It is possible that a small percentage of women undergoing ovarian stimulation for fertility treatments may have to be cancelled. Cancellation of a treatment cycle is recommended when the response of the ovaries to the drugs is contrary to our expectations. Our aim is to always give patients the best chances of success in each cycle undertaken and to eliminate the already minimal risk of possible complications.

Cancellation during treatment cycle is usually recommended in the following cases:

During the phase of stimulation with the use of gonadotropins, it is possible to see reduced ovarian response. If following the correction of the daily gonadotropin dose by the doctors of the Unit, the ovarian response is still low or non-existent, cancellation of the cycle and start of a new treatment cycle with a different protocol or a higher starting dose of gonadotropins is recommended.

If the ovarian response is considered to be higher than certain limits during monitoring, there is a real danger of developing severe ovarian hyperstimulation syndrome that can pose a great risk for patient's health. This is more common in women with polycystic ovarian syndrome, who show a certain response according to the gonadotropin dose. If the dose is below a certain level there is no response and if the dose is above that level this results in hyperstimulation. It is therefore preferable to cancel a cycle, despite the increased negative phychological effect that this may entail for the patient, instead of presenting the patient with an increased risk of developing severe ovarian hyperstimulation syndrome.

A new treatment cycle can then be undertaken in a different menstrual cycle, with a different dosage and probably a change in the protocol used.

During the long protocol, it is possible to cancel the cycle during the suppression phase, either due to the appearance of a functional ovarian cyst which reforms following aspiration, or due to the inefficient suppression of ovarian function.

In the case of protocols for the transfer of frozen thawed embryos, the cancellation of the cycle is recommended when the thickness or the echo pattern of the endometrium is deemed unsatisfactory.

Also, it is possible for the treatment cycle not to reach its final stage (embryo transfer) for various reasons such as failed egg collection (when no oocytes are collected), fertilization failure, no embryo cleavage, or even zero survival of frozen embryos following their thaw. However, the chances of any of that happening are quite low (about 1-4% in all cycles, depending of the age of the woman).