title: Monozygotic twin birth after the transfer of a cleavage stage embryo resulting from a single pronucleated oocyte.
abstract: OBJECTIVE
  To present a case involving the transfer of a single pronucleated oocyte resulting in a monozygotic twin pregnancy.
  
  
  METHODS
  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.
authors.affiliation: Stanford University Medical Center, Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, Palo Alto, California 94304, USA. ddasig@hotmail.com
authors.forename: Daniel
authors.initials: D
authors.lastname: Dasig
authors.forename: Jennifer
authors.initials: J
authors.lastname: Lyon
authors.forename: Barry
authors.initials: B
authors.lastname: Behr
authors.forename: Amin A
authors.initials: AA
authors.lastname: Milki
mesh_terms: D000328:Adult; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro / Q000379:methods*; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D006801:Humans; D008297:Male; D009865:Oocytes / Q000378:metabolism*; D011247:Pregnancy; D011272:Pregnancy, Multiple; D014430:Twins, Monozygotic
chemical_list: D005640:Follicle Stimulating Hormone