We evaluated the results of cryopreserved/thawed embryo replacement (FER) to determine if the outcome following transfer in a natural cycle in a defined group was different to that from a hormone replacement cycle, and also to assess vaginal ultrasonographic features that assist in predicting the timing of the transfer. At the London Fertility Centre, 149 consecutive FER cycles were studied retrospectively. Women with proven ovulation and regular cycles were included during natural cycles (n = 77). The hormone replacement cycle group included women with anovulation, irregular cycles and older women (n = 72). In the natural cycle group, transfer was performed following positive urinary luteinizing hormone (LH) surge and confirmation of ovulation by ultrasonography. With the hormone replacement therapy group, gonadotrophin-releasing hormone analogue was used to induce pituitary down-regulation, oestradiol valerate was supplemented followed by regular ultrasound monitoring, and FER 2 days following the initiation of progesterone, which was started once adequate endometrial development was noticed on ultrasonography. The pregnancy and ongoing/delivery rates were analysed in relation to the treatment cycle, age, number and quality of embryos transferred. Ultrasonographic features were examined to evaluate their relationship with the outcome of treatment. The results showed that no difference existed between natural and hormone replacement cycles in pregnancy rates per cycle (26 and 25%), ongoing/delivery rate (20.8% in both groups), and implantation rate (10.3 and 10.6%). Pregnancy rates were not influenced by the number of embryos transferred, stage at which the embryos were cryopreserved, or whether they were extra embryos from in-vitro fertilization/embryo transfer, or gamete intra-Fallopian transfer.(ABSTRACT TRUNCATED AT 250 WORDS)
We present results of in-vitro fertilization (IVF) cycles using assisted fertilization at our centre. Assisted fertilization was performed in those couples who had failed to fertilize oocytes with conventional IVF, or where this was predicted by the presence of severe male factor infertility. In 20 consecutive assisted fertilization cycles 223 oocytes were subjected exclusively to subzonal insemination (SUZI). Subsequently in 32 consecutive assisted fertilization cycles 418 oocytes were subjected to intra-cytoplasmic sperm injection (ICSI). More oocytes were damaged by ICSI (8.9%) than by SUZI (2.3%) (P = 0.03), but normal fertilization resulted more often after ICSI (56.9%) than SUZI (35.8%) (P = 0.004). Sperm parameters, other than sufficient numbers to perform the procedures, had no effect on fertilization or pregnancy rates. Every cycle led to the transfer of at least one embryo. Pregnancy resulted from eight of the SUZI cycles (40%) and nine of the ICSI cycles (28%). Implantation rates were calculated as 25 and 12% for SUZI and ICSI respectively. The presence of living spermatozoa is the only semen parameter limiting assisted fertilization. At present more centres are able to perform SUZI than ICSI and we feel it is premature to abandon SUZI altogether. Local conditions and success rates should be considered when decisions are made in assisted fertilization cycles.
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