Higher prevalence of gestational diabetes mellitus following assisted reproduction technology treatment.

STUDY QUESTION: Do mothers following assisted reproduction technology (ART) treatment have increased likelihood of gestational diabetes mellitus (GDM) compared with non-ART mothers after controlling for maternal factors and plurality? SUMMARY ANSWER: ART mothers had 28% increased likelihood of GDM compared with non-ART mothers. WHAT IS KNOWN ALREADY: Advanced maternal age and multiple pregnancies are independently associated with increased likelihood of GDM. Given the average age of mothers having ART treatment is higher than non-ART mothers and the higher multiple pregnancy rate following ART treatment, ART treatment might be expected to be associated with increased risk of GDM. STUDY DESIGN, SIZE, DURATION: A population retrospective cohort study of 400 392 mothers who gave birth in Australia between 2007 and 2009, using the Australian National Perinatal Data Collection from five states (Australian Capital Territory, Queensland, Tasmania, Victoria and Western Australia) where a code for ART treatment is available. PARTICIPANTS/MATERIALS, SETTING,
METHODS: The study included 13 732 ART mothers and 386 660 non-ART mothers. The prevalence of GDM was compared between ART and non-ART mothers. Logistic regressions were used to assess the association between ART treatment and GDM. Odds ratio (OR), adjusted OR (AOR) and 95% confidence interval (CI) were calculated. MAIN RESULTS AND THE ROLE OF CHANCE: A larger proportion of ART mothers were aged ≥40 years compared with non-ART counterpart (11.7 versus 3.4%, P < 0.01). The prevalence of GDM was 7.6% for ART mothers and 5.0% for non-ART mothers (P < 0.01). Mothers who had twins had higher prevalence of GDM than those who gave births to singletons (8.8 versus 7.5%, P = 0.06 for ART mothers; and 7.3 versus 5.0%, P < 0.01 for non-ART mothers). Overall, ART mothers had a 28% increased likelihood of GDM compared with non-ART mothers (AOR 1.28, 95% CI 1.20-1.37). Of mothers who had singletons, ART mothers had higher odds of GDM than non-ART mothers (AOR 1.26, 95% CI 1.18-1.36). There was no significant difference in the likelihood of GDM among mothers who had twins between ART and non-ART (AOR 1.18, 95% CI 0.94-1.48). For mothers aged <40 years, the younger the maternal age, the higher the odds of GDM for ART singleton mothers compared with non-ART singleton mothers. LIMITATIONS, REASONS FOR CAUTION: It was not possible to investigate which ART procedure is associated with increased risk of GDM and how the risk could have been minimized. The information on BMI and smoking during pregnancy was not stated for a large proportion of mothers. These limitations may have reduced the validity of the study. WIDER IMPLICATIONS OF THE
FINDINGS: In agreement with other studies, our data suggest that the underlying cause of subfertility and some particular ART procedures might have played an important role in the increased likelihood of GDM. Together with the public education on not delaying motherhood, minimizing multiple pregnancies by applying single embryo transfer may diminish the excess risk of GDM related to ART treatment.