Diabetes in pregnancy: a population-based study of incidence, referral for care, and perinatal mortality.

During 1979 and 1980 in Washington State, 260 infants (live births plus fetal deaths greater than or equal to 20 weeks' gestation) were born to women with preexisting diabetes mellitus, the equivalent to a population-based incidence of 2.1 per 1000 total births. One quarter of these women had non-insulin-dependent diabetes prior to pregnancy. The perinatal mortality rate for all infants of diabetic mothers in this series was 108 per 1000, which was eight times the state perinatal mortality rate. Only 45% of births occurred in the five tertiary centers in the state, whereas 39% occurred in hospitals that had fewer than six deliveries per year complicated by overt diabetes. The mortality rate was slightly, but not significantly, lower among infants born in referral hospitals than among those born in primary-level hospitals. Congenital malformations accounted for 43% of the 28 perinatal deaths, and fetal losses between 20 and 27 weeks' gestation accounted for another 21%. During the 2-year study period there were only three cases in which antepartum care in nonspecialty centers may have contributed to a perinatal loss.