April 26th, 2011
01:31 PM ET
Lisa Shives, M.D., is the founder of Northshore Sleep Medicine in Evanston, Illinois. She blogs on Tuesdays on The Chart. Read more from her at Dr. Lisa Shives’ Sleep Better Blog.
It is common for women to feel extreme sleepiness and fatigue in the first trimester, which is assumed to be secondary to rising progesterone levels because progesterone is known to have a hypnotic affect. Progesterone levels continue to rise throughout pregnancy yet in the second trimester most women report feeling more daytime alertness and they feel that their sleep quality is improved compared with the first trimester.
The third trimester ushers in a host of problems that are mostly connected to the increased girth. During the later months, women often experience shortness of breath and reflux because their diaphragm is elevated, pressing on the lungs and the stomach. They also have to urinate frequently during the night. That alone is quite a disruption to sleep.
These are normal problems encountered during pregnancy and there is not a lot a doctor can do about it. However, there are other sleep problems that represent the emergence of a bona fide sleep disorder and these can be treated.
There are many factors that increase the likelihood of sleep apnea in pregnant women. It is not all mediated by weight gain, although pre-gestational obesity significantly increases the risk of OSA with one study showing that nearly 40% of obese pregnant patients developed OSA by the third trimester.
The hormonal changes of pregnancy create the perfect set up for OSA. While progesterone increases swelling in the throat tissues, estrogen causes relaxation of the blood vessels, which leads to further swelling. There is even a hormone that is released only during pregnancy that is called relaxin, and, as the name denotes, it causes muscle relaxation.
Untreated sleep apnea during pregnancy has been associated with increased risk of high blood pressure, pre-eclampsia, as well as low birth weight in the infants and low APGAR scores at birth. One interesting study found that fetal movement in women who had OSA was decreased by 50% during non-REM sleep and by 65% while in REM sleep. Fetal movements increased significantly when women’s breathing was normalized with a continuous positive airway pressure machine, known commonly as CPAP.
There are some studies suggesting that untreated OSA in the mother puts the child at future risk for cardiovascular and metabolic. Much more research needs to be done on the prevalence of OSA in pregnant women and on the health consequences it poses to them and their unborn children.
For now, I urge women with risks factors for gestational OSA to have an overnight sleep test. To summarize, the risk factors include: pregestational obesity, excessive weight gain during the pregnancy, large neck, small throat, snoring, daytime sleepiness or fatigue, high blood pressure, development of pre-eclampsia.
OSA is one of the few medical disorders that if we diagnose it in pregnant women, we actually have treatments that are safe for her and her baby. The two main therapies, CPAP and the oral appliance, are both non-pharmacologic (they're not drugs) and perfectly safe in pregnancy. Because gestational OSA often resolves after the birth of the child, most women would probably not want to spend thousands of dollars on the oral appliance.
The CPAP, which is the gold standard therapy and which should be the first line therapy for anyone who is severe, is probably the best treatment for OSA in pregnancy. The therapy can get started immediately after the sleep test is interpreted and it can be billed through insurance as a rental and the machine can be returned if the woman’s OSA resolves after delivery.
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