Multiple follicular stimulation for IVF may be associated with greatly elevated serum E concentrations that are presumed to be antinidatory. This factor was analyzed in 825 consecutive embryo transfer cycles. The pregnancy rate decreased significantly after the transfer of one and two embryos in association with preovulatory E levels greater than the 90th percentile for the group (2320 pg/ml). The pregnancy rate did not vary with preovulatory E concentration following the transfer of three embryos. Highly significant correlations were noted between preovulatory E and early luteal phase concentrations of E and P. In a subgroup of 245 cycles, there were no significant relationships between implantation and early luteal phase levels of P or the ratio of E /P. There was a small but nonsignificant tendency for the pregnancy rate to decrease in association with raised luteal E . It is concluded that excessive E levels at the time of ovulation induction with hCG had an adverse effect on implantation when one or two embryos are transferred, but this may be overcome by the transfer of three embryos. The consequences for embryo transfer are discussed.
There have been several causes of infertility attributed to gamete quality, congenital anatomical abnormalities and surgical complications. Published research into the reasons for failure of implantation of embryos has been confined to histochemical and histological studies of the endometrium. This paper presents preliminary data from an ongoing study to test the hypothesis that poor uterine perfusion is a cause of failure of implantation of embryos. It would follow that poor uterine perfusion is a cause of infertility. One-hundred-and-fifty-three patients who had been unsuccessful in conceiving despite three previous in-vitro fertilization attempts have been studied. Doppler ultrasound studies of the ascending branch of the uterine artery, during spontaneous ovarian cycles, revealed a poor mid-secretory uterine response in 48% of patients studied. Patients with poor mid-secretory uterine response were treated with orally administered hormone therapy to improve the mid-secretory uterine response prior to subsequent embryo replacement. The results of subsequent in-vitro fertilization therapy in patients with good uterine response and in women with improved uterine response after hormone therapy are presented. The numbers of patients in each group are insufficient for statistical analyses, but the trends observed support the hypothesis that poor uterine blood flow is a cause of infertility. Further evaluation is warranted.
Early cleavage stage human embryos and 8-cell mouse embryos were snap-frozen after a brief exposure to high concentrations of dimethyl sulfoxide (DMSO; 2 or 3.5 M) and 0.25 M sucrose and thawed in a warm water bath. Eleven of 12 3- to 8-cell human embryos survived freezing and thawing with more than 50% of their original blastomeres intact. However, pregnancy was not initiated when the 11 embryos were transferred to six patients. It was shown that continuation of embryonic development in vitro and in vivo was significantly better when 8-cell mouse embryos were snap-frozen in 3.5 M DMSO than in 2 M DMSO. When frozen in 3.5 M DMSO, 78% of 8-cell embryos survived on thawing, 84% developed to blastocysts in vitro, 63% implanted, and 42% developed to fetuses. Ultrarapid freezing is a quick and inexpensive method for mouse embryo cryobanking, but further studies are required to confirm the viability of frozen human embryos.
Although the pregnancy rate per transfer of the Norfolk In Vitro Fertilization-Embryo Transfer (IVF-ET) program has been reported as between 25% and 35%, the viable pregnancy rate per transfer is only 15% to 20%. An understanding of the mechanism(s) and etiologic factors of miscarriage among IVF patients might suggest changes that could prevent some early pregnancy wastage. Forty-seven consecutive single pregnancies and 26 miscarriages (October 1985 to November 1986) were included in this study. Factors such as implantation time, date of corpus luteum rescue (CLR), embryo quality, and corpus luteum activity after rescue were studied and compared between term pregnancy and miscarriage groups. Results are discussed in detail in this paper.