Clinical factors associated with live birth after single embryo transfer.

OBJECTIVE

To identify patient, cycle, and retrieval characteristics associated with embryo implantation and live birth in patients undergoing single embryo transfer (SET).

DESIGN

Analysis of prospectively collected IVF database.

SETTING

Academic IVF program.

PATIENT(S): All patient cycles meeting criteria for SET between June 2004 and September 2010.

INTERVENTION(S): None.

MAIN OUTCOME MEASURE(S): Clinical pregnancy and live birth.

RESULT(S): Single embryo transfer was performed in 438 cycles, resulting in a clinical pregnancy rate of 76.2% and a live birth rate of 66.8% per transfer. Clinical pregnancy was associated with younger female age, ≥ 58% mature (metaphase II) oocytes at the time of retrieval, and increasing blastocyst expansion. Ongoing pregnancy was associated with younger female age and more advanced blastocysts. A diagnosis of uterine factor was negatively associated with live birth.

CONCLUSION(S): Even in a favorable prognosis population, younger female age is associated with clinical pregnancy and live birth. Although all patients underwent blastocyst transfer, expanded and hatching blastocysts were strongly associated with pregnancy and live birth. A diagnosis of uterine factor was the only infertility diagnosis found to affect live birth after SET. Obesity did not negatively affect SET outcome. These findings may assist physicians in determining the best candidates for SET.