Comparison of a fixed and dynamic protocol for embryo replacement in an IVF/et programme

Dov Feldberg, Jack A. Goldman, Michal Shelef, Jack Ashkenazi, Dov Dicker, Aryeh Yeshaya

Research output: Contribution to journalArticlepeer-review


Implantation after embryo transfer is considered a major obstade in terms of pregnancy rates after in-vitro fertilization. A flexible approach to the date of replacement, based on the fact that the most suitable embryonic structure for proper implantation is the four- to eight-cell embryo, has been studied. One-hundred-and-twenty patients with various aetiologies of infertility were stimulated with HMG or combined HMG and FSH, then treated by three different methods of embryo replacement. In group I embryos were replaced in mothers 48 h after ovum retrieval; in group II replacements were carried out 72 h after retrieval; and in group III replacements were related to embryonic cleavage development. Mean levels of oestradiol when HCG was given averaged 1301 ± 121 pg/ml, 1016 ± 96 pg/ml and 1182 ± 101 pg/ml in the three groups, respectively. There was no significant difference in the average number of embryos transferred among the various groups. The pregnancy rates per transfer were 21.8, 24.2 and 38.7%, respectively (P < 0.001). Although more investigation is required, a dynamic approach to embryo replacement might significantly improve pregnancy rates, because of improved interactions between the embryos and the uterus.

Original languageEnglish
Pages (from-to)747-750
Number of pages4
JournalHuman Reproduction
Issue number6
StatePublished - Aug 1988


  • Embryo replacement
  • IVF
  • Implantation


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