Determination of the Predictors of Nocturnal Desaturation in Postpartum Women

The primary aim of the study is to evaluate the effect of the method of delivery (vaginal delivery vs. cesarean section) on oxygen saturation in the first postpartum night. The investigators hypothesize that nocturnal desaturation occurs more frequently in cesarean section compared with vaginal delivery, expressed as either the duration of SpO2 below 90% or the Oxygen Desaturation Index (ODI). The ODI is defined as number of oxygen desaturations by at least 3 % per hour. Furthermore, the investigators expect a higher pulse rate and a lower mean and minimum SpO2 in the cesarean section group compared with the vaginal delivery group. The secondary aim of the study is to investigate how the upper body position during sleep (45 degree elevated vs. non-elevated) affects the oxygen saturation during the first postpartum night. The investigators hypothesize that an upper body elevation to 45 degrees decreases the incidence of desaturation events, expressed as either the duration of SpO2 below 90% or the ODI , compared with a non-elevated body position within each delivery group (vaginal delivery or cesarean section). The third aim of the study is to identify independent predictors of nocturnal desaturation in postpartum women. To that end, the investigators will administer questionnaires and collect demographic and clinical data according to various obstructive sleep apnea screening scores, including the P-SAP, STOP-Bang, and Epworth Sleepiness Scale. The investigators will also ask the patient to rate the pain during the study night on a verbal numerical rating scale.

Sleep-disordered breathing is common in pregnancy, persisting into the early postpartum period. Postpartum airway obstruction is a main cause of anesthesia-related maternal death in North America. Upper airway edema following labor and delivery may impair pharyngeal anatomy, which can lead to increased vulnerability of the airway collapse during sleep. This study evaluates whether the kind of delivery (vaginal birth versus cesarean section) has an effect on nocturnal desaturation in the first night after delivery. Furthermore, the investigators examine if the upper body position during sleep has an effect on the occurrence of oxygen desaturation. In addition, the investigators evaluate if preexisting conditions, as indicated by a high P-SAP or STOP-Bang-score increase the likelihood of nocturnal desaturation.

If the patient is randomized in this study arm after enrollment, the investigators will elevate the patients upper body to 45 degree prior to sleeping. The patient will wear a pulseoximeter (WristOx Model 3150) during the night. The investigators will collect the SpO2 and pulse rate with this device and then quantify desaturation events. The investigators will ask the patient to fill out a questionnaire, which includes the P-SAP score, the STOP-BANG score, the Epworth Sleepiness Scale and the self-reported pain.

If the patient is randomized in this study arm after enrollment, the investigators will flatten the patients upper body to a supine position prior to sleeping. The patient will wear a pulseoximeter (WristOx Model 3150) during the night. The investigators will collect the SpO2 and pulse rate with this device and then quantify desaturation events. The investigators will ask the patient to fill out a questionnaire, which includes the P-SAP score, the STOP-BANG score, the Epworth Sleepiness Scale and the self-reported pain.

The noninvasive wrist pulse oximeter (WristOx Model 3150) is used to measure the SpO2 and the pulse rate of the patient in the first night after delivery.

The Stop-Bang questionnaire is a well-established clinical tool to quantify the risk factors of Obstructive Sleep Apnea, which can lead to desaturation in the patient. The STOP Bang questionnaire includes snoring, tiredness, observed apneas, blood pressure, Body Mass Index, age, neck circumference and gender. The investigators will ask the patient to answer the questionnaire and measure the neck circumference.

The Epworth Sleepiness Scale is a well-established clinical tool to quantify daytime sleepiness. It is clinically used for the diagnosis of sleep disorders. The investigators will ask the patient to complete the questionnaire and will specify that the questionnaire pertains to the patient's pre-admission condition.

The P-SAP Score is a well-established clinical tool to quantify the risk factors of Obstructive Sleep Apnea, which can lead to desaturation in the patient. The investigators will ask the patient to answer the questionnaire and will assess the Mallampati Score. The investigators will also measure the neck circumference and the Thyromental distance.

Oxygen Saturation (SpO2) value below 90%, assessed by pulse oximetry during the first night after delivery

ODI (oxygen desaturation index), assessed by pulse oximetry during the first night after delivery. ODI is defined as number of desaturation events per hour; a desaturation event is defined as drop in SpO2 of 3% or more from baseline SpO2. Baseline SpO2 is defined as the mean SpO2 of the SpO2 values taken over the preceding 120 seconds.

A Perioperative sleep apnea prediction (P-SAP) Score. This score ranges from 0 to 69, 0 representing low risk of obstructive sleep apnea and 69 representing high risk of obstructive sleep apnea.

The STOP BANG (This abbreviation consists of the first letter of each question in the questionnaire. S-Snore, T-Tired, O-Observed stop in breathing, P-High blood pressure, B-BMI, A - Age, N-Neck circumference, G-Gender. This questionnaire is a proven tool that can be used to screen for obstructive sleep apnea (OSA). This tool will assess if you are low, moderate or high risk group for sleep apnea. Scores range from 0-8. 0 indicates low risk for sleep apnea, 8 indicates high risk for sleep apnea.

Assessment of intensity of acute pain. Measured from 0-10, 0 being no pain and 10 being highest level of pain.

Inclusion Criteria: Postpartum mothers within 24 hours of delivery Age over 18 years. Admitted to the Massachusetts General Hospital OB service for the delivery. Interventions will be randomly assigned to the patients enrolled in this study Exclusion Criteria: 1 Age under 18 years