Abstract
Objective: To examine the results of 7 years of thawed ET during natural or controlled cycles using exogenous steroids. Design: Retrospective evaluation to compare implantation and pregnancy rates with two protocols for transfer of cryopreserved-thawed pre-embryos. Setting: Tertiary care academic center. Patients: From January 1987 to December 1993, 521 patients who were <40 years of age underwent 628 thawed embryo transfers. Main Outcome Measure: Pregnancy and implantation rates per thawed embryo transfer cycle. Results: A total 1,987 pre-embryos survived the thawing process and were used in 628 thaw-transfer cycles. Transfer was performed in a natural cycle 2 days after the LH peak or on day 17 of a programmed cycle using a GnRH-agonist and hormone replacement therapy protocol; 182 pregnancies were established (182/628; 29%). Similar pregnancy rates were seen in the natural cycle (112/398; 28%) and the programmed cycle (70/230; 30%). The implantation rates were similar in the two methods of transfer cycles (11.9% versus 10.3%, natural versus programmed cycle). There were no significant differences in clinical or ongoing pregnancy rates in a natural or programmed cycle, correcting for the number of cryopreserved-thawed pre-embryos transferred. Patient's age at the time of freezing and the number of cryopreserved-thawed pre-embryos transferred are more important determinants of pregnancy than the type of cycle in which transfer occurs. Conclusion: Transferring cryopreserved-thawed pre-embryos in a natural or programmed cycle yields similar pregnancy results.
Original language | English (US) |
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Pages (from-to) | 545-550 |
Number of pages | 6 |
Journal | Fertility and sterility |
Volume | 62 |
Issue number | 3 |
DOIs | |
State | Published - 1994 |
Externally published | Yes |
Keywords
- Cryopreservation
- IVF
- endometrial preparation
- natural cycle
ASJC Scopus subject areas
- Reproductive Medicine
- Obstetrics and Gynecology