Laser zona pellucida thinning--an alternative approach to assisted hatching.

BACKGROUND: The purpose of this study was to assess the efficacy and hatching characteristics of in-vitro cultured human embryos subjected to laser zona pellucida thinning. METHOD: Zona thinning was performed on 110 embryos using a non-contact 1.48 microm diode laser and the hatch rate in vitro was compared with 42 control embryos. Variation of zona thickness and degree of zona expansion was assessed. Scanning electron microscopy was performed on embryos entrapped during hatching to identify the site of hatching. RESULTS: The rate of hatching was significantly higher in laser thinned blastocysts compared with control embryos (68 versus 33% respectively, P < 0.01). Laser thinning increased the variation of zona thickness in embryos from 11.6-27.3%. Natural zona thinning occurred in 92% of laser thinned hatching blastocysts and 100% of control embryos. CONCLUSION: These results suggest that laser zona thinning is effective and may provide significant advantages over conventional assisted hatching techniques, which create holes.

Prognostic factors for the success rate of embryo freezing.

To find some prognostic factors for the outcome of frozen-thawed cycles, we have retrospectively analysed all frozen pre-embryos that were thawed during 1993 and 1994 at two in-vitro fertilization (IVF) units in Sweden. Supernumerary pre-embryos were frozen from 551 oocyte retrievals and these resulted in 660 frozen-thawed cycles which lead to 623 thawed embryo transfers. The outcome of these transfers was 137 clinical pregnancies with a pregnancy rate of 22% per frozen-thawed embryo transfers. Women <40 years of age had a higher birth rate than those > or =40 years, 19 and 5% respectively (P < 0.01). Transfers with two and three pre-embryos resulted in pregnancy rates of 23 and 27%, respectively, compared with 14% for transfer of one embryo. A pregnancy resulting from the initial embryo transfers had a predictive value for results of the subsequent frozen-thawed cycle. Embryo grade and cleavage stage at the time of freezing was important for the survival of the frozen-thawed pre-embryos. The pregnancy rate was not influenced by the cleavage stage, but a tendency toward a lower pregnancy rate was seen for the embryos with lower grading. To conclude, cryopreservation seems to be beneficial in women <40 years of age, who have supernumerary pre-embryos of good quality for freezing and of which at least two can be transferred.

The outcome of intracytoplasmic sperm injection is unrelated to 'strict criteria' sperm morphology.

Sperm morphology was assessed according to the 'strict criteria' established for in-vitro fertilization treatment in the semen samples used for 354 consecutive treatment cycles for intracytoplasmic sperm injection (ICSI). The semen samples were classified according to the three predictive categories of the Tygerberg strict criteria: excellent prognosis (>14% morphologically normal spermatozoa), good prognosis (4-14%) and poor prognosis (<4%). It was found that 37 (10.5%) of the ICSI cycles belonged to the excellent prognosis category, 197 (55.6%) to the good prognosis category, and 120 (33.9%) to the poor prognosis category. The outcomes of the ICSI treatments were evaluated and compared with the sperm morphology classification in order to determine whether the strict criteria could aid in predicting the outcome of ICSI. The fertilization rates in the three categories were 61.6, 66.8, and 61.9%, the pregnancy rates per oocyte retrieval 18.9, 24.9, and 28.3%, and the implantation rates 9.9, 13.0, and 14.9% respectively. No significant differences were found in fertilization, pregnancy, or implantation rates between the three prognosis categories, i.e. the poor prognosis category had an equal chance of obtaining pregnancy compared with the good prognosis category. The results indicate that strict sperm morphology is not related to the outcome of ICSI.

Human chorionic gonadotrophin self-administered by the subcutaneous route to induce oocyte maturation in an in-vitro fertilization and embryo transfer programme.

This study was initiated to evaluate oocyte maturation and the outcome of in-vitro fertilization (IVF) cycles following the s.c. administration of human chorionic gonadotrophin (HCG) by the patient herself or her partner. A group of 104 women who entered our IVF embryo transfer programme were prospectively randomized to have 5000 IU or 10,000 IU HCG s.c. or i.m. The HCG was administered for induction of the final oocyte maturation in cycles with pituitary down-regulation with a gonadotrophin-releasing hormone agonist according to a long protocol and where ovarian stimulation had been achieved with pure follicle stimulating hormone. The mean concentration of HCG in serum 12 and 36 h after the HCG injection was significantly higher in the women receiving 5000 IU i.m. compared to the s.c. route. However, in women receiving 10,000 IU HCG there were no significant differences in the mean concentrations 12 and 36 h after the injection, irrespective of the route of administration. Furthermore, there were no significant differences in the relative numbers of retrieved mature oocytes between the groups. When comparing the clinical outcome in the different groups, no significant differences were found between those receiving 5000 IU or 10,000 IU HCG, i.m. or s.c. Our data indicate that HCG can be given s.c. without reducing the chance of retrieving a mature oocyte and that the clinical outcome with regard to pregnancies is not negatively affected.

Factors of importance for the establishment of a successful program of intracytoplasmic sperm injection treatment for male infertility.

OBJECTIVE: To establish an intracytoplasmic sperm injection treatment program for couples with male infertility and to determine those factors important for success. DESIGN: A retrospective analysis of 171 consecutive cycles of intracytoplasmic sperm injection concerning 145 infertile couples. SETTING: Infertility clinic in a private hospital associated with a university hospital. PATIENTS: Couples with infertility in the male partner whose sperm parameters were unacceptable for conventional IVF or in whom fertilization by conventional IVF failed repeatedly. INTERVENTIONS: One hundred seventy-one transvaginal oocyte retrievals were completed after superovulation with GnRH agonist and gonadotropins. MAIN OUTCOME MEASURES: The parameters evaluated included fertilization, cleavage, implantation, pregnancy, and spontaneous abortion in relation to patient indications and improved procedures. RESULTS: After intracytoplasmic sperm injection, normal fertilization occurred in 45% of the oocytes (n = 1,499). Of 171 treatment cycles, 93% of the couples had fertilization and 86% had ET. Thirty-six pregnancies were achieved. During the period studied, the mean fertilization rate increased from 21.3% during the first 17 weeks to 67.8% during the last 13 weeks, and the pregnancy rate (PR) per started cycle increased from 12.8% to 31.3%. CONCLUSIONS: Technical factors critical for achieving high rates of fertilization and pregnancy were the use of standardized intracytoplasmic sperm injection pipettes, the immobilization of sperm before injection, and the aspiration of a minimal amount of ooplasm before reinjection with the sperm. Intracytoplasmic sperm injection appears to be superior to other micromanipulation methods for alleviating male infertility.

Subzonal insemination (SUZI) or in vitro fertilization (IVF) in microdroplets for the treatment of male-factor infertility.

PURPOSE: The results of subzonal insemination (SUZI) and in vitro fertilization with microdroplet insemination used in couples with male-factor infertility are presented. RESULTS: The total fertilization rate was 17.4% for SUZI (n = 89) and 49.3% for microdroplet IVF (n = 100). The fertilization rate for standard IVF (n = 510), not including any male-factor infertility and performed during the same period, was 73.2%. The "take-home baby rate" per started cycle and per embryo transfer (ET), respectively, was 10 and 17.6% for SUZI and 20 and 24.7% for microdrop IVF. For standard IVF these figures were 27 and 31.7%. CONCLUSION: It was concluded that microdroplet IVF can be used with good results in cases of moderate male-factor infertility. The normal (2PN) fertilization rate with the SUZI technique was only 15.1%. However, despite the low fertilization rate, SUZI should be considered when dealing with severe male-factor infertility.