A total of 1308 women (445 from KP-WC and 863 from SFGH) met the inclusion criteria and were included in the analysis. At SFGH in 2005, the rate of cesarean delivery was 24.5% overall and 22.6% among study participants (P = .3); at KP-WC, the overall rate in 2005 was 26.4% and the rate among study participants was 30.1% (P = .1).
The distribution of maternal and infant characteristics varied significantly by site (Table 1 ). Over half of all women at the KP-WC site were White and one quarter were Latina, whereas three quarters of SFGH participants were Latina and only 4% were White. Delivery complications were more common among the KP-WC participants (27.4%) than among participants at SFGH (7.0%); the higher rate at KP-WC is probably because this facility is a subregional referral center with a level III neonatal intensive care unit (i.e., a nursery that routinely provides intensive care) and therefore receives high-risk patients from the neighboring Kaiser Permanente facilities. Women at KP-WC were also more likely to have delivered by cesarean than women at SFGH (30% [n = 134] vs 23% [n = 195]; P = .003).