Gestational Diabetes Diagnostic Methods

This is a pilot feasibility study of 40 pregnant women between 24-28 weeks gestation to test
the investigators recruitment, enrollment and randomization procedures in preparation to
conduct a larger randomized control trial to compare diagnostic methods for gestational
diabetes.

Forty women 18 years of age or older will be recruited at 20-24 weeks pregnancy from the
ob/gyn outpatient practices at Magee-Women's hospital (MWH). Eligible women will return to
MWH main lab between 24-28 weeks gestation for the routine 1 hour 50gm glucose challenge
test. Women with blood glucose values less than 200 will be randomized to receive either the
fasting 2 hour 75 gm oral glucose tolerance test (OGTT)or the 3 hour 100 gm OGGT within two
weeks. Gestational diabetes will be determined for the 2 hour 75 gm OGGT arm based on the
2011 ADA guidelines and the 3 hour 100 gm OGGT arm based on the Carpenter and Coustan
criteria. Patients and their providers will be informed of the diagnosis of gestational
diabetes, but they will be blinded to the criteria used to make the diagnosis as well as the
specific results of glucose tolerance testing.

Chart reviews will be conducted to assess for perinatal maternal and infant health factors
(e.g.pregnancy weight, gestational weight gain, co morbidities) as well as for data on
perinatal outcomes related to GDM such as macrosomia, c-sections, and birth trauma. Two
brief self-administered questionnaire will assess participants' views on screening for
gestational diabetes and assess participants experience with and solicit feedback on the
study procedures.

At the end of this pilot study, the investigators will have experience with recruitment,
retention, and randomization procedures and have made the necessary protocol revisions. If
successful, this feasibility study will provide the preliminary data and feasibility
justification needed to conduct a larger randomized control trial to compare the
effectiveness of two diagnostic methods for gestational diabetes.

Inclusion Criteria:

- Singleton pregnancy

- Plan to undergo gestational diabetes screening at 24-28 weeks' gestation.

Exclusion Criteria:

- Existing Type 1 or Type 2 diabetes

- Diabetes diagnosed early in pregnancy (less than 24 weeks gestation)

- Multiple gestation (e.g. twins, triplets)

- Chronic hypertension (requiring medications)

- Oral, IM or IV corticosteroid use within the previous 30 days

- Major congenital anomaly or anticipated preterm delivery before 28 weeks

- Inability to complete 50 gram GCT before 28 completed weeks' gestation

- Patients with known HIV, Hepatitis B or C virus.