Successful Pregnancy after Microsurgical Transplantation of an Intact Ovary

Abstract

these two lines of evidence provide support for the role of the NHERF1 variants in the decrease in TmP/GFR values in our patients. Since FGF-23 decreases renal phosphate reab-sorption and can induce hypophosphatemia, we studied patients with normal serum FGF-23 concentrations. Rendina et al. hypothesized that serum FGF-23 concentrations should be low in patients with hypophosphatemia. Undetectable FGF-23 levels are considered normal. We did not assess the serum FGF-23 concentrations in our patients according to whether the TmP/GFR values were normal or low, so we do not know whether hypophosphatemia lowered FGF-23 production. Although the serum FGF-23 concentration correlates with the serum phosphate concentration in patients with kidney disease, such a correlation has not been reported, to our knowledge , in patients with normal renal function. It is not known whether, when renal function is normal , FGF-23 concentrations are lower in patients with hypophosphatemia than in patients with normal serum phosphate levels. We agree that further studies are required to clarify this point. Successful Pregnancy after Microsurgical Transplantation of an Intact Ovary To the Editor: Successful human ovarian trans-plantation was first reported with the use of a cortical-tissue grafting technique in monozygotic twins who were discordant for premature ovar-ian failure. 1 Subsequently, six additional cases have been reported, which have resulted in a return of ovulation in all patients, with spontaneous conception and delivery of six healthy infants, with one from tissue that had been frozen. 2 The concept of ovarian cortical grafting is based on the fact that all follicles containing eggs are located in the outer 1 mm of the ovary, which can be sutured to the recipient's medulla just like a full-thickness skin graft. However, a limitation of this technique is that the graft generally loses two thirds of its follicles from ischemia during revascularization, which reduces its life span. 3 The patients we have described previously became menopausal after 3 years, although pregnancy then occurred again after grafting of frozen ovarian tissue. Data from studies in animals suggest that microvascular whole-ovary transplanta-tion could avoid this problem. 4 A pair of 38-year-old monozygotic twins requested ovary transplantation. One of the sisters had two children and normal ovarian function, whereas the other had undergone premature menopause at the age of 15 years, with amenor-rhea for 23 years and a follicle-stimulating hormone (FSH) level of 81 mIU per milliliter. After the procedure was approved by the review board at our institution and written informed consent was obtained from the patients, we laparoscopically removed one ovary from the fertile sister by dividing the infundibulopelvic ligament at its base for maximum length. The ovary was then prepared for microvascular trans-plantation in the recipient. With the use of mini-laparotomy, the donor's ovarian veins (3.0 mm in diameter) were anastomosed to the recipient's ovarian veins with 9-0 nylon sutures, and the donor's ovarian arteries (0.5 mm in diameter) were anastomosed to the recipient's ovarian arteries with 10-0 nylon interrupted sutures (Fig. 1). Normal-appearing blood flow was immediately observed through the ovarian vessels of the transplanted ovary after an ischemic period of 100 minutes. The recipient's first menstruation in 22 years occurred on day 101 after transplantation; by day 158, the FSH level had dropped to 7.4 U per liter. Ultrasonography revealed continuing normal blood flow to the transplanted ovary and normal follicular development. The patient had 11 regular menstrual cycles until, by day 427 after trans-plantation, the level of beta human chorionic The New England Journal of Medicine Downloaded from nejm.org at UNIVERSITY OF MICHIGAN on September 2, 2020. For personal use only. No other uses without permission.