools to help these women—and also the data that prove those tools will be effective at modifying risk factors and improving pregnancy outcomes.”

The sleep sub-studies of the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (NuMoM2B), funded by the National Heart, Lung, Blood Institute (NHLBI), in partnership with the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), aim to provide this data. 

Launched in 2010, the NuMoM2B is a prospective cohort study of a racially, ethnically, and geographically diverse population of 10,000 pregnant women who will be delivering for the first time.  The researchers believe that by looking at pregnancy, they can learn about women’s cardiovascular health over a lifetime.

The study evaluates the underlying and interrelated causes of several common complications of pregnancy, such as preterm birth, preeclampsia, and fetal growth restriction—all of which can show up unpredictably in women who have  no pregnancy history. Part of their focus is on the role sleep may be playing—and the treatments that might help.

“During pregnancy, short sleep duration, altered sleep timing, and irregular breathing during sleep are associated with higher risks of gestational diabetes, high blood pressure, preeclampsia, and preterm birth,” Facco, part of a team evaluating the role of sleep health in pregnancy, explained. “We are trying to tease out if these associations are causal or if there are other factors at play influencing the outcomes. And, of course, the burning question is, ‘Are these risks modifiable?’”

People who suffer from sleep apnea have irregular respiratory patterns or stop breathing momentarily while asleep, causing their airways to repeatedly close, completely or partially.

Approximately 18 million U.S. adults suffer from obstructive sleep apnea, which occurs in up to 15% of women of reproductive age, and it is estimated 93% of these women remain undiagnosed.

Findings from the NuMoM2B Sleep-Disordered Breathing study show that sleep-disordered breathing, mainly obstructive sleep apnea, occurs in 3-8% of pregnant women. And the risk increases for women with a body mass index (BMI) of 30 or higher, usually considered obese. In fact, pregnancy itself puts women at risk of developing sleep apnea, and it tends to worsen the condition in those who already have it.

One of the main reasons, researchers believe, is excessive weight gain, which can lead to obesity—a known risk factor for sleep apnea. “The risks for developing sleep apnea during pregnancy appear to be most strongly associated with changes in weight and, possibly, fluid retention, which result in a narrowing of the upper airway,” said Susan Redline, M.D.,M.P.H., senior physician in the Division of Sleep and Circadian Disorders at Brigham and Women’s Hospital and Farrell Professor of Sleep Medicine at Harvard Medical School.

And this is where things get complicated. Only about 15-20% of women with obesity issues have sleep apnea in early pregnancy, Facco said. “And since studies have shown that women with higher BMIs are at increased risk of pregnancy complications, the question becomes: ‘Are the bad pregnancy outcomes driven by the obesity or by the sleep apnea?’”

It’s an important question, because the answer could help guide targeted treatment options for pregnant women with sleep conditions—something Redline, director of the Sleep Reading Center for the NuMoM2B study, and her colleagues called for after their 2014 research linked obstructive sleep apnea to severe maternal morbidity, cardiovascular morbidity, and in-hospital death.

An important consideration, Facco said, is that “obesity is very hard to modify in pregnancy. That’s not the case for sleep apnea. Continuous positive airway pressure is an effective therapy, if used regularly during sleep.”

Continuous Positive Airway Pressure (CPAP) is a treatment that uses mild air pressure to keep the airways open during sleep. Two clinical trials, co-funded by NHLBI and NICHD, are looking into the effects of this therapy during pregnancy.

Facco is the lead investigator for the Sleep Disordered Breathing, Obesity and Pregnancy Study (SOAP), which is still recruiting, and seeks to better understand how sleep apnea may affect pregnancy, as well as determine the effects of CPAP in pregnant women with sleep apnea.

The second one, the Continuous Positive Airway Pressure (CPAP) for Sleep Apnea in Pregnancy (SLEEP), also still recruiting, is assessing whether treating pregnant women with obstructive sleep apnea with CPAP reduces the rate of hypertensive disorders of pregnancy.

Since researchers already know there is a link between obesity, sleep apnea, and adverse pregnancy outcomes, the essential question now, according to Facco, is how many bad outcomes can be prevented by treating sleep apnea in the pregnant women who have it.

“Without an intervention study in which you women take at risk, test them for sleep apnea, and then study the effects of therapy on pregnancy outcomes, you are not really going to be able to answer that question,” Facco concluded.

For her part, Redline argues that women and their doctors can and should take action now. Trying to meet optimal weight gain goals, for example, might prevent sleep- disordered breathing during pregnancy, she said. 

“Since sleep-disordered breathing may be worse when lying on your back, women can discuss with their doctors the best position to sleep in,” Redline said. “Women also should try to follow regular sleep (wake up and bed) times, get at least seven to eight hours of sleep per night, and discuss new or worsening snoring, daytime sleepiness, or disrupted sleep with their health care providers.”

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