Noting that pregnant women with obstructive sleep apnea (OSA) show an increased risk for preeclampsia, researchers led by Visasiri Tantrakul examined the impact of continuous positive airway pressure (CPAP) on preeclampsia as well as blood pressure among women with OSA and high-risk pregnancies.
According to the results, which were published in Respiratory Research, their multicenter, open-label, randomized controlled trial found CPAP therapy reduced both diastolic blood pressure (DBP) and the frequency of preeclampsia, even among patients with mild-to-moderate OSA and high-risk pregnancy. CPAP therapy also induced a sustained reduction in DBP throughout the gestation period.
High-risk status was defined as pregnancies with any high-risk condition, including chronic hypertension, obesity, diabetes, or history of preeclampsia or gestational diabetes in a previous pregnancy.
CPAP Improved Outcomes of Pregnancies With OSA
The study enrolled 340 patients, of whom 96.5% were in their first trimester. After 30 exclusions, 153 patients were assigned to CPAP therapy and 157 were assigned to standard antenatal care. The primary end point of analysis was blood pressure during antenatal care, and the secondary end point was incidence of preeclampsia.
Authors noted the CPAP adherence rate was 32.7%, with an average use of 2.5 hours per night. Overall, CPAP therapy lowered DBP by −2.2 mmHg (95% CI, −3.9 to 0.4; P=.014), for an approximate decrease of −0.5 mmHg per hour of CPAP therapy (95% CI, −0.89 to −0.10; P=.013).
Compared with gestational weeks 0 to 16, CPAP use led to a mean DBP difference of −3.09 mmHg (95% CI, −5.34 to −0.93) at weeks 18 to 20, −3.49 mmHg (95% CI, −5.67 to −1.31) at weeks 24 to 28, and −3.03 mmHg (95% CI, −5.20 to −0.85) at weeks 32 to 34.
The rate of preeclampsia was 20 (13.1%) out of 153 patients in the CPAP group and 35 (22.3%) out of 157 patients in the standard care group, representing a risk difference of −9% (95% CI, −18 to −1; P=.032) and a number-needed-to-treat of 11 (95% CI, 1-21).
“Early CPAP treatment significantly lowers DBP [and mean arterial pressure] and reduces the incidence of preeclampsia and hypertensive disorders in pregnancy,” the authors concluded. “This [finding] raises the need for early diagnosis and treatment of OSA in high-risk pregnancies.”