One year's experience with elective transfer of two good quality embryos in the human in-vitro fertilization and intracytoplasmic sperm injection programmes

Objective evaluation of the viability of cryopreserved oocytes

Recent studies of fundamental cryobiology, empirical observations and more systematic clinical experiences have generated a renewed interest in oocyte cryopreservation. Poor survival rate has long been the limiting factor which has prevented widespread adoption of oocyte storage. Slow-cooling and vitrification protocols developed in the last few years have apparently solved this problem, ensuring high recovery of viable oocytes from liquid nitrogen storage. However, the definition of oocyte viability appears rather vague. In fact, post-storage survival as assessed on morphological criteria, indicated by the absence of overt cell degeneration, is not necessarily synonymous with viability. Despite its sensitivity to low temperatures, the meiotic spindle can be preserved after cryopreservation and its constitution after thawing can be monitored non-invasively through polarized light microscopy. Assessment of oocyte cryopreservation via clinical parameters is a daunting task. Most studies are small and difficult to interpret because of confounding factors, such as age, patient selection and quality and strategy of use of the cryopreserved material. Some progress has been made, however, as suggested by recent experiences in which the implantation efficiency of embryos produced from thawed oocytes approaches that reported using cryopreserved embryos directly.

Elective transfer of two embryos: reduction of multiple gestations while maintaining high pregnancy rates

PURPOSE

To determine if the elective transfer of two embryos reduced the incidence of multiple gestations while maintaining high pregnancy rates.

METHODS

IVF patients and recipients of oocyte donation with an elective day-3 transfer of 2 or 3 embryos were studied.

RESULT(S)

In IVF, the elective transfer of 2 embryos resulted in similar pregnancy rate but significantly reduced the overall incidence of multiple gestations (20% versus 39%) when compared to the elective transfer of 3 embryos. Twin gestations decreased from 28% to 19%, and triplets significantly decreased from 9% to 1%. In oocyte donation, the elective transfer of 2 embryos resulted in similar pregnancy rate but also significantly reduced the overall incidence of multiple gestations (26% versus 48%), with twins decreasing from 34% to 24%, and with a significant reduction of triplets (13% versus 2%).

CONCLUSIONS

In IVF and oocyte donation, the elective transfer of 2 embryos resulted in similar pregnancy rates and significantly reduced multiple gestation rates when compared to the elective transfer of 3 embryos.

Guidelines for the number of embryos to transfer following in vitro fertilization

OBJECTIVE

To review the effect of the number of embryos transferred on the outcome of in vitro fertilization (IVF), to provide guidelines on the number of embryos to transfer in IVF-embryo transfer (ET) in order to optimize healthy live births and minimize multiple pregnancies.

OPTIONS

Rates of live birth, clinical pregnancy, and multiple pregnancy or birth by number of embryos transferred are compared.

OUTCOMES

Clinical pregnancy, multiple pregnancy, and live birth rates.

EVIDENCE

The Cochrane Library and MEDLINE were searched for English language articles from 1990 to April 2006. Search terms included embryo transfer (ET), assisted reproduction, in vitro fertilization (IVF), ntracytoplasmic sperm injection (ICSI), multiple pregnancy, and multiple gestation. Additional references were identified through hand searches of bibliographies of identified articles.

VALUES

Available evidence was reviewed by the Reproductive Endocrinology and Infertility Committee and the Maternal-Fetal Medicine Committee of the Society of Obstetricians and Gynaecologists of Canada and the Board of the Canadian Fertility and Andrology Society, and was qualified using the Evaluation of Evidence Guidelines developed by the Canadian Task Force on the Periodic Health Exam.

BENEFITS, HARMS, AND COSTS

This guideline is intended to minimize the occurrence of multifetal gestation, particularly high-order multiples (HOM), while maintaining acceptable overall pregnancy and live birth rates following IVF-ET.

Influence of embryo quality and number of previous cycles on pregnancy and multiple pregnancy rates in women aged 35 to 37 years who received two or three embryos

Women aged 35-37 years undergoing IVF-ET with fresh embryos at a university infertility center were analyzed to evaluate factors useful in determining whether two or three embryos should be transferred in this age group. Embryo quality and number, but not number of previous failed cycles, were important in determining outcome, and all triplet pregnancies could have been avoided at our program in this age group by limiting the transfer to two good-quality embryos, without reducing pregnancy rates.

A modified embryo cryopreservation method increases post-thaw survival with a concomitant increase in implantation

OBJECTIVE

To achieve maximum post-thaw survival of frozen embryos.

DESIGN

Historical controlled study.

SETTING

Hospital-based fertility center.

PATIENT(S)

One hundred forty-five patients whose embryos were frozen and thawed according to the standard method, and 56 patients whose embryos were frozen and thawed according to a modified method.

INTERVENTION(S)

Modifications were made to the various steps of cryopreservation: freezing and thawing solutions, loading of embryos into the straws, and warming rates.

MAIN OUTCOME MEASURE(S)

Post-thaw survival, implantation, and pregnancy rates.

RESULT(S)

With the modified method, 138 (93%) of the 149 embryos thawed for 56 patients survived freezing, and 79.8% had all their blastomeres intact, which is almost double the result obtained (41.8%) for patients whose embryos were thawed with the standard method. The implantation and pregnancy rates were also significantly higher with the modified method compared with the standard method.

CONCLUSION(S)

Greater post-thaw embryo survival was achieved, with a concomitant increase in implantation and pregnancy rates, by modifying the various steps in the standard cryopreservation methodology. This has important implications in IVF practice.

Prevention of multiple pregnancies after IVF in women 38 and older: a randomized study

The objective of this study was to answer the question of whether a double instead of triple embryo transfer strategy in patients over 38 years would substantially reduce the number of multiple pregnancies while maintaining the chance of a term live birth at an acceptable level. A randomized controlled two-centre trial was performed. Forty-five patients, 38 years or older, were randomized. Double embryo transfer over a maximum of four cycles (DET group) or triple embryo transfer over a maximum of three cycles (TET group) was performed. The cumulative term live birth rate was 47.3% after four cycles in the DET group and 40.5% after three cycles in the TET group. The difference between the DET and the TET group was 6.8% in favour of the DET group (95% CI -25 to 38). The multiple pregnancy rates in the DET and TET group were 0% (95% CI 0 to 24) and 30% (95% CI 7 to 65) respectively (P = 0.05). In the DET patients, the mean number of treatment cycles was 2.9 compared with 2.1 in the TET group (P = 0.01). In women of 38 years and older, double embryo transfer after IVF may result in similar cumulative term live birth rates compared with triple embryo transfer, provided that a higher number of treatment cycles is accepted.

Belgian legislation and the effect of elective single embryo transfer on IVF outcome

In order to reduce the number of multiple pregnancies following IVF, the Belgian government agreed to reimburse laboratory expenses for six IVF cycles up to the age of 42 years, in exchange for restriction of the number of embryos replaced. Data on assisted reproduction outcome before and after the introduction of this new legislation were analysed retrospectively in terms of implantation, pregnancy and multiple pregnancy rates. After the introduction of the new law, the percentage of single embryo transfer increased from 14 to 49%. Implantation rates were 25.9 and 23% respectively. There was no difference in the overall pregnancy rate before and after the introduction (36 versus 37%). Twin pregnancies, however, decreased from 19 to 3%. These findings indicate that elective single embryo transfer significantly decreases the twin pregnancy rate without a reduction in the overall pregnancy rate.

Reproductive performance of couples discordant for hepatitis B and C following IVF treatment

PURPOSE

To examine the reproductive performance of hepatitis B (HBV) and C (HCV) discordant couples following IVF-ET.

METHODS

A retrospective cohort study of 25 IVF-ET cycles in HBV and HCV discordant couples was performed. Thirteen patients in the study cohort were discordant for HBV (10 males and 3 females), and 12 (9 males and 3 females) for HCV. Twenty-seven consecutive age matched patients comprised the control group. All patients underwent controlled ovarian hyperstimulation using the long downregulation protocol followed by IVF or ICSI.

RESULTS

Patients in the three groups (HBV, HCV, and controls) had similar ages, and day 3 FSH concentrations. Despite comparable response to COH, and similar fertilization, and cleavage rates in the three groups, couples discordant for HBV or HCV had significantly poorer implantation and pregnancy rates (7.7%, 0% respectively) compared with controls (41%).

CONCLUSIONS

Despite comparable response to COH, HBV and HCV positive discordant couples, have significantly lower implantation and pregnancy rates compared with age-matched controls.

Comparison of blastocyst transfer with or without preimplantation genetic diagnosis for aneuploidy screening in couples with advanced maternal age: a prospective randomized controlled trial

BACKGROUND

It is generally accepted that the age-related increased aneuploidy rate is correlated with reduced implantation and a higher abortion rate. Therefore, advanced maternal age (AMA) couples are a good target group to assess the possible benefit of preimplantation genetic diagnosis for aneuploidy screening (PGD-AS) on the outcome after assisted reproductive technology (ART).

METHODS

A prospective randomized controlled clinical trial (RCT) was carried out comparing the outcome after blastocyst transfer combined with PGD-AS using fluorescence in situ hybridization (FISH) for the chromosomes X, Y, 13, 16, 18, 21 and 22 in AMA couples (aged > or =37 years) with a control group without PGD-AS. From the 400 (200 for PGD-AS and 200 controls) couples that were allocated to the trial, an oocyte pick-up was performed effectively in 289 cycles (148 PGD-AS cycles and 141 control cycles).

RESULTS

Positive serum HCG rates per transfer and per cycle were the same for PGD-AS and controls: 35.8% (19.6%) [%/per embryo transfer (per cycle)] and 32.2% (27.7%), respectively (NS). Significantly fewer embryos were transferred in the PGD-AS group than in the control group (P<0.001). The implantation rate (with fetal heart beat) was 17.1% in the PGD-AS group versus 11.5% in the control group (not significant; P=0.09). We observed a normal diploid status in 36.8% of the embryos.

CONCLUSIONS

This RCT provides no arguments in favour of PGD-AS for improving clinical outcome per initiated cycle in patients with AMA when there are no restrictions in the number of embryos to be transferred.

What is the most relevant standard of success in assisted reproduction?

National and international registries are essential tools for establishing new standards and comparing success rates, but they do not take into account the total pregnancy/delivery rate per oocyte recovery. In Switzerland and Germany, because of legal constraints, a maximum of three two-pronuclear zygotes are allocated for transfer whereas all the supernumerary pronuclear zygotes are immediately cryopreserved, preventing selection of the transferred embryos. We report on a 10 years' experience (1993-2002) of our centre which performs transfers of unselected embryos and cryopreservation at the two-pronuclear zygote stage. As approximately 30% of all deliveries are from cryo cycles, it is essential to take into account the contribution of the cryo transfers, and we propose therefore to evaluate, as a measure of IVF performance, the cumulated delivery rate per oocyte pick-up. This delivery rate is broken down further into the cumulated singleton delivery rate (CUSIDERA) and the cumulated twin delivery rate (CUTWIDERA). The sum (S) of these two rates is a measure of efficacy while the ratio CUTWIDERA/S as a percentage is a measure of safety of IVF treatments. Using these new indexes, the average 10 year efficacy and safety of our IVF programme were 26 and 19%, respectively. Both CUSIDERA and CUTWIDERA can be calculated easily in any clinical situation and yield useful parameters for patient counselling and internal/external benchmarking purposes.

Single or multiple embryo transfer following in vitro fertilisation for improved neonatal outcome: A systematic review of the literature

BACKGROUND

The aim of the current review was to determine if single versus two or more embryos, or double versus three or more embryos, transferred to the woman of a subfertile couple at in vitro fertilisation (IVF) maximises the likelihood of pregnancy, while minimising the likelihood of multiple pregnancy and adverse sequelae.

METHODS

Studies were identified that reported maternal, infant and cost outcomes following embryo transfer at IVF.

RESULTS

Three randomised trials and 17 cohort studies were included. From two randomised trials, single embryo transfer was found to result in decreased incidence of clinical pregnancy, multiple pregnancy and low birthweight. In the cohort studies for single embryo transfer compared with transfer of two or more embryos the incidence of live birth and singleton pregnancies was unchanged, and the incidence of multiple pregnancies and low birthweight was reduced. For double embryo transfer compared with the transfer of three or more embryos, the incidence of clinical pregnancy, live birth, preterm birth and low birthweight babies was reduced.

CONCLUSIONS

Information on neonatal and maternal outcomes following transfer of different numbers of embryos is limited. Transfer of one embryo does not alter the likelihood of a singleton pregnancy or birth when compared to transfer of two or more embryos. Transfer of one or two embryos decreases the risk of a multiple pregnancy, preterm birth and low birthweight. Further large, well-designed randomised trials are required to provide maternal and neonatal outcomes of relevance to a couple undergoing IVF.

Joseph Price oration. The multiple gestation epidemic: the role of the assisted reproductive technologies

Human IVF has transformed so many lives, but there has been one major drawback--namely the so-called epidemic of multiple gestations.

Patient-friendly ovarian stimulation

The ultimate goal of successful IVF is the birth of a healthy child with no maternal complications. Advances in ovarian stimulation protocols using gonadotrophin-releasing hormone agonists (GnRHa) and high doses of gonadotrophins have resulted in increased oocyte numbers with improved pregnancy and birth rates. However, the efficacy of such therapy is controversial when measured against the potential side effects. These side effects include those arising from oestrogen deprivation during desensitization, complications associated with an increased risk of ovarian hyperstimulation syndrome (OHSS), and an increased possibility of multiple births. Additionally, the increased cost due to more frequent monitoring and increased drug dosage negatively impacts on patient care. Thus, refinements in drug regimens are needed not only to address these side effects, but also to target the quality, not the quantity, of oocytes. In studies comparing GnRH antagonist (GnRHnt) to GnRHa, patients receiving GnRHnt underwent a shorter induction using less gonadotrophin, the incidence of OHSS was reduced and they reported a better quality of life. While larger studies are needed to confirm these promising findings, it appears that milder stimulation protocols could represent an interesting option, at least for selected patients.

Preimplantation genetic diagnosis using FISH for carriers of Robertsonian translocations: the Portuguese experience

Preimplantation genetic diagnosis (PGD) is an alternative to prenatal diagnosis for couples at risk of transmitting genetic disorders to their offspring. We present a fluorescence in situ hybridization (FISH) analysis of embryos obtained after seven PGD cycles in six couples with Robertsonian translocations and male factor infertility: 4 der(13;14), 1 der(14;21) and 1 der(15;21). Of 74 metaphase II (MII) injected oocytes, 61 (82.4%) fertilized normally and cleaved. Of these, 37/61 (60.7%) embryos were of high morphological quality with >or=6 blastomeres. After biopsy of 44 embryos at day 3 of development, seven degenerated, seven arrested in development and 30/44 (68.2%) evolved, of which 25/30 (83.3%) reached the morula/blastocyst stage. Analysis of biopsied blastomeres showed 23/44 (52.3%) of normal/balanced embryos, of which 15 (11 at the morula/blastocyst stage) were transferred in six cycles. One term pregnancy was achieved, which ended by cesarean section at 37 weeks of gestation, giving birth to two healthy newborn. Analysis of 49 embryos (excluding 12 inconclusive cases) showed a predominance of alternate segregation (38/49, 77.6%) over adjacent segregation (7/49, 14.3%), with one (2%) being a polyploid mosaic and three (6.1%) chaotic.

Preimplantation genetic diagnosis for familial amyloidotic polyneuropathy (FAP)

Preimplantation genetic diagnosis (PGD) was developed more than a decade ago to offer an alternative to prenatal diagnosis for couples at risk of transmitting an inherited disease to their offspring. Portuguese-type familial amyloidotic polyneuropathy (FAP type I), is an autosomal dominant disease presenting an inherited mutation in the gene encoding the plasma protein transthyretin (TTR). We here report the first protocol for single-cell detection of the Met30 mutation in FAP type I and its application to PGD. A nested PCR reaction for exon 2 of the TTR gene was developed. The PCR product was then analysed by restriction enzyme analysis and SSCP allowing the detection of the point mutation. Ten clinical cycles were performed in seven couples. From the 93 metaphase II (MII) injected oocytes, 82 were normally fertilized and 78 were biopsied. A positive signal in the nested PCR reaction was obtained in 61 blastomeres, corresponding to a DNA amplification efficiency of 78.2%. No allele dropout (ADO) or contamination were detected. A biochemical pregnancy was obtained in three cases and a clinical pregnancy in one couple is actually in normal evolution.

Developmental potential of elongating and elongated spermatids obtained after in-vitro maturation of isolated round spermatids

BACKGROUND

Round spermatid injections are associated with disappointing clinical outcomes, and although these cells have been shown to mature into late spermatids in vitro, the developmental potential of such gametes remains to be demonstrated.

METHODS

Round spermatids were isolated from 12 testicle samples of patients with obstructive azoospermia, hypoplasia, complete maturation arrest, and incomplete Sertoli cell-only syndrome. They were cultured for 7 days at 32 degrees C, 5% CO(2)in air, in microdrops of Vero cell-conditioned medium containing 10% synthetic serum substitute.

RESULTS

From the 238 round spermatids cultured, 25.2% attained the elongating and 5.5% the elongated spermatid stage (3-4 days per step). Relatively higher maturation rates were found in cases with obstructive azoospermia, but differences were significant only for elongated spermatids (9.3%). No differences were found in maturation rates between cases with non-obstructive azoospermia (4.3% of elongated spermatids). Experimental microinjections with elongating and elongated spermatids revealed a low fertilization rate (40.9%) but a normal blastocyst formation rate (60%).

CONCLUSIONS

Late spermatids resulting from in-vitro culture of round spermatids in conditioned medium, either in controls in cases with a spermiogenetic block, appeared able to successfully fertilize the human oocyte and elicit normal embryo development.

Achieving pregnancy against the odds: successful implantation of frozen-thawed embryos generated by ICSI using spermatozoa banked prior to chemo/radiotherapy for Hodgkin's disease and acute leukaemia

Two cases are reported of successful pregnancies following long-term semen banking prior to chemotherapy and radiotherapy for malignancy. With the first case, the patient banked semen at the age of 20 years prior to chemotherapy for Hodgkin's disease; 11 years later the thawed semen was used for IVF with intracytoplasmic sperm injection (ICSI), resulting in twins being born following the transfer of frozen-thawed embryos. In the second case, the patient banked semen at the age of 17 years prior to chemotherapy and radiotherapy for acute myeloid leukaemia; 8 years later it was used for ICSI, resulting in triplets being born following the transfer of frozen-thawed embryos. These cases support long-term semen banking for men whose future fertility may be compromised by suppression of spermatogenesis secondary to administration of chemo/radiotherapy treatment. The advent of successful ICSI combined with embryo cryopreservation has increased the chance of thawed cryopreserved semen achieving fertilization. Banking of a single ejaculate prior to commencement of chemotherapy/radiotherapy treatment may preserve potential fertility without compromising the oncology treatment.

Embryo implantation after biopsy of one or two cells from cleavage-stage embryos with a view to preimplantation genetic diagnosis

Preimplantation genetic diagnosis (PGD) can be offered as an alternative to prenatal diagnosis (PND) to couples at risk of having a child with a genetic disease. The affected embryos are detected before implantation by fluorescent in situ hybridisation (FISH) for sexing (X-linked diseases) and chromosomal disorders (numerical and structural) or by polymerase chain reaction (PCR) for monogenic disorders (including some X-linked diseases). The accuracy and reliability of the diagnosis is increased by analysing two blastomeres of the embryo. However, the removal of two blastomeres might have an effect on the implantation capacity of the embryo. We have evaluated the implantation of embryos after the removal of one, two or three cells in 188 PGD cycles where a transfer was done. The patients were divided into five groups: a first group which received only embryos from which one cell had been removed, a second group which received only embryos from which two cells had been removed, a third group which received a mixture of embryos from which one and two cells had been taken, a fourth group where two and three cells had been removed, and a fifth group where three cells had been removed. The overall ongoing pregnancy rate per transfer was 26.1%, the overall implantation rate per transfer was 15.2% and the overall birth rate was 14.2%. Although pregnancy rates between the groups cannot be compared because the second group (two cells removed) contains more rapidly developing and therefore 'better quality' embryos, an ongoing pregnancy rate of 29.1% and an implantation rate of 18.6% per transferred embryo in this group is acceptable, and we therefore advise analysing two cells from a > or =7-cell stage embryo in order to render the diagnosis more accurate and reliable.

Embryo freezing after intracytoplasmic sperm injection

This study reports on the safety and efficiency of the cryopreservation of human embryos obtained after intracytoplasmic sperm injection. For this, we evaluated the morphological survival, the capacity of the surviving embryo to develop further in vitro and in vivo. After freezing-thawing embryos obtained after ICSI, 40% of the embryos do not survive the cryopreservation procedure. After selective transfer of further cleaving frozen-thawed embryos, pregnancy loss was 31% (subclinical pregnancy rate of 13% and miscarriage rate of 18%). As a result the livebirth rate per transferred embryos and per thawed embryo was 7 and 3% respectively. Obstetric outcome as well as further follow-up of the children born indicate that cryopreservation of ICSI embryos is a safe procedure, long term follow-up of the children born however is still warranted.

Prospective randomized study of two cryopreservation policies avoiding embryo selection: the pronucleate stage leads to a higher cumulative delivery rate than the early cleavage stage

OBJECTIVE

To compare the cumulative live birth rates obtained after cryopreservation of either pronucleate (PN) zygotes or early-cleavage (EC) embryos.

DESIGN

Prospective randomized study.

SETTING

University hospital.

PATIENT(S)

Three hundred eighty-two patients, involved in an IVF/ICSI program from January 1993 to December 1995, who had their supernumerary embryos cryopreserved either at the PN (group I) or EC (group II) stage. For 89 patients, cryopreservation of EC embryos was canceled because of poor embryo development (group III). Frozen-thawed embryo transfers performed up to December 1998 were considered.

MAIN OUTCOME MEASURE(S)

Age, oocytes, zygotes, cryopreserved and transferred embryos, damage after thawing, cumulative embryo scores, implantation, and cumulative live birth rates.

RESULT(S)

The clinical pregnancy and live birth rates were similar in all groups after fresh embryo transfers. Significantly higher implantation (10.5% vs. 5.9%) and pregnancy rates (19.5% vs. 10.9%; P< or = .02 per transfer after cryopreserved embryo transfers were obtained in group I versus group II, leading to higher cumulative pregnancy (55.5% vs. 38.6%; P < or = .002 and live birth rates (46.9% vs. 27.7%; P< or = .0001.

CONCLUSION(S)

The transfer of a maximum of three unselected embryos and freezing of all supernumerary PN zygotes can be safely done with significantly higher cumulative pregnancy chances than cryopreserving at a later EC stage.

Reproductive performance of patients undergoing intracytoplasmic sperm injection with 100% implantation rate

PURPOSE

To characterize the differences between two matched groups of patients treated by ICSI: those pregnant after all embryos transferred implanted (100% implantation rate) compared with nonpregnant patients.

METHODS

Twenty-one patients in whom one transferred embryo achieved a singleton pregnancy (group A) and 21 pregnant patients to whom two or three embryos were transferred and achieved 11 twin and 10 triplet pregnancies (group B) compared with matched nonpregnant patients (group C and D, respectively).

RESULTS

The singleton pregnant patients were significantly older than the twin and triplet pregnancy patients. Although a similar number of human menopausal gonadotropin ampules were used in the singleton compared with the twins and triplets a significantly lower number of oocytes and embryos were achieved at lower levels of estradiol on the human chorionic gonadotropin day in the former than in the latter respectively. No difference was found between the pregnant women and their nonpregnant controls in any of the mentioned parameters. Good embryo morphology was found in 86% of the embryos in group A compared with 62% in group C (P = 0.08) and 92% in group B compared with 66% in group D (P < 0.002).

CONCLUSIONS

The only parameter in which pregnant patients with 100% implantation rate differ from their nonpregnant controls was embryo quality.

The influence of supernumerary embryos on the clinical outcome of IVF cycles

PURPOSE

To assess the influence of the presence of quality supernumerary embryos on the clinical outcome and risk of multiple conception in patients having their first in vitro fertilization (IVF) cycle.

METHODS

Retrospective cohort study of 1448 women having their first IVF treatment cycle who received 4004 embryos where at least six embryos were available for transfer treated in an Assisted Conception Unit based in a large teaching hospital.

RESULTS

The replacement of three rather than two embryos to women under 35 years who had good-quality supernumerary embryos resulted in a higher twin (12.5 vs. 11.9%) and triplet birth rates (2.1 vs. 0%), without significantly improving the clinical pregnancy (50.5 vs. 45.2%) or total live birth rates (38.9 vs. 35.7%). In the absence of quality spare embryos, these women who had three rather than two embryos replaced had a significantly higher clinical pregnancy rate (39.3 vs. 28.8%; P = 0.04), total live birth (32.7 vs. 19.4%; P = 0.02) and singleton birth rate per cycle (20.8 vs. 14.4%; P = 0.04), without significantly influencing the multiple birth rate. In women over 35 years, the replacement of three instead of two embryos in the presence or absence of quality supernumerary embryos led to a significant improvement in clinical outcome, without being associated with a concurrent increase in the multiple birth rate. Women in both age groups who had either two or three embryos replaced in the presence of quality supernumerary embryos had a notably better clinical outcome compared with their counterparts who had the same number of embryos replaced, but with no quality embryos to spare.

CONCLUSIONS

The presence of good-quality supernumerary embryos can be used as a reference to determine the optimal number of embryos to transfer and as an indicator of the probability of success of an individual couple in a given cycle. Optimal pregnancy rates and simultaneous reduction of multiple gestation can be achieved with a flexible embryo replacement policy that is based on embryo quality, maternal age, and the presence or absence of surplus quality embryos.

Intracytoplasmic sperm injection. Survey of world results

The widespread application of intracytoplasmic sperm injection (ICSI) has raised concern about the efficacy and safety of this novel technique. The European Society of Human Reproduction and Embryology (ESHRE) has established an ICSI Task Force to collect annually the clinical results, the outcome of pregnancy, and the follow-up of children after ICSI using ejaculated, epididymal, and testicular sperm in order to address these important issues in a relatively short time. Over a 3-year span (1993-1995), the number of centers for ICSI increased from 35 to 101, and the total number of ICSI cycles per year rose from 3,157 to 23,932. The incidence of oocytes damaged by the procedure remained low (< 10%), whereas the fertilization rates obtained with ejaculated, epididymal, and testicular spermatozoa for 1995 were 64%, 62%, and 52%, respectively. Thus, 86-90% of the couples had embryo transfer, and the viable pregnancy rate was 21% for ejaculated, 22% for epididymal, and 19% for testicular sperm, while the incidence of multiple gestations was 29%, 30%, and 38%, respectively. It is noteworthy that no difference was found in ICSI results concerning the etiology of azoospermia, for example, obstructive (congenital or acquired) or nonobstructive. Furthermore, 3,149 transfers of frozen-thawed embryos after ICSI with ejaculated, epididymal, or testicular sperm were performed, and in 11%, 9%, and 7% of them, respectively, a viable pregnancy was achieved. The ICSI results were similar during this 3-year period, irrespective of the origin of the sperm. The perinatal outcome of children born after ICSI was not different from that after in vitro fertilization or natural conception and was only affected by multiplicity. Moreover, the incidence of major or minor malformations was not increased, but the chromosomal, especially the sex chromosomal, aberration rate was slightly elevated (approximately 2%). Therefore, ICSI has opened new horizons in the treatment of male infertility. The achievement of pregnancy after ICSI using ejaculated, epididymal, or testicular sperm is very satisfactory. The procedure seems to be safe, but further follow-up of the children is necessary to more accurately assess its safety.

A randomized prospective cross-over study of highly purified follicle-stimulating hormone and human menopausal gonadotrophin for ovarian hyperstimulation in women aged 37-41 years

PURPOSE

In the present study, we investigated the benefits of highly purified FSH (H.P. FSH) in comparison with human menopausal gonadotrophin (hMG) in IVF patients aged 37-41 years.

METHODS

Twenty patients experienced within a period of four months both preparations in subsequent cycles through a prospective randomized cross-over design. A standard hormonal treatment consisting of a flare-up protocol using gonadotrophin-releasing hormone agonist (GnRHa) in combination with the same starting dose of H.P. FSH or hMG was used in all cycles.

RESULTS

Cycles stimulated with H.P. FSH resulted in a significantly higher mean number (10.3 +/- 3) of ovocytes retrieved with a significantly shorter (13 +/- 2.3 days) duration of stimulation compared to cycles treated with hMG [mean number of oocytes 7.3 +/- 5 (P < 0.01) and mean duration of stimulation 14.7 +/- 3.9 days (P < 0.02)]. No detrimental effect of basal or exogenous LH on oocyte quality was observed in our study.

CONCLUSIONS

In our experience, H.P. FSH preparations seemed to be more effective than hMG preparations for ovarian stimulation in this group of women aged 37-41 years.

Conventional in-vitro fertilization versus intracytoplasmic sperm injection in sibling oocytes from couples with tubal infertility and normozoospermic semen

An auto-controlled study was conducted in couples with tubal infertility and normozoospermic semen. The fertilization rates and embryonic development in sibling oocytes treated, using the same semen sample, either by conventional in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) at the same time were compared. Sibling oocyte-cumulus complexes (OCC) of 56 different couples with tubal infertility and normozoospermic semen were randomly divided in order of retrieval into two groups inseminated either by conventional IVF or by ICSI. Of the retrieved OCC in the same cohort, 53.0 +/- 31.2 and 62.0 +/- 26.6% showed two distinct pronuclei after conventional IVF and ICSI respectively (not significant). Complete fertilization failure occurred after conventional IVF in 12.5% (7/56 couples). After ICSI, the comparable figure was 3.6% (2/56). The number of cases was too small to apply a statistical test to this difference. Total cleavage rates were quite similar: 86.7 +/- 28.0 and 90.1 +/- 21% of the zygotes developed into transferable embryos after IVF and ICSI respectively (not significant). Similarly, no difference in embryo quality was observed. Although injection and insemination of the oocytes were performed at the same time in the two groups, at 42 h post-insemination more embryos were at the four-cell stage after ICSI (P < 0.001) than after conventional IVF, where more embryos were still at the two-cell stage (P < 0.02). Embryo transfer was possible in all 56 couples, resulting in 16 positive serum human chorionic gonadotrophin tests (28.6% per embryo transfer), from which a clinical pregnancy resulted in 15 couples. The best embryos were selected for transfer independently of the insemination procedure, but preferably from the same origin. There appeared to be no difference in implantation potency of the embryos obtained with either technique after the non-randomized transfers.

Cumulative delivery rates after intracytoplasmic sperm injection: 5 year follow-up of 498 patients

The use of life-table analysis for infertility data has the advantages of clarity and ease of application. Success rates per cycle have been reported, but not cumulative delivery rates for intracytoplasmic sperm injection (ICSI). We selected retrospectively 498 Belgian patients <37 years old, who had their first ICSI cycle between July 1992 and December 1993. Follow-up was till the end of October 1997. Outcome measure was any delivery >25 weeks. These couples underwent 963 ICSI cycles using fresh ejaculated spermatozoa. The indications for ICSI were long-standing severe male infertility or fertilization failure after conventional in-vitro fertilization (IVF). Cumulative delivery rates were calculated by life-table analysis and compared according to age groups and sperm quality. There were 298 deliveries within a mean rate per cycle of 31%. The average number of cycles required for a delivery was 3.15 (CI 2.88; 3.43). Twenty-three (4.6%) spontaneous pregnancies occurred after the patients had finished therapy. There was no significant difference between the sperm quality groups but delivery rates decreased significantly with increasing female age. The real delivery rate after six cycles was 60%, while the expected cumulative delivery rate was 86%. This life-table analysis may provide a means by which to counsel couples on the likelihood of a delivery following ICSI.

Characterization of a top quality embryo, a step towards single-embryo transfer

In most in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) programmes approximately one ongoing pregnancy in three is multiple. The need to characterize embryos with optimal implantation potential is obvious. We retrospectively examined all of 23 double transfers resulting in ongoing twins, occurring between January 1, 1996 and May 19, 1997. Characteristics of these top quality embryos were absence of multinucleated blastomeres, four or five blastomeres on day 2, seven or more cells on day 3, and </=20% anucleated fragments. In a subsequent series of 400 IVF/ICSI cycles (out of which 372 were selected for embryo transfer) from May 20, 1997 to July 31, 1998, only women <38 years of age had multiple pregnancies: after 221 transfers of two embryos, 45/116 (39%) were multiple, and after 77 transfers of >2 embryos, 11/31 (35%) were multiple. We applied our top quality criteria to the 221 double transfers: 106 transfers with two top embryos resulted in 65 (63%) ongoing pregnancies with 37 (57%) twins, 65 transfers with one top embryo in 38 (58%) ongoing pregnancies with eight (21%) twins. In the group without top embryos, 12/52 (23%) ongoing singletons occurred, with no twins. The corresponding ongoing implantation rates were 49, 35 and 12%. This analysis suggests that single embryo transfer with an acceptable pregnancy rate might be considered if a top quality embryo is available.

In vitro fertilization outcome according to age and follicle-stimulating hormone levels on cycle day 3

PURPOSE

In a retrospective study, the prognostic factors of in vitro fertilization outcome were studied in women of 39 years of age or older, with an elevated cycle day 3 follicle-stimulating hormone (FSH) level.

METHODS

Ovarian stimulation was achieved with a combination of gonadotropin-releasing hormone agonist/human menopausal gonadotropin in a short protocol. All patients underwent FSH dosage on cycle day 3 prior to stimulation. The pregnancy rate was studied according to age, FSH levels, and stimulation parameters.

RESULTS

There was a negative correlation between day 3 FSH levels and the number of ovocytes retrieved. Cycles canceled because of the absence of ovarian response had a significantly higher mean FSH value (18.2 mlU/ml) than cycles ending in ovocyte retrieval (14.6 mlU/ml). Patients with three or more growing follicles during stimulation achieved a significantly higher pregnancy rate per egg retrieval (16%) compared to patients with fewer than three growing follicles (6%). Eighty percent of those pregnancies were obtained during the first two IVF cycles. Even with an elevated FSH level, some patients developed three or more follicles after stimulation. In such cases, the number of embryos available for transfer was the only significant limiting factor to achieving pregnancy.

CONCLUSIONS

As our results suggest, there is a discrepancy between biological and chronological ovarian age. In patients with an elevated cycle day 3 FSH level and over 40 years of age, alternatives to fertility treatments (ovum donation, adoption, or no treatment) should not be considered as first choices. Indeed, even with elevated FSH levels, a 16% pregnancy rate per egg retrieval may be obtained if three or more growing follicles can be seen during ovarian stimulation. However, in the presence of fewer than three growing follicles during ovarian stimulation, the patient should be informed about the discouraging prognosis of the running cycle.

Fertilization, embryo quality, and cryosurvival in in vitro fertilization and intracytoplasmic sperm injection cycles

PURPOSE

Our purpose was to investigate the influence of semen quality on fertilization, embryo morphology, cleavage, and cryosurvival in conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) programs.

METHODS

A retrospective analysis of 513 couples undergoing IVF and 255 couples undergoing ICSI was done.

RESULTS

Semen quality influenced fertilization in IVF and abnormal fertilization in IVF and ICSI, but no effects on the development, morphology, implantation capacity, or cryosurvival of embryos were found. Fertilization, embryo quality, and cryosurvival rates were similar after IVF and ICSI. The fertilization rate of mature oocytes in IVF was lower when cytoplasmic immaturity in the oocyte population was frequent. The speed of development of embryos was 2 hr faster after ICSI than after IVF. Two-cell-stage embryos survived best after cryopreservation with propanediol and sucrose on day 2.

CONCLUSIONS

After fertilization, semen parameters had no effect on the quality or cryosurvival of embryos in either IVF or ICSI.

Strategies to prevent multiple pregnancies in assisted conception programmes

All assisted conception techniques are associated with an increase in the multiple pregnancy rate. Iatrogenic multiple births are increasing as the use of these technologies expands. The cornerstone of safe ovulation induction is careful ultrasound monitoring, with cancellation of cycles if excessive ovulation is expected. In in vitro fertilization (IVF) cycles, the main determinant of multiple pregnancy risk is the number of embryos replaced. The current move in IVF clinics is to reduce the risk of multiple pregnancy by reducing the number of embryos transferred. We would suggest a maximum of two embryos transferred to women under, for example, 39 years of age. Women of 39 years or over have a reduced chance of embryo implantation; they should be allowed the transfer of up to three embryos (the UK legal maximum).

A new indication for an intracytoplasmic sperm injection procedure outside the cases of severe male factor infertility

OBJECTIVE

To show the success of intracytoplasmic sperm injection (ICSI) in cases of a low number of oocytes retrieved.

STUDY DESIGN

715 microinjection cycles, which were performed at our center, were analyzed retrospectively.

RESULTS

Within the analyzed cycles, there were 50 cycles with less than four oocytes retrieved. Twelve, 18, and 20 cases were treated with one, two, and three oocytes, respectively. The rate of metaphase II oocytes injected and subsequently fertilized, and intact oocytes was similar in the three groups. The transfer rate was not significantly different from those cases with more than three oocytes (84% vs. 94%). Therefore, the rate of fertilization failure was not higher in the low-number group. The number of embryos transferred was statistically significantly lower in the group with one and two oocytes compared to the group with three oocytes (1, and 1.31 vs. 2.27; P < 0.01) and the group of all patients (2.63; P < 0.01), as well as between the group of less than four oocytes and all patients (1.63 vs. 2.63; P < 0.01). There was no statistically significant difference between the pregnancy rates of the three groups (36.4% vs. 20% vs. 22.2%), and also no difference was found between the group with less than four oocytes and the data of all patients (22% vs. 26.9%).

CONCLUSION

In our opinion, these data show that ICSI guarantees a successful treatment even if only as many oocytes are present as embryos are planned to be transferred, i.e. three embryos. This has been accepted to be a new indication in our center. Therefore it should be possible to stimulate patients mildly, with e.g. clomiphene citrate, to avoid unnecessary hyperstimulation syndromes, and to lower the cost of hormonal superstimulation.

Intracytoplasmic sperm injection

Intracytoplasmic sperm injection (ICSI) can now alleviate infertility in couples who could not conceive by other means. Most patients with obstructive azoospermia and some patients with non-obstructive azoospermia can now be treated. The practice of five years of ICSI (1991-1995) is reviewed in terms of patients selection and counselling, controlled ovarian stimulation and oocyte handling, semen evaluation and preparation, ICSI procedure, oocyte damage and pronuclear status after ICSI, embryo development, embryo transfer, freezing of supernumerary embryos, obstetrical outcome, prenatal diagnosis and follow-up study of the children resulting from ICSI.