Two cycles with single embryo transfer versus one cycle with double embryo transfer: a randomized controlled trial

Selective single blastocyst transfer reduces the multiple pregnancy rate and increases pregnancy rates: a pre- and postintervention study

Objective

To examine the clinical pregnancy rate (CPR) and multiple pregnancy rate (MPR) in a large in vitro fertilisation (IVF) programme before and after the introduction of single blastocyst transfer (SBT) strategy in a selected group of women.

Design

A 3-year pre- and postintervention study.

Setting

A tertiary reproductive medicine and assisted conception unit in a London teaching hospital.

Population

Two thousand four hundred and fifty-one fresh IVF cycles performed between July 2004 and June 2007 at the Assisted Conception Unit at Guy’s and St Thomas’ Hospital NHS Foundation Trust were included in the study.

Methods

In January 2006, we implemented a multidisciplinary intervention involving the introduction of a selective day 5 SBT service together with an educational programme on the risks of multiple pregnancy and potential advantages of blastocyst transfer aimed at couples at high risk of multiple pregnancy.

Main outcome measures

The CPR per cycle started and MPR per clinical pregnancy achieved.

Results

A statistically significant increase in the CPR from 27% (324/1198) to 32% (395/1253) (risk difference [RD] 5%, risk ratio [RR] 1.17, 95% CI 1.03–1.32, P = 0.015) and reduction in the MPR per clinical pregnancy from 32% (103/272) to 17% (69/395) (RD 15%, RR 0.46, 95% CI 0.35–0.60, P < 0.001) were observed after introduction of the SBT service.

Conclusion

Selective SBT in women with good prognosis can reduce the MPR after IVF while maintaining the overall success rate of the IVF programme.

Please cite this paper as:Khalaf Y, El-Toukhy T, Coomarasamy A, Kamal A, Bolton V, Braude P. Selective single blastocyst transfer reduces the multiple pregnancy rate and increases pregnancy rates: a pre- and postintervention study. BJOG 2008;115:385–390.

Preferences of subfertile women regarding elective single embryo transfer: additional in vitro fertilization cycles are acceptable, lower pregnancy rates are not

With identical pregnancy rates after elective single embryo transfer (ET) and double ET strategies consisting of three cycles of IVF or intracytoplasmic sperm injection (ICSI) plus transfers of thawed/frozen embryos if available, 46% of the women undergoing IVF/ICSI favor elective single ET. If elective single ET lowers pregnancy chances with 1%, 3%, or 5%, the percentage of women preferring elective single ET drops to 34%, 24%, and 15%, respectively. If four, five, or six cycles with elective single ET are needed to match the success rate of three cycles with double ET, the percentage of women with a preference for elective single ET drops from 46% to 40%, 36%, and 35% respectively.

Towards the elective replacement of a single embryo (eSET) in the United Kingdom

In the UK, the live birth rate after IVF in women aged less than 36 is >25%. The multiple birth rates in these women are excessive (20% to 25%). The perinatal mortality rate is increased significantly with IVF twins and triplets (8/1000 singletons, 20/1000 twins and 34/1000 triplets). Multiple pregnancies and births significantly increase the risks to the mother and the children, adversely affect family life and are economically disadvantageous to the couple and the wider community. The elective transfer of a single fresh embryo, followed if necessary by a single thawed embryo, in women at high risk of a multiple birth does not reduce the live birth rate and all but prevents the conception of twins and triplets.

Predictors of ongoing pregnancy after single-embryo transfer following mild ovarian stimulation for IVF

OBJECTIVE

To develop a prognostic model for the prediction of ongoing pregnancy after single-embryo transfer (SET) following mild stimulation for IVF in women less than 38 years of age.

DESIGN

Prospective cohort study.

SETTING

Two fertility centers in tertiary referral university hospitals.

PATIENT(S)

A total of 152 women with an elective SET following mild ovarian stimulation (cycle day 5 start of 150 IU/day recombinant FSH and late follicular phase GnRH antagonist cotreatment).

INTERVENTION(S)

Database analysis.

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy.

RESULT(S)

The ongoing pregnancy rate per elective SET was 28% (42 of 152). In a multivariate logistic regression analysis, body mass index, the total gonadotrophin dose needed, and number of oocytes retrieved were negatively correlated whereas the availability of a top-quality embryo was positively correlated with ongoing pregnancy. The predictive ability of the model assessed by the area under the receiver operating characteristic curve was 0.68. At a probability cut-off level of 0.20 the model showed a sensitivity of 37% and a specificity of 90%.

CONCLUSION(S)

The developed prediction model for ongoing pregnancy provides an evidence-based strategy for guidance under which conditions SET may be performed. After external validation, application of the model may help to improve overall singleton pregnancy rates.

A detailed cost analysis of in vitro fertilization and intracytoplasmic sperm injection treatment

OBJECTIVE

To provide detailed information about costs of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatment stages and to estimate the cost per IVF and ICSI treatment cycle and ongoing pregnancy.

DESIGN

Descriptive micro-costing study.

SETTING

Four Dutch IVF centers.

PATIENT(S)

Women undergoing their first treatment cycle with IVF or ICSI.

INTERVENTION(S)

IVF or ICSI.

MAIN OUTCOME MEASURE(S)

Costs per treatment stage, per cycle started, and for ongoing pregnancy.

RESULT(S)

Average costs of IVF and ICSI hormonal stimulation were euro 1630 and euro 1585; the costs of oocyte retrieval were euro 500 and euro 725, respectively. The cost of embryo transfer was euro 185. Costs per IVF and ICSI cycle started were euro 2381 and euro 2578, respectively. Costs per ongoing pregnancy were euro 10,482 and euro 10,036, respectively.

CONCLUSION(S)

Hormonal stimulation covered the main part of the costs per cycle (on average 68% and 61% for IVF and ICSI, respectively) due to the relatively high cost of medication. The costs of medication increased with increasing age of the women, irrespective of the type of treatment (IVF or ICSI). Fertilization costs (IVF laboratory) constituted 12% and 20% of the total costs of IVF and ICSI. The total cost per ICSI cycle was 8.3% higher than IVF.

Intracytoplasmic sperm injection (ICSI) in 2006: Evidence and Evolution

The introduction of intracytoplasmic sperm injection (ICSI) in 1992 has dramatically changed the management of severe male infertility. In severe male infertility, live birth rates with ICSI are superior to those with other non-donor treatments. In non-male infertility, however, pregnancy rates are not better with ICSI than with in vitro fertilization (IVF). With obstructive or non-obstructive azoospermia, reasonable pregnancy rates are now possible with ICSI after recovery of sperm from the testes followed by ICSI. Genetic counselling is indicated for severe male infertility, whether or not ICSI is considered. ICSI is indicated in preimplantation genetic diagnosis (PGD) to avoid contamination by extraneous DNA in the case of PCR-based testing and to increase the number of embryos available for testing. In turn, PGD may be indicated in pregnancies that are at high risk of aneuploidy because of genetic factors associated with azoospermia. As with IVF, not all couples succeed, but 2% of couples with failed ICSI cycles will conceive without treatment. ICSI outcome studies indicate that there is a significant increase in prematurity, low birthweight, and perinatal mortality associated with single and multiple births, similar to the outcomes of conventional IVF. However, as evidenced in long-term follow-up studies, the higher rates of urogenital abnormalities and increased use of healthcare may be associated with paternal characteristics.

Reducing the number of embryos transferred in Sweden-impact on delivery and multiple birth rates

BACKGROUND

Reduction of the number of embryos transferred has been introduced to decrease the multiple birth rates (MBRs) after IVF and the associated risks for the children. The aim of this report is to present the effect of two steps in reduction of the number of embryos transferred, when applied in the majority of the patients, on national data for delivery and MBR after IVF in Sweden.

METHODS

This observational study is based on annual reports from all IVF clinics in Sweden to the National Board of Health and Welfare for the time period 1991-2004.

RESULTS

The main finding is that despite a successive reduction in the number of embryos transferred, delivery rates were maintained at around 26% while MBR decreased dramatically, from about 35% to around 5%. The same pattern was noticed, independent of age, for all women below 40. In comparison with the USA, lower delivery and MBR were noted for Sweden whereas a higher 'birth per embryo transferred' was found.

CONCLUSIONS

Single embryo transfer (SET) results in satisfactory delivery rates and a dramatic decrease in the MBRs, also when applied on a broad scale. The experience from Sweden ought to encourage other countries to introduce SET more widely.

eSET irrespective of the availability of a good-quality embryo in the first cycle only is not effective in reducing overall twin pregnancy rates

INTRODUCTION

In several clinics, elective single-embryo transfer (eSET) is applied in a selected group of patients based on age and the availability of a good-quality embryo. Whether or not eSET can be applied irrespective of the presence of a good-quality embryo in the first cycle, to further reduce the twin pregnancy rate, remains to be elucidated.

METHODS

In patients <38 years two transfer strategies were compared, which differed in the first cycle only: group A (n = 141) received eSET irrespective of the availability of a good-quality embryo, and group B (n = 174) received eSET when a good-quality embryo was available while otherwise they received double embryo transfer (DET; referred to as eSET/DET transfer policy). In any subsequent cycle, in both groups the eSET/DET transfer policy was applied.

RESULTS

After completion of their IVF treatment (including a maximum of three fresh cycles and the transfer of frozen-thawed embryos), comparable cumulative live birth rates (62.4% in group A and 62.6% in group B) and twin pregnancy rates (10.1 versus 13.4%) were found. However, patients in group A required significantly more fresh (2.0 versus 1.8) and frozen (0.8 versus 0.5) cycles.

CONCLUSIONS

The transfer of one embryo in the first cycle, irrespective of the availability of a good-quality embryo, in all patients <38 years, is not an effective transfer policy for reducing the overall twin pregnancy rate.

A mild treatment strategy for in-vitro fertilisation: a randomised non-inferiority trial

BACKGROUND

Mild in-vitro fertilisation (IVF) treatment might lessen both patients' discomfort and multiple births, with their associated risks. We aimed to test the hypothesis that mild IVF treatment can achieve the same chance of a pregnancy resulting in term livebirth within 1 year compared with standard treatment, and can also reduce patients' discomfort, multiple pregnancies, and costs.

METHODS

We did a randomised, non-inferiority effectiveness trial. 404 patients were randomly assigned to undergo either mild treatment (mild ovarian stimulation with gonadotropin-releasing hormone [GnRH] antagonist co-treatment combined with single embryo transfer) or a standard treatment (stimulation with a GnRH agonist long-protocol and transfer of two embryos). Primary endpoints were proportion of cumulative pregnancies leading to term livebirth within 1 year after randomisation (with a non-inferiority threshold of -12.5%), total costs per couple up to 6 weeks after expected date of delivery, and overall discomfort for patients. Analysis was by intention to treat. This trial is registered as an International Standard Randomised Clinical Trial, number ISRCTN35766970.

FINDINGS

The proportions of cumulative pregnancies that resulted in term livebirth after 1 year were 43.4% with mild treatment and 44.7% with standard treatment (absolute number of patients=86 for both groups). The lower limit of the one-sided 95% CI was -9.8%. The proportion of couples with multiple pregnancy outcomes was 0.5% with mild IVF treatment versus 13.1% (p<0.0001) with standard treatment, and mean total costs were 8333 euros and 10745 euros, respectively (difference 2412 euros, 95% CI 703-4131). There were no significant differences between the groups in the anxiety, depression, physical discomfort, or sleep quality of the mother.

INTERPRETATION

Over 1 year of treatment, cumulative rates of term livebirths and patients' discomfort are much the same for mild ovarian stimulation with single embryos transferred and for standard stimulation with two embryos transferred. However, a mild IVF treatment protocol can substantially reduce multiple pregnancy rates and overall costs.

A 47-year-old woman with fertility problems who desires a multiple pregnancy

Mrs Z is a 47-year-old woman with long-standing infertility who is about to undergo in vitro fertilization (IVF) using donor oocytes from an anonymous donor. She has already undergone an IVF cycle with her own oocytes and an IVF cycle using donor oocytes from a known donor without a successful pregnancy. Mrs Z has been advised by her infertility physician to consider the transfer of a single embryo, but she does not wish to decrease her likelihood of conception, and, after her long and expensive infertility saga, wishes to conceive twins. The science of IVF has evolved significantly in the last several years, increasing the likelihood of successful pregnancy and reducing the need to transfer more than 1 embryo with its inherent risks of multiple pregnancy. The state of the science and why patients may continue to want multiple embryos transferred, including costs and lack of insurance coverage for infertility treatments, are discussed.

ART: iatrogenic multiple pregnancy?

Assisted reproductive technologies (ART) are now widely accepted as effective treatment for most causes of infertility. With improving success rates, attention has turned to the problem of multiple pregnancies, which are associated with a poor perinatal outcome, maternal complications and significant financial consequences. The challenge is to reduce multigestational pregnancies while maintaining good treatment outcomes. Methods to prevent multiple pregnancy include restrictive use of ART in couples with a good chance of spontaneous pregnancy, cautious use of gonadotrophins, and increased use of natural-cycle intra-uterine insemination and elective single embryo transfer in in-vitro fertilization and intracytoplasmic sperm injection. The aim of this article is to review the contribution of fertility treatment to multiple pregnancies and strategies for reducing multiples in ART.

Incidence and complications of multiple gestation in Canada: proceedings of an expert meeting

This paper reports the proceedings of a consensus meeting on the incidence and complications of multiple gestation in Canada. In addition to background presentations about current and possible future practice in Canada, the expert panel also developed a set of consensus points. The need for infertility to be understood, and funded, as a healthcare problem was emphasized, along with recognition of the emotional impact of infertility. It was agreed that the goal of assisted reproduction treatment is the delivery of a single healthy infant and that even though many positive outcomes have resulted from twin or even triplet pregnancies, the potential risks associated with multiple pregnancy require that every effort be made to achieve this goal. The evidence shows that treatments other than IVF (such as superovulation and clomiphene citrate) contribute significantly to the incidence of multiple pregnancy. There is an urgent need for studies to understand better the usage and application of these other fertility technologies within Canada, as well as the non-financial barriers to treatment. The final consensus of the expert panel was that with adequate funding and good access to treatment, it will be possible to achieve the goal of reducing IVF-related multiple pregnancy rates in Canada by 50%.

Intrauterine insemination in The Netherlands

The aim of this retrospective study was to assess the results of intrauterine insemination (IUI) in The Netherlands, using data from 2003 taken from hospital annual reports and reports from individual gynaecologists. By extrapolation, the total number of IUI cycles performed that year nationwide, and the related outcomes, was estimated. IUI was performed in 91 of the country's 101 hospitals. Of these, 58 (64%) registered their IUI results and performed 19,846 IUI cycles. The mean pregnancy rate per cycle was 9.0% and the ongoing pregnancy rate per cycle was 7.3%. Multiple pregnancies occurred in 9.5% of the ongoing pregnancies. Extrapolation of the data suggested that approximately 28,500 IUI cycles were performed, of which approximately 2000 resulted in an ongoing pregnancy. The number of multiple pregnancies following IUI was estimated to be 180 (9.0%). According to the national IVF registry, 9761 IVF cycles were started in 2003, resulting in 2,028 ongoing pregnancies (20.8% per cycle) and 439 twin pregnancies (21.6% per ongoing pregnancy). In conclusion, the pregnancy rate per IUI cycle in The Netherlands (9.0%) was comparable with that reported in the international literature (8.7%). The contribution made by IUI to the number of multiple pregnancies in The Netherlands was much smaller than the contribution made by IVF.

Cumulative impact of adding frozen–thawed cycles to single versus double fresh embryo transfers

Randomized control trials have shown that single embryo transfer (SET) results in lower live birth rates than double embryo transfer (DET), while observational, retrospective studies find no decrease in overall live birth rate when using a SET policy. The cumulative (fresh transfer followed by frozen - thawed transfers of embryos from the same stimulated cycle) live birth rate after the first and the second stimulated cycle of SET and DET respectively has been analysed. All couples who received their first fresh embryo transfer at Sahlgrenska University Hospital during 2003 and 2004 were included (n = 689). The live birth rates after DET versus SET in the first and second fresh cycles were 29.7 (47/158) versus 23.9% (127/531) and 30.8 (41/133) versus 22.0% (45/205). The cumulative live birth rate per patient after the addition of frozen-thawed embryo transfers were similar: 33.5 (53/158) and 34.8% (185/531) for DET and SET respectively after the first cycle and 32.3 (43/133) versus 32.2% (66/205) after the second cycle. A logistic regression analysis showed no significant correlation for SET or DET with cumulative live birth. Thus, cumulative live birth rates are similar after SET and DET in a routine IVF programme with a majority of SET transfers, although a higher number of frozen-thawed cycles were needed in the SET group.

Pregnancy prediction models and eSET criteria for IVF patients--do we need more information?

PURPOSE

The purpose of the present study was to evaluate statistical prediction models and simple allocation criteria, based on predictors for pregnancy, as tools to identify a good prognosis group in a possible eSET setting.

METHODS

A pregnancy prediction model based on logistic regression models was generated by analysis of 1675 DET treatment cycles. The model was evaluated and compared to simple eSET allocation criteria.

RESULTS

Embryo quality, patient age, and basal FSH were identified as significant predictors (at 5% significance level) of pregnancy. Although comparable to previously generated models, the predictive ability of the present model was relatively poor and practically similar to simple allocation criteria based on age and embryo quality.

CONCLUSIONS

Existing prediction models, or simple allocation criteria, are limited in identifying good prognosis patients. Future studies of the applicability of improved pregnancy prediction models will need very comprehensive and detailed patient and embryo information.

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.

Economic evaluations of single- versus double-embryo transfer in IVF

Multiple pregnancies lead to complications and induce high costs. The most successful way to decrease multiple pregnancies in IVF is to transfer only one embryo, which might reduce the efficacy of treatment. The objective of this review is to determine which embryo-transfer policy is most cost-effective: elective single-embryo transfer (eSET) or double-embryo transfer (DET). Several databases were searched for (cost* or econ*) and (single embryo* or double embryo* or one embryo* or two embryo* or elect* embryo or multip* embryo*). On the basis of five exclusion criteria, titles and abstracts were screened by two individual reviewers. The remaining papers were read for further selection, and data were extracted from the selected studies. A total of 496 titles were identified through the searches and resulted in the selection of one observational study and three randomized studies. Study characteristics, total costs and probability of live births were extracted. Besides this, cost-effectiveness and incremental cost-effectiveness were derived. It can be concluded that DET is the most expensive strategy. DET is also most effective if performed in one fresh cycle. eSET is only preferred from a cost-effectiveness point of view when performed in good prognosis patients and when frozen/thawed cycles are included. If frozen/thawed cycles are excluded, the choice between eSET and DET depends on how much society is willing to pay for one extra successful pregnancy.

Commentary: Is elective single embryo transfer a cost-effective alternative to double embryo transfer?

Elective single embryo transfer (eSET) is increasingly being considered as a means to reduce twin pregnancies associated with in vitro fertilisation treatment. However, it is important to consider the cost-effectiveness of alternative strategies when considering a change in policy. A review of the literature showed only five studies assessing both costs and consequences of strategies involving eSET compared with double embryo transfer. Several limitations in these studies prevent a definitive conclusion on the cost-effectiveness of eSET being reached. Future economic evaluations need to compare strategies relevant to routine practice, include all relevant costs, measure and value longer term outcomes appropriately, and assess the cost-effectiveness of eSET across different subgroups of women.

Policy efforts to prevent ART-related preterm birth

At 12.5%, the preterm birth rate is the highest it has ever been in the US. In tandem with the rise in preterm birth is a dramatic increase in multiple birth rates. The recent trend of delayed maternal age at first birth and the associated use of assisted reproductive technologies (ARTs) have led to the increase in multiple gestation and its attendant increased risk for preterm birth. While ARTs are not responsible for the majority of preterm births, the attributable fraction has increased, is iatrogenic- and preventable. Despite widespread recognition of this problem, the rate of associated twin gestation has not decreased. We offer options for policymakers on several levels--from medical to health systems to societal policy--to decrease ART-related preterm births.

Is twin pregnancy necessarily an adverse outcome of assisted reproductive technologies?

It has recently been suggested that the measure of success of assisted reproductive technologies (ART) should be the birth of a singleton baby, whereas a twin pregnancy should be considered as a complication. Although the maternal and neonatal complications in twin pregnancies are significantly higher than those in singleton pregnancies, the classification of a twin pregnancy as a complication of ART is in our opinion debatable. Most twin pregnancies result in the birth of two healthy babies, with little or no complication for the mother, and only few twin pregnancies results in serious morbidity of the mother and of one or both of the children. The crux of our arguments is that one should consider those cases as poor outcomes and not a twin pregnancy per se.

Elective single embryo transfer in women aged 36–39 years

BACKGROUND

The elective single embryo transfer policy is the only effective strategy known to minimize the risk of multiple pregnancy. However, little is known about its applicability to women older than 35 years.

METHODS

Analysis was carried out on 1224 fresh IVF/ICSI cycles with embryo transfer and 828 frozen embryo transfer (FET) cycles of women aged 36-39 years. In the fresh cycles, 335 elective single top quality embryo (eSET), 110 elective single non top quality embryo (nt-eSET), 194 compulsory single embryo (cSET) and 585 double embryo transfers (DET) were carried out.

RESULTS

Pregnancy rate/embryo transfer (33.1 versus 29.9%) and live birth rate (26.0 versus 21.9%) in fresh cycles did not differ significantly between the eSET and the DET groups. However, women in the eSET group had a higher cumulative pregnancy rate (54.0% versus 35.0%) and a higher cumulative live birth rate (41.8% versus 26.7%, P < 0.0001) compared with those in the DET group. The cumulative multiple birth rate in the eSET group was 1.7%, whereas in the DET group it was 16.6% (P < 0.0001).

CONCLUSIONS

The eSET policy can be applied also to patients aged 36-39 years, reducing the risk of multiple birth and increasing the safety of assisted reproduction technique (ART) in this age group.

Single versus double embryo transfer: cost-effectiveness analysis alongside a randomized clinical trial

BACKGROUND

Twin pregnancies after IVF are still frequent and are considered high-risk pregnancies leading to high costs. Transferring one embryo can reduce the twin pregnancy rate. We compared cost-effectiveness of one fresh cycle elective single embryo transfer (eSET) versus one fresh cycle double embryo transfer (DET) in an unselected patient population.

METHODS

Patients starting their first IVF cycle were randomized between eSET and DET. Societal costs per couple were determined empirically, from hormonal stimulation up to 42 weeks after embryo transfer. An incremental cost-effectiveness ratio (ICER) was calculated, representing additional costs per successful pregnancy.

RESULTS

Successful pregnancy rates were 20.8% for eSET and 39.6% for DET. Societal costs per couple were significantly lower after eSET (7334 euro) compared with DET (10,924 euro). The ICER of DET compared with eSET was 19,096 euro, meaning that each additional successful pregnancy in the DET group will cost 19,096 euro extra.

CONCLUSIONS

One cycle eSET was less expensive, but also less effective compared to one cycle DET. It depends on the society's willingness to pay for one extra successful pregnancy, whether one cycle DET is preferred from a cost-effectiveness point of view.

The relative myth of elective single embryo transfer

The option of single embryo transfer (SET) has recently dominated the pages of this and other medical journals. Opinions, in regards to the utility of such an approach, appear to differ between Europe and the US. While US guidelines promote a more individualized approach, European opinions, at times, even advocate mandated practice patterns. The European approach, however, fails to recognize the rather significant differences in supportive arguments between the historical switch from multiple embryo transfers to 2-embryo transfers and the current discussion, favouring a switch from 2-embryo transfer to elective (e)-SET. In the former, a significant risk of (at times, high-order) multiple pregnancies was reduced without loss of pregnancy potential. In the latter, a comparably relatively low twinning risk is reduced at the expense of declining pregnancy rates, a need for more treatment cycles, a potential delay in treatment success and, potentially, higher treatment costs. These consequences of e-SET, together with the preference of some infertility patients to actually conceive twins, raise serious questions about the wide utilization of e-SET, as has been propagated by many authorities. According to US guidelines, e-SET, therefore, appears to represent an appropriate transfer option for only a small minority of IVF patients. Argument in favour of indiscriminate SET appears unrealistic and should be reconsidered.

What about the remaining twins since single-embryo transfer? How far can (should) we go?

Single-embryo transfer (SET) and more specifically elective SET (eSET) have taken their place in good clinical IVF/ICSI practice. After the initial cautious search for the characteristics of the twin-prone patient and of the selection of the embryo with the highest implantation potential many centres have embarked on the (progressive) implementation of SET, either by conviction or forced by legislation or both. It was only because the ongoing pregnancy rates remained largely unaffected that SET was accepted. Generally speaking, it can be said that the twinning rate after IVF/ICSI has dropped by at least 50% simply by transferring only one good-quality embryo in the first and second fresh IVF/ICSI cycles in young women, without decrease in the overall pregnancy rate. Preventing 'the second half' of IVF/ICSI twins constitutes another and probably tougher challenge because the target group is a heterogeneous mix consisting of patients in very different clinical situations. Can we expand our experience for further twin prevention to women of older age and to cycles of higher rank without a significant drop in pregnancy rates? Can we extend it to more cryopreservation cycles? To have an idea of future target groups for increased application of SET, we analysed the remaining twins after double-embryo transfer (DET), and from these data we suggest expanding the eSET policy to women <38 years of age until the third cycle and to cryopreservation cycles.

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.

Contribution of embryo cryopreservation to elective single embryo transfer in IVF–ICSI

Single embryo transfer is the best way to reduce the risk of multiple pregnancy in IVF-intracytoplasmic sperm injection (ICSI). Between June 2002 and December 2004, all patients (first cycle, female age <38 years) were offered the choice between having one (SET) or two (DET) embryos transferred. Among 493 couples, 428 had at least two good quality embryos, and among them, 32% opted for SET. The SET and DET populations were not comparable (patients in the SET group were younger and had more oocytes retrieved), and therefore a paired, case-control analysis was performed involving 130 SET couples and 130 DET couples, matched according to the female partners' ages and the numbers of embryos available. All of the SET patients, and 82% of the DET group, had at least one embryo cryopreserved, (3.9 versus 2.8 embryos). The option of SET was continued for the frozen-thawed embryo transfers. The pregnancy rate following embryo transfer was significantly lower after SET compared with DET for both fresh (27.6 versus 36.9%; P < 0.05) and frozen-thawed (14.4 versus 23.5%) embryos. However, the cumulative live birth rates following the transfer of fresh and frozen embryos were identical between the two groups (43 versus 45%), with a high prevalence of twins following DET (34 versus 0%).

The psychological impact of mild ovarian stimulation combined with single embryo transfer compared with conventional IVF

BACKGROUND

The objective of this study was to assess the psychological implications of mild ovarian stimulation combined with single embryo transfer (SET) during a first IVF cycle.

METHODS

We conducted a randomized controlled two-centre trial. Three hundred and ninety-one couples were randomized to undergo either mild ovarian stimulation with GnRH antagonist co-treatment and SET (n=199) or conventional GnRH agonist long protocol ovarian stimulation with double embryo transfer (DET) (n=192). Women completed the Hospital Anxiety and Depression Scale, the Hopkins Symptom Checklist and the Subjective Sleep Quality Scale at baseline, on the first day of ovarian stimulation and following embryo transfer. Affect was assessed daily with the Daily Record Keeping Chart from the first day of ovarian stimulation until the day treatment outcome became known.

RESULTS

The conventional IVF group experienced elevated levels of physical and depressive symptoms during pituitary downregulation. At oocyte retrieval, this group experienced more positive affect and less negative affect than the mild IVF group. In the conventional IVF group, cycle cancellation was associated with less positive and more negative affect.

CONCLUSIONS

During the first IVF treatment cycle, mild ovarian stimulation and SET does not lead to more psychological complaints than conventional IVF.

In unselected patients, elective single embryo transfer prevents all multiples, but results in significantly lower pregnancy rates compared with double embryo transfer: a randomized controlled trial

BACKGROUND

Elective single embryo transfer (eSET) in a selected group of patients (i.e. young patients with at least one good quality embryo) reduces the number of multiple pregnancies in an IVF programme. However, the reduced overall multiple pregnancy rate (PR) is still unacceptably high. Therefore, a randomized controlled trial (RCT) was conducted comparing eSET and double embryo transfer (DET) in an unselected group of patients (i.e. irrespective of the woman's age or embryo quality).

METHODS

Consenting unselected patients were randomized between eSET (RCT-eSET) (n = 154) or DET (RCT-DET) (n = 154). Randomization was performed just prior to the first embryo transfer, provided that at least two 2PN zygotes were available. Non-participants received our standard transfer policy [SP-eSET in a selected group of patients (n = 100), otherwise SP-DET (n = 122)].

RESULTS

The ongoing PR after RCT-eSET was significantly lower as compared with RCT-DET (21.4 versus 40.3%) and the twin PR was reduced from 21.0% after RCT-DET to 0% after RCT-eSET. The ongoing PRs after SP-eSET and SP-DET did not differ significantly (33.0 versus 30.3%), with an overall twin PR of 12.9%.

CONCLUSION

To avoid twin pregnancies resulting from an IVF treatment, eSET should be applied in all patients. The consequence would be a halving of the ongoing PR as compared with applying a DET policy in all patients. The transfer of one embryo in a selected group of good prognosis patients leads to a less drastic reduction in PR but maintains a twin PR of 12.9%.

Life table (survival) analysis to generate cumulative pregnancy rates in assisted reproduction: an alternative method of calculating the cumulative pregnancy rate in assisted reproduction technology

The current method of calculating cumulative pregnancy rate can lead to an overestimation of treatment efficacy, especially over many cycles of assisted reproduction treatment. The choice of scale of passage of time should be dependent upon the types of treatment to be evaluated. The number of treatment cycles to which patients' effort and commitment is directly related may be appropriate where the chance of pregnancy is expected to be significantly higher than non-treatment for them. Limiting the calculation of cumulative pregnancy rate only to the second or third cycle within 1 or 2 years will ensure that most patients are included in the calculation. More research is needed to assess different methods and develop better variables for assessing the efficacy of infertility treatment that can be informative for patients over the course of their treatment.

Number of embryos for transfer following in-vitro fertilisation or intra-cytoplasmic sperm injection

BACKGROUND

The traditional reliance on the transfer of multiple embryos during in vitro fertilisation (IVF) in order to maximise the chance of pregnancy, has resulted in increasing rates of multiple pregnancies. Women undergoing IVF had a 20 - fold increased risk of twins and 400 - fold increased risk of higher order pregnancies (Martin 1998). The maternal and perinatal morbidity and mortality as well as national health service costs associated with multiple pregnancies is significantly high in comparison with singleton births (Luke 1992; Callahan 1994; Goldfarb 1996). Single embryo transfer is now being considered as an effective means of reducing this iatrogenic complication. This systematic review evaluates the effectiveness of elective two embryo transfer in comparison with single and more than two embryo transfer following IVF and ICSI (intra cytoplasmic sperm injection) treatment.

OBJECTIVES

The aim of this review is to determine, whether in couples who undergo IVF/ICSI: (1) the elective transfer of two embryos improves the probability of livebirth compared with: (a) Single embryo transfer, (b) Three embryo transfer or (c) Four embryo transfer.(2) the elective transfer of three embryos improves the probability of livebirth compared with: (a) Single embryo transfer, or (b) Four embryo transfer,

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group's trials register (searched June 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2003), MEDLINE (1970 to 2003), EMBASE (1985 to 2003) and reference lists of articles. We also handsearched relevant conference proceedings and contacted researchers in the field.

SELECTION CRITERIA

Only randomised controlled trials were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed eligibility and quality of trials.

MAIN RESULTS

We found no studies that compared a policy of transferring multiple embryos on one cycle versus a policy of cryo- preservation and transfer of a single embryo over multiple cycles. We also found no trials comparing transfer of two versus three embryos. Three small, poorly reported trials compared transfer of two versus one embryo in a single cycle, and one small, poorly reported trial compared transfer of two versus four embryos in a single cycle. The clinical pregnancy rate per woman/couple associated with two embryo transfer was significantly higher compared to single embryo transfer (OR 2.08, 95% CI 1.24 to 3.50; test for overall effect p = 0.006). The live birth rate per woman/couple associated with two embryo transfer was also significantly higher than that associated with single embryo transfer (OR 1.90, 95% CI 1.12 to 3.22, test for overall effect p=0.02). The multiple pregnancy rate was significantly lower in women who had single embryo transfer (OR 9.97, 95% CI 2.61 to 38.19; p = 0.0008). The effectiveness of double embryo transfer versus four embryo transfer was tested in a single trial. There was no statistically significant differences in the clinical pregnancy rate (OR 0.75, 95% CI 0.26 to 2.16; p=0.6), and multiple pregnancy rates (OR 0.44. 95% CI 0.10 to 1.97; p = 0.28) between the two groups. The livebirth rate in the four embryo transfer group was higher compared to the two embryo transfer group, but the results were not statistically significant (OR 0.35, 95% CI 0.11 to 1.05; p = 0.06).

REVIEWERS' CONCLUSIONS

The results of this systematic review suggest that live birth and pregnancy rates following single embryo transfer are lower than those following double embryo transfer as are the chances of multiple pregnancy including twins. As such, it is unlikely that the conclusions are robust enough to catalyse a change in clinical practice. The studies included are limited by their small sample size, so that even large differences might be hidden. Cumulative livebirth rates are seldom reported. The data were inadequate to draw conclusions about single embryo transfer and first frozen single embryo transfer (1FZET) or subsequent single frozen embryo transfers. Until more evidence is available single embryo transfer may not be the preferred choice for all patients undergoing IVF/ICSI. Clinicians may need to individualise protocols for couples based on their risks of multiple pregnancy. A definitive pragmatic, large multi centre randomised controlled trial comparing single embryo versus double embryo transfer in terms of clinical and cost effectiveness as well as acceptability is required. The primary outcome measured should be cumulative livebirth per woman/couple.