Cryo-thawed embryo transfer: natural versus artificial cycle. A non inferiority trial.
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Endometrium preparation in patients undergoing frozen thawed embryo transfer can be achieved in several ways. The two most common used methods in the Netherlands are the artificial cycle using hormonal substitution versus the natural cycle using ultrasound based ovulation induction. Pregnancy rates in both methods are supposed to be equal.
Regretfully there are no randomized controlled trials supporting this believe. Aim of this trial is therefore to compare live birth rates between patients undergoing artificial cycle frozen-thawed embryo transfer (FET) versus patients undergoing natural cycle FET.
non-inferiority, randomized controlled trial.
Patients between 18 and 40 receiving FET after regular IVF or IVF-ICSI treatment.
intervention 1: ultrasound monitored natural cycle FET.
Intervention 2: artificial cycle FET using estrogen/progesterone substitution without downregulation.
primairy outcome: live birth rate
Secundairy outcome: clinical and ongoing pregnancy rate, cancellation rate, cost-efficiency, perceived burden.
1150 patients need to be included in order to meet statistical power. Calculations are based on a pregnancy rate of 20 %, a clinical important difference of 7 %, type I error of 5 % and a type II error of 80%. Data analysis will be performed using both a per protocol analyses as well as a intention to treat analyses.
Cost-efficiency will be calculated.
March of 2009 inclusion is started, aim is to meet the necessary inclusion in march 2012.
dr. B.J. Cohlen, gynaecologist at Fertility centre Isala klinieken
drs. E.R. Groenewoud, researcher at Fertility centre Isala klinieken
educational grand Organon BV, Oss, the Netherlands.
For questions please contact drs. E.R. Groenewoud, researcher.