Fertilization, pregnancy, and neonatal outcomes after IVF, rescue ICSI, and ICSI in unexplained infertility: A retrospective study

Abstract

Conventional intracytoplasmic sperm injection (ICSI) is not recommended for nonmale infertile patients to avoid fertilization failure (FF) in view of controversies regarding safety issues. Among the strategies that may help to promote the use of in vitro fertilization (IVF) for women with a high risk of FF, rescue ICSI (R-ICSI) has attracted attention. This study aimed to evaluate the efficacy of short-term insemination combined with early R-ICSI in the treatment of unexplained infertility. A total of 952 controlled ovarian stimulation (COS) cycles for unexplained infertility were divided into short-term IVF (short-term insemination without R-ICSI, n = 500), R-ICSI (short-term insemination with R-ICSI, n = 141), and ICSI (conventional ICSI, n = 311) groups. Patients underwent consecutive transfer cycles until live birth, or until all embryos from the first COS cycle were used. Laboratory data and clinical outcomes from short-term IVF, R-ICSI, and ICSI groups were compared. Short-term IVF and ICSI groups were superior to R-ICSI group in polyspermy rate, available embryo rate, and top-quality embryos rate. Short-term IVF, R-ICSI, and ICSI groups underwent 705 (500 fresh and 205 frozen-thawed cycles), 190 (141 fresh and 49 frozen-thawed cycles), and 445 (311 fresh and 134 frozen-thawed cycles) transfer cycles, resulting in 294, 76, and 190 live birth cycles, respectively. Comparison of pregnancy outcomes among these three groups demonstrated similar clinical pregnancy rates and live birth rates in fresh and frozen-thawed embryo transfer cycles. There was no significant difference in the cumulative live birth rate among these three groups. R-ICSI group showed similar neonatal outcomes compared with short-term IVF and ICSI groups, including the rates of low birth weight, fetal macrosomia, small for gestational age and large for gestational age. Short-term insemination combined with early R-ICSI achieved satisfactory pregnancy and neonatal outcomes, albeit with a high polyspermy rate, which was an effective alternative to avoid excessive use of ICSI in unexplained infertility.