Development of children born from freeze-only versus fresh embryo transfer: follow-up of a randomized controlled trial.

Objective: To compare the longer-term development outcomes in children born after freeze-only versus fresh embryo transfer (ET) in women with an ovulatory cycle.

Design: Long-term follow-up study (NCT04099784) of babies born alive after the first ET in a randomized controlled trial (RCT) comparing ongoing pregnancy and live birth rates after use of a freeze-only versus fresh ET strategy (NCT02471573).

Setting: Private clinic.