Risk sleep apnea presents to women during pregnancy highlighted

Toronto – While sleep apnea is recognized as a potentially serious disorder in the general population, attention is only just beginning to focus on the risks it presents to women during pregnancy. Obstructive sleep apnea (OSA) is characterized by pauses in breathing during sleep which causes intermittent blood oxygen desaturation and repeated awakenings. Recent studies suggest that pregnant women with untreated OSA have a significantly higher risk of developing gestational hypertension, preeclampsia, or eclampsia as well as increased blood sugar and issues around that. There are also strong associations with low birthweight infants, intrauterine growth restriction and greater neonatal intensive care unit admission. High blood sugar during pregnancy “can lead to complications such as large fetal size, delivery complications, risk for requiring Cesarean-section,” said Dr. Sushmita Pamidi, an associate professor of medicine at McGill University. She gave an overview of sleep apnea in pregnancy at the recent annual virtual conference of the Canadian Thoracic Society. OSA is problematic for the fetus as well because these issues put them at greater risk for developing metabolic complications later in life, she told the Medical Post in an interview. “In the long run they can develop diabetes or cardiovascular risks from the gestational diabetes exposure,” she said. Dr. Pamidi noted a 2017 population study by researchers in Australia which found that of all children who were hospitalized between their first and sixth birthdays, 35% who had been exposed to maternal OSA were admitted for pediatric sleep apnea compared to only 18% of those whose mothers did not have apnea during pregnancy. The study included 626,188 singleton infants born between 2002 to 2012, and of these 209 were exposed to maternal sleep apnea Research suggests OSA can cause increases in blood sugar and not the other way around, and that blood sugar levels can be reduced by treating the OSA. A study in the American Journal of Respiratory Critical Care Medicine by Dr. Pamidi’s team found that in prediabetic non-pregnant patients, eight-hour nightly continuous positive airway pressure (CPAP) treatment for two weeks improved glucose metabolism. However, studies are needed in pregnant cohorts, she said. For OSA in general, CPAP is the gold standard treatment. OSA is relatively common in pregnancy with several studies reporting a prevalence of about 30% (ranging from 17% to 45%) of women in the third trimester and an increase in associated risks and complications. One study from 2000 in Chest surveyed 502 women about snoring. Researchers found that 23% of the women reported snoring nightly in the week before delivery, compared to only 4% who snored before pregnancy. It also found that hypertension developed in 14% of the snoring women, but in only 6% of non-snorers; and preeclampsia occurred in 10% of snorers, but 4% of non-snorers. The paper concluded that: “Snoring is common in pregnancy and is a sign of pregnancy-induced hypertension.” Snoring also indicated a risk of growth retardation of the fetus. A recent review article in the Journal of Women’s Health about OSA during pregnancy and cardiovascular disease (CVD) risk highlighted several studies showing increased snoring during pregnancy and an increased likelihood of gestational hypertension. The authors noted one study found a threefold increase in the prevalence of snoring across trimesters, and another found an increase in sleep disordered breathing from 10.5% in the first trimester to 27% in the third trimester. The authors of that paper stated that OSA “triggers autonomic, immune, and vascular pathobiology in adults that potentially contributes to mechanisms of cardiovascular disease during gestation. Impaired placental vascularization is a critical mechanism in the etiology of preeclampsia.” Why is OSA more common during pregnancy? There are a number of hypotheses, said Dr. Pamidi. It could be due to weight gain during pregnancy, since weight gain alone is often associated OSA in the general population. It could be related to fluid shifts, especially during the third trimester when fluid can accumulate in the lower extremities. “When people lie down the fluid from the legs can shift closer to the neck area and that can narrow the airway. This has not yet been shown in pregnancy but has been shown in heart and renal failure,” Dr. Pamidi said. Another route is upper airway or nasal congestion known as "estrogen related rhinitis" which is experienced by 20% to 30% of women in the third trimester. Upper airway congestion increases airway resistance and hence an increased risk for OSA. There can also be a narrowing of other parts of the upper airway and an increase in tongue size relative to the oral cavity which can contribute to obstruction. Several risk factors can predispose women to OSA, but the key factors doctors should be aware of are a history of snoring, a history of hypertension which might pre-date pregnancy also, obesity and, advanced age. Data from the US shows 15% to 20% of obese pregnant women have OSA. Whether OSA commonly resolves after giving birth is not yet known. Dr. Pamidi’s team is currently studying that, and some preliminary data suggests about half of women continue to have some degree of OSA several months later. At this point, there are no guidelines or official recommendations on OSA in pregnancy. But if pregnant patients show hallmark signs of possible OSA, such as reports of snoring, daytime sleepiness, partner reports of intermittent pauses in breathing as well as known risk factors, then these women should be referred for an urgent sleep study and followed by a specialist, Dr. Pamidi said.

Risk sleep apnea presents to women during pregnancy highlighted

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