In natural cycle IVF the oocyte that is released during the normal monthly cycle is collected, without administering medication to stimulate the ovary. In certain cases, a low dose of hormones is administered during the last days of therapy to avoid early ovulation.
This therapy is mostly indicated in the case of women who cannot or do not wish to undergo ovarian stimulation. It is also recommended for women with very poor response to ovarian stimulation in a previous attempt. It is a milder treatment compared with the usual ovarian stimulation cycle and, inasmuch as a single oocyte is fertilized, the danger of a multiple pregnancy is minimized. Since the ovaries are not artificially stimulated, the patient can repeat the procedure directly in case of failure. Finally, the cost of the procedure is lower.
The basic drawback of natural cycle IVF is that it generally has a significantly lower success rate compared with other treatments due to the smaller number of transferred embryos. This cancels out the advantage of being less expensive, since, on average, more attempts are necessary to achieve a pregnancy.
