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Impact of generic levonorgestrel entry on access to emergency contraception in Japan: An interrupted time-series
Kyosuke Kamijo1, Yuki Kataoka2, Daisuke Shigemi3
1Department of Obstetrics and Gynecology, Nagano Prefectural Shinshu Medical Center, Suzaka, Japan; Scientific Research WorkS Peer Support Group (SRWS-PSG), Osaka, Japan.
Objective:
To estimate the association between generic levonorgestrel (LNG) entry and access to emergency contraception in Japan's prescription-only context.
Study Design:
Interrupted time-series of monthly LNG tablets sold per 1000 women aged 15-49, May 2011-July 2025.
Intervention:
March 2019 (implementation month excluded).
Results:
2881,950 tablets sold. Immediate level change: + 0.157/1000 (+28.4%; 95% CI -61.7% to +118.6%). Slope change: + 0.0009/month (95% CI - 0.0031-0.0048). By July 2025, sales exceeded the counterfactual by + 0.310/1000 (+30.5%; 95% CI 10.8-50.3%).
Conclusions:
Generic entry produced gradual, not immediate, gains; price reductions alone may be insufficient without behind-the-counter or over-the-counter access.
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