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Cryopreserved-thawed human embryo transfer: spontaneous natural cycle is superior to human chorionic
Human Mousavi Fatemi1, Dimitra Kyrou, Claire Bourgain
1Center for Reproductive Medicine, Department of Pathology, Dutch-Speaking Free University Brussels, Brussels, Belgium. hmousavi@uzbrussel.be
Objective:
To assess whether there is a difference in the ongoing pregnancy rate after transferring frozen-thawed embryos in natural cycles with spontaneous LH-P rise compared with natural cycles controlled by hCG for final oocyte maturation and ovulation.
Design:
Randomized controlled trial.
Setting:
Tertiary referral center.
Patient(S):
A total of 168 patients were assigned randomly to undergo frozen ET on day 3 from October 2007 until November 2008. Finally, analysis was performed in 124 patients; 61 belonged to the spontaneous LH group and 63 to the hCG group.
Intervention(S):
In the spontaneous LH group the transfer was planned 5 days after the LH surge. In the hCG group, the cryopreserve ET was planned 5 days after the administration of 5000 IU of hCG, when an endometrial thickness of ≥7 mm and a follicle of ≥17 mm were present on ultrasound examination.
Main Outcome Measure(S):
Ongoing pregnancy rate.
Result(S):
The study was terminated early, when a prespecified interim analysis found a significantly higher ongoing pregnancy rate in the spontaneous LH group as compared with the hCG group (31.1% vs. 14.3%; difference 16.9%, 95% confidence interval 4.4%-28.8%).
Conclusion(S):
The results suggest the superiority of the natural cycle as compared with the natural cycle controlled by hCG administration in cryothawed ET cycles.
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