Oocyte donation in Turner's syndrome: An analysis of the factors affecting the outcome

A total of 29 women with Turner's syndrome (19 monosomy and 10 mosaic) had 68 cycles of oocyte donation that included 29 cycles of initial attempt and 39 cycles of subsequent attempts. Oral oestradiol valerate was used either in a variable dose (42 cycles) or in a constant dose (26 cycles) regimen for the endometrial preparation which was monitored by pelvic ultrasonography. The embryos/ zygotes were transferred either fresh (50 cycles) or after cryopreservation (18 cycles) into the Fallopian tube (41 cycles) and uterine cavity (27 cycles) as appropriate. There were 28 clinical pregnancies including two sets of triplets resulting in a pregnancy rate of 41.2% per treatment cycle and an implantation rate of 17.1% per embryo transferred. The recipient's age, chromosomal constitution or associated uterine or tubal anomaly had no influence on the treatment outcome. The implantation and pregnancy rates were higher in the subsequent than initial cycles (22.6 versus 9.99%, P <0.05; 51.3 versus 27.6%, P <0.05). An endometrial thickness of greater than or equal to 6.5 mm was an important predictor of pregnancy but the endometrial echo pattern failed to predict the outcome. Although the total dose of oestradiol before embryo transfer was higher in the pregnant cycles than the non-pregnant ones and its gradation (<50 mg, 50-100 mg, <100 mg) influenced the implantation (3.4, 17.5, 26.3% respectively, P <0.05) and pregnancy rates (10, 42.2, 61.5% respectively, P <0.05), the effect was indirect by altering the endometrial thickness. The number of oocytes fertilized affected the pregnancy rate irrespective of the number of embryos transferred. The implantation and pregnancy rates were higher when fresh rather than frozen-thawed embryos were transferred (20.3 versus 8.2%, P <0.05; 48 versus 22.2%, P <0.05) but the route of transfer was of no statistical importance. The overall miscarriage rate was higher (50%), and was related to the presence of hypoplastic or bicornuate uterus and to a low oocyte fertilization rate.