While it is more ideal for candidates who respond poorly to controlled ovarian stimulation regimens for IVF it can be contemplated for candidates who wish not to administer hormonal drugs either for personal or medical reasons. Natural cycle as a treatment modality is not suitable for pre-menopausal individuals presenting anovulatory infertility.
Patients who require very high hormonal dosages for ovarian response and which may lead to the harvest of one or two eggs only, natural cycle IVF can be an attractive alternative since it does not incorporate any injection medication. Moreover, it is Genesis standpoint that the quality of the egg which matures during the natural process is superior than any of the counterparts retrieved from stimulated cycles. A disadvantage of this approach to treatment is that it entails several consecutive ultra sound monitoring scans and Estradiol blood tests while realistically the possibility exists that the single follicle will ovulate in advance to collection or it may be immature at retrieval.
In general the recipient of the Natural Cycle treatment is advised to visit the clinic as from 5-6 days prior to the presumed day of ovulation which normally occurs in the middle of the menstrual cycle. Daily ultra sound scans and estrogen tests are undertaken so development of the follicle is closely assessed. Once this reaches a mean size of 18 mm a triggering injection in the form of hCG 10000 IU is administered and egg collection is programmed approximately 34-36 hours later. Prior to the preparation of the patient for the egg retrieval an ultra sound scan is performed to confirm that he follicle did not ovulate. If the examination confirms ovulation then the egg collection is cancelled and the treatment may be diverted to artificial insemination or cancelled.
The follicle is conventionally aspirated under mild general anaesthesia but the latter is optional. If the egg is not retrieved with the initial follicular aspirate the embryologist will notify the surgeon so repeated follicular flushes using appropriate culture fluid is implemented in an endeavour to harvest the egg. Once recovered, the egg will be washed out from the follicular fluid and stored under physiological conditions until the designated fertilisation time similarly to normal IVF. If the egg achieves fertilisation then it is allowed to develop further in culture and its quality is routinely assessed. A transfer is implemented only if the fertilised ovum develops into the blastocyst stage 5 days post collection and when prognosis based on quality is good. If however the egg is immature then the treatment cycle is terminated at that stage.
A natural cycle embryo transfer may be associated with a higher pregnancy rate than if a single embryo was replaced during a medicated cycle. A logical rationale to this is that with the natural cycle the organism is not exposed to any metabolic stress which is an unavoidable consequence of controlled ovarian stimulation mediated by hormonal drugs.