Day 2 transfer improves pregnancy outcome in in vitro fertilization cycles with few available embryos.

OBJECTIVE

Delaying ET to day 3 to optimize embryo selection is well accepted. However, in cases where there are not enough embryos to perform selection, it is not clear whether there is a difference in clinical outcomes with the day of ET.

DESIGN

Cohort study.

SETTING

Academic medical center.

PATIENT(S): Two hundred forty-two fresh IVF/intracytoplasmic sperm injection (ICSI) cycles from 2002-2004, where all generated embryos were transferred irrespective of quality because of an extremely low number of available embryos.

INTERVENTION(S): In time period 1, ET was on day 3. In time period 2, ET was on day 2.

MAIN OUTCOME MEASURE(S): Patient response to stimulation was analyzed along with pregnancy outcome and implantation rate.

RESULT(S): Miscarriage rates were decreased, and ongoing pregnancy rates were increased with a day 2 ET in patients <40 years of age.

CONCLUSION(S): In women <40 years of age, the day of transfer is a significant predictor of clinical outcome in cases in which a low number of embryos are available for transfer. The evidence suggests that limiting embryo culture to only 2 days reduces the incidence of miscarriage and increases ongoing pregnancy rates.