Chronic hepatitis C in children: a clinical and immunohistochemical comparative study with adult patients

A retrospective analysis of clinical and laboratory data was made of all in-vitro fertilization (IVF) patients with tubal pathology who had their first ever embryo transfer cycle between January 1st, 1992 and September 1st, 1996. The aim of the study was to determine the effect of the presence of a hydrosalpinx, whether or not visible by ultrasound, on pregnancy, multiple pregnancy and implantation rates in our patient population. The IVF success rate was also analysed by calculating cumulative ongoing pregnancy rates of the same patient group using the lifetime table approach. In the presence of an ultrasound-visible hydrosalpinx, rates of pregnancy and multiple pregnancy appeared reduced, but the differences were not significant. The rates of implantation, clinical implantation and ongoing implantation were significantly lower in the presence of an ultrasound-visible hydrosalpinx (odds ratios 0.33-0.46, C.I. 0.21-0.96). The cumulative chance of achieving an ongoing pregnancy after one or more IVF cycles was significantly reduced in the presence of an ultrasound-visible hydrosalpinx (relative hazard 0.36, C.I. 0.22-0.59). In the presence of a hydrosalpinx not visible by ultrasound the IVF outcome was not reduced. This retrospective study confirms that patients with hydrosalpinges have an impaired IVF outcome. Unique to this study and previously unobserved is the finding that there is a subgroup of patients with hydrosalpinges, those with ultrasound-visible hydrosalpinges, which is exclusively responsible for this impaired outcome.     

A comparative analysis of embryos derived from routine in-vitro fertilization and subzonal microinsemination

Embryos obtained from patients undergoing routine in-vitro fertilization (IVF) and embryo transfer were compared with those undergoing subzonal microinsemination (SUZI) for male factor infertility. Overall, the proportion of cleaved embryos was significantly higher in the IVF group in comparison with the SUZI group at 48 h post-insemination [1533 out of 1609 (95.3%) versus 776 out of 952 (81.5%)]. The mean +/- SD grading score of the IVF-derived embryos of 3.61 +/- 0.50 was significantly better than that for SUZI of 2.97 +/- 0.86 (P < 0.0005) at the same time. The implantation rates following the replacement of IVF or SUZI embryos at 48 h were comparable: 14.3 and 10.0% respectively. However, the IVF embryo implantation rate of 15.1% at 72 h was significantly better than that following the replacement of SUZI embryos at either 48 (10.0%) or 72 h (8.0%). The replacement of SUZI-derived embryos at 48 h resulted in significantly higher pregnancy (25.0%) and implantation rates (10.0%) than at 72 h, with rates of 10.8 and 8.0% respectively. Similarly, the overall embryo quality deteriorated following in-vitro culture for up to 72 h. The clinical pregnancy loss rate (33.0%) was highest following the replacement of SUZI embryos at 72 h, although the data were limited. It is suggested that these data indicate that a combination of in-vitro manipulation, the injection of multiple spermatozoa into the subzonal space and probably the genomic capacity of spermatozoa derived from poor-quality semen may contribute to the poorer outcome of embryo development following SUZI. Prolonged in-vitro culture beyond 48 h appears to be deleterious to the development of SUZI cleaved embryos and the subsequent outcome of treatment, and hence should be avoided.     

The optimal number of embryos to be transferred in shared oocyte donation: walking the thin line between low pregnancy rates and multiple pregnancies

There has been growing concern about the number of multiple gestations resulting from assisted reproductive technologies. For in-vitro fertilization (IVF), there are guidelines concerning the number of embryos to be transferred. In oocyte donation, however, there is a paucity of studies addressing this issue and common practice is extrapolated from standard IVF procedures. This may not be correct since endometrial receptivity has been shown to be altered in oocyte donation. Thus the purpose of this study was to assess the optimal number of embryos to be transferred in oocyte donation. The study population included 254 patients with ovarian failure who underwent a total of 601 embryo transfers in a single shared oocyte donation programme. Pregnancy rates (PRs), multiple pregnancies, triplet pregnancy rates, and implantation rates were evaluated according to the number of embryos transferred. A significant linear increase in PRs was noted with the increasing number of embryos transferred up to five (11.1% for one embryo, 36.7% for five embryos). Multiple pregnancies increased significantly from 15.8% for two embryos transferred, to 44.4% for five embryos. The rate of triplet pregnancies also increased from 2.7% for three embryos transferred, to 8.3% for five embryos. Optimization of the number of embryos to be transferred is discussed.     

The selection criteria on an IVF program can remove the association between maternal age and implantation

BACKGROUND: 1190 consecutive in vitro fertilization (IVF) treatment cycles from the Southampton University/BUPA Chalybeate unit, spanning a four year period, were studied retrospectively in order to assess the relationship between maternal age and implantation. Our aim was to evaluate the hypothesis that the number of transferred embryos can be determined by age alone. METHOD: The cases were allocated to two age groups, Group 1 was composed of patients of less than or equal to 35 years of age and Group 2 of patients greater than 35 years of age. RESULTS: We found that the selection criteria used in our programme for abandoning treatment cycles led to significantly more older patients being excluded from oocyte collection (p < 0.001). The patients from both groups that progressed to oocyte collection and embryo transfer showed no significant difference in embryo implantation. The overall implantation rate (12.4%) and clinical pregnancy rate per embryo transfer (22.8%) were achieved by being able to transfer comparable numbers of embryos in both age groups and in spite of the younger age group having a significantly better quality of transferred embryos. CONCLUSION: Although advancing maternal age predisposes to a reduced chance of success from IVF treatment, maternal age alone was not a useful predictor of embryo implantation or endometrial receptivity in completed IVF treatment cycles.     

Is hydrosalpinx fluid cytotoxic?

Accumulation of oviductal fluid in the ampullar lumen as a result of occlusion of the infundibulum is referred to as hydrosalpinx. A low pregnancy rate (10%) after in-vitro fertilization (IVF) in hydrosalpinx patients and a relatively high incidence (50%) of abortions during the first trimester suggested that leakage of this fluid into the uterine cavity may exert a cytotoxic effect on the developing embryo. To examine this possibility, we analysed the composition of the hydrosalpinx fluid and tested its effect on human granulosa cells and embryos. Hydrosalpinx fluids and granulosa cells were collected from IVF patients at ovum pick-up. IVF eggs containing three pronuclei (3PN) were employed for this study. Analysis of hydrosalpinx fluids revealed electrolyte concentrations similar to those in serum with lower amounts of total protein and albumin. No blood cells were detected and bacterial cultures were negative. Granulosa cells incubated in hydrosalpinx fluid-containing medium (diluted 1:1) were not morphologically different and showed a steroidogenic capacity that was higher than that of cells incubated in its absence. Fertilized 3PN eggs incubated in IVF culture medium successfully developed into 6- to 8- and 8- to 16-cell embryos within 48 and 72 h, respectively. This rate of embryonal development was not impaired by hydrosalpinx fluid (at either 50 or 100% concentration). In the absence of a demonstrable detrimental effect we suggest that the low implantation rate in hydrosalpinx IVF patients may not be due to an embryotoxic effect. We further suggest that constant passage of fluid into the uterine cavity in these patients could possibly introduce some mechanical interference that may result in implantation failure.     

Intracytoplasmic sperm injection as a routine indication in low responder patients

The aim of this study was to determine if a low response to gonadotrophin stimulation could be considered as an indication for intracytoplasmic sperm injection (ICSI). This prospective study included a total of 96 non-male infertile couples with six or fewer retrieved oocytes, who underwent 104 in-vitro fertilization (IVF) cycles between January 1996 and April 1997. They were randomly divided into two groups for fertilization, one by IVF and the other by ICSI. Groups were compared in terms of fertilization rates, fertilization failure, embryo quality, embryos transferred and reproductive outcome. ICSI provided similar fertilization rates per inseminated oocyte (77.7 versus 70.2%) and per obtained oocyte (56.5 versus 58.8%) as IVF. Furthermore, equal numbers (2.2 versus 2.5) and quality of embryos were obtained and comparable pregnancy (21.1 versus 17.3%) and implantation (14.0 versus 11.1%) rates. Neither the number of retrieved oocytes, nor patient age was relevant for the fertilization rates obtained with both techniques. The number of cases with complete fertilization failure was similar in both procedures. We conclude that the technique of fertilization is not related to the reproductive outcome of low responders, and the routine use of ICSI is not indicated.     

Hydrosalpingeal fluid inhibits in-vitro embryonic development in a murine model

Recent evidence describing a suboptimal clinical outcome in women with hydrosalpinges who undergo in-vitro fertilization (IVF) and embryo transfer suggests a potential deleterious effect of this fluid on in-utero embryo development. Consequently, we evaluated in-vitro mouse embryo development in the presence of hydrosalpingeal fluid (HF) collected from 10 infertile women of reproductive age. Chemical analyses showed both similarities and differences of these fluids to reported values for fluids collected from non-diseased Fallopian tubes. The HF had a significant deleterious effect upon mouse embryo cleavage and development to the expanded and hatched blastocyst stage, although the effect was variable among patients. Dilution of HF to 30% concentration with culture medium failed to negate this effect. This argues against the effect resulting from a relative lack of critical, supportive component(s) in the HF. Additionally, further experiments performed with cultures under an oil overlay significantly reduced the embryotoxicity of the HF. This evidence suggests there may be a lipophilic factor that can impair embryo development. The relatively poor IVF-embryo transfer success in women with proximally patent hydrosalpinges may be explained, at least in part, by reflux of a lipophilic embryotoxic factor(s) into the uterine cavity.     

Clinical evaluation and microbiology of oropharyngeal infection due to fluconazole-resistant Candida in human immunodeficiency virus-infected patients

The aim of the present study was to investigate pregnancy rates ensuing from transfer of embryos with multinucleated blastomeres. In our in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) programme, 1735 embryo transfers were performed from January 1, 1995 to August 31, 1996. In 136 of these transfers at least one embryo with one or more multinucleated blastomeres was present per transfer (study group). For each of these 136 transfers, two matched controls with transfer of exclusively mononucleated embryos were selected (control group). Matching was carried out according to age, method of fertilization (IVF or ICSI), number of transferred embryos and quality score of transferred embryos. In the study group, there were eight transfers of exclusively multinucleated embryos from which one pregnancy ensued and 128 transfers in which multinucleated and mononucleated embryos were transferred together leading to 23 pregnancies. The overall clinical pregnancy rate per transfer was 16.9% in the study group versus 28.7% in the control group (P = 0.01). The ongoing pregnancy rate per transfer was 13.2% in the study group versus 23.2% in the control group (P = 0.03). The implantation rate per transferred embryo was 6.0% in the study group versus 11.3% in the control group (P = 0.003). This study shows that embryos with one or more multinucleated blastomeres have a poorer implantation potential than embryos with mononucleated blastomeres. Transfer of embryos with multinucleated blastomeres should hence only be considered when insufficient numbers of embryos with only mononucleated blastomeres are present.     

Endometrial fluid collection in women with hydrosalpinx after human chorionic gonadotrophin administration: a report of two cases and implications for management

The impact of hydrosalpinx (HSPX) on in-vitro fertilization (IVF) outcome has recently been the subject of intense debate. Most, but not all, studies have reported decreased implantation and pregnancy rates and increased early pregnancy loss in HSPX patients. This has led to prophylactic salpingectomies prior to IVF in HSPX patients despite the lack of any prospective studies to suggest that any improvement will occur. Women with HSPX constitute a heterogeneous population because some conceive easily with IVF while others do not until after surgical correction. HSPX also increases in size with ovarian stimulation, and can cause implantation failure by fluid reflux into the uterine cavity. Careful assessment of the endometrial lining is mandatory in HSPX to rule out fluid reflux from the HSPX. We present two case reports of patients whose HSPX enlarged with ovarian stimulation, causing fluid reflux into the uterine cavity which was only noted after human chorionic gonadotrophin (HCG) administration.     

Relations between scatter factor, quality index and attenuation for x-ray beams

In a human in-vitro fertilization (IVF) programme, the effect of co-culture of embryos with human fibroblasts was evaluated with respect to pregnancy rate and embryo development. Patients were included in the study after giving informed written consent. The IVF treatments were randomly assigned by stratification of both age (<36 versus > or =36 years) and previous IVF attempts (yes versus no). After fertilization was established, the zygotes were transferred to a 4-well dish with or without fibroblasts and cultured for 2 days. On the third day after ovum pick-up (OPU), cell number and quality [5 (good) to 1 (poor)] of the embryos were scored and a maximum of three embryos was transferred. Supernumerary embryos of good quality were cryopreserved. The design of this study was a group sequential trial with the objective of detecting differences between pregnancy rates following IVF with conventional incubation or incubation in co-culture with fibroblasts. This design included one evaluation at half-way data collection. In the study, 148 patients had an OPU, of whom 77 were allocated to the co-culture group. There was no statistically significant difference in pregnancy rate, cell number and embryo quality between the two groups. The ongoing pregnancy rate per embryo transfer was 27% in co-culture and 30% in the conventional culture group. The implantation rates per transferred embryo were 17 and 18% respectively. Using a multivariate logistic regression model for the probability of ongoing pregnancies, the odds ratio of co-culture, adjusted for age and previous IVF attempts, was not statistically significant. In conclusion, co-culture with human fibroblasts does not contribute to an improvement of embryo quality nor to a higher pregnancy rate after IVF in an unselected group of patients.     

Long-term evaluation of implantation of fresh and cryopreserved human embryos following ovarian stimulation with buserelin acetate-human menopausal gonadotrophin (HMG) or clomiphene citrate-HMG

This study is a long-term evaluation of the total pregnancy potential of cohorts of fresh and cryopreserved sibling embryos from in-vitro fertilization (IVF) cycles stimulated with either the gonadotrophin-releasing hormone analogue buserelin (BUS) (long protocol) or clomiphene citrate (CC) both in combination with human menopausal gonadotrophin (HMG). Therefore a retrospective analysis was performed on patients who entered the IVF programme between January 1986 and July 1987 and who had triple embryo transfer in the collection cycle. Significantly more fertilized oocytes developed to good-quality embryos in the CC-HMG group (86.1%) than in the BUS-HMG group (80.8%). Transfer of the three morphologically best-looking embryos was performed in day 2 post-insemination in 106 CC-HMG and 80 BUS-HMG cycles. Supernumerary embryos were cultured for a further 24 h and multicellular embryos with up to 20% of fragments were frozen slowly with 1.5 M dimethylsulphoxide on day 3 post-insemination (162 embryos in CC-HMG cycles, 102 embryos in BUS- HMG cycles). Outcome was measured by embryo survival rate, embryo implantation rate and delivery rate in fresh and frozen embryo transfers. Delivery rates were 31.3 and 21.7% per fresh embryo transfer in BUS-HMG and CC- HMG cycles respectively. Fresh embryo implantation rates were significantly higher in collection cycles stimulated with BUS-HMG (17.9%) than in cycles stimulated with CC-HMG (11.3%). Implantation rates were significantly enhanced in embryos transferred in excess of one in cycles leading to pregnancy, perhaps indicative of higher embryo quality in BUS-HMG cycles. Almost all cryopreserved embryos have by now been thawed, so the contribution of frozen embryos to overall pregnancy rates can be evaluated. Overall morphological survival rates of frozen-thawed embryos have by now been thawed, so the contribution of frozen embryos to overall pregnancy rates can be evaluated Overall morphological survival rates of frozen-thawed embryos were similar for 140 embryos from CC-HMG cycles (50%) and 100 embryos from BUS-HMG cycles (46%). The percentage of fully intact embryos was, however, significantly lower in the BUS-HMG group (19%) than in the CC-HMG group (39.5%). Delivery rates were significantly lower following 30 transfers of frozen-thawed embryos from BUS-HMG-stimulated cycles (3.3%) than following 42 transfers of frozen-thawed embryos from CC-HMG cycles (19.1%). Embryo implantation rates were lower for frozen-thawed embryos from BUS-HMG cycles (2.3%) than from CC-HMG cycles (12.7%). Here we demonstrate that ovarian stimulation with the long protocol BUS-HMG instead of the CC-HMG protocol led to higher embryo implantation rates in collection cycles but to lower intact embryo survival rates and to lower embryo implantation rates for frozen sibling embryos. Despite the lower implantation rates with frozen embryos originating from the BUS-HMG protocol, there was no significant difference between total delivery rate per transfer from cycles stimulated with CC-HMG (30.2%) compared with BUS-HMG (33.8%).     

An android body fat distribution in females impairs the pregnancy rate of in-vitro fertilization-embryo transfer

To assess if the waist:hip ratio (WHR) is associated with the pregnancy rate (PR) in in-vitro fertilization (IVF) and embryo transfer, waist and hip girths, in addition to height, weight, body mass index (BMI), indications for IVF, PR and other related variables, were measured in 220 women undergoing IVF-embryo transfer. Three variables were significantly negatively associated with PR; high age, smoking and WHR >0.80. Women with WHR between 0.70-0.79 had a PR of 29.9% as compared to 15.9% in women with WHR >0.80 [odds ratio 0.42, 95% confidence interval (CI) 0.2-0.9, P = 0.03]. There were no correlations between BMI and PR, nor were there any significant differences for the indications for IVF-embryo transfer, number of oocytes or oocyte fertilization rate, cleavage rate and number of embryos transferred. The association between a low PR and WHR >0.80 remained unchanged after adjustment for age, BMI, smoking, indication for IVF, parity and number of embryos transferred. In IVF-embryo transfer, fertilization is a laboratory and clinically controlled process, until the embryo is transferred to the uterus. Possible reasons for our finding of a decreased PR in women with an android body fat distribution include a different endocrinological and biochemical milieu for the oocyte in the growing follicle, oocytes of poor quality, or endometrial changes due to hormonal dysfunction.     

Multiple attempts at embryo transfer: does this affect in-vitro fertilization treatment outcome?

In this study, we retrospectively analysed data from 877 patients who had 1204 embryo transfer procedures following in-vitro fertilization (IVF) at Midland Fertility Services, UK, between January 1991 and December 1995 to investigate the factors contributing to failure of embryo transfer at first attempt and the impact of immediate retransfer of retained embryos on the treatment outcome. Embryos were significantly more likely to be retained when the embryo transfer catheter was contaminated with mucus (3.3 versus 17.8%, P = 0.000001) or blood (3.3 versus 12%, P = 0.00001) and when the transfer procedure was difficult compared with when it was easy (20.3 versus 0.8%, P = 0.00001). There was no significant difference in the clinical pregnancy rate between those who had all their embryos transferred at the first attempt (24.7%) and those who required more than one attempt (23.2%). The types of embryo transfer catheter used in the unit did not show any difference in terms of embryo retention. Although we recommend aspiration of cervical mucus in order to reduce the rate of retained embryos, there is no evidence from our study to suggest that pregnancy rate is compromised when embryos are retained, provided they are discovered and immediately retransferred into the uterine cavity. Immediate retransfer is more convenient to the patients and reduces the laboratory workload without compromising the treatment outcome.     

The mechanism of decrease in dynamic mitral regurgitation during heart failure treatment: importance of reduction in the regurgitant orifice size

There are numerous studies concerning pregnancy rates in oocyte donation, yet only a handful report the obstetric outcome in such pregnancies. The purpose of this study was to assess factors that influence pregnancy rates, to determine the incidence of complications, and to evaluate obstetric outcome in pregnancies resulting from oocyte donation. This study included 423 oocyte recipients who underwent 1001 oocyte donation cycles at the Oocyte Donation Programme, In-Vitro Fertilization (IVF)-Embryo Transfer Unit, Herzlia Medical Center, Israel. Donors were all healthy women < 34 years old who underwent IVF themselves. In 873 cycles, fertilization occurred and embryo transfer was performed, resulting in 194 clinical pregnancies. Pregnancy rates (PR) significantly declined with the increase in number of previous attempts, and with increasing age of recipient (36.8%/embryo transfer in patients < or = 30 compared to 17.8% in patients > 40 years old). A significant increment in PR was noted with the increasing number of embryos transferred. The overall PR was 22.2%/embryo transfer. However, in young amenorrhoeic patients with normal karyotypes undergoing their first cycle, PR was 52.2%; the 'take home baby' rate was 38.3% per patient undergoing embryo transfer and 17.8% per embryo transfer cycle. A significant increase in the incidence of pregnancy-induced hypertension and a higher proportion of abortions were noted in older patients. A significantly higher incidence of prematurity and low birthweight was observed in multiple pregnancies.     

Serum progesterone at the time of human chorionic gonadotrophin does not predict pregnancy in in-vitro fertilization and embryo transfer

Controversy exists as to whether the serum concentration of progesterone on the day of human chorionic gonadotrophin (HCG) administration following ovarian stimulation for in-vitro fertilization (IVF) and embryo transfer can be used to predict the likelihood of success. This retrospective study was undertaken to answer this question by analysing a large population of IVF and embryo transfer cycles (n = 756). In addition to the concentration of progesterone on the day of HCG administration, all variables known to impact on IVF and embryo transfer success (such as patient age), indication for IVF and embryo transfer, number of oocytes retrieved and the number of embryos generated and transferred were examined. There was a significant increase in the number of oocytes retrieved with increasing progesterone concentration at the time of HCG administration. However, there was no correlation of progesterone concentration at HCG administration with pregnancy and implantation rates. It is concluded that previous reports associating a slight elevation of progesterone in gonadotrophin-releasing hormone agonist ovarian stimulation cycles for IVF and embryo transfer may be misleading because of a small sample size or the presence of confounding variables that affect IVF and embryo transfer success.     

Selection and partial characterization of a Pseudomonas aeruginosa mono-rhamnolipid deficient mutant

A total of 29 women with Turner's syndrome (19 monosomy and 10 mosaic) had 68 cycles of oocyte donation that included 29 cycles of initial attempt and 39 cycles of subsequent attempts. Oral oestradiol valerate was used either in a variable dose (42 cycles) or in a constant dose (26 cycles) regimen for the endometrial preparation which was monitored by pelvic ultrasonography. The embryos/zygotes were transferred either fresh (50 cycles) or after cryopreservation (18 cycles) into the Fallopian tube (41 cycles) and uterine cavity (27 cycles) as appropriate. There were 28 clinical pregnancies including two sets of triplets resulting in a pregnancy rate of 41.2% per treatment cycle and an implantation rate of 17.1% per embryo transferred. The recipient's age, chromosomal constitution or associated uterine or tubal anomaly had no influence on the treatment outcome. The implantation and pregnancy rates were higher in the subsequent than initial cycles (22.6 versus 9.99%, P < 0.05; 51.3 versus 27.6%, P < 0.05). An endometrial thickness of > or = 6.5 mm was an important predictor of pregnancy but the endometrial echo pattern failed to predict the outcome. Although the total dose of oestradiol before embryo transfer was higher in the pregnant cycles than the non-pregnant ones and its gradation (< 50 mg, 50-100 mg, < 100 mg) influenced the implantation (3.4, 17.5, 26.3% respectively, P < 0.05) and pregnancy rates (10, 42.2, 61.5% respectively, P < 0.05), the effect was indirect by altering the endometrial thickness. The number of oocytes fertilized affected the pregnancy rate irrespective of the number of embryos transferred. The implantation and pregnancy rates were higher when fresh rather than frozen-thawed embryos were transferred (20.3 versus 8.2%, P < 0.05; 48 versus 22.2%, P < 0.05) but the route of transfer was of no statistical importance. The overall miscarriage rate was higher (50%), and was related to the presence of hypoplastic or bicornuate uterus and to a low oocyte fertilization rate.     

A prospective randomized trial of blastocyst culture and transfer in in-vitro fertilization

The effectiveness of blastocyst culture and transfer in human in-vitro fertilization (IVF) was evaluated in a prospective randomized trial in patients having a moderate to good response to gonadotrophin stimulation. Embryos were transferred either on day 3 after culture to around the 8-cell stage in Ham's F-10 medium supplemented with fetal cord serum, or on day 5 after culture to the blastocyst stage in the sequential serum-free media G 1.2 and G 2.2. The pregnancy rates after transfer on day 3 or day 5 were equivalent, 66 and 71% respectively; however, significantly more embryos were transferred on day 3 (3.7) than on day 5 (2.2). The number of blastocysts transferred did not affect the implantation rate, and pregnancy rates when either two or three blastocysts were transferred were 68 and 87% respectively. The implantation rate of the blastocysts (50.5% fetal heart beat) was significantly higher compared to the cleavage stage embryos transferred on day 3 (30.1%). The percentage of blastocyst development was not affected by the number of 2-pronuclear embryos, or by maternal age. Irrespective of the number of blastocysts formed, pregnancy rates were similar. Furthermore, the pregnancy rate following blastocyst transfer in patients with 10 or more follicles at the time of human chorionic gonadotrophin administration was not affected by patient age. More than 60% of patients having blastocyst culture and transfer had supernumerary embryos for cryopreservation. The establishment of a pregnancy following thaw and transfer confirmed the viability of cryopreserved blastocysts cultured in the absence of serum or co-culture. The ability to transfer just two blastocysts while maintaining high pregnancy rates will therefore help to eliminate high order multiple gestations and improve the overall efficiency of human IVF.     

Embryo score to predict implantation after in-vitro fertilization: based on 957 single embryo transfers

The purpose of this study was to devise an embryo score to predict the likelihood of successful implantation after in-vitro fertilization (IVF). Unlike most studies dealing with the influence of embryo stage and morphology on pregnancy, our study was based on single rather than multiple embryo transfers. A total of 957 single embryo transfers were carried out. No delivery was obtained after any of the 99 transfers using 1-cell embryos or embryos obtained after delayed fertilization. In the remaining 858 transfers, the embryos had cleaved. Higher pregnancy rates were obtained with embryos displaying no irregular cells (11.7 versus 6.9%; P < 0.01) and embryos displaying no fragmentation (11.5 versus 8.1%; P < 0.05). The 4-cell embryos implanted 2-fold more often than embryos with more or less cells (15.6 versus 7.4%; P < 0.01). Based on these observations, we devised a 4-point embryo score in which embryos are assigned 1 point each if they (i) are cleaved, (ii) present no fragmentation, (iii) display no irregularities, and (iv) have four cells. Both pregnancy rate and take home baby rate were significantly correlated with embryo score. Each point of this score corresponds to a 4% increase in pregnancy rate. Interestingly, pregnancy rate was significantly lower in women aged > 38 years (8.2 versus 11.4%; P < 0.05), even though embryo quality was similar regardless of age. Single embryo transfer allowed us to define a simple and useful embryo score to choose the best embryo for transfer to optimize IVF and embryo transfer outcome. The use of this embryo score could decrease multiple pregnancies after multiple embryo transfers.     

Dizygotic twin pregnancy after intracytoplasmic sperm injection of 1 day old unfertilized oocytes

We report on a case where late intracytoplasmic sperm injection (ICSI) on unfertilized oocytes after standard in-vitro fertilization (IVF) cycles resulted in a dizygotic twin pregnancy. Fifteen oocytes were harvested from a patient with a history of salpingotomy. After a single cycle of IVF, only one oocyte showed two pronuclei. Subsequently ICSI was performed on six unfertilized metaphase II oocytes, and three of these oocytes showed two pronuclei. Three fertilized embryos were transferred (two derived from ICSI and one from IVF). A normal twin pregnancy resulted, and after delivery of two healthy boys the twins were confirmed to be dizygotic by DNA analysis of several loci. We conclude that at least one of the embryos was derived from the reinsemination by 'second day ICSI'.     

Freezing of human embryos. A review of and a suggestion to unified guidelines for treatment at public fertility clinics in Denmark

In Denmark, legislation has made cryopreservation of human oocytes and embryos possible since October 1992. The legislation is reviewed. Cryopreservation of embryos constitutes a significant improvement of infertility treatment. The number of oocyte pick-ups and the number of embryos transferred can be reduced without compromising the total likelihood of success of in-vitro fertilization (IVF) treatment. According to Danish law, frozen embryos can only be stored for one year. This limit will interfere with patient expectations in numerous cases, and the time limit should be expanded. Moreover, freezing of embryos should be allowed in connection with oocyte donation programmes.