# Holiday effect on childbirth: A population-based analysis of 21,869,652 birth records, 1979–2018

## TL;DR

This study analyzed over 21 million birth records in Japan to explore how holidays affect childbirth rates and risks.

## Contribution

The study provides large-scale evidence of the holiday effect on childbirth, particularly for high-risk births.

## Key findings

- Fewer births occur on holidays compared to non-holidays.
- High-risk births like low birthweight and preterm births are less frequent on holidays.
- The variation in birth patterns between holidays and non-holidays has increased over time.

## Abstract

Maternity and neonatal services always have to operate 24 hours a day and 7 days a week, and require well preparedness to guarantee safe deliveries for both mothers and babies. However, the evidence of holiday effect from large-scale data is still insufficient from the obstetrics perspective. We analyzed data of over 21 million births in Japan from January 1, 1979, to December 31, 2018. We revealed that the number of births is lower on holidays, and especially among high-risk births such as low birthweight and preterm births. The frequency of high-risk birth has been increasing over the study period, and the variation by the day of week and between holiday and non-holiday have become more prevalent in recent years.