Sleep-disordered breathing (SDB) has been identified as a risk factor for adverse pregnancy outcomes. In the non-pregnant state, SDB is associated with decreased cardiac output and increased peripheral vascular resistance. We sought to compare hemodynamic parameters in obese women diagnosed with and without sleep-disordered breathing. This is a case-control study of obese women prospectively recruited during pregnancy who underwent overnight polysomnography for diagnosis of SDB. SDB was diagnosed by apnea hypopnea index (AHI) ³5. Women diagnosed with SDB were compared to women without SDB (AHI< 5). Bioreactance cardiography was performed using the NICOM device to assess hemodynamics adjusted for body surface area, including cardiac index (CI), total peripheral resistance index (TPRI) and stroke volume index (SVI) in the second trimester. Statistical analysis was performed using univariate analysis to evaluate the impact of SDB on hemodynamic parameters and multivariable logistic regression with adjustment for identified co-variates including age, pre-pregnancy BMI and tobacco use. Forty controls were compared to twenty-eight women with SDB. Women with SDB were more likely to be older and had a higher pre-pregnancy BMI. Systolic, diastolic and mean arterial blood pressure was higher in women with SDB. There was no difference in cardiac index between groups. SVI and TPRI were similar with mean TPRI of 1739 (95%CI 1646-1831) versus 1656 (95%CI 1563-1646) dynes-sec/cm5/m2 (p=0.8) in women with SDB compared to controls. In multivariable linear regression models, after accounting for age, BMI and tobacco use, SDB and AHI as a continuous variable were not associated with cardiac index or total peripheral resistance index. In our cohort, SDB diagnosed in early pregnancy was not associated with differences in hemodynamic parameters. Further investigation is needed to determine if hemodynamics later in gestation are impacted by SDB and its treatment, which may provide insight into underlying mechanisms linking sleep-disordered breathing and adverse pregnancy outcomes.