# Facility‐Level Factors Associating Antenatal Corticosteroid Administration Rates and Subsequent Term Birth Rates: A Nationwide Cross‐Sectional Observational Study Using the 2020–2022 Perinatal Registry Database in Japan

## TL;DR

This study explores factors at healthcare facilities in Japan that affect the use of antenatal corticosteroids and the likelihood of term births, aiming to improve treatment rates while avoiding unnecessary use.

## Contribution

The study identifies facility-level factors influencing antenatal corticosteroid administration and term birth rates, offering insights for optimizing clinical practice.

## Key findings

- Facility-level factors like threatened preterm labor and cesarean section rate are significantly associated with antenatal corticosteroid administration rates.
- Simulation suggests increasing corticosteroid use could lead to more recipients and term births annually.
- Perinatal care level and delivery volume are inversely related to term birth rates among corticosteroid recipients.

## Abstract

The antenatal corticosteroid (ACS) administration rate in Japan is low. To achieve both high coverage and low overtreatment of ACS, understanding of facility‐level factors is important. This study aimed to identify facility‐level factors associated with ACS coverage and overtreatment and simulate the potential consequences of increased ACS use.

This observational study used data from the 2020 to 2022 Perinatal Registry Database maintained by the Japan Society of Obstetrics and Gynecology. Primary outcomes were: (1) ACS administration rate among preterm births before 34 weeks (ACS/34w rate) and (2) proportion of term births among ACS recipients (term/ACS proportion). Multivariable regression analyses examined associations with facility‐level factors including perinatal care level, location, delivery volume, and prevalence of maternal conditions. A simulation estimated the impact of increasing ACS/34w rate to 80% in facilities with lower baseline rates.

In the facility‐level analysis of 244 facilities (376 717 records), the mean ACS/34w rate was 63.4%, and term/ACS proportion was 12.0%. The proportion of threatened preterm labor (coefficient: 4.4 [95% confidence interval: 2.1–6.7]), deliveries < 34 weeks (3.0 [0.1–5.8]), and cesarean section rate (−2.4 [−4.5 to −0.2]) were significantly associated with ACS/34w rate. ACS/34w rate (2.0 [0.8–3.3]), annual delivery volume (2.1 [0.6–3.5]), and cesarean section rate (1.5 [0.2–2.7]) were positively associated with term/ACS proportion, while perinatal care level was inversely associated (−3.5 [−6.3 to −0.6]). Simulation estimated 2311 additional ACS recipients and 465 term births per year.

Facility‐level factors influence ACS coverage and overtreatment. These findings may inform strategies for optimizing ACS use.