Survey on the incidence of multiple pregnancies and neonatal outcomes by fertility treatment in Tokushima Prefecture, Japan.

A survey on the incidence of multiple pregnancies and neonatal outcomes by assisted reproductive technology (ART) and non-ART fertility treatments was performed in 2011 and 2021. Questionnaires were sent to all institutions with obstetrics and gynecology departments in Tokushima Prefecture, Japan, to collect data on fertility treatments and neonatal outcomes in 2011 and 2021. Non-ART fertility treatments were classified into ovarian stimulation (treatments for cases without ovulation disorder) and ovulation induction (treatments for cases with ovulation disorder). Among all pregnancies, the multiple pregnancy rates in 2011 were 7.7% for ovarian stimulation, 5.5% for ovulation induction, and 8.4% for ART, whereas those in 2021 were 3.8%, 2.3%, and 1.9%, respectively. The rates of triplet pregnancies in 2011 were 0.85% for ovulation induction, 2.4% for ovulation induction, and 1.4% for ART, whereas those in 2021 were 0% for all treatments. The rates of low birth weight, admission to a neonatal intensive care unit, and neonatal death in 2011 were 53.8%, 9.61%, and 9.61%, respectively, whereas those in 2021 were 40.9%, 22.7%, and 0%, respectively. These findings indicate that rates of multiple pregnancies, including higher-order multiple pregnancies, by fertility treatment have decreased over the last 10 years in Tokushima Prefecture. However, some adverse neonatal outcomes have still occurred. J. Med. Invest. 71 : 251-253, August, 2024.