Background and Objectives: Human T lymphotropic virus type I (HTLV-I) is a virus of the Retroviridae family, which has infected more than 20 million people around the world. The study aimed to review the prevalence of HTLV infection in pregnant women. 
           Methods: We searched various databases including PubMed, EMBASE, Scopus, Google Scholar, SID, Magiran and Irandoc using the following keywords: HTLV-1, HTLV-2, Retroviridae, pregnancy, prevalence, incidence, women and female. Abstracts, short/brief reports as well as original and review articles published on HTLV-1 and/or HTLV-2 infection during pregnancy until October 2018 were included in the study.
           Results: We found five articles from Iran and 14 articles from other parts of the world on the prevalence of HTLV-1 infection in pregnant women. Prevalence of HTLV-1 and or HTLV-2 was higher in pregnant women than in non-pregnant women in cities of Mashhad and Neyshabur, Razavi Khorasan Province (1.5 to 3.3 %), northeastern Iran, which are endemic areas of Iran for HTLV-1 infection. The incidence rate of HTLV-1 infection was 400-500 per 10,000 pregnant women in endemic areas of Japan. In Brazil, the rate of HTLV-1 infection in pregnant women was estimated to be 1.05%.
           Conclusion: The prevalence of HTLV-1 varies among pregnant women depending on residence in endemic or non-endemic areas for HTLV-1. In endemic areas, it is recommended to perform routine screening for HTLV-1 infection in the general population, especially pregnant women.