SCOTTSDALE, ARIZ. – Even mild sleep disorders have the potential to affect fetal outcomes during pregnancy, Dr. Susan M. Harding advised at a meeting on sleep medicine sponsored by the American College of Chest Physicians.
Recent research suggests that obstructive sleep apnea might impact hypertension in pregnant women with preeclampsia, according to Dr. Harding, professor of medicine at the University of Alabama, Birmingham, and medical director of the Sleep/Wake Disorders Center there.
Other studies cited by Dr. Harding show a higher risk of lower-birth-weight babies in women who work night shifts, and increases in labor duration and in cesarean section rates when women sleep poorly.
Potential relationships between sleep and pregnancy are “a really ripe area” in need of more research, she noted.
Dr. Harding cited a Swedish study of 502 singleton pregnancies that diagnosed hypertension in 14% of 113 snorers but in only 6% of 389 nonsnorers (Chest 2000;117:137–41). Preeclampsia also was significantly more prevalent, occurring in 10% of snorers vs. 4% of women who did not snore.
The investigators concluded that habitual snoring is an independent predictor of hypertension (odds ratio 2.03) and growth retardation (OR 3.45). Dr. Harding noted that snorers' babies were significantly more likely to have Apgar scores of 7 or lower at 1 minute after birth (12.4% vs. 3.6%) and to be small for gestational age (7.1% vs. 2.6%). Only 4% of women snored before becoming pregnant, whereas 23% snored during their final week of pregnancy.
Another study cited by Dr. Harding delivered continuous positive airways pressure (CPAP) to 11 pregnant women with severe preeclampsia and findings of upper airway resistance syndrome (Am. J. Respir. Crit. Care Med. 2000;162:252–7). CPAP reduced blood pressure in these women.
The shift-work study reviewed 41,150 pregnancies in a Danish database (Am. J. Obstet. Gynecol. 2004;191:285–91). Dr. Harding said women on permanent night shifts had a higher risk of post-term birth (OR 1.35) and delivering a low-birth-weight baby at term (OR 1.80).
She also cited an American study of 131 women in their ninth month of pregnancy (Am. J. Obstet. Gynecol. 2004;191:2041–6). Women who slept fewer than 6 hours each night had longer durations of labor (29 hours vs. 18 hours) and a higher cesarean rate (37% vs. 11%), compared with those who slept more hours. Longer labors and higher cesarean rates also were linked with disrupted sleep.
Although these studies are not conclusive, Dr. Harding said the evidence so far is sufficiently strong that physicians should consider screening pregnant women for obstructive sleep apnea, especially when hypertension is an issue. She noted that CPAP requirements of women treated for obstructive sleep apnea could change during pregnancy and need to be monitored.
Treating two other sleep disorders–restless leg syndrome (RLS) and narcolepsy–is problematic because modafinil and medications used in treating these disorders are contraindicated during pregnancy, according to Dr. Harding. Pregnancy is a risk factor for development of RLS. Up to a third of pregnant women will have RLS symptoms, she said, most often during the last trimester. Symptoms usually resolve within 10 days of giving birth.
Dr. Harding recommended educating women being treated for RLS or other sleep disorders about the need to discontinue modafinil, stimulants, and other medications prior to becoming pregnant. She called on physicians to assess risks, such as patients' driving when drowsy, if drug therapies are stopped. “Off medication, they may have significant problems,” she said.
To prevent RLS during pregnancy, she suggested that all women take folate supplements. Also, about 30% of women are iron deficient at the outset of their pregnancies, she said; third-trimester RLS has been linked to low serum folate and ferritin levels.
Consider testing pregnant women for obstructive sleep apnea, especially when hypertension is an issue. DR. HARDING