Normal birth after single-embryo transfer in a patient with excessive polypronuclear zygote formation following in vitro fertilization and intracytoplasmic sperm injection

Objective: To report an unusual case of idiopathic zygotic polypronuclei. Design: Case report. Setting: Major urban infertility referral center. Patient(s): A 34-year-old woman with unexplained infertility. Intervention(s): The patient underwent two cycles of controlled hyperstimulation and oocyte retrieval followed by in vitro insemination and intracytoplasmic sperm injection (ICSI). Main Outcome Measure(s): Pregnancy and delivery of a normal infant following transfer of a single preembryo from an ICSI cycle in which only one zygote showed a normal pronuclear number (2PN) and 12 zygotes appeared polypronucleated (greater than or equal to3PN). Result(s): On the first IVF cycle, 23 oocytes were retrieved and inseminated with 240 X 1 03 motile sperm/mL, after which two zygotes showed a normal pronuclear number and 20 zygotes appeared polyploid with three to seven pronuclei. Transfer of two poor-quality day-3 preembryos following assisted hatching did not achieve pregnancy. On the subsequent ICSI cycle, 33 oocytes were retrieved, and 17 mature oocytes were subjected to ICSI, after which only one zygote showed 2PN and 12 zygotes appeared polyploid with three to eight pronuclei. The normally fertilized zygote developed into a poor-quality, day-3 embryo and was subjected to assisted hatching. Transfer of this preembryo resulted in an uneventful pregnancy and birth of a normal infant. Conclusion(s): Mechanisms other than polyspermia may result in polypronuclear development in some patients. (C)2004 by American Society for Reproductive Medicine.