J Obstet Gynaecol Res. 2025 Nov;51(11):e70145. doi: 10.1111/jog.70145.
ABSTRACT
AIM: To clarify the current status of human T-cell leukemia virus type 1 (HTLV-1) among pregnant women in Japan, with a focus on its prevalence by age and region and the contribution of horizontal transmission.
METHODS: The Japan Association of Obstetricians and Gynecologists conducted a nationwide questionnaire survey in 2025, collecting 2024 data from 1935 delivery facilities. Facilities reported total deliveries, HTLV-1 carrier cases, and testing details. Information was obtained on birth year, parity, residence, and prior HTLV-1 test results for carriers. Carrier prevalence by region and age group was analyzed, and prior negative results in multiparous carriers were used to estimate horizontal transmission.
RESULTS: Responses were received from 1297 facilities (response rate: 67.0%), covering 461 271 deliveries (67.2% of national births). Among these, 331 HTLV-1 carriers were identified (0.07%), with the highest prevalence in Kyushu and Okinawa (0.25%). Carrier prevalence declined in younger cohorts (0.04% in women born ≥ 1990 vs. 0.09% before 1990; OR 0.435, p < 0.001). Among multiparous carriers, 16.3% had previously tested negative, suggesting horizontal transmission, particularly in urban regions (Kanto, Tokai, Kinki).
CONCLUSIONS: The prevalence of HTLV-1 among pregnant women in Japan has declined, largely due to effective mother-to-child transmission prevention implemented mainly in HTLV-1 high-prevalence areas. However, horizontal transmission accounts for a notable percentage of cases, highlighting the need to reinforce preventive education and strategies targeting sexual transmission and unsafe medical or cosmetic practices alongside continued perinatal screening and counseling.
PMID:41267583 | DOI:10.1111/jog.70145
