Is a technique used for cases in which there is a lack of ova by ovarian failure, either in a spontaneous (the menopause) caused the (surgery to radiotherapy / chemotherapy for the treatment of cancer). Other situations can be benefit from this technique, such as the eggs of poor quality or absence of the low follicular development after the induction of the ovulación. Should be a preparation of the endometrium to sea ready to receive the embryos. For this reason, the use of píldoras of estrogen in increasing doses and following the thickening of the endometrium by ultrasound. When this is the case that empezamos to use the hormone progesterone. The donation of the eggs are fertilized in vitro with the sperm of the husband, and the embryos cultured in the laboratory and then transferred to the recipient uterus al. Rate of pregnancy - from 45 to 55%