Maternal hyperglycemia in singleton pregnancies conceived by IVF may be modified by first-trimester BMI

• Published in: Human reproduction (Oxford) 2017-09, Vol.32 (9), p.1941-1947
• Main Authors: Cai, S., Natarajan, P., Chan, J.K.Y., Wong, P.C., Tan, K.H., Godfrey, K.M., Gluckman, P.D., Shek, L.P.C., Yap, F., Kramer, M.S., Chan, S.Y., Chong, Y.S.
• Format: Article
• Language: English
• Subjects: Adult; Body Mass Index; Cross-Sectional Studies; Diabetes, Gestational - etiology; Female; Fertilization in Vitro - adverse effects; Glucose Tolerance Test; Humans; Original; Pregnancy; Pregnancy Trimester, First; Risk Factors
• ISSN: 0268-1161; 1460-2350
• DOI: 10.1093/humrep/dex243

Abstract STUDY QUESTION Does IVF independently increase the risk of gestational diabetes mellitus (GDM) and is this increase in risk modified by maternal body mass index? SUMMARY ANSWER IVF appears to be an independent risk factor for GDM and elevated blood glucose levels in overweight women (BMI > 25 kg/m2). WHAT IS KNOWN ALREADY IVF has been associated with increased risk of GDM, but most previous studies did not adequately assess confounding or effect modification by other risk factors. STUDY DESIGN, SIZE, DURATION Cross-sectional study using data from 1089 women with singleton pregnancies who participated in a Singaporean birth cohort study (GUSTO) and received a 75 g oral glucose tolerance test (OGTT) at 26–28 weeks gestation. PARTICIPANTS/MATERIALS, SETTING, METHODS A total of 1089 women (n = 1013 conceived spontaneously, n = 76 conceived through IVF) with singleton pregnancies received a 75 g OGTT at 26–28 weeks gestation. Fasting and 2 h postprandial blood glucose levels were assayed. World Health Organization criteria (1999) standard criteria were used to classify GDM: ≥7.0 mmol/L for fasting and/or ≥7.8 mmol/L for 2-h postprandial plasma glucose levels, which was the clinical guideline in use during the study. MAIN RESULTS AND THE ROLE OF CHANCE IVF pregnancies had nearly double the odds of GDM (OR = 1.83, 95% CI: 1.03–3.26) and elevated fasting (mean difference = 0.12 mmol/L, 95% CI: 0.00–0.24) and OGTT 2-h blood glucose levels (mean difference = 0.64 mmol/L, 95% CI: 0.27–1.01), after adjusting for commonly recognized risk factors for GDM. After stratification by first-trimester BMI, these increased risks of GDM (OR = 3.54, 95% CI: 1.44–8.72) and elevated fasting (mean difference = 0.39 mmol/L, 95% CI: 0.13–0.65) and 2-h blood (mean difference = 1.24 mmol/L, 95% CI: 0.56–1.91) glucose levels were significant only in the IVF group who is also overweight or obese (BMI > 25 kg/m2). LIMITATIONS REASONS FOR CAUTION One limitation of our study is the absence of a 1 h post-OGTT plasma glucose sample, as we were using the 1999 WHO diagnostic criteria (the clinical guideline in Singapore) at the time of our study, instead of the revised 2013 WHO diagnostic criteria. Our cohort may not be representative of the general Singapore obstetric population, although participants were recruited from the two largest maternity hospitals in the country and include both private and subsidized patients. WIDER IMPLICATIONS OF THE FINDINGS IVF appears to be an independen