Diabetes after pregnancy - a long-term follow-up in women with normal OGTT

Purpose. Our aim was a follow-up off a cohort of women screened for GDM with normal oral glucose tolerance test in pregnancy, to investigate the incidence and time of diagnosis of manifest diabetes mellitus and to identify the risk factors for later development of diabetes.Methods. A follow-up study of a cohort with normal oral glucose tolerance test (OGTT) in 1991/1992. Of the original 352 only five women were lost to follow up.Results. In total 64 women (18%) had manifest diabetes with median age of 57 years after 28 years of follow-up. This amounts to three times the expected rate compared to the background population. The rate of manifest diabetes rises 10 - 20 years after pregnancy and after the age of 40. A normal fasting glucose at OGTT as well as borderline OGTT during pregnancy were associated with risk of manifest diabetes (p<0.001), also after adjustment for age, BMI, non-Danish origin and smoking during pregnancy (p<0.002).Conclusion. The incidence of diabetes is higher in women with various risk factors for DM and a previous normal OGTT in pregnancy compared to the background incidence. On this background our results are useful in identifying the time where women may benefit from the effective implementation of evidence-based treatment to postpone and advert manifest DM, even though they had a normal OGTT during pregnancy.