Vertical Transmission Rate of Human Immunodeficiency Virus Exposed Twin Pregnancies and Associated Factors in West Bengal, India: a Retrospective Cohort Study.

Twin pregnancies are often associated with adverse obstetric outcomes. The mother-to-child transmission of the human immunodeficiency virus (HIV) in twin pregnancies has been less explored. Therefore, the present study aimed to determine the risk of vertical transmission of HIV in HIV-exposed twin pregnancies compared with that of singleton pregnancies and to explore the associated factors. We conducted a retrospective cohort study involving 348 HIV-exposed babies (58 twins and 290 singletons) through a systematic sampling from the program database of West Bengal, India, from April 2016 to March 2021. HIV vertical transmission rates were compared between single and twin live births. The effects of factors such as maternal age, timing of maternal HIV diagnosis, duration of antiretroviral treatment, mode of delivery, birth weight, and the sex of the baby were determined. The HIV transmission rate for twin pregnancies (15.5%) was significantly higher than that for single live births (5.5%) (adjusted odds ratio [OR] = 3.38 [1.17-9.69]). Among twin deliveries, maternal HIV diagnosis during the intrapartum and postpartum period was associated with HIV transmission (crude OR = 11.0, [2.2-54.9]). Perinatal HIV transmission is more common in twin pregnancies and is associated with the time of detection of maternal HIV. Therefore, early HIV detection and additional antiretroviral regimens should be considered for twin pregnancies.