CPAP Significantly Reduces Nocturnal Glucose Levels in Gestational Diabetes

Women with gestational diabetes (GDM), and their fetus, are at risk of adverse pregnancy and long-term outcomes. Sleep-disordered breathing (SDB) is observed in 17% to 45% of pregnancies; when adjusting for obesity, SDB is associated with about a threefold increased risk of GDM. Although a correlation has previously been established between SDB during pregnancy and elevated nocturnal glucose levels, it has not been determined whether continuous positive airway pressure (CPAP) improves glucose control in pregnancy. A study that was published online as part of the ATS 2020 International Conference used 24-hour continuous glucose monitoring (CGM) in pregnant women with CDM to ascertain whether CPAP helped with glucose control.

The randomized, controlled trial included pregnant women from obstetrics clinics at two centers in Montreal, Canada who were diagnosed with GDM (per the World Health Organization 2013 criteria) and SDB (defined as apnea-hypopnea index [AHI] ≥10 [Chicago Scoring Criteria]). A level-two home sleep study was performed to screen women for SDB. Women were randomized to one of two groups: auto-CPAP (experimental group) or nasal dilator strips (NDS; control group). Before and after the treatment period, women underwent CGM over a 72-hour period; mean 24-hour glucose values were calculated, as were mean glucose values from two time periods: 11 p.m. to 3 a.m. and 3 a.m. to 6 a.m.

A total of 68 pregnant women with GDM (mean age, 35 years; mean body mass index, 32 kg/m²; mean gestation, 29 weeks) were identified and screened for SDB. A total of 45 patients (mean AHI, 22) with SDB were randomized, and 33 completed CGM before and after treatment: 15 in the experimental group and 18 in the control group. Women had an average treatment duration of 34 days; mean CPAP adherence was 3.3 hours per night. The average effect of treatment for CPAP compared with NDS for mean glucose values was –0.43 mmol/L for 24 hours, –0.59 mmol/L for 11 p.m. to 3 a.m., and –0.90 for 3 a.m. to 6 a.m.

The study authors concluded that CPAP was associated with significant reductions in nocturnal glucose levels from 3 a.m. through 6.a.m. They called for future studies to include larger sample sizes.