[Pregnancy outcomes of day-2 versus day-3 embryo transfer in poor responders]

To investigate whether the day of embryo transfer (day 2 or day 3) affects clinical pregnancy outcomes in poor responder patients.

We retrospectively analyzed the pregnancy rates of 265 initial fresh cycles of in vitro fertilization-embryo transfer (IVF-ET), all transferred on day 2 (n = 169) or day 3 (n = 96) irrespective of quality because of an extremely low number of available embryos.

Among the poor responders aged < 35 years, a higher rate of clinical pregnancy was achieved in the day-3 than in the day-2 group (50% vs 32.43% ; RR = 0.65, 95% CI: 0.43 - 0.99), and among those aged years, the two groups showed similar pregnancy outcomes.

Shortening the time of embryo culture has no obvious benefit for the pregnancy outcome. For the poor responders under 35 years of age, day-3 embryo transfer may afford an even higher rate of clinical pregnancy.