IVF: Doctors fail to test for endometriosis, a disease of the lining of the uterus which causes infertility, before giving their patients IVF treatment , suggests an article in the journal Fertility and Sterility. Although the study was based on only 29 women, the research has important implications since endometriosis affects up to 50% of infertile women. Dr Camran Nezhat, of Stanford University, says that the pendulum has swung too far in favour of IVF -- which requires powerful fertility drugs that can carry serious side effects -- and treating endometriosis first may help women conceive.