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.     

A real-life prospective health economic study of elective single embryo transfer versus two-embryo transfer in first IVF/ICSI cycles

BACKGROUND: We analysed the difference in maternal, neonatal and total costs after single (SET) versus double day 3 embryo transfer (DET). METHODS: We performed a two-centre prospective study of women in their first IVF/ICSI cycle choosing between SET or DET. Infertility treatment data were gathered from a database; maternal and neonatal outcome data from a case report form (CRF); health economic data from medical acts registered in the CRF for the outpatient part and from hospital bills. SET was performed in 206/367 (56.1%) and DET in 161/367 (43.9%) women. RESULTS: In all, 367 transfers yielded 186 positive pregnancy tests, 148 ongoing pregnancies and 136 live deliveries (50.7, 40.3 and 37.1% per embryo transfer) of which 15 (11.0%) were twins. Live birth rate was 37.4% for SET, 36.6% for DET. Intention-to-treat analysis showed differences for: duration of pregnancy (SET: 39.0 +/- 1.4 versus DET: 38.3 +/- 2.2 weeks; P = 0.055), percentage prematurity (8.5 versus 23.8%; P = 0.033), percentage of neonates hospitalized (5.7 versus 17.9%; P = 0.121) and duration of neonatal hospitalization (6.3 +/- 2.2 versus 10.3 +/- 10.1 days; P = 0.01). Total cost after DET was higher (SET: 4700 +/- 3239 versus DET: 8613 +/- 10 105; P = 0.105), due to significantly higher neonatal costs (451 +/- 957 versus 3453 +/- 8154; P < 0.001) and not to differences in maternal costs (4250 +/- 2882 versus 5160 +/- 4106; P = 0.152). CONCLUSIONS: This prospective health economic study shows that transfer of a single top quality embryo is equally effective as, but substantially cheaper than, double embryo transfer in women <38 years of age in their first IVF/ICSI cycle.     

Attitudes of IVF/ICSI-twin mothers towards twins and single embryo transfer

BACKGROUND: Our aim was to study attitudes towards twins and single embryo transfer (SET) among IVF/ICSI-twin mothers with 3 to 4-year old children. METHODS: A national survey was conducted by questionnaire (n = 1769). The study population consisted of IVF/ICSI-twin mothers (n = 266), and the two control groups of IVF/ICSI-singleton mothers (n = 764) and non-IVF/ICSI-twin mothers (n = 739), all giving birth in Denmark in 1997. The overall response rate was 81%. RESULTS: More IVF/ICSI-twin mothers (84.7%) preferred twins as their first child compared with IVF/ICSI-singleton mothers (62.3%) and non-IVF twin mothers (60.0%). The IVF/ICSI-twin mothers had a significantly higher wish for twins (OR = 4.4, 95% CI 2.8-6.9) compared with the non-IVF/ICSI-twin mothers. Though relatively few IVF/ICSI-twin mothers (23.4%) and IVF/ICSI-singleton mothers (17.3%) agreed to SET, delivery of a child with very low birth weight (VLBW) (<1500 g) was predictive of high acceptance of SET (OR = 2.9, 95% CI 1.2-6.9). CONCLUSION: Our study suggests that IVF/ICSI-twin mothers have a greater wish for twins compared with non-IVF/ICSI-twin mothers. Despite the fact that only a quarter of IVF/ICSI mothers agreed to SET, delivery of a child with VLBW and hence high morbidity was predictive of high acceptance of SET. The implementation of elective SET requires extensive counselling of the infertile couples and legislation including strict selection criteria may also be used to facilitate this process.     

IVF/ICSI twin pregnancies: risks and prevention

Since the 1970s, the national twin birth rates have been increasing worldwide. Apart from the increasing childbearing age, the main cause is the use of assisted reproductive technologies (ART). To explore the overall consequences of dual embryo transfer (DET), the literature has been reviewed systematically regarding short- and long-term outcomes of IVF/ICSI twin pregnancies i.e. pregnancy complications, maternal risks, obstetric outcome and long-term morbidity including neurological sequelae, cognitive development and family implications. Another consequence of DET is vanishing twins, which seems to be a possible cause of adverse outcome in IVF singletons. The sparse literature on vanishing twins in IVF pregnancies and the influence on the surviving co-twin were also addressed. Finally, to determine the effects of implementing elective single embryo transfer (eSET), trials concerning eSET versus DET were analysed. In the light of the steadily increasing twin birth rates and the findings in this overview, where IVF/ICSI twins carry adverse outcome, it should be emphasized that the major obstacle in IVF remains the high twin birth rate. Furthermore vanishing twins account for another hazard of DET. These problems can be resolved by implementing eSET, diminishing the twin birth rate without affecting the overall goal of achieving a healthy infant.     

Avoiding multiple pregnancies in ART: a plea for single embryo transfer

It has been generally accepted that triplets after IVF/intracytoplasmic sperm injection (ICSI) can and should be avoided by adopting a standard strategy of replacing no more than two embryos. However, there is an increasing awareness of the risks and costs and of the epidemic size of twin pregnancies after IVF/ICSI. This has resulted in efforts to replace no more than one embryo. However, this approach has been hampered by our relative inability to identify embryos with a very high implantation potential. To identify such embryos, a number of strategies are being considered, both at the two pronuclear (2PN), early cleavage and the blastocyst stages. At the 2PN stage, the polarity characteristics of the nucleoli have been shown to be correlated with a high implantation rate. Similarly, the morphological characteristics at day 2 and 3 have been used to describe top quality embryos in approximately 75% of all IVF/ICSI cycles. Blastocyst culture has resulted in very high implantation rates in the hands of some authors. No approach has shown its superiority at present, but initial experience with single embryo transfer (SET) at the early cleavage stage by Scandinavian and Belgian groups shows that an ongoing pregnancy rate of 35% and more can be achieved. Proper identification of patients at risk of a twin pregnancy after double embryo transfer is equally important. It is clear that mainly young patients (aged <34 years) during their first, perhaps first two, IVF/ICSI cycles constitute the main population at risk (responsible for >80% of all twins) and are the main target group for twin prevention by SET of a top quality embryo at whatever stage. Therefore, in our opinion, although a further fine-tuning of both embryo and patient characteristics relating to a high risk for (twin) pregnancy is desirable, SET should be introduced carefully and progressively in each IVF/ICSI programme from now on. Correct counselling is very important and both public and private insurers will have to join in the discussion.     

Investigation of staff and patients' opinions of a proposed trial of elective single embryo transfer

BACKGROUND: In the context of mounting concern about the risks of twin pregnancies resulting from IVF, this study aimed to assess staff and patients' attitudes towards a proposed randomized controlled trial (RCT) of elective single embryo transfer (SET) in a Scottish fertility centre. METHODS: The views of 10 members of IVF clinic staff were assessed by means of a focus group and those of 12 couples by semi-structured interviews. RESULTS: Staff were aware of the risks of twin pregnancies to mothers and babies and the need for evidence of success in SET, but had reservations about the proposed RCT. The need to subject patients to unpopular scientific procedures such as randomization and blinding conflicted with their perceived caring role. They felt it would be hard to recruit and onerous to patients but nevertheless discussed how it could be successfully mounted if necessary. They debated how to ensure that consent was fully informed, and when, and how, to randomize. Patients accepted the possibility of twins but were largely unaware of risks inherent in twin pregnancies. They saw no need for a trial and found the idea of randomization unacceptable except in younger women. They would accept SET if it became unit policy and appeared unaffected by financial considerations. CONCLUSIONS: Involving affected staff at the design stage may make it easier to conduct a SET trial in their clinics. IVF patients whose ultimate goal is pregnancy are less likely to support a trial which aims to minimize twin pregnancies.     

A health-economic decision-analytic model comparing double with single embryo transfer in IVF/ICSI

BACKGROUND: Single embryo transfer (SET) is the sole strategy with which to reduce the incidence of twins following assisted reproductive technology (ART), but SET may increase the number of ART cycles needed per live-born child. Its cost-effectiveness compared with double embryo transfer (DET) is therefore unknown. METHODS: A decision-analytic model comparing SET with DET was developed. Estimates were obtained from literature, national pregnancy registers and local hospital records. A sensitivity analysis was performed, using pregnancy rates from four published studies. The outcome measure was the cost per child born, calculated from IVF procedure-related, pregnancy-related and neonatal care costs. Neonatal mortality and long-term morbidity costs were not taken into account. RESULTS: Independently of the pregnancy rates used, the SET cost per child born was in all instances the same as with DET, varying from EURO= 9520 (SET) versus EURO= 9511 (DET) to EURO= 12254 (SET) versus EURO= 12934 (DET). CONCLUSIONS: More ART cycles are required to obtain the same numbers of children born following SET compared with DET. Because SET allows the avoidance of twins and thus diminishes pregnancy-related and neonatal care costs, there is no difference in the cost per child born between SET and DET. The real advantage of SET is the avoidance of the very high long-term costs resulting from the increased morbidity of twins after birth.     

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

BACKGROUND: With the aim of reducing the number of multiple pregnancies after IVF we investigated the effectiveness of two cycles with single embryo transfer (SET) and one cycle with double embryo transfer (DET) after IVF and calculated the cost-effectiveness of both strategies. Methods: A randomized controlled trial was performed in 107 women, aged <35 years, in their first IVF cycle, with at least one good quality embryo. They were randomized to the SET (n = 54) or DET (n = 53) group using a computer-generated random block number table, stratified for primary or secondary infertility. RESULTS: The cumulative live birth rates per woman randomized of two consecutive cycles of SET [41%; 95% confidence interval (CI) 27-54] versus one cycle of DET (36%; 95% CI 23-49) were comparable, whereas the multiple pregnancy rate was significantly higher: 37% (95% CI 15-59) in the DET and 0% in the in the SET group (P = 0.002). Combining the medical costs of the IVF treatments (where 1.5 more SET cycles were required to achieve each live birth) and of pregnancies up to 6 weeks after delivery, the total medical costs of DET per live birth were 13,680 and 13,438 for SET. CONCLUSIONS: Two cycles with SET were equally effective as one cycle with DET, and the medical costs per live birth up to 6 weeks after delivery were the same. However, if lifetime costs for severe handicaps are included, more than 7000 per live birth will be saved after implementing SET. Because of the high probability of multiple pregnancies in this group of IVF patients, only SET should be performed.     

One versus two embryo transfer after IVF and ICSI: a randomized study

BACKGROUND: The main reason for adverse treatment outcome in assisted reproduction is the high rate of multiple pregnancies. The only strategy to avoid dizygotic twins is to transfer one embryo at a time. METHODS: A total of 144 women, who had had at least four good quality embryos available after IVF/intracytoplasmic sperm injection (ICSI) and who had no more than one previous failed treatment cycle, were randomized to have either one or two embryos transferred. The treatment outcomes including those after frozen embryo transfer were compared between these groups. RESULTS: The clinical pregnancy rate per transfer was 32.4% in the one embryo transfer group and 47.1% in the two embryo transfer group, the difference being not significant. Eleven twin deliveries (n = 39) occurred in the two embryo transfer group and there was one pair of monozygotic twins in the one embryo transfer group. The cumulative pregnancy rate per patient after transfer of fresh and frozen embryos was 47.3% in the one embryo transfer group and 58.6% in the two embryo transfer group. CONCLUSIONS: Our results indicate that among women who have good quality embryos in their first IVF/ICSI, good treatment results can be achieved. They support the idea of changing embryo transfer policy towards one embryo transfer without any remarkable decrease in the success rate, while dizygotic twins can be avoided.     

Day 2 elective single embryo transfer in clinical practice: better outcome in ICSI cycles

BACKGROUND: Single embryo transfer (SET) after IVF/ICSI has been shown to result in an acceptable pregnancy rate in selected subjects. In our unit, SET is routinely carried out among women under the age of 36 in the first or second treatment cycle when a top-quality embryo is available. In order to define further the selection criteria for SET, we have analysed the outcome of elective SET (eSET), including the cumulative pregnancy rate after frozen embryo transfers, performed in the years 2000-2002 in the Oulu Fertility Center. METHODS: During the study period, a total of 1271 transfers were performed, and in 468 cycles SET (39% of all transfers) was carried out. Of the SET cycles, in 308 cases a top-quality embryo was transferred on day 2 and extra embryos were frozen. Of these eSET cycles, ICSI was carried out in 87 cycles (28%). RESULTS: The overall clinical pregnancy rate per transfer was 34.7% in the eSET cycles. In the eSET ICSI cycles, the clinical pregnancy rate was significantly higher than in the corresponding IVF cycles (50.6 versus 28.5%, P < 0.001). The cumulative pregnancy rate per patient after fresh and frozen embryo transfers was also significantly higher after ICSI (71.2 versus 53.4%, P < 0.01). CONCLUSIONS: A high cumulative pregnancy rate per oocyte retrieval can be achieved after eSET in daily clinical practice. The implantation rate of fresh top-quality embryos in the ICSI cycles was significantly higher than in the IVF cycles, possibly due to more successful selection of the embryo for embryo transfer on day 2 after ICSI. In addition, our data suggest that embryo quality is a more important determinant of outcome than the age of the woman.     

Impact of patients' choice for single embryo transfer of a top quality embryo versus double embryo transfer in the first IVF/ICSI cycle

BACKGROUND: The aim of this study was to evaluate the impact of transferring a single top quality embryo in the first IVF/ICSI cycle of patients <38 years old who chose to have one or two embryos transferred. METHODS: A total of 262 patients participated in the study, and 243 transfers were performed: 156 (64%) patients chose the transfer of a single top quality embryo, if available, and two non-top quality embryos if not available; 87 (36%) patients chose to have a double embryo transfer regardless of embryo quality. RESULTS: In the first group an ongoing pregnancy rate of 40% (63/156) with a twin pregnancy rate of 2% (1/63) was achieved. In the second group the ongoing pregnancy rate was 44% (38/87) with 26% (10/38) twin pregnancies. In the patient group with only one embryo transferred, irrespective of the patient's choice, the ongoing pregnancy rate was 43% (54/127) with no twin pregnancies. For the study population as a whole, the ongoing pregnancy rate was 42% (101/243) with 11% (11/101) twins. CONCLUSION: We conclude that the introduction of single embryo transfer in the first IVF/ICSI cycle is highly acceptable in women <38 years old.     

Modelling the impact of single embryo transfer in a national health service IVF programme

BACKGROUND: Greater use of single embryo transfer (SET) to reduce twin ratesassociated with IVF requires good information on prognosticfactors and appropriate models of treatment outcomes. METHODS: Using data from a cohort of 1198 IVF cycles, we have developeda statistical model of live birth and twin outcomes in termsof routinely measured clinical parameters. From this model,we predict potential outcomes if those who had two embryos transferredhad actually received SET. RESULTS: Embryo quality, age, FSH level, idiopathic diagnosis, spermcount, smoking and alcohol consumption are all significant factorspredicting outcome. Couples with good embryos and good prognosishave a much greater risk of producing twins. In this cohort,to achieve a 10% twin rate would require 55% SET which, withoutselection of appropriate cycles, would lead to a reduction insuccess rate from ca. 21% to 17%. Selecting on the basis oftwin risk can partially mitigate this reduction to give a successrate of 18.5%. CONCLUSIONS: The use of SET to reduce twin rates will lead to a significantreduction in treatment success. Around half this reduction couldbe mitigated with careful selection of patients and cycles,including embryo quality.     

A family history of twinning in relation to multiple implantation

BACKGROUND: A familial basis for dizygotic twinning is known for multipleovulation. However, for multiple implantation this remains unclear.In IVF/intracytoplasmic sperm injection (ICSI) ‘multipleovulation’ is artificially induced. If multiple implantationis not hereditary, the incidences of twins in families of patientswith single and multiple implantation after IVF/ICSI with doubleembryo transfer (DET) should be comparable. METHODS: A questionnaire study was conducted among patients with intrauterine pregnancy at 6 weeks of gestation, after IVF/ICSI treatmentwith DET 3 days after oocyte retrieval. RESULTS: There were 940 patients who gave their informed consent. Forwomen with single implantation (Group A), the incidence of oneand of multiple twins among the family was 27.2 and 15.5%, respectively.For women with multiple implantation (Group B), this incidencewas 29.5 and 17.8%, respectively, P = 0.424. The incidence ofone and of multiple twins among first degree relatives was 10.6and 1.1% in Group A; for Group B this was 8.7 and 1.9%, P =0.469. Multivariate regression analysis also did not reveal‘twins in family’ or ‘twins in first degree’as an associated variable for multiple implantation at 6 weeks. CONCLUSIONS: Incidences of twins in families of patients with single implantationand patients with multiple implantation after IVF/ICSI are comparable.Our data do not support the concept that multiple implantationis hereditary.     

What is the most relevant standard of success in assisted reproduction? Redefining success in the context of elective single embryo transfer: evidence, intuition and financial reality

Treatment-related multiple pregnancy poses the biggest threat to the safety of IVF. Despite a double embryo transfer (DET) policy in most European centres, twin rates continue to be unacceptably high, at 20-35%. Elective single embryo transfer (SET) is an effective way to minimize twin pregnancies, but the debate surrounding its routine clinical use continues. A review of the literature was undertaken in order to seek evidence about the effectiveness of SET, and identify barriers to its acceptance in clinical practice. Data from randomized controlled trials (RCTs) indicate that SET results in lower live birth rates per fresh IVF cycle (odds ratio 0.53; 95% confidence interval 0.31-0.89; P = 0.02) in comparison with DET. Data on cumulative live birth rates are unavailable from RCTs, although the expectation is that these are comparable in the two groups. SET is unlikely to be suitable for all women undergoing IVF and outcomes may be sensitive to different laboratory protocols. The perceived effectiveness of SET is influenced by the way existing evidence is interpreted. Other factors affecting the routine use of SET include laboratory techniques, individual preferences and funding issues.     

Obstetric and neonatal outcome after single embryo transfer

BACKGROUND: Single embryo transfer (SET) pregnancies practically lack vanishing twins and may be associated with improved neonatal outcome. Our objective was to compare the obstetric and neonatal outcome of SET singletons with the outcome of singletons following double embryo transfer (DET) and spontaneous conception. METHODS: A 7-year (1997-2003) cohort of fresh SET (n = 269) and DET (n = 230, including 25 vanishing twins) cycles resulting in singleton birth at Helsinki University Central Hospital, Finland, was linked to the Finnish Medical Birth Register and the obstetric and neonatal outcome data compared with that from 15 037 spontaneously conceived singleton pregnancies. RESULTS: The obstetric and neonatal outcome of the SET group was comparable to that in the DET group. Compared with the comparison cohort, gestational hypertension (P = 0.005), placenta praevia (P < 0.001), preterm contractions (P = 0.01) and maternal hospitalization (P < 0.001) was more typical of women in the SET group. After adjusting for age, parity and socio-economic status the SET pregnancies showed increased risks of Caesarean section [odds ratio (OR) 1.54 with 95% confidence interval (CI) 1.18-2.00], preterm birth (OR 2.85; 95% CI 1.96-4.16) and low birthweight (OR 2.01; 95% CI 1.19-3.99) compared with the comparison cohort. CONCLUSIONS: Our results indicate that subject- and infertility-related mechanisms other than the number of transferred embryos influence the neonatal outcome of singleton IVF pregnancies.     

Morbidity in a Danish national cohort of 472 IVF/ICSI twins, 1132 non-IVF/ICSI twins and 634 IVF/ICSI singletons: health-related and social implications for the children and their families

BACKGROUND: There is a lack of knowledge on child health as well as family well-being in IVF/ICSI twins. METHODS: These data originated from questionnaires completed by mothers taking part in a national cohort study of twin and singleton births occurring in Denmark in 1997. The overall response rate was 83%. The three cohorts consisted of all IVF/ICSI twin children (n = 472), all IVF/ICSI singletons (n = 634) and all non-IVF/ICSI twin children (n = 1132) born in Denmark in 1997. RESULTS: No major differences in physical health were observed between IVF/ICSI twins and non-IVF/ICSI twins. Compared with IVF/ICSI singletons, more IVF/ICSI twins were admitted to a neonatal intensive care unit (NICU) (P < 0.01) and more had surgical interventions (P = 0.03) and special needs (P = 0.02), moreover they had poorer speech development (P < 0.01). Correspondingly, IVF/ICSI twin mothers rated their infant's general health poorer than IVF/ICSI singleton mothers did. All discrepancies between IVF/ICSI twins and singletons disappeared after stratification for birthweight except for NICU admissions and speech development. Multiple logistic regression analyses showed that both IVF/ICSI and non-IVF/ICSI twin parents experienced more marital stress [odds ratio (OR) 2.9, 95% CI 2.2-3.8] and that twins had more impact on the mother's life (OR 1.7, 95% CI 1.2-2.4) compared with singletons. Nevertheless, the only predictor of low divorce/separation risk was IVF/ICSI treatment. CONCLUSION: Our study indicates that physical health of IVF/ICSI twins is comparable with that of non-IVF/ICSI twins. However, physical health of IVF/ICSI twins is poorer and the implications for the families stronger compared with IVF/ICSI singletons.     

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%.     

Prevention of twin pregnancy after in-vitro fertilization or intracytoplasmic sperm injection based on strict embryo criteria: a prospective randomized clinical trial.

A prospective randomized study comparing single embryo transfer with double embryo transfer after in-vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) was carried out. First, top quality embryo characteristics were delineated by retrospectively analysing embryos resulting in ongoing twins after double embryo transfer. A top quality embryo was characterized by the presence of 4 or 5 blastomeres at day 2 and at least 7 blastomeres on day 3 after insemination, the absence of multinucleated blastomeres and <20% cellular fragments on day 2 and day 3 after fertilization. Using these criteria, a prospective study was conducted in women <34 years of age, who started their first IVF/ICSI cycle. Of 194 eligible patients, 110 agreed to participate of whom 53 produced at least two top quality embryos and were prospectively randomized. In all, 26 single embryo transfers resulted in 17 conceptions, 14 clinical and 10 ongoing pregnancies [implantation rate (IR) = 42.3%; ongoing pregnancy rate (OPR) = 38.5%] with one monozygotic twin; 27 double embryo transfers resulted in 20 ongoing conceptions with six (30%) twins (IR = 48.1%; OPR = 74%). We conclude that by using single embryo transfer and strict embryo criteria, an OPR similar to that in normal fertile couples can be achieved after IVF/ICSI, while limiting the dizygotic twin pregnancy rate to its natural incidence of <1% of all ongoing pregnancies.     

Attitudes of German infertile couples towards multiple births and elective embryo transfer

BACKGROUND: In Germany, embryo screening programmes combined with elective embryo transfer are illegal, but there is controversial debate about their legalization. Studies about the attitudes of infertile couples towards multiples, elective embryo transfer and multifetal reduction may help to illuminate how this law shapes patient choices. METHODS: A survey of 265 German infertile couples was conducted. Different logistic regression analyses were performed to assess independent factors associated with the parity for multiple births, approval for elective embryo transfer and multifetal reduction. RESULTS: Despite prior information about the risk of multiple births, 81% of respondents saw no risk in twin pregnancies and a sizable minority saw no risk even in triplet pregnancies. Eighty-nine percent of the respondents rated a twin pregnancy as desirable, whereas 35% rated a triplet birth as desirable. When presented with a choice of having multiple births versus having no biological children, 99% of the respondents endorsed twins, 84% triplets and 58% quadruplets. Seventy-four percent of the respondents approve of legalizing embryo screening programmes to select a good-quality embryo combined with elective embryo transfer. Ninety-two percent of the respondents rejected fetal reduction of twins. CONCLUSIONS: German infertile couples might conceivably be more willing to accept elective embryo transfer if screening for viable embryos was permitted.     

Birthweight of singletons after assisted reproduction is higher after single- than after double-embryo transfer

BACKGROUND: Single-embryo transfer (SET) has proven efficient in reducing multiple pregnancy rates after assisted reproduction technologies (ART). This study compares outcome of singletons after SET and double-embryo transfer (DET). METHODS: We studied 404 SET and 431 DET patients, who delivered a singleton child of >500 g after fresh embryo transfer in a first, second or third cycle. Preterm birth and low birthweight incidences and gestational age and birthweight were compared between both groups. Adjustments were made for maternal age, parity, cycle rank number, treatment indication, ART method, embryo characteristics and sex of the child. RESULTS: Singletons born after DET have a significantly lower birthweight than that after SET (3204.3 +/-617.5 g versus 3324.6+/-509.7 g , P<0.01). Also preterm birth (<37 weeks) [odds ratio (OR) 1.77, 95% confidence interval (CI) 1.06-2.94] and low birthweight (<2500 g) (OR 3.38, 95% CI 1.86-6.12) are significantly more common in DET singletons. CONCLUSIONS: Singleton birth after SET is advantageous compared with DET. This sheds new light on the reasons why singleton births following ART do worse than spontaneously conceived singletons in IVF programs, where double- or multiple-embryo transfer is standard.