Association between obstetrician forceps volume and maternal and neonatal outcomes

To estimate the association between obstetric forceps volume and severe perineal lacerations or adverse neonatal outcomes.

This is a retrospective cohort of forceps deliveries performed at a tertiary care hospital. Obstetricians were grouped by quartile of forceps volume over the study time period. Severe (third- or fourth-degree) perineal lacerations and adverse neonatal outcomes were compared across quartiles. Individual patient characteristics were controlled for using multilevel multivariable analysis. This study had 90% power to detect a twofold difference in severe perineal lacerations between the first and fourth quartiles. Additional analyses were performed using physician years in practice or year of residency of the involved resident physicians.

One hundred eighteen attending physicians (2,369 forceps deliveries) were included. The median (interquartile range) annual number of forceps per quartile was 1.3 (1.0-1.8), 3.8 (3.0-4.3), 6.3 (5.5-6.8), and 11.5 (9.8-17.3). The frequency of severe perineal lacerations from lowest to highest quartile was 29.9%, 27.5%, 33.3%, and 36.9% (P=.013). After adjusting for confounders, the relationship between volume quartile and severe perineal lacerations became nonsignificant. Although not powered to this outcome, the frequency of composite adverse neonatal outcome was not associated with volume quartile in either bivariate or multivariable analysis. Similarly, neither physician years of practice nor resident year was associated with severe perineal laceration. However, more experience as a resident was associated with a reduced odds of composite adverse neonatal outcomes.

After controlling for patient factors, neither attending forceps volume nor physician years in practice was associated with severe perineal lacerations or composite neonatal injury.

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