Abnormal preconception oral glucose tolerance test predicts an unfavorable pregnancy outcome after an in vitro fertilization cycle

Objective: To determine the relationship between the 75-g oral glucose tolerance test and pregnancy outcome after women's first IVF cycle. Design: Prospective study. Setting: Infertility center at a private tertiary hospital in Taiwan. Patient(s): All 280 patients who went through their initial IVF cycle at the hospital between January 2004 and April 2005 were included in the study. Intervention(s): Two hundred eighty patients underwent an oral glucose tolerance test before entering an IVF cycle; all pregnancy outcomes and pregnancy complications were recorded. Main Outcome Measure(s): The relationships between glycemic parameters and insulin resistance and IVF pregnancy outcome were determined. Linear regression between birth weight and levels of preconception fasting insulin, 2-hour glucose, and 2-hour insulin was performed. Result(s): One hundred twenty patients conceived after their initial IVF cycle. Twenty-five of 89 ongoing pregnancies had various complications. The most common pregnancy complication was preterm birth (n = 11). These patients had higher body mass index (23.46 vs. 20.97 kg/m ²); higher fasting glucose (107.36 vs. 95.14 mg/dL), fasting insulin (10.55 vs. 6.20 μIU/mL), and 2-hour glucose (120.55 vs. 99.97 mg/dL) levels; and higher homeostatic model assessment of insulin resistance (3.43 vs. 1.45) than did patients with full-term pregnancies. Linear regression between birth weight and the fasting glucose level and between birth weight and the homeostatic model assessment of insulin resistance had positive correlations. Conclusion(s): Before proceeding with IVF, preconception oral glucose tolerance testing is suggested, especially in patients with higher body mass index, to help identify groups who are at high risk for preterm birth.