[Improved implantation rate following embryo transfer in an in vitro fertilization program]

In spite of the efforts made in in-vitro fertilization and embryo transfer in recent years, little progress has so far been made with regard to the pregnancy rate. While embryo transfer rates of over 80% are now being attained, the pregnancy rate achieved with extracorporal fertilization in the majority of study groups is well under 20%. Between 1981 and May 1986, 1088 laparoscopies were performed in our study group with the aim of follicle puncture and subsequent in-vitro fertilization and embryo transfer. A total of 171 pregnancies resulted from 832 embryo transfers. The pregnancy rate has been increased since 1981 to 21.2% at present (1986). Since April 1986 we have been using a modified embryo transfer procedure: in 25 patients embryo transfer has been accomplished under barbiturate anesthesia. Twelve of these patients have become pregnant, i.e., 48% of the embryo transfers. There are signs that this embryo transfer method will lead to a distinct improvement in the pregnancy rate. An attempt should be made to confirm these provisional results in a larger collective.

[Initial results of the cryopreservation of human oocytes]

As a part of an IVF project, "superfluous" ova were frozen, then thawed and fertilized under in-vitro conditions. Altogether 133 oocytes of varying quality, from 22 patients, were frozen. To date, 57 ova have been thawed and 47 oocytes have been found. The survival rate after thawing was 34%, the in-vitro fertilization rate 75%. Out of a total of seven embryo transfers performed there was one pregnancy following transfer of a six-cell embryo.

Successful in-vitro fertilization of frozen-thawed rabbit oocytes

The objective of this study was to evaluate the capacity of frozen-thawed rabbit oocytes to be fertilized in vitro. After superovulation with FSH a total of 1040 oocytes was obtained by puncturing the follicles 6 or 9 h after the injection of LH or by flushing the oviducts 12 h after LH application. 1.5 M dimethylsulphoxide (DMSO) was used as cryoprotective agent and the oocytes were transferred into 0.25 ml French straws and cooled in a methanol bath to -30 degrees C and transferred to liquid nitrogen. After 1-14 days of storage the oocytes were thawed rapidly in a 15 degrees C water bath and DMSO was diluted in a stepwise manner. Subsequently the oocytes were cultured in Ham's F-10 + 10% fetal calf serum at 37 degrees C and 5% CO2 for 14, 7 and 4 h according to the time of oocyte collection. The survival rates of the oocytes based on morphological criteria were 5.4, 20.0 and 28.8%, respectively. For chromosomal analysis, morphologically intact frozen-thawed oocytes were fixed and stained using the technique described by Tarkowski. In 44 successful chromosomal preparations, 2 of 2, 10 of 19 and 22 of 23 preparations of oocytes collected 6, 9 and 12 h after LH application were in metaphase-II, respectively. Furthermore, the viability of the oocytes was also examined by using fluorescein diacetate. Out of 52 morphologically intact oocytes, 50 showed a positive intracellular fluorescence.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of the in-vitro fertilizing capacity of human spermatozoa with sperm morphology as assessed by three classification systems

Stained sperm morphology slides from an in-vitro fertilization programme were evaluated by the modified Williams system, the World Health Organization (WHO) system and morphometric size measurements (image analysis) to determine which system(s) were better predictors of fertility. Amorphous sperm head shape was the best predictor of fertility in both the modified Williams system and the WHO system, predicting the proper fertility status in 65% of the cases. Using only normal sperm in the statistical model, normal sperm became a correct predictor in 66% of the cases in the modified Williams system. Morphometric measurements were not useful in predicting the fertility status of these samples. These studies indicate that morphology can not be used as a sole predictor of fertilizing capacity of human spermatozoa.

Correlation between human sperm swelling in hypoosmotic medium (hypoosmotic swelling test) and in vitro fertilization

Human ejaculates (n = 83) were analyzed for standard sperm parameters (concentration, motility, and morphology), as well as for the ability of the spermatozoa to react (swell) in a hypoosmotic medium (Jeyendran et al, 1984). Subsequently, the fertilizing capacity of the spermatozoa was tested by their ability to fertilize human oocytes in vitro. Although the sperm concentration was adjusted for in vitro fertilization, no adjustments were made for sperm motility and morphology. Correlation of the in vitro fertilizing capacity of the spermatozoa with the hypoosmotic swelling test (r = 0.56) was much higher than with standard sperm parameters (r varied from -0.04 to 0.25). Complete overlap was noted with standard semen parameters whether the ejaculate did or did not fertilize oocytes and ranged from very low to very high values in both cases. By contrast, all the semen samples that fertilized oocytes showed a 60% or higher reaction in the hypoosmotic swelling test, whereas the majority of the "infertile" semen samples showed less than 60% swelling. It therefore appears that, under the conditions of our studies, the hypoosmotic swelling test is a more accurate predictor of successful in vitro fertilization outcome than the conventional semen parameters. A combination of all parameters, however, is likely to be most useful. The hypoosmotic swelling test is simple and economical, and it is recommended that this test be further scrutinized for its value as an additional tool in the assessment of the in vivo fertilizing capacity of ejaculated spermatozoa.

In vitro fertilization and embryo transfer of pre-ovulatory rabbit oocytes

The objective of this study was to develop an effective and successful technique of in vitro fertilization in rabbits that could lead us to start treatment of infertile couples by using extracorporal fertilization. Pre-ovulatory oocytes were harvested from follicles of virgin does 9 h after induction of ovulation by hCG injection, and incubated with in vivo capacitated sperm for 5 h. An 82% in vitro fertilization rate was achieved. The fertilized ova were cultivated for an additional 20, 44 and 68 h, and until they reached the hatched blastocyst stage. Most of these embryos (439) were transferred to 42 pseudopregnant recipients, asynchronous in the sense that they had been given hCG injections 0, 6, 12, 18, 24, 36 and 42 h later than the rabbits from which the ova had been obtained. With this type of synchronicity implantation rates of 31, 78, 52, 33, 52, 33, 51 and 10% were achieved, respectively. One hundred and twenty-eight embryos were not transferred to recipients but cultured in Ham's F-10 medium supplemented with 20% FCS. 77% of these embryos reached the stage of hatched blastocyst. A total of 143 young were born after 28-32 days of gestation and all are fertile till the third generation. Our results were obtained in a consecutive series of experiments, and demonstrated that in vitro fertilization can be made to work quite well in the rabbit, which in the early stages of embryogenesis has sufficient similarity to the human to make it a useful model for those wishing to acquire techniques applicable to human fertilization in vitro and embryo transfer.

Evaluation of acrosome on Papanicolaou-stained sperm and its relationship to the in vitro fertilizing capacity of human spermatozoa

Papanicolaou-stained sperm smears from 1150 ejaculates evaluated from infertility clinic patients and 166 ejaculates in an in vitro fertilization program were studied for the presence of acrosomal abnormalities. Morphologically, a normal acrosome was defined as a sperm having a ratio of 1:1 to 2:1 between the acrosome and postacrosomal part in an oval or round, uniformly shaped head. Acrosomal abnormality was identified in at least a few of the spermatozoa in all the ejaculates (range 8-98%) and appeared to be closely related to normal sperm morphology (r = 0.85). A significantly higher (p less than 0.01) correlation (r = 0.31) was noted between the presence of normal acrosome and in vitro fertilizing capacity of spermatozoa as compared to other standard semen characteristics. Acrosome can be identified on Papanicolaou-stained smears, and since it appears to be related to fertility it may be beneficial to evaluate the acrosome morphologically during routine semen analysis.

[Effect of human follicular fluid on the maturity of rabbit ova by in vitro conditions]

The influence of human follicular fluid from mature and immature oocytes on the maturation of rabbit oocytes under in-vitro conditions was examined. The human follicular fluids were obtained in the course of laparoscopies for extracorporeal insemination and separated into the categories mature and immature ova. In cases of normal early embryonal development the follicular fluid was termed "follicular fluid of a mature ovum"; if the ova were immature or degenerated the fluid was termed "follicular fluid of an immature ovum". Rabbit oocytes were obtained 3 hours after administration of P-LH and immediately cultivated in 3 different culture media for 7 hours. Only 6 out of 50 rabbit oocytes cultivated in Brackett's Defined Medium with the addition of 20% follicular fluid from an immature human ovum for 7 hours reached prometaphase II to metaphase II. This corresponds to a rate of 12%; on the other hand, with the addition of follicular fluid from a mature ovum 18 out of 50 oocytes reached the same phase, i.e., a rate of 36%. This difference is statistically significant (p less than 0.01). Brackett's Defined Medium with no fluid added was used as a control. Only 5 out of 50 oocytes managed to reach prometaphase II to metaphase II. The rate in this case was 10%. In order to prove that the rabbit oocytes were in the chromatin consolidation phase, they were fixed immediately after being obtained (3 hours after P-LH administration) and stained in 5% Giemsa solution. All of the oocytes (31) were in the chromatin consolidation phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Polyspermy in in vitro fertilization of human oocytes: frequency and possible causes

In an IVF program a total of 585 oocytes (180 patients) were examined for the presence of pronuclei 16 to 20 hours after the addition of spermatozoa. The overall fertilization rate was 71%, and in 58 (10%) of the fertilized oocytes, three or more pronuclei, indicating a failure of the block to polyspermy, could be observed. The frequency of polyspermy was related to the maturity of the oocyte, determined according to morphologic criteria. Immature oocytes showed a higher percentage of polyspermic fertilization (32%) compared to that of mature oocytes (6%). Preincubation of oocytes (for 0.5-1.5, 2-4, and 5-8 hours) prior to the addition of spermatozoa increased the fertilization rate (to 67%, 70%, and 83%, respectively). The polyspermy rate, however, was not significantly different between the various preincubation intervals (13%, 14%, and 19%, respectively). The polyspermy rate was affected by the number of spermatozoa used for in vitro fertilization. Insemination with 0.5-0.8, 1.0, or 1.5-2.0 X 10(6) spermatozoa/oocyte resulted in a polyspermy rate of 6%, 20%, and 32%, respectively. The appearance of polyspermic fertilization was not related to the age of the patient (which ranged from 20 to 45 years) nor to the method of ovarian stimulation (clomiphene, hMG, or clomiphene/hMG). Because of the high incidence of polyspermy under in vitro conditions it seems to be important to routinely examine the oocytes in the pronuclear stage. Reduction of the number of spermatozoa used for in vitro fertilization and the exact timing of insemination according to the maturity of the oocyte might reduce the occurrence of polyspermic fertilization.

Semen analysis and in vitro fertilization

Thirty-seven patients underwent ultrasonographic, clinical, and hormonal monitoring of superovulated cycles in order to time HCG administration in an attempt to schedule the laparoscopy at the optimal time for oocyte recovery. Superovulation was induced by Clomiphene in patients under the age of 35, with both ovaries; Clomiphene and HMG were administered in women over age 35 and/or with only one or half an ovary. Twelve patients were excluded because of poor oestradiol values or LH rise prior to HCG administration. Four patients were excluded at laparoscopy because of inadequate ovarian access (a preliminary laparoscopy was not performed). In 21 patients follicular aspiration was performed: 33 mature, 15 immature, and 5 degenerated oocytes were obtained (1.5 mature oocyte per patient). Thirty eggs were fertilized on a total number of 48 eggs (mature and immature)-fertilization rate of 63%. Twenty-nine embryos cleaved and were transferred to 13 patients at the 4- to 8-cell stage.

In vitro fertilization and embryo transfer of rabbit oocytes collected at different times after P-LH injection

No difficulties were encountered in the collection of preovulatory oocytes from the follicles of rabbits. A mean of 11.7 ova were recovered by follicle puncture. In vitro fertilization of the preovulatory oocytes was influenced by their stage of maturation. The highest fertilization rate (83%) was obtained using oocytes collected 9 h after injection of P-LH shortly before ovulation. Only after pretreatment with FSH-P was it possible to fertilize some preovulatory oocytes without administration of P-LH. In vitro fertilized preovulatory oocytes developed in culture. After 4-5 days 47-64% reached the blastocyst stage; the corresponding rate for in vivo fertilized oocytes was 48%. After transfer of in vitro fertilized preovulatory oocytes 19-28% implantations were achieved.

[Polyploidy occurring during in-vitro fertilization of human oocytes: frequency and possible causes]

In an IVF-program a total of 585 oocytes (180 patients) was examined for the presence of pronuclei 16 to 20 hours after the addition of spermatozoa. The fertilization rate was 71% and in 58 (10%) of the fertilized oocytes three or more pronuclei, indicating a failure of the block to polyspermy with polyspermic fertilization, could be observed. The frequency of polyspermy was related to the maturity of the oocyte, determined according to morphological criteria. Immature oocytes showed a higher percentage of polyspermic fertilization (32%) compared to mature oocytes (6%). Preincubation of oocytes (0-1.5, 2-4, 5-8 hours) prior to the addition of spermatozoa increased the fertilization rate (67%, 70%, 83%, respectively). The polyspermy rate seemed to increase (13%, 14%, 19%). The observed frequency, however, was not significantly different between the various preincubation intervals. The polyspermy rate was affected by the number of spermatozoa used for in-vitro fertilization. Insemination with 0.5-0.8, 1.0 or 1.5 X 10(6) spermatozoa/oocyte resulted in a polyspermy rate of 6%, 20%, 32%, respectively. The appearance of polyspermic fertilization was not related to the age of the patient (20 to 45 years) nor to the method of ovarian stimulation (Clomiphene, hMG, Clomiphene/hMG). Because of the high incidence of polyspermy under in-vitro conditions it seems to be important to examine the oocytes in the pronuclear stage on a routine basis. Reduction of the number of spermatozoa used for in-vitro fertilization and the exact timing of insemination according to the maturity of the oocyte might reduce the occurrence of polyspermic fertilization.

[Performance of laparoscopic follicle puncture and oocyte recovery for in-vitro fertilization]

In-vitro fertilisation of human egg cells and subsequent embryonal transfer offers a possibility to sterile women with oviducts incapable of functioning, to become pregnant after all. This article describes the performance of laparoscopic follicular puncture and extraction of egg cells for in-vitro fertilisation. Laparoscopic follicle puncture as described here was performed from July 1982 to March 1983 on 130 patients at the Gynaecological and Obstetric Hospital in Lübeck. 585 follicles were punctured and 404 egg cells obtained, 210 of which met the criteria of a pre-ovulatory egg cell. Of the 210 pre-ovulatory egg cells, 177 could be fertilised. In 95 patients, embryo transfer was effected in the 2-cell to 8-cell stage. The fertilisation rate obtained was 84%, with an embryo transfer rate of 71%. Since this patient group also included andrological causes of sterility, this figure can be considered quite satisfactory, which is decisively due, among other things, to the puncture technique described here. Pregnancy was attained in 14 cases so far. It is certain that the pregnancy rate can be improved still further.

Bilateral tubal pregnancy following in vitro fertilization and embryo transfer

A case of bilateral tubal pregnancy resulting from in vitro fertilization and the transfer of two embryos is reported. Because the husband had retrograde ejaculation after surgical treatment of a malignant testicular tumour, cryopreserved semen was used.

[Cryoconservation of 8-celled stage rabbit embryos in an automated "open system"]

Rabbit embryos were successfully frozen at the 8-cell stage, employing a rapid and a slow freezing-thawing program. They were then stored at -196 degrees C (liquid nitrogen) for 10 to 60 days. After thawing the embryos were examined for viability in vitro and in vivo. Using the slow program B 82.5% were morphologically intact, compared to only 69.3% after the rapid procedure (program A). 88.8% of the group first mentioned above, and 56.8% of the latter developed to the blastocyst stage after 4 to 5 days in culture. The implantation rate was 18.1%, when embryos were transferred to minus 18 hours asynchronous recipients, after thawing. With 40%, a significantly higher implantation rate could be achieved, when the embryos were transferred to minus 24 hours asynchronous foster mothers. 18 viable young were born 30 to 32 days after transfer.

Luteal phase following oocyte aspiration, in vitro fertilization, and embryo transfer in clomid/HCG-stimulated cycles

Using basal body temperature and repeated radioimmunological plasma progesterone estimations we monitored the luteal phase in seven patients after the administration of Clomid/hCG, oocyte recovery, in vitro fertilization and embryo transfer. In six of these women, the transferred embryos did not implant, and they bled 13--16 days after oocyte recovery. Neither the basal body temperature charts nor the plasma progesterone levels provided any indication of a luteal phase defect, being indistinguishable from those obtained in a control group of healthy women during the natural cycle. In the seventh woman, transfer of an eight-cell stage embryo resulted in implantation and a pregnancy which, to date (37th week) is developing normally.