Gestational diabetes: the consequences of not treating.

Objective: Untreated gestational diabetes mellitus carries significant risks of perinatal morbidity at all severity levels; treatment will enhance outcome.
Study Design: A matched control of 555 gravidas, gestational diabetes mellitus diagnosed after 37 weeks, were compared with 1110 subjects treated for gestational diabetes mellitus and 1110 nondiabetic subjects matched from the same delivery year for obesity, parity, ethnicity, and gestational age at delivery. The nondiabetic subjects and those not treated for gestational diabetes mellitus were matched for prenatal visits.
Results: A composite adverse outcome was 59% for untreated, 18% for treated, and 11% for nondiabetic subjects. A 2- to 4-fold increase in metabolic complications and macrosomia/large for gestational age was found in the untreated group with no difference between nondiabetic and treated subjects. Comparison of maternal size, parity, and disease severity revealed a 2- to 3-fold higher morbidity rate for the untreated groups, compared with the other groups.
Conclusion: Untreated gestational diabetes mellitus carries significant risks for perinatal morbidity in all disease severity levels. Timely and effective treatment may substantially improve outcome.