Surrogate embryo transfer combined with estrogen-progesterone therapy in monkeys. Implantation, gestation, and delivery without ovaries.

The collection of in vivo fertilized embryos by lavage of the normal donor's uterotubal lumens and transfer of these surrogate embryos to the uterotubal environs of long-term castrate female monkeys is described. Sequential estrogen-progesterone replacement therapy that mimics the natural ovarian-menstrual cycle was administered to the recipients, causing the development of proliferative and secretory endometrium to accommodate the perinidatory events leading to successful placentation and embryogenesis. Retrograde irrigation of the uterotubal lumens of 23 normal intact donors was performed three to four days after the estimated time of ovulation, coitus, and fertilization. Of the 17 embryos or eggs collected, some were apparently healthy, as assessed by microscopic inspection, whereas others were obviously degenerating. Eleven surrogate embryos were transferred to steroid-treated, long-term castrate female recipients; four viable pregnancies were detected by measurement of chorionic gonadotropin, all concluding with uneventful deliveries of normal live neonates at term. These findings demonstrate the feasibility of establishing and maintaining normal pregnancy by combining surrogate embryo transfer with an exogenous steroid hormone regimen, even in the complete absence of ovarian function. The clinical implications of these primate studies may be far-reaching because they indicate new potential for childbearing by otherwise infertile or sterile women who have a competent uterus but lack the hormonal milieu provided by ovarian follicular maturation and corpus luteum function in the normal menstrual cycle.