Measuring Variation in Interpregnancy Interval: Identifying Hotspots for Improvement Initiatives

Area of Science:

• Reproductive Health
• Public Health Surveillance
• Perinatal Epidemiology

Background:

• Short interpregnate intervals (IPI < 6 months) are associated with adverse perinatal outcomes.
• Identifying variations in IPI is crucial for targeted interventions.
• Existing methods for IPI calculation may not offer near-real-time data.

Purpose of the Study:

• To assess the utility of single-year birth certificate data for identifying regional and hospital-level variations in short interpregnancy intervals (IPI < 6 months).
• To determine if birth certificate data can serve as a reliable tool for quality improvement initiatives in perinatal care.

Main Methods:

• Utilized birth certificate data from 2015-2016 for multiparous women aged 15-44 with singleton live births.
• Calculated interpregnancy intervals (IPI) using data including maternal race and place of birth.
• Presented IPI frequencies as observed rates, comparing with longitudinal data where available.

Main Results:

• Analysis of 562,039 multiparous women confirmed that birth certificate data reliably estimates short IPI rates, consistent with longitudinal data.
• Short IPI rates demonstrated significant variation across hospitals (0.8-9%) and regions (2.9-6.2%).
• Rates also varied by maternal race and Hispanic nativity, highlighting disparities.

Conclusions:

• Single-year birth certificate data provides a reliable method for near-real-time estimation of interpregnancy intervals (IPI).
• This approach enables the identification of substantial hospital and regional disparities in short IPI rates.
• Birth certificate data is a valuable tool for targeting and rapidly assessing the effectiveness of interventions aimed at promoting optimal birth spacing.