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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Gestational Diabetes, Diagnoses Disease, Pregnancy in Diabetic, Glucose, High Blood

Intervention / Treatment
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* Behavioral: Fasting before gestational diabetes screen
* Behavioral: Per oral intake of food and drink


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Pregnant patients 18 years and older Singleton gestation Pregnancy managed at Lucile Packard Children's Hospital (LPCH) Stanford outpatient obstetrics clinic Planned delivery at Lucile Packard Children's Hospital (LPCH) Stanford Labor and Delivery unit Exclusion Criteria: Pregestational diabetes Gestational diabetes diagnosed in the 1st trimester Less than 18 years of age Planned delivery outside LPCH Diabetes medication use prior to pregnancy Inability to give informed consent Chronic steroid use in pregnancy Less than 24 weeks of gestation at the time of the 1 hour oral glucose tolerance test Prior history of bariatric surgery Multifetal gestation

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Fasting before gestational diabetes screen<br>Fasting for at least 6 hours prior to the 1-hour gestational diabetes screen. | Behavioral: Fasting before gestational diabetes screen<br>* Fasting for at least 6 hours before 1-hour gestational diabetes screen.<br>|
| Active Comparator: Fed before gestational diabetes screen<br>Liberal per oral intake within 2 hours of the 1-hour gestational diabetes screen. | Behavioral: Per oral intake of food and drink<br>* Per oral intake of food and drink within 2 hours of gestational diabetes screen<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | Day of GDM screen (occurring between 24-28 weeks gestation) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean Gestational Age at OGTT Screen |  | Day of GDM screen (occurring between 24-28 weeks gestation) | 
| Mean Glucose Level at the OGTT Screen |  | 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. | 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 | 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 | Day of OGTT (occurring at 24-28 weeks gestation up to 42 weeks gestation) | 
| Mean Gestational Age at Delivery |  | At time of delivery (Up to 42 weeks' gestation) | 
| Number of Participants Who Delivered Vaginally | This outcome was assessed in pregnant participants. | At time of delivery (up to 42 weeks' gestation) | 
| Number of Participants Who Delivered Via Operative Vaginal Birth | This outcome was assessed in pregnant participants. | At time of delivery (up to 42 weeks' gestation) | 
| Number of Participants Who Delivered Vaginally After a Prior Cesarean Section | This outcome was assessed in pregnant participants. | At time of delivery (up to 42 weeks' gestation) | 
| Number of Participants Who Delivered Via a Primary Cesarean Section | Primary = first Cesarean section for participant. This outcome was assessed in pregnant participants. | At time of delivery (up to 42 weeks' gestation) | 
| Number of Participants Who Delivered Via a Repeat Cesarean Section | This outcome was assessed in pregnant participants. | At time of delivery (up to 42 weeks' gestation) | 
| Number of Participants Complicated by Shoulder Dystocia at Delivery | Shoulder dystocia is a birth injury (also called birth trauma) that happens when one or both of a baby's shoulders get stuck inside the mother's pelvis during labor and birth. This outcome was assessed in pregnant participants. | At time of delivery (up to 42 weeks' gestation) | 
| Number of Participants Complicated by Third or Fourth Degree Perineal Laceration | A third degree tear is a tear or laceration through the perineal muscles and the anal sphincter. A fourth degree tear goes through the anal sphincter all the way to the anal canal or rectum. This outcome was assessed in pregnant participants. | At time of delivery (up to 42 weeks' gestation) | 
| Number of Participants With Post-partum Hemorrhage | This outcome was assessed in pregnant participants after delivery. | Up to 6 weeks after delivery | 
| Number of Participants Diagnosed With a Hypertensive Disorder of Pregnancy | This outcome was assessed in pregnant participants. | From time of GDM screen up to 6 weeks after delivery | 
| Length of Postnatal Stay From Delivery to Discharge | Average number of days admitted in the hospital after delivery up to discharge | Up to 1 week after delivery | 
| Number of Participants Who Had a Postpartum Readmission | This outcome was assessed in pregnant participants post-delivery. | From initial hospital discharge up to 6 weeks post-partum | 
| Number of Participants With Type 2 Diabetes Mellitus Diagnosis Post-partum | This outcome was assessed in pregnant participants after delivery. | From time of delivery up to 6 weeks post-partum | 
| Mean Neonatal Birthweight |  | Day of delivery (Within approximately 2 hours after delivery) | 
| Number of Neonates With Birth Weight More Than 4000 Grams |  | Day of delivery (Within approximately 2 hours after delivery) | 
| Number of Neonates Considered Large for Gestational Age (LGA) | LGA refers to neonatal birth weight larger than the 90th percentile for gestational age. | Day of delivery (Within approximately 2 hours after delivery) | 
| Number of Neonates Considered Small for Gestational Age (SGA) | SGA are infants whose weight is < the 10th percentile for gestational age. | Day of delivery (Within approximately 2 hours after delivery) | 
| Number of Neonates Admitted to the Neonatal Intensive Care Unit (NICU) |  | Up to 28 days after delivery | 
| Number of Neonates With Hyperbilirubinemia |  | Up to 28 days after delivery | 
| Number of Neonates With Hypoglycemia |  | Up to 28 days after delivery | 
| Number of Neonates Diagnosed With Respiratory Distress Syndrome |  | Up to 28 days after delivery | 
| Number of Neonates Exclusively Breastfeeding at Time of Hospital Discharge |  | Up to 28 days after delivery |