Relationship between sleep-disordered breathing and sleeping position at the 37th week of pregnancy: an observational cross-sectional study

Sleeping in the lateral position during pregnancy can potentially reduce the severity of sleep-disordered breathing (SDB). However, this hypothesis has not been formally investigated in pregnant women. Unlike previous studies that have relied largely on self-reported measures of sleeping position, we investigated the relationship between SDB and sleeping position during late pregnancy using objective measurements. Thirty pregnant women at the 37th gestational week and 30 non-pregnant women (n-Pr) participated in the present study. The pregnant women were divided into 2 groups: those with body mass index (BMI)30kg/m(2) (with obesity, p-Ob), and those with BMI<30kg/m(2) (without obesity, p-nOb). Data were collected using a portable screening device to detect SDB indicated by the respiratory disturbance index (RDI), as well as sleeping position. The occurrence of the lateral sleeping position was higher in pregnant women than in n-Pr (P<0.05). The total RDI significantly differed among the 3 groups [P<0.01; p-Ob, 10.7 (3.1); p-nOb, 7.0 (3.0); n-Pr, 4.3 (2.9)]. The p-Ob group showed significantly lower RDI in the lateral position than in the supine position (P=0.04). Moreover, there was a significant difference in RDI between p-Ob and p-nOb for the supine position (P=0.001), but there was no between-group difference for the lateral position. Sleeping in the lateral position is likely to mitigate existing SDB in pregnant women with obesity in late pregnancy and may be an effective precaution against undiagnosed SDB and associated complications.