Obstructive sleep apnea is associated with alterations in markers of fetoplacental wellbeing.

BACKGROUND: Obstructive sleep apnea (OSA) has been associated with adverse fetal outcomes in some studies. Second trimester Down syndrome screening markers reflect fetal and fetoplacental wellbeing. We aimed to compare markers of fetal and feto-placental wellbeing in women with OSA and low risk controls.

METHODS: A retrospective case-control study of pregnant women with OSA and available second trimester markers was performed. Controls were screened for sleep disordered breathing (SDB) at the time of delivery using a questionnaire. Women at low risk for OSA were selected. Marker levels were adjusted for gestational age and race and reported as multiples of median and later adjusted for body mass index (BMI).

RESULTS: Twenty-four OSA cases and 166 controls were identified. Women with OSA had a higher mean BMI when compared to controls (37.1 ± 12.7 versus 24.1 ± 5.1, p = 0.03). Estriol (uE3) multiples of the median (MoM) levels were lower in women with OSA compared to controls, even after adjusting for BMI, 0.74 (interquartile range (IQR) 0.45) versus 1.06 (IQR 0.38), respectively, p = 0.026. Once adjusted for BMI, alpha feto-protein (AFP) MoM levels were no longer significantly different in women with OSA compared to controls.

CONCLUSION: OSA is associated with reduced serum uE3 levels, independently of BMI, possibly indicating fetal distress.