Betamethasone's effect on glycemia in twin pregnancies, with or without gestational diabetes mellitus, has not been adequately investigated.We assessed the glycemic profile of 30 women with twin pregnancies after in-vitro-fertilization who were given betamethasone.The majority of women were treated eventually with insulin to maintain glycemia. In insulin-treated women the increase in insulin dosage was of 61.1%. Insulin use/dosage was not associated with betamethasone dose, age, gestational age, weight gain in pregnancy, or duration of hyperglycemia.Post-betamethasone, twin pregnancies seem to follow the same glycemia pattern as singleton pregnancies.