Yamamoto Keiko, Uchiyama Koji, Abe Yoshiko, Takaoka Nobuko, Haruyama Yasuo, Kobashi Gen
Department of Public Health, Dokkyo Medical University, School of Medicine, Tochigi, Japan.
Integrated Research Faculty for Advanced Medical Sciences, Dokkyo Medical University, Tochigi, Japan.
J Obstet Gynaecol Res. 2025 Jan;51(1):e16202. doi: 10.1111/jog.16202.
The long-term effects of the COVID-19 pandemic on birth and pregnancy trends in Japan remain unclear. Although major sporting events are usually followed by an increase in births 9 months later, Japan's fifth wave of COVID-19 occurred during the Olympics held in Japan during the summer of 2021. In this study, we analyzed how the number of births and pregnancies changed during the COVID-19 pandemic and large-scale events in Japan.
We utilized monthly vital statistical data from birth certificates spanning the years 2010 to 2022. Our analysis followed the identification, estimation, and forecasting stages of autoregressive integrated moving average (ARIMA) modeling. We found the ARIMA (1, 12, 12) model to be adequate for forecasting the monthly number of births.
Comparing actual birth data from 2020 to 2022 with our forecast, we observed a significant decrease in births across all of Japan, urban residential areas, and 13 prefectures-primarily metropolitan regions-in January 2021 and May 2022. We also observed a decrease in pregnancy notifications in May 2020, May 2021, and October 2021. The decrease in births in May 2022 in Japan aligns with the decrease in pregnancy notifications 8 months earlier in October 2021.
Although major sporting events are expected to lead to an increase in the number of births approximately 9 months later, the number of births decreased in May 2022 during the fifth wave of the COVID-19 pandemic in Japan. These findings suggest that the number of pregnancies and births should be monitored in future pandemics with particular attention to fertility trends.
新冠疫情对日本出生和怀孕趋势的长期影响仍不明确。尽管重大体育赛事之后通常会在9个月后出现出生人数增加的情况，但日本的第五波新冠疫情发生在2021年夏季于日本举办奥运会期间。在本研究中，我们分析了新冠疫情期间及日本重大活动期间出生和怀孕人数的变化情况。
我们利用了2010年至2022年出生证明中的月度生命统计数据。我们的分析遵循自回归积分移动平均（ARIMA）建模的识别、估计和预测阶段。我们发现ARIMA(1, 12, 12)模型足以预测每月的出生人数。
将2020年至2022年的实际出生数据与我们的预测进行比较，我们观察到在2021年1月和2022年5月，全日本、城市居民区以及13个主要为大都市地区的县的出生人数显著下降。我们还观察到2020年5月、2021年5月和2021年10月的怀孕申报数量有所下降。2022年5月日本出生人数的下降与2021年10月提前8个月的怀孕申报数量下降相一致。
尽管预计重大体育赛事会在大约9个月后导致出生人数增加，但在日本新冠疫情第五波期间的2022年5月出生人数却有所下降。这些发现表明，在未来的疫情中应监测怀孕和出生人数，并特别关注生育趋势。
