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A decade of decline and regional disparity: Trends and associated factors in use of ritodrine hydrochloride for threatened preterm labor in Japan, a nationwide ecological study
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A decade of decline and regional disparity: Trends and associated factors in use of ritodrine hydrochloride for threatened preterm labor in Japan, a nationwide ecological study

International Journal of Gynecology & Obstetrics·September 18Open Access
Obstetrics & GynecologyPractice changingPreterm BirthThreatened Preterm LaborEcological StudyTocolytic AgentAdultRitodrine HydrochlorideRitodrine

Summary

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What was studied

Ten-year trends (FY2014–2023) in ritodrine hydrochloride injection use for threatened preterm labor across all 47 Japanese prefectures, using nationwide medical claims and statistical survey data, with a cross-sectional analysis of factors associated with usage.

Key findings

Ritodrine injection use fell by more than 45% per 1000 deliveries over 10 years, with FY2017 as the inflection point after which decline accelerated; prefectural usage still varied up to 13.58-fold, with spatial clustering of high-use regions driven by Perinatal Medical Center density, hospital admission rates for preterm labor/birth, and proportion of hospitals among delivery facilities.

Study limitations

Ecological design prevents inference about individual patient outcomes or clinical appropriateness; aggregated claims data may not capture clinical context (e.g., severity of threatened preterm labor); findings are specific to Japan's healthcare system and may not generalize elsewhere.

Clinical implications

Despite a national shift in guidelines away from ritodrine, wide regional variation persists in Japan—clinicians and policymakers should be aware that local healthcare infrastructure (e.g., Perinatal Medical Center density) is driving practice differences, and efforts to standardize tocolytic use in high-use regions are warranted.

Caveats

  • Ecological design: associations identified at the prefecture level cannot be attributed to individual patients—ecological fallacy applies
  • Results are Japan-specific; the healthcare system, guideline context, and ritodrine availability differ substantially from most other countries, limiting direct generalizability
  • Usage data reflect prescription/dispensing claims, not clinical outcomes; appropriateness or adherence to guidelines at the patient level is unknown

Related Questions

Explore related topics

What are the current evidence-based tocolytic alternatives to ritodrine for threatened preterm labor?How do perinatal care resources and hospital density influence preterm labor management practices?What are the serious adverse effects of ritodrine hydrochloride and why has its use declined internationally?

Publication Details

Year
2026
Journal
International Journal of Gynecology & Obstetrics
Source
View article
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