Aim 1: To test the hypothesis that maternal obesity increases OSA risk but to a greater extent in obese women with excessive gestational weight gain vs. obese women with normal weight gain vs. non-obese women with excessive weight gain. Study team will enroll early pregnant (≤12 weeks of gestation) obese (pre-pregnancy body mass index ≥30 kg/m2) and non-obese (body mass index 18.5-24.9 kg/m2) women and follow participants throughout gestation. In-home sleep testing will be carried out during all phases of pregnancy: early pregnancy (4-12 weeks gestation), late pregnancy (30-34 weeks of gestation) and postpartum (6-10 weeks after delivery). Investigator will compare AHI (primary endpoint), the development or worsening of OSA, and pregnancy outcomes in obese and non-obese women with and without weight gain above the Institute of Medicine (IOM) recommended levels. Various body composition areas, (e.g., neck, waist, or hips) that may be associated with risk for sleep apnea will also be measured.~Aim 2: To test the hypothesis that obesity is associated with sympathetic activation, while OSA magnifies this abnormality during pregnancy. Study team will use the state-of-the-art technique of microneurography to measure resting sympathetic activity (primary endpoint) and sympathetic neural responses to physiological stimulations (e.g., mental stress, exercise and upright posture) during early (<12 weeks) and late (30-34 weeks) pregnancy, and postpartum (6-10 weeks post) in obese women with and without OSA and non-obese women without OSA.~Aim 3: To test the hypothesis that corin content is greater in obese than nonobese women during pregnancy, and it is the greatest in obese pregnant women with OSA. Venous blood samples will be taken in women enrolled in Aim 2 study for measurements of serum corin content (primary endpoint) and pregnancy-specific angiogenic factors such as soluble fms-like tyrosine kinase 1, placental growth factor, and soluble endoglin. The relationships between maternal corin content, pregnancy-specific angiogenic factors, sympathetic activity, and BP will be explored.
The purposes of this project are 1) to compare the impact of maternal obesity versus excessive gestational weight gain on obstructive sleep apnea (OSA) in obese and non-obese women; 2) to investigate the mechanism(s) by which obesity and OSA increase cardiovascular risk during pregnancy; and 3) to identify biomarker(s) for obesity-related OSA in pregnant women.