Out-of-hospital delivery in Washington State, 1975 to 1977.

The annual rate of out-of-hospital deliveries in Washington State increased from 1.6% in 1975, to 2.4% in 1977. Birth certificates, linked birth and death certificates files, and log books from tertiary referral hospitals were used to investigate this trend. As parity increased, rates of home delivery (HD) also increased (p less than 0.001). However, alternative birth center delivery (BCD) rates did not change with parity (p greater than 0.1). HD rates and BCD rates increased with birth weight (p less than 0.001). Obstetric professionals attended 91% of BCD as compared to 65% of HD. Fifty-four percent of the women in the BCD group had 10 or more prenatal visits compared to 40% in the HD group. Infant mortality rates were lower with BCD than with HD. However, our analysis of mortality was limited by countervailing biases inherent in the data. We concluded that out-of-hospital deliveries were a heterogeneous group that in future studies should be stratified into groups of birth center deliveries and home deliveries.