Although some zero pronuclei (0PN) zygotes cleave and develop into good embryos, they are usually discarded because they lack two distinct pronuclei (2PN). In this case report, we followed four couples to determine whether 0PN embryo could be used in late rescue intracytoplasmic sperm injection (L-R-ICSI). Here we report five healthy infants, including one set of twins, derived from "0PN" embryos from four frozen–warmed embryo transfer (FET) cycles in L-R-ICSI between 2015 and 2017. Of nine infants born from L-R-ICSI cycles in our center, five were "0PN" embryos, and all remain healthy. Embryos from "0PNs" such as 2PN can develop into healthy babies using L-R-ICSI. This finding suggests that embryos from "0PNs" in L-R-ICSI may be different from traditional 0PN gametes and more likely to originate from 2PN gametes and they may be used in those infertile couples who lack 2PN embryos, instead of discarding them. The use of "0PN" embryos increases the cycles reaching embryo transfer, allowing some infertile couples to have healthy children and to avoid mental anguish and wasted time and money.

Although some zero pronuclei (0PN) zygotes cleave and develop into good embryos, they are usually discarded because they lack two distinct pronuclei (2PN). In this case report, we followed four couples to determine whether 0PN embryos could be used in late rescue intracytoplasmic sperm injection (L-R-ICSI). Here, we report five healthy infants, including one set of twins, derived from "0PN" embryos from four frozen–warmed embryo transfer (FET) cycles in L-R-ICSI between 2015 and 2017. Of nine infants born from L-R-ICSI cycles in our center, five were "0PN" embryos, and all remained healthy. Embryos from "0PNs", such as 2PN, can develop into healthy babies using L-R-ICSI. This finding suggests that embryos from "0PNs" in L-R-ICSI may be different from traditional 0PN gametes and more likely to originate from 2PN gametes, and they may be used in infertile couples who lack 2PN embryos instead of discarding them. The use of "0PN" embryos increases the cycles reaching embryo transfer, allowing some infertile couples to have healthy children and to avoid mental anguish and wasted time and money.

Although some zero pronuclei (0PN) zygotes cleave and develop into good embryos, they are usually discarded because they lack two distinct pronuclei (2PN). In this case report, we followed four couples to determine whether 0PN embryo could be used in late rescue intracytoplasmic sperm injection (L-R-ICSI). Here we report five healthy infants, including one set of twins, derived from "0PN" embryos from four frozen–warmed embryo transfer (FET) cycles in L-R-ICSI between 2015 and 2017. Of nine infants born from L-R-ICSI cycles in our center, five were "0PN" embryos, and all remain healthy. Embryos from "0PNs" such as 2PN can develop into healthy babies using L-R-ICSI. This finding suggests that embryos from "0PNs" in L-R-ICSI may be different from traditional 0PN gametes and more likely to originate from 2PN gametes and they may be used in those infertile couples who lack 2PN embryos, instead of discarding them. The use of "0PN" embryos increases the cycles reaching embryo transfer, allowing some infertile couples to have healthy children and to avoid mental anguish and wasted time and money.