ATS: Sleep Apnea Raises Pregnancy Complication Risk

SAN FRANCISCO, May 24 -- Pregnant women who have disordered breathing patterns during sleep may be at elevated risk of developing diabetes and high blood pressure -- including eclampsia and pre-eclampsia.

In a national study of almost four million deliveries, sleep apnea increased a woman's risk twofold for gestational diabetes and four-fold for pregnancy-induced hypertension, even after controlling for obesity, said Michael S. Nolledo, M.D., of the University of Medicine and Dentistry of New Jersey at Princeton, and colleagues.

While sleep-disordered breathing flies under the radar for most obstetricians, their findings suggest it deserves more attention, said Dr. Nolledo at the American Thoracic Society meeting here.

The investigators analyzed the Agency for Healthcare Research and Quality's National Inpatient Sample data for 2003. The database includes all inpatient records from about 20% of U.S. hospitals. In 2003, it contained information on 3,979,840 deliveries.

Women who had gestational diabetes -- 167,227 pregnancies in women who did not have preexisting diabetes -- were more likely than the overall population to have sleep apnea, the investigators found: There were 1.14 per 10,000 pregnant women overall with sleep apnea (452 cases), but 4.01 per 10,000 of those with gestational diabetes had the condition (67 of 167,227).

The rate of sleep apnea was even higher among women with pregnancy-induced hypertension at 5.52 per 10,000 (166 of 300,902).

Among the findings, controlled for age and race, the investigators reported:

• Women with sleep apnea were significantly more likely to experience gestational diabetes than women without apnea (odds ratio 3.47, 95% confidence interval 1.96 to 6.18).
• When additionally controlling for obesity, women with sleep apnea were still significantly more likely to have gestational diabetes than women without apnea (OR 2.29, 95% CI 1.27 to 4.14).
• Women with sleep apnea were significantly more likely to have pregnancy-induced hypertension (OR 6.59, 95% CI 4.33 to 10.03).
• When controlling for obesity, women with sleep apnea remained more likely to have pregnancy-induced hypertension than those without apnea (OR 4.24, 95% CI 2.71 to 6.65).

While the absolute number of cases was low and relied upon the fact that sleep apnea had been diagnosed, Dr. Nolledo said that a preliminary analysis of the database for 2004 showed a small increase, likely from increased awareness.

That a link was found should not be surprising, he said. Sleep apnea in the general population has been linked to diabetes and hypertension in other studies.

However, it was important to clarify the relationship in pregnancy because a second life is involved, Dr. Nolledo said. He acknowledged that further study is needed to confirm the findings.

He and his colleagues are going to continue this line of research to clarify how apnea affects the development or perpetuation of gestational diabetes and pre-eclampsia, "so that appropriate therapy can be initiated to avoid adverse maternal and fetal outcomes," Dr. Nolledo said.

However, he noted, treating sleep apnea in pregnancy with continuous positive airway pressure (CPAP) is likely to be effective, as it is in other settings.

Women may need treatment only during pregnancy, he added, since they may develop apnea during pregnancy because of nasal congestion and rhinitis brought on by hormonal changes or because of weight gain.