Introduction
The aim of the study was to determine the association of body mass index (BMI), self‐reported symptoms or diagnosis of polycystic ovary syndrome (PCOS), and hyperandrogenemia with the occurrence of gestational diabetes mellitus (GDM) through reproductive life.

Material and methods
A cohort of women born in 1966 were investigated at ages 14, 31 and 46. Women with self‐reported PCOS symptoms (presence of both oligo‐amenorrhea and hirsutism) at age 31 or with formally diagnosed polycystic ovaries (PCO)/PCOS by age 46 formed the group of self‐reported PCOS (srPCOS, n = 222) and were compared with women without self‐reported PCOS symptoms or diagnosis (n = 1357). We investigated also the association of hyperandrogenism (hirsutism or biochemical hyperandrogenism) at age 31 with the occurrence of GDM throughout reproductive life.

Results
Self‐reported PCOS alone was not a risk factor for GDM, but combined with overweight at age 31 (odds ratio [OR] 2.43, 95% confidence interval [CI] 1.22‐4.86) or 46 (OR 3.04, 95% CI 1.58‐5.83) srPCOS was associated with GDM when compared with normal weight controls. The association disappeared when comparing overweight srPCOS women with overweight controls. However, hyperandrogenemia at age 31, but not hirsutism, was associated with GDM even after adjustment for BMI.

Conclusions
The increased risk of GDM in women with srPCOS was mostly attributed to overweight or obesity. Importantly, normal weight women with srPCOS did not seem to be at increased risk for developing GDM. However, hyperandrogenemia was associated with GDM even after adjustment for BMI. These findings strengthen the importance of weight management in reproductive‐age women and suggest a noteworthy role of hyperandrogenemia in the pathophysiology of GDM.