H.I. Kort

Immunosuppression supports implantation of zona pellucida dissected human embryos

The effect of low dose immunosuppression with methylprednisolone during the first 4 days after oocyte retrieval on potential immune cell invasion of partially zona dissected embryos in utero was investigated in alternate in vitro fertilization patients (n = 32). The incidence of pregnancy was significantly higher in patients receiving methylprednisolone (7 of 18, 39%) than in control patients (1 of 14, 7%). Twenty-eight percent (11 of 39) of the embryos replaced in the corticosteroid treated patients implanted, whereas only 7% (2 of 31) of embryos in control patients had a fetal heart beat. There were no side effects reported in any of the patients receiving corticosteroids. It can be concluded that methylprednisolone supports implantation of embryos with small holes in their zonae. However, the actual mechanisms of corticosteroid support on the interaction between immune cells and micromanipulated embryos are not well understood.

Cryopreserved zygotes and embryos and endocrinologie factors in the replacement cycle

Several parameters relating to features of replacement cycles in 88 patients were found to influence implantation of cryopreserved zygotes and early cleaved embryos. Cryopreserved embryos were replaced in 47 patients with a natural cycle, resulting in 12 (25%) clinical pregnancies. Patients who had anovulation or irregular cycles received either 50 mg clomiphene citrate on days 5 to 9 or 100 mg on days 2 to 6; the incidence of clinical pregnancy was 7 of 23 (30%) and 2 of 18 (11%), respectively. Neither a rise in follicular phase estradiol (E2) nor absolute levels of E2 predicted implantation. The length of the follicular phase during the replacement cycle correlated well with previous menstrual cycles in 43 (54%) of the patients, and 16 (37%) of these patients became pregnant. The follicular phase was either longer or shorter than anticipated in 39 patients, and only 5 (13%) became pregnant: a detrimental effect was especially apparent when the follicular phase was shortened.

STIMULATION CYCLES SUPPRESSED WITH GONADOTROPIN-RELEASING HORMONE ANALOG YIELD ACCELERATED EMBRYOS

A retrospective study was performed to assess embryonic development and morphology in 71 patients whose follicular stimulation was regulated after down regulation with a gonadotropin-releasing hormone analog, leuprolide acetate. The embryos were compared with those from 66 patients who did not receive agonists and who were treated during the same period. A separate group of thawed embryos cryopreserved after down regulation in 21 patients was compared with embryos frozen after conventional stimulation during the same period from 21 other patients. Eleven morphological criteria were assessed in the fresh embryos, and analyses did not reveal any differences between the groups studied. However, the rate of development of embryos obtained during down-regulated cycles was significantly higher than that of embryos developing in conventional stimulation cycles. Although no significant morphological differences could be shown between the groups of cryopreserved embryos, there was a decreased incidence of implantation of embryos from patients who were exposed to analogs. It is suggested that embryos from down-regulated cycles should be cryopreserved earlier to correct for their accelerated development.

Coculture of Human Zygotes on Fetal Bovine Reproductive Tract Cells

When early cleaved human embryos are kept in culture, only one in four can be expected to develop into fully expanded blastocysts.1 Alternatively, only 1% to 12% of them will implant and develop into full-term babies, when replaced into the uterus or fallopian tube before the third cleavage division commences.2,3 Embryonic wastage following assisted reproduction can only in part be explained by an increased incidence of genetic abnormalities or loss at the time of replacement. Other more esoteric factors, like a reduced receptivity of the endometrium in stimulated menstrual cycles, probably play an important role as well.

Evaluation of the first one hundred and thirty one live births following oocyte cryopreservation from a single ivf program utilizing a standardized vitrification technique

OBJECTIVE: Oocyte cryopreservation by vitrification is an efficient procedure, however, limited data is available addressing the safety of this technology. For this reason we analysed live birth outcomes obtained after egg freezing in a comparable patient population. DESIGN: Retrospective, matched control study. MATERIALS AND METHODS: From December 2006 to December 2009, live birth outcomes from 90 deliveries following vitrified donation cycles & from 112 fresh egg donation cycles were tabulated and analysed. Cryopreservation of oocytes was performed by minimum volume vitrification. Oocytes were fertilized by 40 hrs after HCG adminisration (fresh egg donation) or 2-3 hrs after oocyte warming (cryo egg donation) Results were analysed by the One-way Anova or the Fisher’s exact tests, as appropriate (P<0.05). RESULTS: Parameters of live birth outcomes are reported in Table 1.

Partial Zona Dissection for Enhancement of Sperm Passage through the Zona Pellucida

Fertilization in mammals occurs in a number of intricate steps, culminating in the union of male and female genomes. Spermatozoa capacitate prior to sperm receptor binding on the zona pellucida (ZP), where the acrosome reaction is induced. Following ZP penetration membrane fusion occurs, triggering oocyte activation. This leads to the release of cortical granules and the zona reaction, causing a slow, but usually permanent block to polyspermy. Changes in the oolemma may initiate a fast, but often weak and temporary block, as well. Following decondensation and syngamy, the fertilization process is completed with the formation of a genetically new conceptus at the two-cell stage.1 Pathological changes may occur during any of these steps, and fertilization may either be discontinued or result in a genetically abnormal embryo. Discontinued fertilization is common during human in vitro fertilization (IVF), especially when there is a sperm disorder. Although the methods for microsurgical fertilization proposed in recent years only alleviate abnormal ZP-binding, ZP-penetration, and/or membrane fusion, they may be welcome additions to IVF. Basically, three methods, each with its own advantages and disadvantages, have been proposed: