Effect of coasting on the implantation potential of embryos transferred after cryopreservation and thawing

Fertil Steril. 2005 Oct;84(4):867-74. doi: 10.1016/j.fertnstert.2005.03.069.


Objective: To examine the effect of withholding gonadotropins on the outcome of embryos after cryopreservation and thawing.

Design: Retrospective clinical evaluation of patients having cryopreserved-thawed ET trials with coasting during the corresponding ovarian stimulation cycle.

Setting: Academic tertiary clinical care unit.

Patient(s): Patients with cryopreserved embryos having coasting in their fresh IVF cycle and age-matched controls without coasting, both groups receiving the same stimulation protocol (long GnRH agonist plus recombinant FSH).

Intervention(s): All patients had a cycle in which embryos were transferred fresh and a cycle of thawing of cryopreserved embryos with the aim of transferring in a steroid-supplemented cycle.

Main outcome measure(s): Embryo survival, implantation, and clinical pregnancy rates.

Result(s): Post-thawing embryo survival (66.4% vs. 73%), implantation (12.3% vs. 13.0%), and clinical pregnancy rates (31.5% vs. 38.0%) were similar in study and control groups, respectively. Patients with coasting for > or =3 days had significantly lower post-thawing embryo survival rates compared with patients having shorter duration of coasting (<3 days) and controls. Implantation and pregnancy rates, however, were similar in the three groups.

Conclusion(s): Coasting did not seem to have a detrimental effect on oocyte and embryo quality because the implantation competence of transferred concept after cryopreservation and thawing was similar to that of controls. However, prolonged coasting (> or =3 days) had a subtle negative impact on the post-thaw survival rate.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Cryopreservation / methods*
  • Cryopreservation / statistics & numerical data
  • Embryo Implantation / drug effects
  • Embryo Implantation / physiology*
  • Embryo Transfer*
  • Female
  • Gonadotropins / administration & dosage
  • Humans
  • Pregnancy
  • Pregnancy Rate
  • Retrospective Studies
  • Time Factors


  • Gonadotropins