The aim of this study was to examine the safety and the efficiency of a 'non-contact' UV laser to assist hatching through zona opening of human embryos. Between January and November 1995 we performed zona drilling for assisted hatching using a new laser system (PALM UV Laser microbeam), operating in a 'non-contact' mode to create a hole in the zona pellucida of human embryos. In a randomized study, laser zona opening was applied on embryos from two groups of patients with repeated in-vitro fertilization (IVF) failures (two to four attempts): group A was composed of 107 patients who received mixed embryos (216 laser-treated and 223 not treated) and group B of 72 patients who received 218 laser-treated embryos only. Both groups were compared with a control group of 98 patients whose embryos were not laser treated (n = 407) (group C). The mean ages of all groups (38.1, 38.2 and 37.8 years respectively) and the number of IVF attempts (two to four attempts) were similar. The resulting clinical pregnancies were 39 (36.4%) in group A, 32 (44.4%) in group B and 19 (19.3%) in group C. The implantation rates/embryo were 9.3% in A, 16% in B and 5.1% in the control group. In total, 17 normal babies have been delivered (10 in group A and seven in group B). These results show that laser zona drilling increased the pregnancy and implantation rates in all the treated patients. The increase was slight but significant in patients of group A (P < 0.01 and P < 0.02), it was even higher in the patients of group B (P < 0.05).
From 1993 to 1994, in our centre, laser-assisted hatching was performed on 2- to 4-cell stage embryos obtained from in-vitro fertilization (IVF) patients. We treated 376 embryos from 96 patients with repeated IVF failures (two to four attempts) (group A) and 397 embryos from 111 patients undergoing IVF for the first time (group B). Embryos were transferred immediately after the laser treatment. Both groups were compared to control groups (A' and B') whose embryos were transferred with intact zona pellucida (ZP). The resulting clinical pregnancies were 41 in A and 44 in B versus 24 in A' and 23 in B' respectively. The pregnancy rates per patient were 42.7 and 39.6% versus 23.1 and 19% in the control groups (P < or = 0.05), while the implantation rates per embryo were 12.2% in A and 11.8% in B versus 7.3% and 7.1%. These results show that laser zona thinning of human embryos at 48 h after egg retrieval significantly increases the implantation and pregnancy rate (P < or = 0.05).
Oocyte donation was performed by in-vitro fertilization and embryo transfer in 82 women. The average age of the patients was 48 years (range 26-60), and 71 were over 40 years old, with an average follicle stimulating hormone (FSH) value of 74 +/- 14 IU and oestradiol concentration of 30 +/- 9 pg/ml. Overall 32 clinical pregnancies were achieved, of which 21 reached term, three are ongoing, and eight were lost (six miscarriages, one abruptio placentae, and one severe gestational proteinuria hypertension in the second trimester). The 21 term pregnancies produced 26 newborns; one patient who had had three embryos replaced delivered triplets and three patients had twins. Before the embryo transfer was performed, the endometrium thickness was accurately determined by vaginal ultrasound probe. The highest number of implanted embryos was reached when the endometrium thickness was 9-12 mm.
Mechanical partial zonal dissection (PZD) is one of the microinsemination techniques developed to improve the chances of fertilization by in-vitro insemination in subfertile males. We developed a new and safe laser method (erbium laser ablation) for PZD, with the aim of producing a precise opening as well as ablation of some layers of the zona pellucida. From February 1992 to March 1993, 104 couples suffering from male factor infertility were treated in our centre. All patients were affected by severe oligoasthenozoospermia and had previously undergone one failed in-vitro fertilization attempt each. Photoablation of the zona pellucida was induced in 512 oocytes by exposure to an erbium--yytrium aluminium garnet (Yag) laser. The openings obtained were approximately 14 microns in diameter. Of the laser-treated oocytes, 158 (30%) fertilized and 139 (88%) cleaved. Nineteen (18.3%) clinical pregnancies resulted and produced 17 newborns, all in good health. In our series there were four miscarriages, 23 damaged oocytes (4.4%) and 13 with three or more pronuclei (2.5%). Considering that the incidence of damaged oocytes and polyspermy is low, it seems that in some cases of male factor infertility erbium-Yag laser photoablation of the oocyte zona pellucida can be considered a procedure which is effective in enhancing fertilization and which is safe, allowing normal embryo development.
The pregnancies achieved up to April 1994 among 162 recipients who participated in our oocyte donation programme were studied. Of these, 113 were > 45 years old and 49 were < 45 years old (25-44); approximately 300 women were not admitted to our programme for various reasons. The 113 recipients considered in this study were divided into two age groups: group A, 45-49 years old (54 patient cycles); and group B, 50-60 years old (58 patient cycles); there was also one case of a 63 year old woman. Overall, 44 clinical pregnancies were established in 113 recipient cycles (38.9%) and 44 healthy babies have been delivered; 10 babies were lost (eight miscarriages, one abruptio placentae and one severe gestational proteinuria hypertension at 25 weeks). There was also one case of medium hypertension (at 32 weeks) and four cases of mild hypertension (30, 32, 33 and 35 weeks). There were no cases of maternal diabetes among the pregnant women due to the strict selection criteria. There were no maternal deaths associated with these pregnancies. Regarding neonatal morbidity and mortality, there was one premature labour in the 31st week in a 53 year old woman because of an accidental fall in an airport, and another one in a 51 year old woman in the 25th week. The remaining babies had good Apgar scores and good weights. There were no child deaths and to date there have been no reports of fetal malformation. All babies delivered are in good health.2
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