The effect of storage time after vitrification on pregnancy and neonatal outcomes among 24 698 patients following the first embryo transfer cycles

STUDY QUESTION To evaluate the impact of storage time after vitrification on embryo viability, pregnancy outcomes and neonatal outcomes. SUMMARY ANSWER The prolonged storage time of vitrified embryos negatively affected pregnancy outcomes, including biochemical pregnancy rate, clinical pregnancy and live birth rate; but did not influence neonatal outcomes. WHAT IS KNOWN ALREADY Although vitrification has been the fundamental tool of ART...