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Frozen embryo transfer with GnRH-antagonist (Cetrotide)

The main aim of this study is to find out if one of the drugs routinely used in frozen embryo transfer (FET) cycles is beneficial. Some clinics such as ours routinely administer the drug Cetrotide to patients as part of a medicated FET cycle, although not all clinics do this.

It is thought the effect of Cetrotide on the body reduces the chances of FET cycles being cancelled, but we do not know if this is correct. The cancellation rate for FET cycles is thought to be small (around 5%) and using Cetrotide is not thought to make any difference to the change of having a baby following the FET cycle. Cetrotide is a safe medication, given as an injection, but we believe that patients will prefer not to use medication if it is shown to be unnecessary.

This study aims to compare cycles of FET, either with or without Cetrotide, in women/couples over the next 18 months to find out whether there is any difference in cycle cancellations and other outcomes including preference by patients.


Ginny Mounce
Oxford Fertility/University of Oxford


Start date: July 2018
Delivery date: January 2020


Prof. Tim Child
Oxford Fertility/University of Oxford, Dept Women’s & Reproductive Health

Dr Matt Noble Senior Clinical Research Fellow
Oxford Fertility/University of Oxford & Bristol

Dr Ginny Mounce
University of Oxford, Dept Women’s & Reproductive Health

Dr Charles Muteshi
Oxford Fertility/University of Oxford

Nikki Turner
Oxford Fertility

- Dr Matt Noble -

Administration of a GNRH antagonist involves multiple injections over several days, which is uncomfortable for women. Given that it may no be necessary, robust scientific investigation of the effect of omitting the GNRH-antagonist in medicated FET is essential.

Doctor holding treatment

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