In vitro maturation of human oocytes can be used for fertility preservation. In vitro maturation-IVM indicates that eggs are retrieved without stimulation or after a short period-about 3 days-of treatment with fertility medication. Oocytes are then either 1. Frozen as immature eggs, 2. Matured in the lab for 24 to 30 hours and then frozen as mature eggs or 3. matured in the lab and fertilized using direct injection of sperm-ICSI and the resulting embryos as frozen. Freezing mature eggs generally yields better outcomes that freezing immature eggs. Vitrification appears to result in better survival than slow freezing of oocytes.
Advantages of in vitro maturation
IVM can be accomplished without prolonged exposure to fertility medication-3 days versus 14 to 21 days for classic IVF cycles. Estrogen does not increase to the same levels as seen with IVF, which may be advantageous for some estrogen sensitive cancers as breast cancer. Newer approach to ovarian stimulation using aromatase inhibitors in women diagnosed with breast cancer, enables ovarian stimulation to proceed without marked increase in estrogen levels. Because less fertility medication are used, the cost and the risk for ovarian hyperstimulation syndrome are less than conventional IVF
Disadvantages of in vitro maturation
As a reproductive endocrinologist attempt to retrieve eggs from small immature follicles, he or she is successful in doing so 50% of the time-approximately five eggs are retrieved from 10 follicles. Furthermore, 70 to 80% of those complete maturation in the lab making the process much less efficient than IVF. Very few labs in the world reported consistent success with IVM and only in select patients-those with high ovarian reserve. Research is ongoing to improve our ability to complete maturation of eggs in the lab. The success of this method is however, limited by woman’s ovarian reserve and our ability to retrieve these immature eggs. IVM is more suitable for women with PCOS or large number of small follicles in the ovary.
Safety of in vitro maturation
A relatively small number of babies were borne worldwide using IVM. There are no long term data on the health of children conceived using IVM. Moreover, data on outcomes are very scarce on babies borne after both IVM and egg freezing. One study showed that babies born after IVM are larger than those conceived with IVF and more frequently required cesarean delivery. Long term neurological outcomes are still unknown.
In vitro Maturation of immature oocytes after a conventional IVF cycle can be performed, aiming at increase the egg yield. After stimulation with fertility medication for 10-14 days, eggs are retrieved. Mature eggs are fertilized with sperm and immature eggs are left in culture to mature-instead of discarding them. Immature eggs are left over oocytes and in the experience of many labs seldom produce a good quality embryo or pregnancy.
In select patients with good ovarian reserve, in vitro maturation can be considered after counseling patients that this so far a less efficient approach than IVF and that the long term outcomes of children conceived via IVM is still unknown. Read more at http://nycivf.org