Fasting Versus Fed: Effect of Oral Intake Prior to the Glucose Tolerance Test in Pregnancy

Stanford University200 enrolled

Overview

Studies suggest that the timing interval between oral intake and the 1-hour gestational diabetes screen may have a significant impact on gestational diabetes screening glucose levels. The investigators plan to conduct a prospective randomized trial comparing a 6-hour fast versus liberal oral intake within 2 hours prior to the glucose tolerance test in pregnancy in order to evaluate the effect of the fasting versus the fed state on routine gestational diabetes screening results.

Gestational diabetes (GDM) complicates approximately 400,000 pregnancies in the United States annually and is associated with significant adverse pregnancy outcomes, including increasing the lifetime risk of type 2 diabetes. The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant women undergo GDM screening between 24-28 weeks gestation utilizing a 1-hour oral glucose tolerance test that was designed to be administered without regard to the last meal or time of day. However, studies suggest that the timing of one's last meal prior to the 1-hour GDM screen may have a significant impact on GDM screening glucose levels. In addition, providers routinely alter the timing of the 1-hour GDM screen based on patients' self reported oral intake prior to the exam. The investigators plan to conduct a prospective randomized trial comparing a 6-hour fast versus liberal oral intake within 2 hours prior to the glucose tolerance test in pregnancy in order to evaluate the effect of the fasting versus the fed state on routine GDM screening results.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Enrollment

200

Conditions

Outcomes

Primary Outcomes

Number of Participants With a Positive Gestational Diabetes Mellitus (GDM) Screen (>= 140 mg/dL) on the 1 Hour 50-g Oral Glucose Tolerance Test (OGTT)

Number of positive GDM screen (\>= 140 mg/dL) on the 1 hour 50-g oral glucose tolerance test conducted between 24-28 weeks gestation This outcome was assessed in pregnant participants.

Time frame: Day of GDM screen (occurring between 24-28 weeks gestation)

Secondary Outcomes

Mean Gestational Age at OGTT Screen

Time frame: Day of GDM screen (occurring between 24-28 weeks gestation)

Mean Glucose Level at the OGTT Screen

Time frame: Day of GDM screen (occurring between 24-28 weeks gestation)

Number of Participants With Positive GDM Diagnosis Based on the OGTT

This outcome was assessed in pregnant participants.

Time frame: Day of GDM screen (occurring between 24-28 weeks gestation)

Average Time of Last Oral Intake Prior to the OGTT Screen

Average number of hours since the participant's last oral intake prior to OGTT screen

Time frame: Day of GDM screen (occurring between 24-28 weeks gestation)

Number of Participants With Positive GDM Diagnosis

GDM diagnosis based on 1-hour OGTT ≥ 180 mg/dL or 2 elevated values on the 3-hour OGTT using Carpenter and Coustan criteria. This outcome was assessed in pregnant participants Carpenter and Coustan Criteria is as follows (if 2 or more values are elevated, this is gestational diabetes): * Fasting glucose \< 95; * One hour glucose \< 180; * Two hour glucose \< 155; * Three hour glucose \< 140

Time frame: Day of OGTT (occurring at 24-28 weeks gestation up to 42 weeks gestation)

Mean Gestational Age at Delivery

Time frame: At time of delivery (Up to 42 weeks' gestation)

Number of Participants Who Delivered Vaginally

This outcome was assessed in pregnant participants.