Vuong LN, Ly TT, Nguyen NA, et al. - In the present study, the researchers compared the longer-term development outcomes in children born after freeze-only vs fresh embryo transfer (ET) in women with an ovulatory cycle. It was a long-term follow-up study of babies born alive after the first ET in a randomized controlled trial (RCT) comparing ongoing pregnancy and live birth rates after the use of a freeze-only vs fresh ET strategy. Of the 391 couples randomized to each treatment group in the RCT, 132 (97 singleton/35 twins) and 123 (95 singleton/28 twins) had a live birth in the freeze-only and fresh ET groups; 113 parents (86%) of the freeze-only group (147 babies) and 99 (80%) from the fresh ET group (120 babies) returned questionnaires for this follow-up analysis. At the end of follow-up, the mean age of children was 37 months. Height (95.0 ± 6.1 vs. 95.7 ± 5.6 cm) and weight (14.9 ± 2.6 vs. 14.8 ± 2.6 kg) were identical in both freeze-only and fresh ET groups (results were similar when singletons and twins were analyzed separately). Such information provides additional information for physicians to base decisions on the relative merits of different approaches to infertility treatment. After using a freeze-only strategy, there does not seem to be any reason for concern about worse outcomes. However, for firm conclusions to be drawn, additional research comparing childhood development after a freeze-only approach, fresh ET, and natural cycles are required.