There are many differences between men and women in regards to physiology, and nowhere is this more apparent than in pregnancy.  Pregnancy results in physiologic and anatomic changes in women which can promote sleep disordered breathing (SDB).  The most common sleep disordered breathing is obstructive sleep apnea (OSA).  The changes in pregnant women that tend to promote OSA include: weight gain and edema of the upper airway.  Frequent snoring is a common symptom in OSA and can be found in 15-25% of pregnant women.  The consequences of OSA can lead to hypertension, in a form known as preeclampsia and gestational diabetes.  In a large clinical trial of over 3700 pregnant women, it was found that some type of sleep disordered breathing was present in up to 8% with preeclampsia being present in 6%.  The importance of this data rests in the fact that SDB, and OSA in particular, is a modifiable condition. 

The unfortunate problem at this time is that there is no good data on how the use of continuous positive airway pressure (CPAP) during pregnancy reduces the risk of preeclampsia and gestational diabetes and, moreover, how well this therapy would be accepted by pregnant women. At this point in time the recommendations are that women who are using CPAP and get pregnant should continue to use it.  Obstetricians who have patients reporting significant sleep disordered breathing should refer them to a sleep center and a sleep specialist.