[Single pregnancy outcome after blastocyst transfer: comparison with cleavage stage embryo transfers]

It has been clearly shown that transfer of fresh blastocysts was efficient in in vitro fertilization cycles. However, only few data have been published about pregnancy outcome and health of children born. This study including only single pregnancies compared pregnancy, delivery and neonatal outcomes after blastocyst transfers in comparison with early cleavage stage embryo transfers (Day 2).

A retrospective study has been performed at the hospital of Tours from January 2002 to June 2009. Considering only primiparous women with similar ages, the outcome of 1574 single pregnancies issued from blastocyst transfers (n=588) or early cleavage stage transfers (n=959) has been compared. Data have been collected from FIVNAT forms, filled in by voluntary couples.

The rate of return of FIVNAT forms was 97.6%. The pregnancy and delivery outcomes, sex ratio, birth weight, health of newborns were similar between both groups.

Regarding pregnancy, obstetric and delivery outcomes after blastocyst transfers, the literature data remain poor, much debated, and mixing often single and multiple pregnancies. The results of this study seem reassuring but have to be confirmed by further studies.