A new study presented at the annual meeting of the American Academy of Sleep Medicine and the Sleep Research Society suggests that adopting a supine position for sleep by the pregnant woman in the third trimester of pregnancy may hinder maternal breathing with more oxygen desaturation.¹

A secondary analysis of a sleep apnea monitoring study in 126 obese and overweight pregnant women with average BMI of 34, mean age 30 years and suspected to have sleep disordered breathing, was conducted by US researchers to assess change in sleeping position in the three trimesters and its impact on respiration of the mother. The Noxturnal T3 devices were used to monitor sleep apnea in the first and third trimesters of pregnancy. Five sleeping positions during one night’s sleep were delineated as supine, right lateral, left lateral, prone, and upright and the participants could choose any position to sleep.

The mean number of changes in sleeping position every night was comparable in the early and late trimesters of pregnancy and did not show substantial variation at 14.19 vs 14.58, respectively. The study also showed a significant association between the sleep-onset position and predominant sleep position in the first and the third trimesters. The going-to-bed position in overweight and obese pregnant women was not necessarily the same as the sleep-onset position. Only 47% of women who adopted the supine going-to-bed position maintained it as their main sleep position. The supine sleep position reduced from early to late pregnancy from 51.6% to 30.2%, while the left lateral sleep position rose from 24.6% to 37.3%. The oxygen desaturation index (ODI) deteriorated significantly in mothers who slept for a longer time in supine position, but this effect was evident only during the third trimester.

Supine sleep in the late trimester was associated with sleep-disordered breathing as shown by the worsening of the oxygen desaturation index. The study suggests sleep position change as a “potentially modifiable risk factor” for the health of the mother and her child.

Reference

1. Katz J, et al. 0713 Longitudinal Sleep Position Patterns and Breathing Parameters in Pregnancy, Sleep, Volume 45, Issue Supplement_1, June 2022, Pages A312–A313, https://doi.org/10.1093/sleep/zsac079.709.