Cesarean section, fetal monitoring, and perinatal mortality in California.

The rate of cesarean section in California has been growing at a compound rate of about 10 per cent per annum since 1969, coinciding with the advent of fetal monitoring. It is of interest, therefore, to study the distribution and efficacy of obstetric interventions. Information derived from the 1977 California birth cohort and a survey questionnaire was used to study the factors associated with the rate of cesarean section in 323 hospitals. Significant positive correlations were observed between the cesarean rate (CSR) and hospital factors indicative of a high degree of technology, including the proportion of labors electronically monitored. Significant negative correlations were observed between the CSR and hospital-specific variables suggestive of socioeconomically underprivileged patient populations. Other factors being constant, hospitals characterized by prepayment health care financing also had lower CSRs. A standaridized mortality ratio (SMR) based on 2.3 million births in the 1970--1976 cohorts was used to adjust the 1977 hospital specific perinatal mortality rates for birth weight, gestational age, sex, race, and plurality. The results show that hospitals which intervene technologically in a large proportion of births have lower risk adjusted perinatal mortality rates.