Pregnancy rate doesn't differ between frozen and fresh embryo transfer, study finds

A small, new study finds that the pregnancy rate was no higher for women that underwent a frozen embryo transfer versus a fresh transfer. As embryo freezing technology for assisted reproduction has improved in recent years, many countries are moving toward a "freeze all" approach, in which women are encouraged to freeze eggs and embryos for later use. In the new study, 460 women from three European countries were randomly assigned to either the freeze-all group or a fresh transfer group, where eggs for creating embryos are retrieved up to five days before the transfer. The pregnancy rate and live birth rate of both groups were similar, between 27%-29% for both categories. Time to pregnancy was longer in the "freeze all" group, however, and both groups experienced similar rates of complications. The findings should warn against a blanket "freeze all" approach to embryo transfer, the authors suggest.

Correction: Yesterday's item on fewer cancer diagnoses during Covid-19 incorrectly stated when the study began looking at data. The study looked at data going back to January 2018.