Recurrent hypoglycemia during pregnancies in a woman with multiple autoantibodies including anti-insulin receptor antibody and anti-platelet antibody, whose serum lowered murine blood glucose levels and phosphorylated insulin receptor of CHO-IR cells

We report a rare case of recurrent hypoglycemia in a pregnant woman during the period of pregnancies. She suffered from severe hypoglycemia and intrauterine fetal death during the first pregnancy. Thereafter, there was no hypoglycemia, and no obvious cause of hypoglycemia was found by close examinations. Two years later, at eight weeks into the second pregnancy, hypoglycemia recurred. The patient had multiple auto-antibodies including anti-insulin receptor antibody and anti-platelet antibody associated with decreased platelet count. She completed the pregnancy with continuous intravenous administration of glucose that prevented hypoglycemia and finally delivered a healthy baby by Caesarian section. Both the hypoglycemia and thrombocytopenia, and the auto-antibodies disappeared after the delivery. We analyzed the patient's serum as a possible cause of hypoglycemia. Administration of the serum lowered blood glucose levels of mice more strongly than control serum. In addition, the serum phosphorylated tyrosine of insulin receptor of Chinese hamster ovary cells overexpressing human insulin receptors (CHO-IR cells) in vitro. These results suggest that multiple autoantibodies might have been induced by a trigger of pregnancy, although the precise mechanism was unclear, and the antiinsulin receptor antibody and anti-platelet antibody might have induced hypoglycemia and thrombocytopenia, respectively, during the pregnancy.