(RxWiki News) Any woman who has been pregnant can tell you that getting enough sleep becomes more challenging as her unborn baby grows. If a pregnant woman has other conditions, the challenge can be even greater.
A recent small study found that having gestational diabetes also increased a pregnant woman's odds of having obstructive sleep apnea.
Gestational diabetes means having the symptoms of diabetes only while pregnant. Obstructive sleep apnea has to do with difficulty breathing while asleep.
The researchers found that women in their second to third trimester of pregnancy experienced more disturbed sleep in general than non-pregnant women.
"Discuss sleep troubles with your OB/GYN."
This study, led by Sirimon Reutrakul, MD, of Rush University Medical Center in Chicago, aimed to understand how pregnancy, obstructive sleep apnea and gestational diabetes might be connected.
The researchers compared sleep studies for 45 women, divided into three groups that were similar in age and race/ethnicity.
One group of 15 women were not pregnant and did not have diabetes. Another group of 15 were pregnant but had normal glucose tolerance levels (did not have diabetes).
The last group of 15 women were pregnant and had gestational diabetes. Gestational diabetes is a condition in which the body does not use insulin properly to process sugars in the body, but it exists during pregnancy specifically.
All the pregnant women in the study were in their late second trimester or early third trimester.
The researchers compared the sleep study results among the women in terms of the apnea-hypopnea index (AHI). This index measures how many times patients stop breathing or slow their breathing considerably while asleep.
The score a person receives represents the number of times they stop breathing for at least 10 seconds or have a drop in the saturation of blood oxygen of at least 4 percent for at least 10 seconds during one hour of sleep.
A score of 5 to 15 means the person has mild obstructive sleep apnea while a score of 15 to 30 is moderate and over 30 is severe.
The pregnant women without gestational diabetes had a slightly higher AHI (an average of 2) than the non-pregnant women (an average of 0.5).
The pregnant women without diabetes also had more disrupted sleep than the non-pregnant women. The non-pregnant women only spent 21 minutes awake after having gone to sleep, compared to 66 minutes for the pregnant women.
When the researchers compared only the pregnant women, however, those with gestational diabetes had much higher AHI and less total sleep time.
The AHI for pregnant women with gestational diabetes was about 8.2, and they only slept about 6.6 hours, compared to 7.7 hours for the pregnant women without diabetes.
Obstructive sleep apnea was also more common among the pregnant women with gestational diabetes. A total of 73 percent of the women with gestational diabetes had obstructive sleep apnea, compared to 27 percent of the pregnant women without diabetes.
Being overweight can increase the risk for both gestational diabetes and obstructive sleep apnea.
Even after making adjustments to account for the women's weight before becoming pregnant, having gestational diabetes meant the odds of having sleep apnea were more than six times higher for pregnant women than if they didn't have gestational diabetes.
The researchers concluded that pregnancy in general is linked to disrupted sleep but that women with gestational diabetes may be at higher risk for sleep disturbances and for obstructive sleep apnea than other pregnant women.
William Kohler, MD, director of the Florida Sleep Institute in Spring Hill, Florida, said this conclusion matches up with both his clinical experience and what is understood about sleep apnea, diabetes and pregnancy.
But it is unclear which condition contributes to which other one because they are so interrelated.
"It's hard to say what's the cart and what's the horse," Dr. Kohler said. "People with obstructive sleep apnea have problems with glucose intolerance, so it's well known that patients with obstructive sleep apnea have an increased potential for diabetes."
He noted the very small number of patients in the study but that it still emphasizes the need to evaluate women for possible sleep apnea during pregnancy.
"Sleep problems are very common during pregnancy, and there are increased problems with sleep apnea during pregnancy," Dr. Kohler said. "Sleep apnea also already increases the likelihood of preeclampsia occurring, so that's another reason during pregnancy to check for possible sleep apnea."
This study was published August 20 in the Journal of Clinical Endocrinology & Metabolism.
The research was funded by the ResMed Foundation, the Diabetes Research Training Center at the University of Chicago, a specialized Center of Research on Women's Health Grant, the National Institute of Aging, the Blum-Kovler Family Foundation and a grant from the National Institutes of Health.
One author has received grants from Philips/Respironics, the ResMed Foundation and Amylin/Lilly and has consulted for Pfizer and Viropharma. He has also served as an expert witness for a law firm and is an associate editor of the journal Sleep.
Another author has received research funding from the ResMed Foundation and the Kovler Family Foundation. No other potential conflicts of interest were noted.