Preconception predictors of gestational diabetes: a multicentre prospective cohort study on the predominant complication of pregnancy in polycystic ovary syndrome.

STUDY QUESTION: Can we develop an adequate preconception prediction model to identify those women with polycystic ovary syndrome (PCOS) who have an increased risk of developing gestational diabetes mellitus (GDM) during subsequent pregnancy?

STUDY ANSWER: The risk of developing GDM in women with PCOS can be adequately predicted prior to conception by a prediction model.

WHAT IS KNOWN ALREADY: Women with PCOS are at increased risk of pregnancy complications, especially GDM. GDM has serious short-term and long-term effects on mother and baby.

STUDY DESIGN, SIZE, DURATION: This study is a part of a multicentre prospective cohort study, which was conducted between April 2008 and April 2012. A total of 326 women with PCOS were included.

PARTICIPANTS/MATERIALS, SETTING, METHODS: Women with PCOS and a wish to conceive were included prior to conception and followed until 6 weeks after delivery. Maternal, neonatal and birth complications were reported. A multivariate model was developed to predict the most common pregnancy complication, GDM, by using univariate and multivariate logistic regression of preconception patient characteristics. The area under the curve (AUC) of the receiver-operating characteristic was used to test the performance of the model.

MAIN RESULTS AND THE ROLE OF CHANCE: A total of 189 women (58%) achieved an ongoing pregnancy (8% multiples) and delivered a live-born neonate. One or two maternal complications occurred in 62 (33%) pregnant women, mainly GDM (n = 41; 22%) and pregnancy-induced hypertension (n = 14; 7%). In children, one or two complications were observed in 49 (26%) of 206 children born, e.g. premature delivery (n = 23; 12%) and small for gestational age (n = 15; 8%). The preconception prediction model for GDM performed well (AUC 0.87, 95% CI 0.81-0.93). First-degree relatives with type 2 diabetes mellitus, serum levels of fasting glucose, fasting insulin, androstenedione and sex hormone-binding globulin before conception were identified as predictors.

LIMITATIONS, REASONS FOR CAUTIONS: The prediction model has not yet been externally validated in another group of patients. Also, there were missing data for some of the determinants, which were accounted for by multiple imputation.

WIDER IMPLICATIONS OF THE FINDINGS: Women with PCOS who achieve a pregnancy have an increased risk of GDM. The prediction model can be used to identify women particularly at risk for GDM who should be monitored closely to enable preventative measures that may reduce the risk of developing GDM and its adverse consequences.

STUDY FUNDING/COMPETING INTEREST(S): No external funding was used for the study. M.A.W., S.M.V.V., A.J.G., A.F. and M.P.H.K. have nothing to disclose. C.B.L has received fees and grant support from the following companies (in alphabetic order): Auxogen, European Society of Human Reproduction and Embryology and MSD. J.S.E.L. has received fees and grant support from the following companies (in alphabetic order): Ferring, Gennovum, Merck-Serono, MSD, Organon, Schering Plough, Sharp & Dome and Serono. M.J.C. has received grant support from the following companies (in alphabetic order): Illumina and MSD. B.C.J.M.F. has received fees and grant support from the following companies (in alphabetic order): Ferring, Ova-Science, PregLem SA, Roche and Watson Laboratories.

TRIAL REGISTRATION NUMBER: NCT00821379 [Clinicaltrials.gov].