Predictors of sleep-disordered breathing in pregnancy

Abstract

Background: Sleep-disordered breathing (SDB) is common in pregnancy, but there are limited data on predictors.

Objectives: The objective of this study was to develop predictive models of sleep-disordered breathing during pregnancy.

Study design: Nulliparous women completed validated questionnaires to assess for symptoms related to snoring, fatigue, excessive daytime sleepiness, insomnia, and restless leg syndrome. The questionnaires included questions regarding the timing of sleep and sleep duration, work schedules (eg, shift work, night work), sleep positions, and previously diagnosed sleep disorders. Frequent snoring was defined as self-reported snoring ≥3 days per week. Participants underwent in-home portable sleep studies for sleep-disordered breathing assessment in early (6-15 weeks gestation) and mid pregnancy (22-31 weeks gestation). Sleep-disordered breathing was characterized by an apnea hypopnea index that included all apneas, plus hypopneas with ≥3% oxygen desaturation. For primary analyses, an apnea hypopnea index ≥5 events per hour was used to define sleep-disordered breathing. Odds ratios and 95% confidence intervals were calculated for predictor variables. Predictive ability of the logistic models was estimated with area under the receiver-operating-characteristic curves, along with sensitivities, specificities, and positive and negative predictive values and likelihood ratios.

Results: Among 3705 women who were enrolled, data were available for 3264 and 2512 women in early and mid pregnancy, respectively. The corresponding prevalence of sleep-disordered breathing was 3.6% and 8.3%, respectively. At each time point in gestation, frequent snoring, chronic hypertension, greater maternal age, body mass index, neck circumference, and systolic blood pressure were associated most strongly with an increased risk of sleep-disordered breathing. Logistic regression models that included current age, body mass index, and frequent snoring predicted sleep-disordered breathing in early pregnancy, sleep-disordered breathing in mid pregnancy, and new onset sleep-disordered breathing in mid pregnancy with 10-fold cross-validated area under the receiver-operating-characteristic curves of 0.870, 0.838, and 0.809. We provide a supplement with expanded tables, integrated predictiveness, classification curves, and an predicted probability calculator.

Conclusion: Among nulliparous pregnant women, logistic regression models with just 3 variables (ie, age, body mass index, and frequent snoring) achieved good prediction of prevalent and incident sleep-disordered breathing. These results can help with screening for sleep-disordered breathing in the clinical setting and for future clinical treatment trials.

Keywords: home sleep test; prediction; pregnancy; sleep-disordered breathing.

Figure 1

Flowchart showing enrollment in the Sleep Disordered Breathing Study within the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (nuMoM2b) and inclusion in modelling for prediction of SDB at the first study visit and the third study visit, and new onset SDB at the third study visit.

Figure 2

Ten-fold cross-validated receiver operating characteristic (ROC) curves for the final parsimonious models for prediction of SDB at the first study visit (transformed BMI at V1, maternal age at V1, and frequent snoring at V1; AUC=0.870), SDB at the third study visit (transformed BMI at V3, maternal age at V3, and frequent snoring at V3; AUC=0.838), and new onset SDB at the third study visit (also transformed BMI at V3, maternal age at V3, and frequent snoring at V3; AUC=0.809). BMI was transformed using a Box-Cox power transformation with λ = −1.25 (see methods). Frequent snoring was defined as snoring ≥3 days per week during the 4 weeks prior to the visit.