Elective frozen-thawed embryo transfer (FET) in women at risk for ovarian hyperstimulation syndrome

Reprod Biol. 2018 Mar;18(1):46-52. doi: 10.1016/j.repbio.2017.12.004. Epub 2017 Dec 24.


Elective cryopreservation of cultured embryos has become a treatment option for women at risk for ovarian hyperstimulation syndrome (OHSS). The aim of our study was to investigate the outcome of elective cryopreservation and consecutive frozen-thawed embryo transfer (FET) in a large IVF clinic in Austria. A total of 6104 controlled ovarian hyperstimulation cycles (COH) were performed on 2998 patients including 200 patients (6.7%) who were undergoing elective cryopreservation and FET due to high risk of OHSS. We estimated the cumulative live birth rate using the Kaplan-Meier method and evaluated independent predictors for successful live births with a Cox model. A total of 270 frozen-thawed embryo transfers were performed on 200 patients with up to 4 transfers per patient. The first embryo transfer showed a live birth rate of 42.0%, the second transfer showed a cumulative rate of 58.5%. After a total of 4 FETs from the same COH cycle, a cumulative live birth rate of 61.0% per COH cycle could be achieved. Four cases of OHSS occurred amongst these patients (2.0%), all of them of moderate severity. Multivariate analysis identified maternal age, the use of assisted hatching and the number of embryos transferred at the blastocyst stage as independent predictors for cumulative live birth. Our study clearly suggests that elective FET is safe and shows excellent cumulative live birth rates. This concept can, therefore, be used to avoid the severe adverse events caused by COH and the inefficient use of cultured embryos.

Keywords: Cumulative live birth rate; Elective frozen-thawed embryo transfer; Ovarian hyperstimulation syndrome; Polycystic ovary syndrome.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Austria / epidemiology
  • Birth Rate
  • Blastocyst
  • Cohort Studies
  • Cryopreservation*
  • Embryo Transfer*
  • Embryo, Mammalian*
  • Family Characteristics
  • Female
  • Follow-Up Studies
  • Humans
  • Infertility, Female / complications
  • Infertility, Female / therapy*
  • Infertility, Male
  • Live Birth
  • Male
  • Ovarian Hyperstimulation Syndrome / epidemiology
  • Ovarian Hyperstimulation Syndrome / etiology*
  • Ovarian Hyperstimulation Syndrome / physiopathology
  • Ovarian Hyperstimulation Syndrome / prevention & control
  • Ovulation Induction / adverse effects*
  • Polycystic Ovary Syndrome / complications*
  • Proportional Hazards Models
  • Retrospective Studies
  • Risk
  • Severity of Illness Index