Obstructive sleep apnea and diet-controlled gestational diabetes

Obstructive sleep apnea (OSA) was shown to be associated with gestational diabetes mellitus (GDM). However, prevalence of OSA in GDM women, its relationship to metabolic control, and predictive factors have not been studied.

Eighty-two obese pregnant women with diet-controlled GDM between 24 and 34 weeks of gestation participated. The Berlin questionnaire was used to assess OSA symptoms. OSA was diagnosed using an overnight monitor. Fasting glucose and hemoglobin A1c (HbA1c) were obtained. Those with OSA underwent meal tolerance test (MTT) to assess their metabolic parameters. Classification tree analysis was used to develop a screening tool for OSA.

At a median gestational age of 29 weeks, OSA was diagnosed in 52.4% of the women, with a median apnea hypopnea index of 9.4 (interquartile range 6.4, 12.4). More severe OSA was significantly correlated with higher fasting glucose but not HbA1c. For those with OSA, sleep parameters related to oxygen desaturation significantly correlated with higher fasting insulin resistance and more severe β-cell dysfunction, as evaluated by MTT. A screening tool involving two variables, neck circumference and Berlin Questionnaire score, was developed. The sensitivity and specificity were 86% and 51%, respectively. The overall accuracy was 70%.

OSA is prevalent in obese pregnant women with diet-controlled GDM in the late second to early third trimester. OSA severity, especially the degree of oxygen desaturation, correlated with fasting glucose, insulin resistance, and β-cell function. A simple screening tool involving the Berlin Questionnaire and neck circumference can aid in predicting OSA in this patient group.