This study seeks to understand the physical, physiologic and biologic features that predispose a woman to the development of obstructive sleep apnea once they are exposed to the cardiopulmonary and metabolic physiological changes of pregnancy. Knowing these specific predictive factors can help identify a population at risk and guide clinicians to develop suitable targeting screening strategies.

Patients will be recruited from multiple community and hospital-based practices that care for pregnant women. Subjects will have:

1. measurements of body composition
2. anthropometric measures
3. sleep and mood questionnaires
4. Home sleep studies
5. blood testing for biological markers
6. salivary testing for hormonal markers
7. pulmonary function tests and upper airway patency measurements

Women without sleep apnea at enrollment will then be followed longitudinally for the development of obstructive sleep apnea during pregnancy with repeat assessment during their third trimester. Women diagnosed with sleep apnea at enrollment will have no further assessment in late pregnancy.

Monetary incentives will also be issued at data collection points. Subjects will receive small gift incentives such as baby-related items.

Inclusion Criteria:

• <13 completed weeks of gestation
• BMI >30 kg/m2 at recruitment
• >18 years of age
• Ability to give informed consent

Exclusion Criteria:

• Unable to meet inclusion criteria
• Twin pregnancies

Pregnant women, 18 years or older, at less than 13 completed weeks of gestation and who have a BMI that is greater than 30 kg/m2 at recruitment.

De-identified data for primary and secondary outcome measures will be made available.

Data will be available within 12 months of study completion.

Investigators data access requests will be reviewed by an independent review committee. Requestors will need to sign a data access agreement.