Obstructive Sleep Apnea in Pregnancy

Obstructive sleep apnea (OSA) is a risk factor for complications during pregnancy and current screening tools for OSA have not been shown to be reliable in pregnant women. The primary aim of this study is to develop a valid screening tool to identify at-risk pregnant women, so that they can be further evaluated and treated. Women with OSA may also be at risk for respiratory complications related to opiate administration for post-cesarean delivery pain. A secondary aim of this study is to evaluate post-operative minute ventilation in women who undergo cesarean delivery using a novel method of non-invasive minute ventilation monitoring.

Following recruitment and informed consent, subjects will complete 3 screening questionnaires for OSA: the Berlin and STOP-BANG questionnaires, and the Epworth Sleepiness Scale. They will also undergo a physical exam by one of the study investigators including examination of the neck and upper airway to assess neck circumference, retrognathia, thyromental space, tongue scalloping, MMS, modified MMS, tonsil size and lateral pharyngeal wall narrowing.

Subjects will all receive ApneaLink™ Air (ResMed, Poway, CA), a FDA-approved, non-invasive, portable, home polysomnography device, and instructions for using the device during one night of sleep. They will be given contact information if they have questions regarding use of the device. Subjects will receive a prepaid FedEx envelope to return the device. They will receive a parking voucher worth up to a maximum of $7 during this appointment. Subjects will be compensated ($50 check by mail) once the device is received. A follow-up phone call will be made by the PI to inform the subject of the results of the home polysomnography study. Subjects who screen positive (AHI \> 5) by home polysomnography will be referred to Duke Sleep Medicine for further evaluation. Pregnancy outcomes will be followed for all subjects.

Enrolled subjects who go on to have a cesarean delivery will be studied using ExSpiron (Respiratory Motion, Inc., Waltham, MA), a FDA-approved, non-invasive respiratory volume monitor for 24 hours. The monitor has three adhesive pads that attach to the chest wall and a cord that attaches to the monitoring device, similar to an electrocardiogram. The monitor can be detached and the study suspended when patients ambulate to the restroom, and should not interfere with breastfeeding. The monitor will be connected to the patient in the pre-operative holding area, and the monitor will be calibrated with baseline spirometry measurements using a Wright spirometer over one minute. The subject will wear the device for the duration of the surgery, in the recovery room, and for 24 following surgery. The non-invasive respiratory volume monitor will be collected by study personnel at the conclusion of the 24 hours, and no data collected from the monitor will be used for clinical decision-making. Standard of care will be followed for the antepartum, intrapartum and postpartum management of those patients. Patients will continue to be monitored using the investigators' standard protocol for patients who have received neuraxial morphine which consists of continuous monitoring for 2 hours, followed by monitoring every 2 hours for 24 hours of the following: vital signs, oxygen saturation, respiratory rate, pain score and sedation score. The investigators also have nursing standing orders for naloxone administration for respiratory rate \< 8 breaths/min or Richmond Agitation Sedation Scale (RASS) ≤ -3, together with immediate notification of medical staff, as well an order to notify medical staff for oxygen saturation \< 90% or RASS \< -2.

Eligibility Criteria:
Inclusion Criteria:

* gestational age 24 to 35 weeks
* BMI \> or equal to 40 kg/m2
* 18 years or older

Exclusion Criteria:

* Non-English speaking subjects
* Established diagnosis of OSA
* chronic narcotic use