[Fertilization in vitro and embryo transfer (FIVET) and endometriosis. Uncertainties and issues]

The progressive improvements in the results and extra simplification of the recent techniques for in vitro fertilisation and embryo transfer (IVFET) have contributed to broadening the indications for this method of assisted reproduction. Endometriosis has not escaped this evolution and more and more works referring to the use of IVFET for this indication. All the same, there are many questions which have not been clearly answered. The possible variety of causes for this condition, the number of factors that may be causing the infertility, make it difficult to assess completely the method of therapy, and require that controlled studies should carried out. These are not always easy to perform. IVFET is no exception to these difficulties. The relationships between endometriosis and infertility are complex and very often difficult to assess. All the same, very many hypotheses have been put out to explain the deleterious effect of this abnormality. Certain mechanisms have been suggested (such as troubles with maturation of the follicle and of the oocyte and the production of a hostile environment for the gametes and for the embryo). These are logical arguments for IVFET which initially produces follicular maturation and takes the gametes and the embryo away from the peritoneal and tubal environment. In spite of certain hypotheses which would be unfavourable in cases of endometriosis (oocytes being less likely to be fertilised, poorer quality of the embryos, defective implantation...) the results that have been obtained after IVFET are overall very favourable and certainly can compare with those obtained when it has been used for, for instance, tubal indication.(ABSTRACT TRUNCATED AT 250 WORDS)