Short communication: Cryopreserved sibling oocytes and intracytoplasmic sperm injection rescue unexpectedly poor fertilization in conventional in vitro fertilization

Shee Uan Chen, Yih Ron Lien, Li Jung Chang, Yi Yi Tsai, Hong Nerng Ho, Yu Shih Yang

Research output: Contribution to journalArticle

9 Citations (Scopus)


Purpose: To report a successful pregnancy from cryopreserved sibling oocytes and intracytoplasmic sperm injection (ICSI) for an infertile couple with an unexpectedly low fertilization rate in the fresh in vitro fertilization (IVF) cycle. Methods: The woman had bilateral tubal obstruction and polycystic ovarian syndrome. The man had normal semen parameters. The couple underwent a cycle of controlled ovarian hyperstimulation in that 20 oocytes were retrieved. Twelve oocytes were conventionally inseminated and eight were cryopreserved using a slow freezing method. However, only one oocyte was fertilized, and no pregnancy was achieved. In the next cycle, the frozen oocytes were thawed and ICSI was performed. Results: After thawing, seven oocytes (88%) survived and one was damaged. Six were at the metaphase II stage and were injected. Five (83%) achieved normal fertilization, and all of them cleaved (100%). After replacement of the embryos, a singleton pregnancy developed. A healthy female baby was delivered at term. Karyotyping revealed 46, XX. Conclusions: In addition to well-known indications, cryopreservation of excess sibling oocytes for patients receiving IVF has a possible advantage of preventing unexpectedly low fertilization rate or fertilization failures.

Original languageEnglish
Pages (from-to)367-369
Number of pages3
JournalJournal of Assisted Reproduction and Genetics
Issue number10
Publication statusPublished - Oct 1 2004
Externally publishedYes



  • Cryopreserved oocytes
  • intracytoplasmic sperm injection
  • unexpected fertilization failures

ASJC Scopus subject areas

  • Obstetrics and Gynaecology
  • Developmental Biology
  • Genetics
  • Reproductive Medicine

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