Sleep Disordered Breathing—An Unrecognized Contributor to Abnormal Glycemic Profiles in Pregnancy

Sleep disordered breathing (SDB), particularly obstructive sleep apnea (OSA), is poorly understood in pregnancy, yet may insidiously worsen metabolic function. We hypothesized that worse SDB in part accounts for higher 24 hour patterns of glycemia in late pregnancy complicated by obesity without gestational diabetes. At 33±1 weeks, 18 pregnant women without OSA symptoms (29.4±1.2 years [mean±SEM], BMI 34.3±0.6 kg/m²) were provided a eucaloric diet (50% carb, 35% fat) for 72 hour while wearing a continuous glucose monitor (CGM). SDB severity was measured in-home with a WatchPAT200 wrist-worn device and quantified by the apnea hypopnea index (AHI; apneas and hypopneas/hour) and oxygen desaturation index (ODI; O₂ desaturations ≥4%/hour). Surprisingly, (12/18) women had an AHI≥5 (mild OSA). Total sleep time was 370.3±12.4 min (∼6 hours), sleep efficiency was impressively low (80.1±1.5%), and AHI and ODI were at least mild at 11.6±2 and 5.2±1.3, respectively. Importantly, AHI was correlated with 24 hour glucose area-under-the-curve (AUC) (r=0.50, p=0.03) and mean 24 hour glucose (r=0.55, p=0.02). ODI was correlated with both 24 hour AUC (r=0.54, p=0.02, Figure 1a) and mean 24 hour glucose (r=0.58, p=0.01, Figure 1b). Poor sleep and undiagnosed mild OSA are common in late pregnancy complicated by obesity, and may contribute to higher patterns of glycemia. SDB may be a treatable risk factor potentially improving maternal and fetal outcomes.