Fulminant Type 1 Diabetes Mellitus Presenting 15 Days after Delivery Diagnosed in Cooperation with Obstetricians

The patient was a 32-year-old Japanese woman who was given a 75-g oral glucose tolerance test at the 35th week of pregnancy and was normoglycemic. She had excessive thirst and polyuria from 15 days after delivery. When she visited for the 1-month postpartum checkup, her plasma glucose level was 479 mg/dL, HbA1c was 7.4%, and urinary C-peptide was 1.1 μg/mL; she was therefore diagnosed with fulminant type 1 diabetes mellitus associated with pregnancy. All physicians should be aware of this disease so as to provide a prompt diagnosis and emergency treatment and consequently improve the maternal prognosis.