Clinical indications for abnormal early gestational 50-g glucose tolerance testing.

Providers occasionally screen women thought to be at particularly increased risk of gestational diabetes mellitus (GDM) with a first- or second-trimester (“early”) glucose tolerance test (GTT). We sought to describe how the frequency of abnormal early GTT varies by indication for testing. This is a retrospective cohort study of women receiving prenatal care in our clinic who underwent a 50-g GTT at less than 24 weeks between 2003 and 2006. Three hundred five women received an early GTT. The most common indications for early screening were obesity (53%), family history of diabetes (15%), prior history of GDM (10%), and multifetal gestation (5%). The frequency of abnormal testing in patients with multifetal gestations and a personal history of GDM was higher than in those undergoing early testing because of obesity. The frequency of abnormal early GTT varies by indication for testing. These data may be used in the allocation of health care resources.