Transfer of two versus three embryos in women less than 40 years old undergoing frozen transfer cycles

Objective

To compare outcomes of frozen embryo transfer (FET) cycles when two or three embryos were transferred in women aged <40 years.

Design

Retrospective chart review.

Setting

A university-affiliated IVF program.

Patient(s)

Women undergoing FET cycles between January 2004 and December 2005.

Intervention(s)

Transfer of two or three embryos.

Main Outcome Measure(s)

Clinical pregnancy rate (PR), multiple pregnancy rate (MPR), and live birth rate (LBR).

Result(s)

In patients aged <35 (n = 145), two versus three embryo group had similar PR and LBR, but the MPR was significantly higher in the three-embryo group (41% for three embryos vs. 9.4% for two embryos). Clinical pregnancy in the fresh cycle from which the frozen embryos were obtained did not affect the PR, and an increase in MPR was still observed. In patients aged 35 to 39 (n = 93), there were no differences in the PR, MPR, or LBR between the two groups.

Conclusion(s)

Transfer of two instead of three frozen embryos in patients <35 years old resulted in a significant decrease in MPR without compromising PR or LBR. Transferring additional embryos when a patient had an unsuccessful fresh cycle was not warranted. In the age group 35–39 years, transferring two instead of three embryos did not decrease PR or LBR, and had no effect on the risk of high-order multiples.

Key Words: Frozen embryo transfer, number of embryos to transfer, IVF, frozen cycle outcome, multiple pregnancy