Effect of re‐cryopreservation on pregnancy and neonatal outcomes: Analysis using propensity score matching

Abstract

ObjectiveTo comprehensively assess the effect of re‐cryopreservation procedure on pregnancy and neonatal outcomes by using propensity matching (PSM) analysis.MethodsThe patients were divided into two groups according to the times of embryo cryopreservation: the cryopreservation group (n = 8034) and the re‐cryopreservation group (n = 66). To optimize the precision of the present study, we used PSM to adjust the different baseline characteristics between the two groups, including maternal age, the number of good‐quality embryos transferred and endometrial preparation protocols. The primary outcome was live‐birth rate. The secondary outcomes were biochemical pregnancy rate, clinical pregnancy rate, and miscarriage rate.ResultsWe found that the rates of biochemical pregnancy and clinical pregnancy were comparable between the two groups, whereas miscarriage rate was increased, resulting in significantly reduced live‐birth rate in the re‐cryopreservation group. No differences were observed in terms of neonatal outcomes, including cesarean section, birth weight, and malformation as well as pregnancy complications. Moreover, multivariable analysis demonstrated that re‐cryopreservation was an independent risk factor for live‐birth rate.ConclusionThe present study demonstrated the adverse effect of re‐cryopreservation on pregnancy outcomes, providing valuable information for clinical decision making and patient counseling.