CPAP Therapy May Reduce Hypertensive Disorders of Pregnancy by More than 30%: Meta-Analysis

Among a cohort of pregnant women with obstructive sleep apnea (OSA), those who used continuous positive airway pressure (CPAP) treatment during gestation vs those who did not had a 35% reduced risk of experiencing gestational hypertension and a 30% reduced risk of experiencing preeclampsia. The results remained consistent after analysis for effects of age or body mass index (BMI) on the occurrence of either outcome.

The findings come from a new systematic review and meta-analysis published in JAMA Network Open by a team of investigators from Taiwan.

"Currently, there is still no consensus guideline on the management of OSA during pregnancy due to underestimated consequences and vulnerability of the population," first author Yi-Chieh Lee, MD, PhD, of the department of otolaryngology–head and neck surgery, New Taipei Municipal Tucheng Hospital, in New Taipei City, Taiwan, and colleagues wrote. The team also pointed to inconsistent findings in current published research, all leading to inconclusive assessment of the association between CPAP treatment and composite hypertension outcomes in pregnancy. These gaps in evidence served as impetus for the current meta-analysis of all the available randomized controlled trials (RCTs) and observational studies on the potential relationships.

Study details

The database search and screening process identified 46 articles of which 6 remained for the meta-analysis after applying the study's inclusion criteria: 1) pregnant women with OSA confirmed by polysomnography or home sleep test, 2) treatment with CPAP, 3) clearly defined experimental and control groups, and 4) outcome measurements that included risk of composite hypertensive outcomes (eg, gestational hypertension or preeclampsia).

The 6 studies included 809 women (mean age 31.4 years, mean BMI 34 kg/m²). Events for hypertensive disorder of pregnancy (ie, gestational hypertension, preeclampsia) were reported in all; intervention groups were treated with CPAP, control groups with standard of care for pregnant women, according to the study. The team's review of data for adherence to CPAP treatment found a range across the studies, from less than 10% to 85%.

The differences in risk between the intervention and control groups were statistically significant, with pooled results revealing a reduction in relative risk of hypertension of 0.65(95% CI, 0.47-0.89; P = .008) and of preeclampsia of 0.70 (95% CI, 0.50-0.98; P = .04). After metaregression analysis, there was no correlation between participant age (coefficient, −0.0190; P = .83) and BMI (coefficient, −0.0042; P = .87) with reduction of risk for the composite outcome.

Pregnancy and OSA

Estimates are that between 10% and 30% of middle-aged adults (aged 30 to 69 years) are affected by OSA, with the global increase in obesity driving a steady rise in the condition. Among pregnant women who have OSA and experience more severe disease or those who develop OSA during pregnancy, evidence attributes exacerbation or new symptoms to 4 factors: hormonal changes, anatomic changes, weight gain, and fluid retention. The authors cite research that demonstrates an increase in sleep disordered breathing as pregnancy progresses, rising from less than 5% early in the 9 months to approximately 10% in midpregnancy.

The primary interventions for OSA include lifestyle change, increased physical activity, CPAP, certain mandibular devices, and surgery. CPAP remains the first line and "criterion standard" therapy and is considered the most feasible choice throughout and after pregnancy, the authors wrote.

Potential mechanisms. The decrease in risk of gestational hypertension among women using CPAP may be the result of the treatment’s effect on sleep architecture, ie, CPAP ventilation helps maintain airway patency, reducing frequent awakening. The decrease in sleep fragmentation may in turn mitigate sympathetic activity that ultimately drives hypertension, according to Lee and colleagues. The team also cites literature that suggests the lower risk of preeclampsia could be attributable to the amelioration, vis CPAP use, of hypoxia-induced endothelial dysfunction. As a result of hypoperfusion, the placenta produces vasoconstrictive agents, the effects of which could escalate to preeclampsia.

Indications. Indications for use of CPAP during pregnancy vary widely, the authors explained, ranging from a confirmed diagnosis of OSA to the identification of risk factors for the condition. Although CPAP implementation should follow a shared decision-making conversation with a clinician, the specialist may prioritize treatment in the presence of severe OSA or of OSA and comorbidities including chronic hypertension, obesity, or history of hypertensive disorders of pregnancy.

Initiation of CPAP treatment also should be individualized and account for OSA severity and any gestational complications. Generally, the researchers noted, women with a preexisting OSA diagnosis and established CPAP treatment should continue using CPAP during pregnancy, while those with newly diagnosed OSA should begin CPAP treatment as soon as possible.

Lee et al note among the study’s limitations the small number of eligible articles for the meta-analysis and the inconsistency among them in documenting duration of and adherence to CPAP treatment.

Those issues notwithstanding, “Based on current knowledge about OSA in pregnancy and its associated adverse outcomes, screening women with high-risk pregnancies for OSA, followed by CPAP treatment, may reduce the incidence of composite hypertensive syndromes without apparent safety issues,” the authors concluded.

Reference

1. Lee Y-C, Chang Y-C, Tseng L-W, et al. Continuous positive airway pressure treatment and hypertensive adverse outcomes in pregnancy: a systematic review and meta-analysis. JAMA Netw Open. 2024;7(8):e2427557. doi:10.1001/jamanetworkopen.2024.27557