SHEE-UAN CHENYIH-RON LIENChang L.-JTsai Y.-YHONG-NERNG HOYU-SHIH YANG2020-02-062020-02-0620041058-0468https://scholars.lib.ntu.edu.tw/handle/123456789/454522Purpose: 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.[SDGs]SDG3adult; article; artificial insemination; case report; cell damage; cell isolation; cell survival; cryopreservation; delivery; embryo; embryo development; female; fertilization in vitro; human; infertility; intracytoplasmic sperm injection; karyotype; male; marital therapy; metaphase; newborn; oocyte; ovary hyperstimulation; ovary polycystic disease; pregnancy; priority journal; sibling; sperm; thawing; treatment outcome; uterine tube occlusion; X chromosome; methodology; pregnancy outcome; Adult; Cryopreservation; Female; Humans; Male; Metaphase; Oocytes; Pregnancy; Pregnancy Outcome; Siblings; Sperm Injections, Intracytoplasmicjournal article10.1023/B:JARG.0000046205.15721.d42-s2.0-16644403640