SAN DIEGO – The prevalence of sleep-disordered breathing during pregnancy is low, but a large prospective study links it to both hypertensive disorders of pregnancy and gestational diabetes.
In an analysis of 3,702 nulliparous women, researchers found that the prevalence of sleep-disordered breathing (SDB) was 3.3% during early pregnancy (weeks 6-15) and 8.1% in midpregnancy (weeks 22-31).
SDB in midpregnancy was significantly associated with hypertensive disorders of pregnancy, while having SDB in both early and midpregnncy was significantly associated with gestational diabetes mellitus (GDM).
Dr. Francesca L. Facco
While the majority of sleep-disordered breathing cases in the study were mild, “clinical experience tells us that these women are not routinely being diagnosed and treated for SDB,” Dr. Francesca L. Facco said at the annual Pregnancy Meeting sponsored by the Society for Maternal-Fetal Medicine. “Our data demonstrate that even modest elevations of apnea-hypopnea index scores in pregnancy are associated with cardiometabolic morbidity. These findings are important because SDB, unlike many other risk factors, is potentially modifiable.”
In a study that Dr. Facco presented on behalf of the National Institute of Child Health and Human Development NuMoM2b Network, researchers at eight clinical sites in the United States set out to determine if SDB during pregnancy is a risk factor for adverse pregnancy outcomes.
Obstructive sleep apnea is the most common type of sleep disorder, said Dr. Facco of the department of obstetrics and gynecology at Magee-Women’s Hospital at the University of Pittsburgh Medical Center. In adults, an apnea-hypopnea index (AHI) of greater than or equal to 5 is the minimum criterion for establishing a sleep-disordered breathing diagnosis, while severity is classified by the number of events per hour.
“The prevalence, incidence, and severity of SDB and its impact on pregnancy remain undetermined,” Dr. Facco said. “This is despite the fact that pregnant women may be particularly disposed to SDB, given the physiologic changes associated with the gravid state, such as rapid weight gain and edema.”
Researchers recruited 3,702 women from a prospective cohort of 10,000 nulliparous women. The subjects underwent overnight in-home assessments of SDB during early pregnancy and midpregnancy. All studies were scored by a central sleep reading center.
“Currently there are no pregnancy-specific guidelines for SDB treatment and no data on which to base fetal and maternal parameters for treatment,” Dr. Facco noted. “Given the clinical equipoise that surrounds the issue, all participants and care providers were blinded to the sleep study results unless a study was identified as an urgent alert study.”
The primary outcome measures were hypertensive disorders of pregnancy and gestational diabetes. Hypertensive disorders included mild, severe, or superimposed preeclampsia, eclampsia, and gestational hypertension diagnosed in the antepartum period. The Embletta Portable Diagnostic System was used to perform the home sleep test.
Data were analyzed using multivariable logistic regression adjusted for age, body mass index, and the presence of chronic hypertension in early pregnancy analyses, as well as weight gain between visits for the midpregnancy analyses. All of the women included in the study had singleton pregnancies.
The researchers obtained complete data from 3,261 women in early pregnancy and from 2,511 women in midpregnancy. Among the 3,132 women with hypertension data, there was a 12.4% incidence of hypertensive disorders at baseline, with a 5.5% incidence of preeclampsia. Among 3,076 women with gestational diabetes mellitus data (cases of pregestational diabetes were excluded), the rate of GDM was 3.9%.
The mean age of study participants was 27 years; 60% were non-Hispanic white, 18% were Hispanic, 14% were non-Hispanic black, and the remainder were from other ethnic groups. At baseline, about half (49%) were normal weight, 25% were overweight, 23% were obese or morbidly obese, and the remainder were underweight.
SDB in midpregnancy was significantly associated with hypertensive disorders of pregnancy (an adjusted odds ratio of 1.62; P = .0156). A similar trend was seen in early pregnancy, but the association did not reach statistical significance in adjusted analyses (aOR, 1.44; P = .1434), according to Dr. Facco.
SDB in both early and midpregnancy was significantly associated with GDM (aOR, 3.62; P < .0001 and aOR, 2.79; P = .0002, respectively).
The study was funded by the NICHD. Dr. Facco reported having no relevant financial conflicts.
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