論文・講演抄録

In vitro maturation（ IVM） refers to maturation in culture of immature oocytes at different stages that may or may not have been exposed to short courses of gonadotropins. The source of immature oocytes is an important feature for the subsequent embryonic development and pregnancy, but the developmental competence of oocytes derived from the small antral follicles seems not to be adversely affected by the presence of a dominant follicle.
The use of IVM technology can thus be broadened to treat women suffering from all causes of infertility with acceptable pregnancy and live birth rates. Although IVM as an efficient treatment resulted several thousands of healthy babies born, IVM technology is still considered experimental by the society. Maybe, it is time to reconsider the IVM technology as efficient clinical treatment.

Today, given the efficiency of IVF and improvements in the culture system, natural cycle IVF or mild stimulation may be more suitable for women undergoing IVF treatment. Several studies have shown that natural cycle IVF treatment has advantages over standard stimulation IVF treatment pa rticula rly in the management of women with low ovarian reserve.
In contrast to stimulation IVF treatment, the aim of mild stimulation is to develop safer and patient-friendlier protocols where the risks of the treatment are minimized.
A recent large retrospective study has found a significant decrease in live birth rate associated with increasing FSH dose regardless of the number of oocytes retrieved,
cautioning against high doses of FSH in IVF treatment cycles albert falling short of recommending mild IVF treatment. There is also evidence that mild stimulation or
modified natural cycle protocols may have equal or even improved success rates compared with conventional IVF in women with a history of poor ovarian response.

As the development of IVM treatment continues, an attractive possibility for increasing the successful outcome rate is combining natural cycle IVF treatment with immature oocyte retrieval followed by IVM of those immature oocytes. If the treatment processes can be simplified, especially for immature oocyte retrieval, more
infertile women may be able to take advantage of these treatments. Mild stimulation IVF combined with IVM treatment may represent a viable alternative to standard
treatment. As we accumulate more experience and outcome data, mild stimulation IVF combined with IVM may prove to be not just an alternative to standard  treatments, but potentially first-line treatment choices.