Cryopreserved-thawed human embryo transfer: spontaneous natural cycle is superior to human chorionic gonadotropin-induced natural cycle.
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.


METHODS
Randomized controlled trial.


METHODS
Tertiary referral center.


METHODS
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.


METHODS
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.


METHODS
Ongoing pregnancy rate.


RESULTS
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%).


CONCLUSIONS
The results suggest the superiority of the natural cycle as compared with the natural cycle controlled by hCG administration in cryothawed ET cycles.
Fatemi
Human Mousavi
HM
Center for Reproductive Medicine, Department of Pathology, Dutch-Speaking Free University Brussels, Brussels, Belgium. hmousavi@uzbrussel.be
Kyrou
Dimitra
D
Bourgain
Claire
C
Van den Abbeel
Etienne
E
Griesinger
Georg
G
Devroey
Paul
P
D000328:Adult; D001755:Blastocyst; D006063:Chorionic Gonadotropin / Q000009:adverse effects / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use*; D015925:Cryopreservation; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008597:Menstrual Cycle / Q000097:blood / Q000187:drug effects* / Q000502:physiology*; D010062:Ovulation Induction / Q000009:adverse effects; D011247:Pregnancy; D018873:Pregnancy Rate; D011786:Quality Control
D006063:Chorionic Gonadotropin; D007986:Luteinizing Hormone