Five-years of a mandatory single-embryo transfer (mSET) policy dramatically reduces twinning rate without lowering pregnancy rates.

OBJECTIVE

To report the outcomes of a program policy instituted in 2004 mandating single-embryo transfer (mSET) for all women aged <38 years, with at least seven zygotes, no prior failed fresh cycle at our center, and at least one good-quality blastocyst.

DESIGN

Retrospective cohort study.

SETTING

Academic medical center.

PATIENT(S): All women <38 years old undergoing a fresh cycle with autologous oocytes and all women undergoing a fresh cycle with donor oocytes from June 1, 1999, to May 31, 2004 (before mSET) and from June 1, 2004, to May 31, 2009 (after mSET).

INTERVENTION(S): mSET policy implementation.

MAIN OUTCOME MEASURE(S): Live-birth rate, multiple pregnancy rate, clinical volume, and outcomes of all mSET fresh IVF transfers were analyzed.

RESULT(S): Clinical volume was unchanged between the two time groups. After implementation of mSET, live-birth rates improved from 51.1% to 55.9% and multiple-birth rates dropped from 34.8% to 17.5%. A total of 364 mSET fresh transfers were performed with a live-birth rate of 64.6% and a multiple-birth rate of 3.4%.

CONCLUSION(S): A mandatory SET policy based on prognostic factors can be instituted with no drop in clinical volume and no negative effect on delivery rates. Multiple gestation rates can be dramatically lowered.