Monozygotic twin birth after the transfer of a cleavage stage embryo resulting from a single pronucleated oocyte

J Assist Reprod Genet. 2004 Dec;21(12):427-9. doi: 10.1007/s10815-004-8758-2.


Purpose: To present a case involving the transfer of a single pronucleated oocyte resulting in a monozygotic twin pregnancy.

Method: A descriptive case report of a single patient.

Results: The patient conceived and was found to have a monochorionic diamnionic pregnancy which resulted in the birth of normal identical twin boys at 32 weeks of gestation.

Conclusions: The case report addresses an issue that has not received proper attention in the literature. It illustrates that observing a single PN in an oocyte at fertilization check should not be an absolute deterrent to transferring the resulting embryo even in an older patient with a high FSH level. This report also suggests that single observations, especially at the assessment of fertilization, in the IVF laboratory are limited when evaluating embryo potential and normalcy.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Female
  • Fertilization
  • Fertilization in Vitro / methods*
  • Follicle Stimulating Hormone / metabolism
  • Humans
  • Male
  • Oocytes / metabolism*
  • Pregnancy
  • Pregnancy, Multiple
  • Twins, Monozygotic*


  • Follicle Stimulating Hormone