Chest

Chest

Volume 120, Issue 5, November 2001, Pages 1448-1454
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Clinical Investigations
SLEEP
Sleep-Related Disordered Breathing During Pregnancy in Obese Women

https://doi.org/10.1378/chest.120.5.1448Get rights and content

Study objectives

This study was designed to evaluate sleep-related disordered breathing in obese women during pregnancy. Obesity is known to predispose to sleep-related breathing disorders. During pregnancy, obese mothers gain additional weight, but other mechanisms may counteract this effect.

Design

A case-control study to compare sleep-related breathing in obese pregnant women (mean prepregnancy body mass index [BMI] > 30 kg/m2) with pregnant women of normal weight (mean BMI, 20 to 25 kg/m2).

Setting

University teaching hospital with a sleep laboratory.

Participants

We recruited 11 obese women (BMI, 34 kg/m2; mean age 31 years) and 11 control women (BMI, 23 kg/m2; mean age 32 years).

Interventions

Overnight polysomnography was performed during early (after 12 weeks) and late (after 30 weeks) pregnancy.

Measurements and results

During pregnancy, obese mothers gained 13 kg and control women gained 16 kg. Sleep characteristics did not differ between the groups. During late pregnancy, the women in both groups slept more poorly and slept in supine position less. During early pregnancy, their apnea-hypopnea indexes (1.7 events per hour vs 0.2 events per hour; p < 0.05), 4% oxygen desaturations (5.3 events per hour vs 0.3 events per hour; p < 0.005), and snoring times (32% vs 1%, p < 0.001) differed significantly. These differences between the groups persisted in the second polysomnography, with snoring time further increasing in the obese. Preeclampsia and mild obstructive sleep apnea were diagnosed in one obese mother. One obese mother delivered a baby showing growth retardation (weight − 3 SD).

Conclusions

We have shown significantly more sleep-related disordered breathing occurring in obese mothers than in subjects of normal weight, despite similar sleeping characteristics.

Section snippets

Subjects and Study Design

Eleven obese but otherwise healthy pregnant women were recruited in the Helsinki region. Obesity was defined as a BMI > 30 kg/m2 prior to pregnancy. Eleven healthy, nonobese (normal weight = BMI of 20 to 25 kg/m2 prior to pregnancy) pregnant women were recruited in a similar manner. Subjects were ineligible if they were receiving any medication other than vitamin or iron supplements or if they had smoked > 20 pack-years.

All subjects were referred for the first polysomnography after their first

Subjects

Prepregnancy data on the obese and control subjects are given in Table 1. All study subjects were white and born in Finland. Mean age of the mothers was 31 to 32 years. There were a few smokers in either group, and all had smoked < 10 years. None reported smoking during pregnancy. Self-reported snoring prior to becoming pregnant was more common in obese subjects, but the difference was not statistically significant. In the obese group, two women were primiparas, but only four had had a child or

Discussion

Our study found significantly more sleep-related disordered breathing in these obese but otherwise healthy pregnant women than in their normal-weight control counterparts, a finding not explained by differing sleep characteristics or sleep positions. These differences were observed even during early pregnancy and persisted thereafter. Preeclampsia and mild obstructive sleep apnea were diagnosed in one obese woman during late pregnancy, but she gave birth to a normal child. More importantly, one

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    • Cited by (0)

    This study has been funded by the Helsinki University Hospital Special Funds.

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    Copyright © 2001 The American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.