Women with gestational diabetes mellitus (GDM) diagnosed in the period 1978-1984 were followed for on average 6 yr after the index pregnancy. Thirty percent had diabetes mellitus at the follow-up examination, and preliminary results indicate that at least another third will develop diabetes during a subsequent pregnancy. Therefore, family planning and contraceptive guidance should follow the lines for women with pregestational diabetes. When low-dose hormonal contraceptives containing ethinyl estradiol and levonorgestrel were given to women with previous GDM, glucose tolerance and lipoprotein levels remained unchanged during a 6-mo treatment. However, insulin response to oral glucose increased significantly after hormonal intake for 6 mo. A triphasic preparation resulted in a significantly lower insulin response than a low-dose monophasic preparation. However, the results indicate that low-dose oral-contraceptive compounds appear to be safe for women with previous GDM when administered for limited periods. At the follow-up examination, we found no increased risk of developing diabetes in women with previous GDM who used oral contraception. We consider the intrauterine contraceptives (IUD) a safe and effective alternative for women with previous GDM. Of 154 women with GDM, 33% chose IUD, 22% a combination-type oral contraceptive, and 16% barrier methods as their first choice of contraception 2 mo postpartum. We conclude that family planning and qualified contraceptive advice are important in women with previous GDM.