Obstructive sleep apnoea in pregnancy and its association with pre-eclampsia

Abstract

Background: Obstructive sleep apnoea (OSA) in pregnancy is associated with an increased morbidity and mortality to both mother and foetus. In the South African setting the proportion of pregnant females suffering from OSA has not been well studied; nor has the association with pre-eclampsia. This study aimed to determine the prevalence of OSA in females before 35 weeks gestation using the STOP-BANG questionnaire and to determine the association with pre-eclampsia in a local South African setting.
Methods: A cross-sectional analytical study including 234 patients was conveniently sampled from Kalafong Hospital’s antenatal ward, clinic and labour ward. Participants were of more than 20 weeks and less than 35 weeks gestation. All participants were interviewed with a modified STOP-BANG questionnaire. Patients were consecutively enrolled without prior knowledge of the presence of pre-eclampsia. At Kalafong hospital all pregnant patients are routinely screened and investigated for pre-eclampsia according to standard criteria.
Results: The median gestational age in this sample was 28 weeks; 80.3% (CI 74.62–85.2%) of pregnant females had a low risk for OSA, 15.4% (CI 11.01–20.65%) had an intermediate risk and 3% (CI 6.47–14.58%) had a high risk for OSA. A modified STOP-BANG questionnaire had a sensitivity of 62.5% and a specificity of 82.1% for pre-eclampsia when a score of 3 and more was scored. Females at high risk of OSA had an OR of 8.4 (CI 2.88–24.6) for having pre-eclampsia.
Conclusions: The authors report 15.4% of the study’s pregnant population to be at intermediate risk and 3% at high risk of OSA. The association between the hypertensive disorders and OSA must be considered and screening implementation considered.

Keywords: anaesthesia, obstructive sleep apnoea, pre-eclampsia, STOP-BANG questionnaire