Depot medroxyprogesterone acetate. Patterns of use and reasons for discontinuation

In some countries, sperm counts in normal human semen seem to have declined over the last 50 years. If this decline is real and due to environmental factors, falls might also be seen in sperm numbers in the semen of farm animals. Sperm counts are available for bull, boar and ram from the early 1930s, obtained using techniques similar to those used for human semen. Data have been obtained from the literature between 1932 and 1995 from 137 studies involving bulls, 76 involving boars and 130 involving rams. All were normal adult animals, from which semen was collected regularly but at a frequency which would not be likely to cause a fall in sperm counts. The references were obtained systematically from Animal Breeding Abstracts, and where possible the original articles were consulted to obtain mean values for each study; where the original reference was not easily obtainable, values were taken from the abstract. The bull data showed no correlation of sperm count with year of publication (r2 = 0.000), for the boars there was a slight but non-significant positive correlation (r2 = 0.041), and for the sheep there was a slight, but significant, rise in sperm counts with time (r2 = 0.124 for sperm counts and 0.126 for total sperm per ejaculate; not all authors gave both values). It would appear that, if the fall in human sperm counts is real, then it must be due to something which is not affecting farm animals.     

Surface plasmon resonance biosensors as a tool in antibody engineering

The objective of this study was to perform intracytoplasmic sperm injection (ICSI) on in vitro matured equine oocytes and to improve in vitro embryonic development on Vero cells after activation of the microinjected oocytes with calcium ionophore. After maturation (23 or 40 h, 38.5 degrees C, 5% CO2), the cumulus-oocyte complexes were denuded, centrifuged and all oocytes exhibiting the first polar body were microinjected. ICSI was performed using fresh semen from three fertile stallions. Microinjected oocytes were activated with calcium ionophore A23187 (10 min, 10 microM) and cultured individually for 7 days on Vero cells in microdrops. In seven trials, 353 cumulus-oocyte complexes were matured and 103 oocytes were microinjected. Eight oocytes were sham microinjected. After ICSI, 85 oocytes (82.5%) survived the sperm injection procedure. Among the 76 successfully microinjected oocytes, 52 (68%) were fertilized (two pronuclei, syngamy stage and cleaved ova). Sham microinjected oocytes were not activated. After in vitro culture, 35 ova (46%) were cleaved 2 days after ICSI and early embryonic development was obtained (three embryos of 23 cells, 50 cells and more than 80 cells) 5 to 7 days after ICSI.     

Intracytoplasmic sperm injection of in vitro-matured equine oocytes

Intracytoplasmic sperm injection (ICSI) was performed on equine oocytes matured in vitro. The oocytes were aspirated from abattoir ovaries and matured in vitro for 36 h at 38 degrees C. ICSI was performed using frozen/thawed stallion semen after swimup in medium containing human serum albumin. Sperm-injected oocytes were either 1) cultured in vitro for 10, 20, or 72 h; 2) transferred to oviducts of pseudopregnant mice; or 3) transferred to a synchronized mare after initial in vitro culture. The transferred ova were recovered after 72 h, and all ova were subsequently fixed, stained, and processed for light and transmission electron microscopy. Single pronucleus formation was observed in 2 out of 12 presumptive zygotes 10 h postinjection, at which time abundant cortical granules were observed in the subplasmalemmal region. Twenty hours postinjection, however, 2 pronuclei were observed in 6 of 12 injected oocytes (fertilization rate 50%), and almost all cortical granules were released. The cleavage rate in vitro was 16% after 72 h in culture, and the most advanced embryo stages obtained were 6- to 8-cell embryos. The cleavage rate in vivo was very low since only 1 of 10 recovered had cleaved to the 2-cell stage. Thus, in conclusion, ICSI fertilization of equine oocytes did result in fertilization, pronucleus formation, and cortical granule release. However, the observed fertilization rate and oocyte activation was not paralleled by substantial cleavage of the zygotes.     

Outcome of ''whiplash'' neck injury

In this study, the relationships between semen production and semen quality of Normande bulls in performance test station and in two IA centers were evaluated and the genetic characteristics and evolution of semen production of young bulls in station were calculated. When analysing the relationship between semen production of young and adult Normande bulls data from 2,677 bulls between 12 and 15 months of age exhibited large difference between 5 groups corresponding to an overall classification given by a technician. Correlations between corrected data collected in station and bull effect estimates in AZ studs were quite high for volume and concentration, and moderate for motility and number of doses per ejaculate or per month. The correlations calculated are underestimates of the true ones, as bulls with undesirable semen characteristics were culled before entering AI. Nevertheless, among the remaining bulls, important differences (40%) in semen output were observed between extreme groups, as classified by the technician. Genetic parameters evaluated from a subset of 1957 young Normande bulls confirms earlier results reported in the literature. The heritability of the average volume of the ejaculate is very high (h2 = 0.65 +/- 0.09). Sperm quality traits are moderately heritable (h2 = 0.23 +/- 0.08 for motility score to 0.37 +/- 0.09 for concentration) and strongly correlated. Total percentage of abnormal spermatozoa estimated from a selected subset seems less heritable (h2 = 0.19 +/- 0.07). A Best Linear Unbiased Prediction was then carried out on the records from 2,387 bulls using these estimates. No clear genetic trend could be detected in the population, although the phenotypic selection performed should be efficient. This apparent contradiction results from the increasing influence in the breed of one family of heavily used bull sires with a poor genetic merit on sperm production traits.     

In vitro maturation and fertilization techniques for assessment of semen quality and boar fertility

The reliability of using different in vitro-derived measures of sperm quality to predict boar fertility was examined. On three occasions during a 20-wk period of breeding, special collections of the first sperm-rich fraction of the ejaculate from six boars were carried out. After in vitro capacitation procedures, three dilutions (5 x 10(5), 1.25 x 10(5), and 3.125 x 10(4) sperm/mL) of these semen samples were used in a standardized in vitro fertilization (IVF) test with oocytes recovered from prepubertal slaughterhouse ovaries and matured in vitro. Routine assessments of sperm motility, concentration, and morphology were also carried out for all collections used for AI during the 20-wk period. Semen from the same ejaculate, processed according to normal commercial practice using the AndroHEP extender, was used to inseminate equal numbers of recently weaned sows with either 3 x 10(9) or 2 x 10(9) total sperm, three times during the estrous period. Data from a total of 444 sows were used to determine boar fertility; between 12 and 54 sows were bred with each semen dose across the six boars. All measures of sperm fertilizing ability in vitro were different among boars (all P < .05) and use of different semen dilutions for IVF allowed further discrimination of apparent sperm quality among boars. The laboratory evaluation of semen collected during the period of breeding indicated effects of boar on ejaculate volume, total number of sperm per ejaculate, motility, and the percentage of sperm with normal morphology (all P < .01). Sperm dose used in AI had no effect on farrowing rate (80.7 vs 81.5%), but the lower AI dose resulted in a reduction (P < .05) in total numbers born (10.8 vs 10.0). For all three semen dilutions, estimated potential embryo production rate accounted for up to 70% of the variation in litter size obtained with 3 x 10(9) sperm per AI dose, and the number of sperm attached per oocyte was a major factor accounting for variation in litter size obtained with 2 x 10(9) sperm per AI dose. These IVF variables may, therefore, be effective indicators of boar sperm quality for use in AI. With 2 x 10(9) sperm per AI dose, the percentage of sperm with normal morphology also explained a large part of the variance in litter size born (R2 = .59), indicating that morphological characteristics are a useful measure of semen quality.     

A logistic regression model including DNA status and morphology of spermatozoa for prediction of fertilization in vitro

To determine predictive values of routine semen analysis, sperm morphology evaluation using strict criteria and DNA status for in-vitro fertilization (IVF), 66 consecutive couples undergoing IVF in a university hospital IVF programme were prospectively investigated. Semen samples from 66 men were evaluated by routine semen analysis, morphology evaluation using strict criteria and acridine orange staining for determination of DNA status. A new technique is described for acridine orange scoring which consisted of evaluation of two smears per case, with and without heat treatment. Resistance to heat-provoked denaturation was determined by the difference between two evaluations. A logistic regression model was built and receiver operating characteristic curves were constructed to determine the threshold values and to compare diagnostic properties. Morphology evaluation using strict criteria and concentration of progressively motile spermatozoa were found to be the principal parameters determining the sperm fertilizing capacity in vitro. The logistic regression model composed of morphology evaluation using strict criteria and acridine orange score had a powerful diagnostic capability for prediction of fertilization in vitro.     

Relationships between the number of small follicles prior to superovulatory treatment and superovulatory response in Holstein cows

In order to determine relationships between the number of small follicles prior to superovulatory treatment and superovulatory response, a total of 55 superovulations were induced in Holstein cows. The ovaries were examined ultrasonographically once 0-1.5 days before the initiation of superovulatory treatment. The number of small follicles 3-6 mm in diameter on both ovaries before superovulatory treatment was found to be significantly correlated with the numbers of corpora lutea after superovulation (r = 0.440, P < 0.001), total ova recovered (r = 0.503, P < 0.001) and transferable embryos recovered (r = 0.482, P < 0.001). These results indicate that a single ultrasonographic examination of follicles 3-6 mm in diameter prior to superovulatory treatment can be utilized to predict superovulatory response.     

Superovulatory responses in Japanese black beef cows following largest follicle aspiration or human chorionic gonadotrophin (hCG) treatment

The effect of largest follicle aspiration or hCG administration before induction of superovulation on the ovarian response of Japanese Black beef cows was investigated using a crossover design in which induction of superovulation was attempted in every cow. The superovulatory response of cows whose largest follicle had been aspirated from the ovaries by ultrasound-guided follicular aspiration 1 day before induction of superovulation, did not differ from the response in non-treated control cows. In contrast, in cows given 5,000 IU of hCG 3 days before induction of superovulation, the proportions of fertilized ova and transferable embryos significantly decreased compared with the other groups.     

Manual collection and characterization of semen from Asian elephants (Elephas maximus)

The implications of collecting semen from elephants for use in artificial insemination programs are profound in the context of propagating captive elephants. Using a manual manipulation technique, semen was collected and characterized from five adult Asian elephants (Elephas maximus) and ejaculate fluid was obtained from one castrated elephant bull. The penis was stimulated to protrusion and erection by rectal massage of the pelvic portion of the urethra. During an ejaculatory response, massage was also directed onto the area of the ampulla of the ductus deferens. Sperm rich ejaculates were usually collected as a result of each ejaculatory contraction. Ejaculates were evaluated for spermatozoal concentration and pH (when possible) and sperm rich fractions combined for determination of total volume. Mean total volume of each collection was 27.5+/-4.4 ml. Mean concentration of the first and second ejaculatory responses from a collection was 2.05+/-0.17 x 10(9) and 1.34+/-0.19 x 10(9) sperm/ml, respectively. Measurement of seminal pH revealed no significant differences between the fractions. Mean pH of the first and second ejaculatory responses were 7.05+/-0.07 and 7.04+/-0.13. This method of collecting elephant sperm can be utilized for semen evaluation of bulls of unknown reproductive status in conjunction with other evaluation techniques (i.e. ultrasonographic, endocrinologic). It also has the potential for providing valuable genetic material for genome resource banks and for use with assisted reproductive techniques like artificial insemination.     

Environmental, management, and genetic factors affecting semen production in Holstein bulls

The objective of this study was to evaluate the importance of environment, management, physiological status, and genetics on semen quality (volume of the ejaculate, sperm concentration, sperm motility, number of sperm, and number of motile spermatozoa per ejaculate) of Canadian Holstein bulls. For this purpose, semen production data from 198 bulls were analyzed using mixed linear models. Young bulls (up to 30 mo old) and mature bulls (between 4 and 6 yr old) were analyzed separately. Semen characteristics generally improved significantly with age of young bulls. Season significantly affected all semen traits in young bulls but did not significantly affect volume and sperm motility of mature bulls. Performance was better in winter than in summer. The highest numbers of motile spermatozoa per ejaculate were obtained with intervals of at least 4 to 5 d between collections. Although the bull handler and semen collector caused less than 10% of the variance, the collection team significantly affected semen volume, number of sperm, and number of motile sperm per ejaculate for both growing and mature bulls. Heritabilities for volume, concentration, sperm motility, number of sperm, and number of motile sperm per ejaculate were, respectively, 0.24, 0.52, 0.31, 0.38, and 0.49 for young bulls and 0.44, 0.36, 0.01, 0.54, and 0.64 for mature bulls. Repeatability of semen traits varied from 0.41 to 0.64. Genetics, management, and environmental factors clearly contribute to semen production in Holstein bulls.     

Fertility of bull semen frozen with beta-amylase, beta-glucuronidase, and catalase

"Capacitase," a product combining beta-amylase and beta-glucuronidase, was compatible with survival of bull spermatozoa frozen in whole milk-glycerol extender at final concentrations per ml of 0, 5, 10, and 20 mug of beta-amylase combined with 0, 75, 150, and 300 units of beta-glucuronidase, respectively. Bull semen was frozen in whole milk-glycerol extender containing the three lower concentrations of enzymes tested in the previous trial and used to inseminate 9057 first-service cows within 4 mo of freezing. The 60- to 90-day percent nonreturns were 74.6, 75.6, and 75.0. The same treatments plus a fourth one containing 10 mug of catalase per ml were fertility tested in another trial. Insemination of 16,842 cows resulted in 75.6, 74.1, 74.6, and 74.2% nonreturns. In this trial semen was held immersed in liquid nitrogen and distributed for immediate use each mo for 6 mo. There was no change in fertility during 6 mo of continuous storage at --196 C. Under the conditions tested neither catalase nor beta-amylase with beta-glucuronidase enhanced fertility of frozen bull semen.     

Comparisons of intravaginal and intrauterine insemination of bitches with fresh or frozen semen

To compare the importance of the route of insemination when using fresh or frozen semen, six groups of five bitches were inseminated either into the uterus (groups 4, 5 and 6) or the vagina (groups 1, 2 and 3) with fresh (groups 1 and 4) or frozen semen (groups 2, 3, 5 and 6). The fresh semen was collected when needed from the same dog. The frozen semen used in groups 2 and 5 was obtained from seven dogs on the same day, and pooled and processed simultaneously so that the groups were inseminated with exactly the same semen. The frozen semen used in groups 3 and 6 was obtained from different dogs and processed independently to evaluate not only the effect of the route of insemination but also the potential effect of the dog. The mean concentration of the fresh semen was 310 x 10(6) spermatozoa/ml, its motility was greater than 80 per cent and the percentage of normal live spermatozoa was 80 to 92 per cent. The mean spermatozoal concentration of the frozen semen was 200 x 10(6) spermatozoa/ml, its motility was greater than 60 per cent and the percentage of normal live spermatozoa was 80 per cent. In all the groups there were fewer than 15 per cent abnormal spermatozoa. The animals inseminated with fresh semen received significantly more spermatozoa than the others. The bitches were inseminated twice, three and five days after the estimated peak of luteinising hormone, with a total volume of 5 ml for the vaginal inseminations and 2 ml for the intrauterine inseminations. Sixty per cent of the bitches inseminated with frozen semen and 100 per cent of the bitches inseminated with fresh semen became pregnant, irrespective of the insemination technique used.     

Computer-assisted sperm analysis for assessing initial semen quality and changes during storage at 5 degrees C

Computer-assisted sperm analysis equipment was used to evaluate bull sperm initially in a modified Tyrode's solution, in Cornell University extender, and in egg yolk-glycerol-Tris extender (following cooling and storage in the latter two extenders). Two ejaculates of semen were collected from each of eight bulls. Semen was divided into aliquots using a factorial arrangement. The semen, diluted to approximately 20 x 10(6) sperm/ml, was loaded into two 20-micron chambers, and six microscope fields from each chamber were videotaped for each treatment of each ejaculate of semen. Eight sperm characteristics analyzed with the Hamilton Thorne integrated visual optical system (Hamilton Thorne, Beverly, MA) were reported, and some of these characteristics differed significantly among bulls. The initial values of motile sperm in modified Tyrode's solution, Cornell University extender, and egg yolk-glycerol-Tris extender were 87, 79, and 66%; little change followed cooling and storage at 5 degrees C in the latter two extenders. Also, there was a small but significant decline in sperm velocity during 3 d of storage. Hyperactive sperm increased slightly during storage. The procedures used can rapidly and accurately measure many sperm characteristics in fresh semen and in semen stored in egg yolk extenders, and differences among bulls can be detected.     

Pregnancy following intracytoplasmic sperm injection from an HIV-1-seropositive man

The first pregnancy achieved in a seronegative woman following in-vitro fecundation through intracytoplasmic sperm (ICSI) injection from a man with autoimmune deficiency syndrome (AIDS; HIV-1 carrier) is reported. The semen was prepared by PureSperm and swim-up techniques. Some of the motile spermatozoa obtained were used to detect the presence of HIV-1 using the polymerase chain reaction technique. HIV-1 in DNA or RNA form was not detected using this technique. The remaining spermatozoa were frozen. Ovarian stimulation in the woman was performed with long-protocol analogues and gonadotrophins. Thirteen mature oocytes were recovered, into which the thawed spermatozoa were microinjected. Nine embryos were obtained. Four were frozen, four transferred and one discarded. The woman became pregnant. Analyses for HIV-1 in the woman, performed in the first and third months of pregnancy, gave negative results. This case provides further experience with washed semen of sufficient quality for performing artificial insemination in HIV-1-serodiscordant couples (101 inseminations, 31 pregnancies, 28 deliveries, 37 babies, all healthy). In women with obstructed Fallopian tubes, or when the semen is not of sufficient quality for artificial insemination techniques to be performed, ICSI can be carried out using frozen, HIV-1-free semen.     

Male-dependent variability of fertilization and embryo development in two bovine in vitro fertilization systems and the effects of casein phosphopeptides (CPPs)

This study investigated the effects of semen from five different bulls and two different ejaculates of the same bull on penetration, cleavage, blastocyst formation, and cell allocation in bovine blastocysts produced in vitro. Casein phosphopeptides (CPPs) were tested for their ability to enhance fertilization and minimize variability among bulls and ejaculates. In Experiment 1, the BO-fertilization system was employed. Penetration and polyspermy both displayed great variation among bulls and between ejaculates, whereas no significant differences were observed in cleavage and blastocyst-formation rates. Similar variability was observed in penetration, polyspermy, cleavage, blastocyst-formation rates and cell allocation and distribution when the two fertilization systems, TALP and BO, were compared in Experiment 2. The BO-system supported penetration and polyspermy better (P < 0.05) than the TALP-system, whereas the TALP-system was superior (P < 0.05) in supporting cleavage and blastocyst formation. Significant interactions existed between bulls and the fertilization system employed. It is concluded that the success of in vitro fertilization is markedly dependent on individual bulls as well as on ejaculates from the same bull. CPPs are able to enhance penetration and embryo development in certain bulls or ejaculates and thus contribute to reducing the degree of individual variability, but they do not generally improve the success of bovine embryo production in vitro.     

Development of in vitro derived bovine embryos following pronuclear transplantation and in vitro culture

This study was designed to evaluate the survival and development of in vitro derived bovine embryos following pronuclear transplantation and in vitro embryo culture. Bovine zygotes were produced by in vitro maturation and in vitro fertilization. Pronuclei were removed by micromanipulation and either transferred back to the same cell (Group 1) or into a previously enucleated zygote (Group 2) by electrofusion. Micromanipulated and non-micromanipulated (Group 3, control) zygotes were co-cultured with oviductal cells in a sealed modular chamber filled with 5% CO2, 5% O2 and 90% N2 at 39 degrees C for 7-8 days. Fusion rates were similar for Groups 1 and 2 (90.7 and 85.1%, respectively, P > 0.05). The percentage of embryos that cleaved was not different for Groups 1 (82.0%), 2 (90.0%) and 3 (76.9%, P > 0.05). Also, the percentage of embryos developing to the compact morula or blastocyst stage was similar (25.6, 22.5 and 22.3%, respectively, for Groups 1, 2 and 3, P > 0.05). The results of this experiment are the first to demonstrate that pronuclear transfer can be carried out successfully using bovine embryos derived from in vitro oocyte maturation and in vitro fertilization. In addition, pronuclei can be transferred from one bovine embryo to another and the reconstructed embryos develop to the compact morula and blastocyst stage in vitro. This technique, used in combination with oocyte retrieval by ultrasound-guided follicular aspiration and embryo transfer, offers the potential to study cytoplasmic inheritance in cattle directly, and to evaluate the effect of cytoplasmic inheritance on traits of economic importance.     

Diurnal testosterone and 17alpha-hydroxyprogesterone in peripheral plasma of young post-pubertal bulls. A study by frequent sampling

Testerone and 17alpha-hydroxyprogesterone were measured in the peripheral plasma of 6 young post-pubertal bulls of 1 year of age, by separate radioimmunoassays. Samples were collected every hour for 25 h at the beginning of each of four seasons. On a separate occasion blood samples were collected from one bull every 10 min for 2 h. As a result of the study, testosterone and 17alpha-hydroxyprogesterone appeared to be secreted episodically. These two steroid peaks showed good correlation. Each 24 h period showed its own characteristic pattern of pulsatile changes. Episodic secretion seems to be progressive rather than rapid and short lived. No real circadian rhythm was observed but at about 10.00 a.m. a trough in these steroid secretions occurred. This was followed by an increase in peripheral plasma concentration. These troughs occurred at all seasons after the morning feed and while semen was being collected in the performance test station.     

The effect of a propofol-based sedation technique on cumulative embryo scores, clinical pregnancy rates, and implantation rates in patients undergoing embryo transfers with donor oocytes

STUDY OBJECTIVE: To determine the effect, if any, of a propofol-based sedation technique on the reproductive outcomes of patients undergoing embryo transfers with donor oocytes. These ova recipients form a unique subgroup, whose clinical outcomes are unrelated to direct anesthetic effects on their reproductive tracts. DESIGN: Retrospective chart review. SETTING: A 1200-bed university medical center. PATIENTS: 117 patients who received fresh embryo transfer cycles between January 1991 and December 1995. MEASUREMENTS AND MAIN RESULTS: The anesthesia records of 106 women who donated ova were reviewed for propofol usage during the transvaginal needle aspiration of the ova. The medical records of the 117 patients who received these donated embryos were reviewed for cumulative embryo scores, clinical pregnancy rates, and implantation rates. Fourteen patients received ova from women who were sedated with fentanyl and midazolam during ovum retrievals, while 103 patients received ova from women who had been given fentanyl, midazolam, and propofol in doses of 1.87 mg/kg to 8 mg/kg. The pregnancy rate among all patients who received ova from women who received propofol (44 of 103 = 42.7%) was 14.1% greater than those whose ovum donors did not receive propofol (4 of 14 = 28.6). 78.6% of both propofol and non propofol-exposed groups had cumulative embryo scores of greater than 50. Among patients who became pregnant, 52.3% of propofol-exposed and 50% of nonpropofol-exposed cases had greater than 20% implantation rates. CONCLUSION: There is no evidence from our data that the administration of propofol during the aspiration of ovarian follicles for oocyte donation had a negative impact on the oocytes as measured by cumulative embryo scores, probability of a clinical pregnancy, or implantation rate.     

A sterilizing tail stump sperm defect in a Holstein-Friesian bull

A case of sterility in an 18-month-old bull of the Holstein-Friesian breed was investigated. A semen sample sent to the laboratory showed a very low sperm concentration and abnormal sperm morphology. On the preliminary examination, the major sperm defect (60-70%) seemed to be tailless heads. When higher manification was used it was found that most of the defective heads had a short tail rudiment, a tail stump 2-3 mu long. Loose sperm tails were seldom seen in the smears. The defect has been described previously from Canada where it has occurred in different breeds, including Holstein-Friesians. The dam of the Danish bull in question was inseminated with imported American semen, and the sire is one of the most demanded Holstein-Friesian bulls at present. The possible heredity of the defect is discussed.     

Sub-zonal insemination for extreme male factor infertility

When in-vitro fertilization (IVF) is used for severe male infertility, the zona pellucida constitutes a major barrier to sperm-oocyte interaction, a barrier that may, in principle, be overcome by micro-injecting one or more spermatozoa into the sub-zonal perivitelline space ('sub-zonal insemination' or SZI). We have defined suitable patients for SZI as having 'extreme' male factor in that they have either shown a failure of fertilization in previous IVF cycles or had < 50 000 motile spermatozoa recoverable after semen preparation. (This is distinct from those with only 'severe' male factor in whom sufficient (> 50 000) motile spermatozoa could be recovered from a semen preparation.) A total of 213 SZI cycles were performed at Sydney IVF in the 4 year period September 1988 to September 1992, for extreme male factor patients with previous IVF failures or extremely low sperm numbers for whom SZI was the first option (about two-thirds and one-third of cases respectively). A total of 138 embryo transfers are reported, producing 20 clinical pregnancies after performing SZI on 1899 oocytes. One patient miscarried at 12 weeks gestation and there have been nine normal deliveries (so far) of 10 healthy infants. The first delivery was in February 1990. One pregnancy was achieved in the only patient in whom spermatozoa were obtained by epididymal aspiration, and transfer of three cryopreserved embryos in another patient resulted in a singleton pregnancy. Of the 492 oocytes fertilized, 282 had two pronuclei (57.3%) and normal embryos were transferred in 138/213 (64.8%) treatment cycles, giving an overall pregnancy rate of 14.5% per embryo transfer or 9.4% per cycle.(ABSTRACT TRUNCATED AT 250 WORDS)