Background: The risk of developing diabetes mellitus after pregnancy complicated with gestational diabetes mellitus (GDM) is considerable. Furthermore, women with previous GDM report increased prevalence of sick leave and hesitation towards additional pregnancies than women with normal pregnancies. Health and wellbeing after GDM has not previously been studied within a Swedish context. Aim: To compare health and wellbeing in women with GDM and women with normal pregnancy and the prevalence of diabetes mellitus three to four years after pregnancy. Method: The design is a retrospective case-control study. Data consists of register and questionnaire data. Medical outcomes of pregnancy and birth for 890 women who gave birth in 2005 have been obtained from the Medical Birth Register (650 women with normal pregnancies and 240 women with GDM diagnosis). The groups were matched for age and parity. The women were invited to a follow-up study addressing health and wellbeing three to four years after childbirth. Half of the women in the case and control group respectively accepted the invitation and completed a questionnaire consisting of questions regarding health, wellbeing and lifestyle including for example SF-36 form. Data is analyzed using a selection of statistical methods for comparisons of groups. Findings: Preliminary analysis show that significantly more women in the GDM group were born abroad and 17% of women with previous GDM had developed diabetes mellitus compared to none of the women in the control group. Women in the GDM group reported significantly more periods of sick leave exceeding one week, poorer self-rated health and significantly more women do not want additional pregnancies due to the negative effect on their health. The control group reported significantly more use of medication for asthma and allergy as well as anti-depressants. Women in the GDM group showed significantly more use of thyroidal medication and analgesia. The analysis is in progress and further results will be presented at the congress. Conclusion: The analysis of data is in progress; however the preliminary results indicate that women with previous GDM report poorer health and wellbeing compared to women with normal pregnancies. Furthermore, approximately 1 in 6 women with previous GDM have developed diabetes mellitus within three to four years postpartum.