Measuring Variation in Interpregnancy Interval: Identifying Hotspots for Improvement Initiatives

Objective The study aimed to determine if single year birth certificate data can be used to identify regional and hospital variation in rates of short interpregnancy interval (IPI < 6 months). Study Design IPI was estimated for multiparous women ages 15 to 44 years with singleton live births between 2015 and 2016. Perinatal outcomes, place of birth, maternal race, and data for IPI calculations were obtained by using birth certificates. IPI frequencies are presented as observed rates. Results The cohort included 562,039 multiparous women. Short IPI rates were similar to those obtained with analyses by using linked longitudinal data and confirmed the association with preterm birth. Short IPI rates varied by race and Hispanic nativity. There was substantial hospital (0.8-9%) and regional (2.9-6.2%) variation in short IPI rates. Conclusion IPI rates can be reliably obtained from current year birth certificate data. This can be a useful tool for quality improvement projects targeting interventions and rapidly assessing their progress to promote optimal birth spacing.

Automated summary

This study uses single year birth certificate data to identify regional and hospital variation in rates of short interpregnancy interval (IPI < 6 months). The results confirm the association between short IPI rates and preterm birth. Variations in short IPI rates are observed among different races and Hispanic nativity.