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Variations of IVM
Our approach to IVM varies with the patient. There are significant differences in the eggs of different women's ovaries at different times of the menstrual cycle. Some of these differences are only apparent after a cycle has been undertaken. Having several approach appears to be a key to high success rates.
A programmed IVM cycle is the most structured approach to IVM. The endometrial lining is intentionally developed with estrogen, the day of retrieval is scheduled in advance of the cycle, and neither exogenous or endogenous gonadotropins are not used to mature the eggs in the patient. Most other variations of IVM use fertility drugs to partly stimulate the ovaries and obtain varying amounts of follicle development. These may be injectable gonadotropins or oral medications. Some cycles utilize endogenous hormones in ovulatory patients to stimulate the ovaries and the lining. This is a natural cycle approach to IVM, which also stimulates some follicle development. With these tyopes of cycles, retrieval may be scheduled or determined by ultrasound findings as the ovaries change. We call this an augmented IVM cycle.
Programmed vs Augmented Cycles
Programmed cycles work best in PCO or PCO-like patients with "larger" antral follicles. When appropriate, programmed cycles are best for patients for practical reasons. They are the easiest and least expensive IVF cycles that a woman can undertake. Programmed IVM involves preparing the lining of the uterus for implantation and coming in for egg harvesting. The eggs have been growing in the ovary for about three months and have just reached the point where they can begin responding to the hormone FSH. Some of them have not yet received any stimulation from FSH. (In the more severe PCO patients, the eggs have been resting and waiting for stimulation for up to three months. Some of the eggs retrieved will have received some FSH stimulation by the patient over that time.)
We also like the type of IVM developed by the McGill group which we refer to as natural IVF/IVM. This approach uses the FSH produced by women who ovulate and have PCO patterns in their ovaries to naturally develop one or two mature eggs in their ovaries before harvesting those eggs together with immature ones. The immature eggs are treated as in programmed IVM. It is a great advance over pure "natural IVF" which in several studies only yields a pregnancy rate of about 7%.
For patients who don't ovulate or who do not get pregnant in programmed IVM or natural IVF/IVM, we utilize oral and or injectible medications together with IVM. Often these cycles also require estrogen to enhance development of the endometrial lining.
Another important use of IVM is for hyperstimulation IVM rescue. This is where the patient intends to do IVF, but early in the ovulation induction it becomes clear that she is at high risk of severe ovarian hyperstimulation. Many programs manage hyperstimulation with "coasting" which involves delaying the egg retrieval while withholding gonadotropins. Other programs proceed with the egg retrieval, but freeze all embryos for transfer in a later time period. We believe that conversion to IVM is a better approach.
Other programs do things differently, but an augmented version of IVM may be recommended in our program for some patients who have failed IVF, but don't produce a large number of eggs or have failed programmed IVM. These variations of IVM provide tools that can be adapted to the differing patient problems that we encounter.