Objective: To describe the medical care and outcome of diabetic pregnancy and gestational diabetes in France and study their associations with glycemic control. Research Design and Methods: We performed a multicenter prospective survey with systematic collection of clinical and biological data (HbA1c analysis in a central laboratory) at five successive examinations and consecutive recruitment of women at any stage of pregnancy in 46 specialized centers from all parts of France. Pregnancies were followed to the end. There were 483 single pregnancies (232 women with insulin-dependent diabetes mellitus [IDDM], 78 with non-insulin-dependent diabetes mellitus [NIDDM], and 173 with gestational diabetes mellitus [GDM]), and 11 twin births (8 IDDM, 3 GDM). Results: We observed 30 abortions (6%), 8 perinatal deaths (1.8%, 4 IDDM, 4 GDM), and 13 congenital malformations (3%). In the 11 twin pregnancies, there were 7 congenital malformations. Premature births and cesarean sections were found very frequently (42 and 61% IDDM, 29 and 55% NIDDM, 22 and 32% GDM, respectively). In the three groups, birth weight adjusted for gestational age was much > national reference values. HbA1c levels during the first trimester were significantly higher in women who aborted (mean ± SE 7.1 ± 0.4 vs. 5.6 ± 0.1%, P < 0.001) and those who gave birth to malformed infants (6.8 ± 0.4 vs. 5.9 ± 0.1%, P < 0.05). Conclusions: Perinatal mortality was slightly higher in diabetic women than the general population (1.8 vs. 1.2%), but the prematurity rate was much higher, possibly due to an interventionist policy in some centers. Fetal loss and congenital malformations were associated with poor glycemic control.