Pregnancy after vitrification of pronuclear stage oocytes biopsied for polar body aneuploidy screening

This paper reports the case of a patient undergoing IVF and polar body analysis for aneuploidy screening because of advanced maternal age. A total of nine fertilized oocytes were obtained from the patient's third treatment cycle. Three supernumerary pronuclear stage oocytes were identified as suitable after aneuploidy screening for five chromosomes and vitrified. Because the fresh cycle did not result in a pregnancy, vitrified pronuclear stage oocytes were warmed for transfer in an artificial cycle. All three zygotes survived warming and were transferred to the patient's uterus 2 days later as 4-, 5- and 6-cell stage embryos. After 2 weeks, a positive pregnancy test indicated successful implantation. The gestation is developing normally and is presently (end of September 2007) in the 22nd week.