Objective: Women with a history of gestational diabetes mellitus (GDM) and women with polycystic ovary syndrome (PCOS) both demonstrate abnormalities in insulin action and secretion, and both are at increased risk of developing type 2 diabetes. To determine whether these similarities reflect a common pathophysiological basis, we examined the prevalence of ultrasound-based polycystic ovarian morphology in a large multiethnic group of women with a history of GDM and a group of women who had normal glucose tolerance during pregnancy.
Patients and design: We studied 91 women with previous GDM (48 European, 20 South Asian, 10 Afro-Caribbean and 13 of other or mixed ethnicity) and 73 normoglycaemic control women (56 European, one South Asian, 14 Afro-Caribbean and two of other or mixed ethnicity), a median (interquartile range) of 20 (11-36) and 29 (17-49) months postpartum, respectively. A detailed history was taken, and the prevalence of PCO morphology on ultrasound scan was assessed. Fasting lipids, insulin, glucose status, gonadotrophins and testosterone were measured. Estimates of beta-cell function (%B) and insulin sensitivity (%S) were derived using the HOMA algorithm.
Results: Women with previous GDM had higher fasting glucose (5.4 (4. 8-6.0) vs. 4.7 (4.4-5.0) mmol/l, P<0.0001) and features reminiscent of syndrome X: higher BMI (26.4 (22.8-31.4) vs. 23.8 (21. 0-27.5) kg/m2, P = 0.002), waist/hip ratio (0.82 (0.79-0.88) vs. 0. 77 (0.73-0.81), P<0.0001), fasting insulin (165 (68-299) vs. 54 (24-156) pmol/l, P<0.0001), triglycerides (1.1 (0.8-1.6) vs. 0.8 (0.6-1.1) mmol/l, P<0.0001) and lower insulin sensitivity (%S) (27 (16-62) vs. 86 (34-139)%, P<0.0001) compared to control women. The prevalence of PCO was higher in the previous GDM group than in the control subjects (47/91 (52%) vs. 20/73 (27%), chi2 = 9.86, P = 0. 002 overall, odds ratio 2.7, P = 0.007 by logistic regression allowing for ethnicity). There was no difference in any metabolic parameter between the post-GDM PCO group and the post-GDM normal ovaries group, but irregular cycles were more prevalent in the PCO group (22/47 (47%) vs. 9/44 (21%), chi2 = 7.03, P = 0.008).
Conclusions: We found a higher prevalence of polycystic ovarian morphology in women with a history of gestational diabetes. Among the women with previous gestational diabetes, irregular cycles were more prevalent in the PCO group than in the women with normal ovarian morphology, but no other differences in endocrine or metabolic parameters were detected. These findings confirm an association between PCO and gestational diabetes and suggest that women with gestational diabetes display metabolic abnormalities irrespective of ovarian morphology.