What Is the Role of Mini IVF?
by Dr. Paul R. Gindoff, MD · · Updated
From Dr. Paul Gindoff of Chelsea Fertility NYC
About two decades ago we started performing IVF on patients without using fertility drugs, otherwise known as a natural cycle IVF. The objective was to collect the single dominant follicle egg and use this egg to produce an embryo that would offer a reasonable pregnancy rate in younger woman with tubal factor.
Mini-IVF is a derivative of natural IVF historically. Some patients prefer to harvest the single dominant egg to improve pregnancy rates during a conception cycle without using fertility drugs. The success is limited by one egg and no more than one resultant embryo. For young patients this option can improve success over timed intercourse or IUI but most patients will not benefit from IVF unless fertility medications are utilized. So mini-IVF was developed to perform the same technical steps but with addition of mild amount of fertility pills and injections yielding a moderate number of eggs (2-5). This incremental advantage does translate into higher pregnancy rates as enough embryos may be created even to attempt PGT-A. However, if budget allows using standard higher dosing of fertility drugs will optimize outcome for almost all patients unless they are very poor responders.
During this time, we learned a lot about IVF and egg retrievals with minimal stimulation, or essentially one follicle to aspirate. However, the major pitfall was pre-mature ovulation rate. That is, the patient would lose the egg by ovulating before we could perform the egg retrieval. So even after 36 hours from trigger shot, the odds of not getting an egg were 40% - this made the program untenable and not sustainable.
It was only about 10 years ago that a new drug was introduced that has had amazing impact on the efficiency of natural cycle or mini IVF. This drug called GnRH antagonist, trade name Ganirelix or Cetrotide, allows efficient egg harvesting and nearly non-existent premature ovulation. By combining natural cycle monitoring or minimal stimulation with GnRH antagonists, the efficiency of harvesting even one follicle for one egg has dramatically skyrocketed, making this a sustainable cost- effective option for some patients.
The best candidates for mini IVF are those patients who only need one embryo to have a good pregnancy rate, i.e. women under 35 years of age. Another group that can benefit from natural cycle IVF are those women with very poor ovarian reserve, who even with extremely high doses of costly injectable fertility drugs do not yield more than one or two eggs. Thus, it is cost-effective to treat both these groups and utilize all the comprehensive treatment power of in vitro fertilization even for one egg and embryo.
Pregnancy rates are ultimately driven by egg quality which can be evaluated as embryo quality by morphological and chromosomal integrity. Blastocysts are graded in their appearance and can be biopsied and their chromosome integrity can be checked by PGT-A. Predictions of this are driven by the chronological age of the patient. There is no mystery here that older women have higher incidence of abnormal embryos for any given IVF attempt and therefore lower pregnancy rates. Donor egg cycles are used as gold standard comparison for pregnancy averaging between 50-70% implantation for one tested embryo.
The clear advantage in utilizing mini IVF is cost. The down side is that the cycle will not yield supernumerary embryos for a freeze, and will be very limited in supporting a management plan that involves pre implantation genetic testing or screening as multiple embryos are needed for both.