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

ESHRE guideline: number of embryos to transfer during IVF/ICSI†

STUDY QUESTION

Which clinical and embryological factors should be considered to apply double embryo transfer (DET) instead of elective single embryo transfer (eSET)?

SUMMARY ANSWER

No clinical or embryological factor per se justifies a recommendation of DET instead of eSET in IVF/ICSI.

WHAT IS KNOWN ALREADY

DET is correlated with a higher rate of multiple pregnancy, leading to a subsequent increase in complications for both mother and babies. These complications include preterm birth, low birthweight, and other perinatal adverse outcomes. To mitigate the risks associated with multiple pregnancy, eSET is recommended by international and national professional organizations as the preferred approach in ART.

STUDY DESIGN, SIZE, DURATION

The guideline was developed according to the structured methodology for development and update of ESHRE guidelines. Literature searches were performed in PUBMED/MEDLINE and Cochrane databases, and relevant papers published up to May 2023, written in English, were included. Live birth rate, cumulative live birth rate, and multiple pregnancy rate were considered as critical outcomes.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Based on the collected evidence, recommendations were discussed until a consensus was reached within the Guideline Development Group (GDG). A stakeholder review was organized after the guideline draft was finalized. The final version was approved by the GDG and the ESHRE Executive Committee.

MAIN RESULTS AND THE ROLE OF CHANCE

The guideline provides 35 recommendations on the medical and non-medical risks associated with multiple pregnancies and on the clinical and embryological factors to be considered when deciding on the number of embryos to transfer. These recommendations include 25 evidence-based recommendations, of which 24 were formulated as strong recommendations and one as conditional, and 10 good practice points. Of the evidence-based recommendations, seven (28%) were supported by moderate-quality evidence. The remaining recommendations were supported by low (three recommendations; 12%), or very low-quality evidence (15 recommendations; 60%). Owing to the lack of evidence-based research, the guideline also clearly mentions recommendations for future studies.

LIMITATIONS, REASONS FOR CAUTION

The guideline assessed different factors one by one based on existing evidence. However, in real life, clinicians' decisions are based on several prognostic factors related to each patient's case. Furthermore, the evidence from randomized controlled trials is too scarce to formulate high-quality evidence-based recommendations.

WIDER IMPLICATIONS OF THE FINDINGS

The guideline provides health professionals with clear advice on best practice in the decision-making process during IVF/ICSI, based on the best evidence currently available, and recommendations on relevant information that should be communicated to patients. In addition, a list of research recommendations is provided to stimulate further studies in the field.

STUDY FUNDING/COMPETING INTEREST(S)

The guideline was developed and funded by ESHRE, covering expenses associated with the guideline meetings, the literature searches, and the dissemination of the guideline. The guideline group members did not receive payment. DPB declared receiving honoraria for lectures from Merck, Ferring, and Gedeon Richter. She is a member of ESHRE EXCO, and the Mediterranean Society for reproductive medicine and the president of the Croatian Society for Gynaecological Endocrinology and Reproductive Medicine. CDG is the past Chair of the ESHRE EIM Consortium and a paid deputy member of the Editorial board of Human Reproduction. IR declared receiving reimbursement from ESHRE and EDCD for attending meetings. She holds an unpaid leadership role in OBBCSSR, ECDC Sohonet, and AER. KAR-W declared receiving grants for clinical researchers and funding provision to the institution from the Swedish Cancer Society (200170F), the Senior Clinical Investigator Award, Radiumhemmets Forskningsfonder (Dnr: 201313), Stockholm County Council FoU (FoUI-953912) and Karolinska Institutet (Dnr 2020-01963), NovoNordisk, Merck and Ferring Pharmaceuticals. She received consulting fees from the Swedish Ministry of Health and Welfare. She received honoraria from Roche, Pfizer, and Organon for chairmanship and lectures. She received support from Organon for attending meetings. She participated in advisory boards for Merck, Nordic countries, and Ferring. She declared receiving time-lapse equipment and grants with payment to institution for pre-clinical research from Merck pharmaceuticals and from Ferring. SS-R received research funding from Roche Diagnostics, Organon/MSD, Theramex, and Gedeo-Richter. He received consulting fees from Organon/MSD, Ferring Pharmaceuticals, and Merck Serono. He declared receiving honoraria for lectures from Ferring Pharmaceuticals, Besins, Organon/MSD, Theramex, and Gedeon Richter. He received support for attending Gedeon Richter meetings and participated in the Data Safety Monitoring Board of the T-TRANSPORT trial. He is the Deputy of ESHRE SQART special interest group. He holds stock options in IVI Lisboa and received equipment and other services from Roche Diagnostics and Ferring Pharmaceuticals. KT declared receiving payment for honoraria for giving lectures from Merck Serono and Organon. She is member of the safety advisory board of EDQM. She holds a leadership role in the ICCBBA board of directors. ZV received reimbursement from ESHRE for attending meetings. She also received research grants from ESHRE and Juhani Aaltonen Foundation. She is the coordinator of EHSRE SQART special interest group. The other authors have no conflicts of interest to declare.

DISCLAIMER

This guideline represents the views of ESHRE, which were achieved after careful consideration of the scientific evidence available at the time of preparation. In the absence of scientific evidence on certain aspects, a consensus between the relevant ESHRE stakeholders has been obtained. Adherence to these clinical practice guidelines does not guarantee a successful or specific outcome, nor does it establish a standard of care. Clinical practice guidelines do not replace the need for application of clinical judgement to each individual presentation, nor variations based on locality and facility type. ESHRE makes no warranty, express or implied, regarding the clinical practice guidelines and specifically excludes any warranties of merchantability and fitness for a particular use or purpose (full disclaimer available at https://www.eshre.eu/Guidelines-and-Legal).

Transfer of a poor-quality along with a good-quality embryo on in vitro fertilization/intracytoplasmic sperm injection-embryo transfer clinical outcomes: a systematic review and meta-analysis

OBJECTIVE

To investigate the effect on the pregnancy rate of transfer of a good-quality embryo (GQE) and a poor-quality embryo (PQE) in comparison with a single GQE transfer.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Infertility patients undergoing in vitro fertilization/intracytoplasmic sperm injection- embryo transfer.

INTERVENTION(S)

Three major electronic databases (PubMed, Embase, and Cochrane Library) for studies those compared single GQE transfer to double embryo transfer of a GQE + PQE were searched. The Newcastle-Ottawa Quality Assessment Scale was used to evaluate the study quality. Random-effect meta-analysis was performed on all data for an overall analysis, followed by a subgroup analysis (fresh cleavage-stage embryos, fresh blastocysts, frozen-thawed blastocysts, and the same assessment criteria for blastocyst quality).

MAIN OUTCOME MEASURE(S)

The primary outcome was clinical pregnancy rate (CPR).

RESULT(S)

A total of 17 studies with 17,612 cycles for GQE transfer and 6,431 cycles for GQE + PQE transfer were included in the meta-analysis. No significant differences were found in CPR (relative risk [RR] = 1.02; 95% confidence interval [CI], 0.91-1.14) and live birth rate (RR = 0.96; 95% CI, 0.87-1.07) between GQE + PQE and GQE transfers. However, the transfer of GQE + PQE increased multiple pregnancy rate (RR = 0.14; 95% CI, 0.09-0.20) and multiple birth rate (RR = 0.08; 95% CI, 0.06-0.12), when compared with the patients undergoing a single GQE transfer. Subgroup analyses by type of embryo for transfer and assessment criteria for embryo quality showed similar trends.

CONCLUSION(S)

Double embryo transfer with GQE + PQE does not result in increased or decreased CPR and live birth rate when compared with a single GQE transfer but leads to a higher multiple pregnancy rate and multiple birth rate.

CLINICAL TRIAL REGISTRATION NUMBER

Prospero CRD42022296681 (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=296681) registered on January 7, 2022.

Nucleation status of Day 2 pre-implantation embryos, acquired by time-lapse imaging during IVF, is associated with live birth

The primary purpose of this time-lapse data analysis was to identify the association between the nucleation status of a Day 2 preimplantation embryo and live births following in vitro fertilization (IVF). The retrospective data analysis was based on 2769 transferred embryos from 1966 treatment cycles and utilised only Known Implantation Data (KID) for live births. Nucleation errors (NE) such as micronucleation, binucleation, multinucleation and minor error groups, were annotated in the time-lapse images which were taken every 15 minutes for a minimum of 44 hours post insemination. Further, factors that may impact NE and the relationship of early morphological attributes and morphokinetic variables with NE occurrence were explored. The frequency of NE among the transferred embryos was 23.8%. The reversibility of NE evidenced by their presence at the two-cell stage, but absence at the four-cell stage was 89.6%. Embryos exhibiting nucleation errors at the two-cell stage had significantly lower live birth rates compared to embryos with no nucleation errors, constituting a significant predictor. A Generalized Additive Mixed Model was used to control for confounders and for controlling clustering effects from dual embryo transfers. Increased incidences of NE were observed with increasing age, with delayed occurrence of cell divisions and in oocytes inseminated with surgically retrieved spermatozoa. NE assessment and their impact on live birth provides valuable markers for early preimplantation embryo selection. In addition, the high incidence of reversibility of NE and their possible impact on live birth suggest that incorporating two-cell nuclear status annotations in embryo selection, alongside morphology and morphokinetics, is of value.

The parent trap: desire for multifetal gestation among patients treated for infertility

Objective

To evaluate predictors for patient preference regarding multifetal or singleton gestation among women presenting for infertility care.

Design

Cross-sectional study.

Setting

Academic university hospital-based infertility clinic.

Patient(s)

Five hundred thirty-nine female patients with infertility who presented for their initial visit.

Main outcome measure(s)

Demographic characteristics, infertility history, insurance coverage, desired treatment outcome, acceptability of multifetal reduction, and knowledge of the risks of multifetal pregnancies were assessed using a previously published 41-question survey. Univariate analysis was performed to assess patient factors associated with the desire for multiple births. Independent factors associated with this desire were subsequently assessed by multivariate logistic regression analysis.

Result(s)

Nearly a third of women preferred multiples over a singleton gestation. Nulliparity, lower annual household income, older maternal age, marital status, larger ideal family size, openness to multifetal reduction, and lack of knowledge of the maternal/fetal risks of twin pregnancies were associated with pregnancy desire. Older age (OR (95% CI) 1.66 (1.20–2.29)), nulliparity (OR (95% CI) 0.34 (0.20–0.58)), larger ideal family size (OR (95% CI) 2.34 (1.73–3.14)), and lesser knowledge of multifetal pregnancy risk (OR (95% CI) 0.67 (0.55–0.83)) were independently associated with desire.

Conclusion(s)

A large number of patients undergoing fertility treatment desire multifetal gestation. Although a lack of understanding of the risks associated with higher order pregnancies contributes to this desire, additional individual specific variables also contribute to this trend. Efforts to reduce the incidence of multiples should focus not only on patient education on comparative risks of multiples vs singleton pregnancies but also account for individual specific reservations.

Twinning in ART: Single embryo transfer policy

It is more than thirty years that perinatologists and healthcare personnel aim to reduce the morbidity associated with multiple pregnancy. In many cases, these complications stem from pregnancies achieved through artificial reproductive technologies (ART). Although dramatic measures have been taken to control those risks by increasing the proportion of single embryo transfers, the multiple pregnancy rate still remains relatively high among patient conceived through ART, carrying risks to both mothers and newborns, and is coupled with the related economic burden associated with prematurity. The aim of this review is to provide the current evidence regarding single embryo transfer to assist decision-makers and to promote patient knowledge toward an elective policy to reduce the risk of twinning. Single embryo transfer may aid in the further reduction of multiple pregnancy and, in most cases, will maintain patient autonomy and right of choice.

Comparisons of benefits and risks of single embryo transfer versus double embryo transfer: a systematic review and meta-analysis

BACKGROUND

Evidence referring to the trade-offs between the benefits and risks of single embryo transfer (SET) versus double embryo transfer (DET) following assisted reproduction technology are insufficient, especially for those women with a defined embryo quality or advanced age.

METHODS

A systematic review and meta-analysis was conducted according to PRISMA guidelines. PubMed, EMBASE, Cochrane Library and ClinicalTrials.gov were searched based on established search strategy from inception through February 2021. Pre-specified primary outcomes were live birth rate (LBR) and multiple pregnancy rate (MPR). Odds ratio (OR) with 95% confidence interval (CI) were pooled by a random-effects model using R version 4.1.0.

RESULTS

Eighty-five studies (14 randomized controlled trials and 71 observational studies) were eligible. Compared with DET, SET decreased the probability of a live birth (OR = 0.78, 95% CI: 0.71-0.85, P < 0.001, n = 62), and lowered the rate of multiple pregnancy (0.05, 0.04-0.06, P < 0.001, n = 45). In the sub-analyses of age stratification, both the differences of LBR (0.87, 0.54-1.40, P = 0.565, n = 4) and MPR (0.34, 0.06-2.03, P = 0.236, n = 3) between SET and DET groups became insignificant in patients aged ≥40 years. No significant difference in LBR for single GQE versus two embryos of mixed quality [GQE + PQE (non-good quality embryo)] (0.99, 0.77-1.27, P = 0.915, n = 8), nor any difference of MPR in single PQE versus two PQEs (0.23, 0.04-1.49, P = 0.123, n = 6). Moreover, women who conceived through SET were associated with lower risks of poor outcomes, including cesarean section (0.64, 0.43-0.94), antepartum haemorrhage (0.35, 0.15-0.82), preterm birth (0.25, 0.21-0.30), low birth weight (0.20, 0.16-0.25), Apgar1 < 7 rate (0.12, 0.02-0.93) or neonatal intensive care unit admission (0.30, 0.14-0.66) than those following DET.

CONCLUSIONS

In women aged < 40 years or if any GQE is available, SET should be incorporated into clinical practice. While in the absence of GQEs, DET may be preferable. However, for elderly women aged ≥40 years, current evidence is not enough to recommend an appropriate number of embryo transfer. The findings need to be further confirmed.

Effectiveness and Safety of Two Consecutive Cycles of Single Embryo Transfer Compared With One Cycle of Double Embryo Transfer: A Systematic Review and Meta-Analysis

OBJECTIVE

To date, evidence regarding the effectiveness and safety of two consecutive cycles of single embryo transfer (2SETs) compared with one cycle of double embryo transfer (DET) has been inadequate, particularly considering infertile women with different prognostic factors. This study aimed to comprehensively summarize the evidence by comparing 2SETs with DET.

METHODS

PubMed, Embase, Cochrane Library databases, ClinicalTrails.gov, and the WHO International Clinical Trials Registry Platform were searched up to March 22, 2022. Peer-reviewed, English-language randomized controlled trials (RCTs) and observational studies (OS) comparing the outcomes of 2SETs with DET in infertile women with their own oocytes and embryos were included. Two authors independently conducted study selection, data extraction, and bias assessment. The Mantel-Haenszel random-effects model was used for pooling RCTs, and a Bayesian design-adjusted model was conducted to synthesize the results from both RCTs and OS.

MAIN RESULTS

Twelve studies were finally included. Compared with the DET, 2SETs were associated with a similar cumulative live birth rate (LBR; 48.24% vs. 48.91%; OR, 0.97; 95% credible interval (CrI), 0.89-1.13, τ^{2 =} 0.1796; four RCTs and six observational studies; 197,968 women) and a notable lower cumulative multiple birth rate (MBR; 0.87% vs. 17.72%; OR, 0.05; 95% CrI, 0.02-0.10, τ^{2 =} 0.1036; four RCTs and five observational studies; 197,804 women). Subgroup analyses revealed a significant increase in cumulative LBR (OR, 1.33; 95% CrI, 1.29-1.38, τ^{2 =} 0) after two consecutive cycles of single blastocyst transfer compared with one cycle of double blastocyst transfer. Moreover, a lower risk of cesarean section, antepartum hemorrhage, preterm birth, low birth weight, and neonatal intensive care unit admission but a higher gestational age at birth and birth weight were found in the 2SETs group.

CONCLUSION

Compared to the DET strategy, 2SETs result in a similar LBR while simultaneously reducing the MBR and improving maternal and neonatal adverse outcomes. The 2SETs strategy appears to be especially beneficial for women aged ≤35 years and for blastocyst transfers.

Pregnancy Outcomes Following the First Frozen Blastocyst Transfer Among Women Aged Less Than 35 Years Old: A Retrospective Cohort Study

Background: Many guidelines have been issued regarding the number of embryos to be transferred after in vitro fertilization (IVF), but patients and clinicians may be reluctant to accept or offer a single embryo transfer due to the expected lower chance of pregnancy or live birth. This study was aimed to provide additional information on cycle outcome according to the number and quality of thawed transferred blastocysts.

Methods: A retrospective cohort study was designed to collect the data of 505 patients who performed the first frozen blastocysts transfer at Tam Anh General Hospital from June 2018 to September 2019. One good-quality embryo was transferred for 121 patients (Group 1), two good for 214 patients (Group 2), one good and one poor for 112 patients (Group 3), one good and two poor for 25 patients (Group 4), and one or two poor for 33 patients (Group 5).

Results: The pregnancy rate was 71.9%, 74.8%, 69.4%, 84.0%, and 39.4% in Group 1–5, respectively. The multiple pregnancy rate was 36.9%, 16.9%, and 32.0% in Groups 2–4, respectively, higher than Group 1 (4.9%). The live birth rate was 55.6%, 50.9%, and 60.0% in Group 2–4, respectively, but not significantly different from the Group 1 (47.9%).

Conclusions: Transferring an additional good or poor embryo, along with a good embryo, does not increase the live birth rate while the incidence of multiple pregnancies rises significantly.

Time-lapse imaging derived morphokinetic variables reveal association with implantation and live birth following in vitro fertilization: A retrospective study using data from transferred human embryos

The purpose of this retrospective time-lapse data analysis from transferred preimplantation human embryos was to identify early morphokinetic cleavage variables that are related to implantation and live birth following in vitro fertilization (IVF). All embryos were monitored from fertilization check until embryo transfer for a minimum of 44 hours. The study was designed to assess the association between day 2 embryo morphokinetic variables with implantation and live birth based on Known Implantation Data (KID). The kinetic variables were subjected to quartile-based analysis. The predictive ability for implantation and live birth was studied using receiver operator characteristic (ROC) curves. Three morphokinetic variables, time to 2-cells (t2), duration of second cell cycle (cc2) below one threshold and cc2 above another threshold had the highest predictive value with regards to implantation and live birth following IVF treatment. The predictive pre-transfer information has little divergence between fetal heartbeat and live birth data and therefore, at least for early morphokinetic variables up to the four-cell stage (t4), conclusions and models based on fetal heartbeat data can be expected to be valid for live birth datasets as well. The three above mentioned variables (t2, cc2 below one threshold and cc2 above another threshold) may supplement morphological evaluation in embryo selection and thereby improve the outcome of in vitro fertilization treatments.

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

BACKGROUND

Transfer of more than one embryo during in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) increases multiple pregnancy rates resulting in an increased risk of maternal and perinatal morbidity. Elective single embryo transfer offers a means of minimising this risk, but this potential gain needs to be balanced against the possibility of jeopardising the overall live birth rate (LBR).

OBJECTIVES

To evaluate the effectiveness and safety of different policies for the number of embryos transferred in infertile couples undergoing assisted reproductive technology cycles.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group specialised register of controlled trials, CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform from inception to March 2020. We handsearched reference lists of articles and relevant conference proceedings. We also communicated with experts in the field regarding any additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing different policies for the number of embryos transferred following IVF or ICSI in infertile women. Studies of fresh or frozen and thawed transfer of one to four embryos at cleavage or blastocyst stage were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial eligibility and risk of bias. The primary outcomes were LBR and multiple pregnancy rate. The secondary outcomes were clinical pregnancy and miscarriage rates. We analysed data using risk ratios (RR), Peto odds ratio (Peto OR) and a fixed effect model.

MAIN RESULTS

We included 17 RCTs in the review (2505 women). The main limitation was inadequate reporting of study methods and moderate to high risk of performance bias due to lack of blinding. A majority of the studies had low numbers of participants. None of the trials compared repeated single embryo transfer (SET) with multiple embryo transfer. Reported results of multiple embryo transfer below refer to double embryo transfer. Repeated single embryo transfer versus multiple embryo transfer in a single cycle Repeated SET was compared with double embryo transfer (DET) in four studies of cleavage-stage transfer. In these studies the SET group received either two cycles of fresh SET (one study) or one cycle of fresh SET followed by one frozen SET (three studies). The cumulative live birth rate after repeated SET may be little or no different from the rate after one cycle of DET (RR 0.95, 95% CI (confidence interval) 0.82 to 1.10; I² = 0%; 4 studies, 985 participants; low-quality evidence). This suggests that for a woman with a 42% chance of live birth following a single cycle of DET, the repeated SET would yield pregnancy rates between 34% and 46%. The multiple pregnancy rate associated with repeated SET is probably reduced compared to a single cycle of DET (Peto OR 0.13, 95% CI 0.08 to 0.21; I² = 0%; 4 studies, 985 participants; moderate-quality evidence). This suggests that for a woman with a 13% risk of multiple pregnancy following a single cycle of DET, the risk following repeated SET would be between 0% and 3%. The clinical pregnancy rate (RR 0.99, 95% CI 0.87 to 1.12; I² = 47%; 3 studies, 943 participants; low-quality evidence) after repeated SET may be little or no different from the rate after one cycle of DET. There may be little or no difference in the miscarriage rate between the two groups. Single versus multiple embryo transfer in a single cycle A single cycle of SET was compared with a single cycle of DET in 13 studies, 11 comparing cleavage-stage transfers and three comparing blastocyst-stage transfers.One study reported both cleavage and blastocyst stage transfers. Low-quality evidence suggests that the live birth rate per woman may be reduced in women who have SET in comparison with those who have DET (RR 0.67, 95% CI 0.59 to 0.75; I² = 0%; 12 studies, 1904 participants; low-quality evidence). Thus, for a woman with a 46% chance of live birth following a single cycle of DET, the chance following a single cycle of SET would be between 27% and 35%. The multiple pregnancy rate per woman is probably lower in those who have SET than those who have DET (Peto OR 0.16, 95% CI 0.12 to 0.22; I² = 0%; 13 studies, 1952 participants; moderate-quality evidence). This suggests that for a woman with a 15% risk of multiple pregnancy following a single cycle of DET, the risk following a single cycle of SET would be between 2% and 4%. Low-quality evidence suggests that the clinical pregnancy rate may be lower in women who have SET than in those who have DET (RR 0.70, 95% CI 0.64 to 0.77; I² = 0%; 10 studies, 1860 participants; low-quality evidence). There may be little or no difference in the miscarriage rate between the two groups.

AUTHORS' CONCLUSIONS

Although DET achieves higher live birth and clinical pregnancy rates per fresh cycle, the evidence suggests that the difference in effectiveness may be substantially offset when elective SET is followed by a further transfer of a single embryo in fresh or frozen cycle, while simultaneously reducing multiple pregnancies, at least among women with a good prognosis. The quality of evidence was low to moderate primarily due to inadequate reporting of study methods and absence of masking those delivering, as well as receiving the interventions.

Strategies to reduce multiple pregnancies during medically assisted reproduction

Multiple birth rates after fertility treatment are still high in many countries. Multiple births are associated with increased rates of preterm birth and low birth weight babies, in turn increasing the risk of severe morbidity for the children. The multiple birth rates vary in different countries between 2% and 3% and up to 30% in some settings. Elective single-embryo transfer, particularly in combination with frozen-embryo transfer and milder stimulation in ovulation induction/intrauterine insemination, to avoid multifollicular development is an effective strategy to decrease the multiple birth rates while still achieving acceptable live-birth rates. Although this procedure is used successfully in many countries, it ought to be implemented broadly to improve the health of the children. One at a time should be the normal routine.

Factors affecting pregnancy outcomes following the surgical removal of intrauterine adhesions and subsequent in vitro fertilization and embryo transfer

This study aimed to investigate the clinical factors affecting pregnancy rates following the surgical removal of intrauterine adhesions (IUAs) and subsequent in vitro fertilization and embryo transfer (IVF-ET). We retrospectively evaluated case data from patients who had undergone hysteroscopic surgery to remove varying degrees of IUAs and who had subsequently received assisted reproductive treatments with IVF-ET (in all 140 cycles) at our hospital between January, 2011 and January, 2015. The patient data were divided into either the pregnancy or non-pregnancy groups based on the pregnancy outcomes, and a number of clinicopathological variables were compared these two groups, such as age, infertility (type and duration), the number of prior surgical treatments for and severity of IUAs, the baseline follicle-stimulating hormone/luteinizing hormone (FSH/LH) ratio and estradiol level, endometrial thickness on the day of human chorionic gonadotropin (hCG) administration, etc. We selected the variables with statistically significant differences to generate multivariate logistic regression and linear correlation analyses. We found that i) the mean endometrial thickness on the day of hCG administration was greater in the pregnancy group, and that the average gestational age was younger than that in the non-pregnancy group. The different age groups had significantly different pregnancy rates. The mean baseline FSH/LH ratio of the women in the pregnancy group was lower than that in the women in the non-pregnancy group. The number of embryos transferred in the pregnancy group was higher than that in the non-pregnancy group. However, the other variables exhibited similar values between these two groups. ii) Our multivariate logistic regression analyses revealed that age and endometrial thickness on the day of hCG administration had significant effects on the pregnancy outcome. The baseline FSH/LH ratio and the number of embryos transferred were similar between the groups. On the whole, age and endometrial thickness on the day of hCG administration are the most important predictors of pregnancy outcome in the patients undergoing IVF-ET following the surgical removal of IUAs. Importantly however, the identification of effective methods with which to improve the endometrial thickness and the ovarian response in patients with diminished ovarian reserves warrants further investigation in future research.

IVF for unexplained subfertility; whom should we treat?

STUDY QUESTION

Which couples with unexplained subfertility can expect increased chances of ongoing pregnancy with IVF compared to expectant management?

SUMMARY ANSWER

For couples in which the woman is under 40 years of age, IVF is associated with higher chances of conception than expectant management.

WHAT IS KNOWN ALREADY

The clinical indications for IVF have expanded over time from bilateral tubal blockage to include unexplained subfertility in which there is no identifiable barrier to conception. Yet, there is little evidence from randomized controlled trials that IVF is effective in these couples.

STUDY DESIGN, SIZE, DURATION

We compared outcomes in British couples with unexplained subfertility undergoing IVF (n = 40 921) from registry data to couples with the same type of subfertility on expectant management. Those couples on expectant management (defined as no intervention aside from the advice to have intercourse) comprised a prospective nation-wide Dutch cohort (n = 4875) and a retrospective regional cohort from Aberdeen, Scotland (n = 975). We excluded couples who had tried for <1 year to conceive and also those with anovulation, uni- or bilateral tubal occlusion, mild or severe endometriosis or male subfertility i.e. impaired semen quality according to World Health Organization criteria.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We matched couples who received IVF and couples on expectant management based on their characteristics to control for confounding. We fitted a Cox proportional hazards model including patient characteristics, IVF treatment and their interactions to estimate the individualized chance of conception over 1 year—either following IVF or expectant management for all combinations of patient characteristics. The endpoint was conception leading to ongoing pregnancy, defined as a foetus reaching a gestational age of at least 12 weeks.

MAIN RESULTS AND THE ROLE OF CHANCE

The adjusted 1-year chance of conception was 47.9% (95% CI: 45.0–50.9) after IVF and 26.1% (95% CI: 24.2–28.0) after expectant management. The absolute difference in the average adjusted 1-year chances of conception was 21.8% (95%CI: 18.3–25.3) in favour of IVF. The effectiveness of IVF was influenced by female age, duration of subfertility and previous pregnancy. IVF was effective in women under 40 years, but the 1-year chance of an IVF conception declined sharply in women over 34 years. In contrast, in woman over 40 years of age, IVF was less effective, with an absolute difference in chance compared to expectant management of 10% or lower. Regardless of female age, IVF was also less effective in couples with a short period of secondary subfertility (1 year) who had chances of natural conception of 30% or above.

LIMITATIONS, REASONS FOR CAUTION

The 1-year chances of conception were based on three cohorts with different sampling mechanisms. Despite adjustment for the three most important prognostic patient characteristics, namely female age, duration of subfertility and primary or secondary subfertility, our estimates might not be free from residual confounding.

WIDER IMPLICATIONS OF THE FINDINGS

IVF should be used selectively based on judgements on gain compared to continuing expectant management for a given couple. Our results can be used by clinicians to counsel couples with unexplained subfertility, to inform their expectations and facilitate evidence-based, shared decision making.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Tenovus Scotland [grant G17.04]. Travel for RvE was supported by the Amsterdam Reproduction & Development Research Group [grant V.000296]. SB reports acting as editor-in-chief of HROpen. Other authors have no conflicts.

Effect of transfer of a poor quality embryo along with a top quality embryo on the outcome during fresh and frozen in vitro fertilization cycles

OBJECTIVE

To evaluate the impact of a poor quality embryo (PQE) during double ET (DET) with a top quality embryo (TQE) on IVF outcome.

DESIGN

A review of prospectively collected data.

SETTING

Tertiary level fertility clinic.

PATIENT(S)

All patients undergoing blastocyst transfers as part of fresh IVF (n = 939) and frozen ET (n = 1,009) cycles performed between 2010 and 2016.

INTERVENTION(S)

Single ET (SET) with TQE (group 1) was set as control and compared with outcomes for SET with PQE (group 2), DET with 2 TQEs (group 3), PQE plus TQE (group 4), and 2 PQE (group 5).

MAIN OUTCOME MEASURE(S)

Live births and multiple births.

RESULT(S)

The live birth rates for group 4 were statistically similar to group 1 during fresh IVF (26.5% vs. 33.7%; odds ratio [OR], 0.95; 95% confidence interval [CI] 0.53-1.7) and frozen ET (24.2% vs. 32.7%; OR, 0.75; 95% CI 0.48-1.2), although there was a trend for lower success. Conversely, multiple births were higher in group 4 for fresh IVF (19% vs. 4.7%; OR, 2.9; 95% CI 1.3-6.6) and frozen ET (10.3% vs. 2.6%; OR, 2.4; 95% CI 1.2-4.9). The live birth rates for group 2 (12.2% for fresh IVF and 14.6% for frozen ET) and group 5 (21.2% for fresh IVF and 14% for frozen ET) were lower and for group 3 were higher (40.8% for fresh IVF and 40.3% for frozen ET) when compared with group 1. Multiple births were significantly higher with DET.

CONCLUSION(S)

This study does not support DET with one PQE along with a TQE, when there is only one TQE and one or more PQEs available for fresh IVF or frozen ET.

Making IVF more effective through the evolution of prediction models: is prognosis the missing piece of the puzzle?

Assisted reproductive technology has evolved tremendously since the emergence of in vitro fertilization (IVF). In the course of the recent decade, there have been significant efforts in order to minimize multiple gestations, while improving percentages of singleton pregnancies and offering individualized services in IVF, in line with the trend of personalized medicine. Patients as well as clinicians and the entire IVF team benefit majorly from 'knowing what to expect' from an IVF cycle. Hereby, the question that has emerged is to what extent prognosis could facilitate toward the achievement of the above goal. In the current review, we present prediction models based on patients' characteristics and IVF data, as well as models based on embryo morphology and biomarkers during culture shaping a complication free and cost-effective personalized treatment. The starting point for the implementation of prediction models was initiated by the aspiration of moving toward optimal practice. Thus, prediction models could serve as useful tools that could safely set the expectations involved during this journey guiding and making IVF treatment more effective. The aim and scope of this review is to thoroughly present the evolution and contribution of prediction models toward an efficient IVF treatment.

ABBREVIATIONS

IVF: In vitro fertilization; ART: assisted reproduction techniques; BMI: body mass index; OHSS: ovarian hyperstimulation syndrome; eSET: elective single embryo transfer; ESHRE: European Society of Human Reproduction and Embryology; mtDNA: mitochondrial DNA; nDNA: nuclear DNA; ICSI: intracytoplasmic sperm injection; MBR: multiple birth rates; LBR: live birth rates; SART: Society for Assisted Reproductive Technology Clinic Outcome Reporting System; AFC: antral follicle count; GnRH: gonadotrophin releasing hormone; FSH: follicle stimulating hormone; LH: luteinizing hormone; AMH: anti-Müllerian hormone; DHEA: dehydroepiandrosterone; PCOS: polycystic ovarian syndrome; NPCOS: non-polycystic ovarian syndrome; CE: cost-effectiveness; CC: clomiphene citrate; ORT: ovarian reserve test; EU: embryo-uterus; DET: double embryo transfer; CES: Cumulative Embryo Score; GES: Graduated Embryo Score; CSS: Combined Scoring System; MSEQ: Mean Score of Embryo Quality; IMC: integrated morphology cleavage; EFNB2: ephrin-B2; CAMK1D: calcium/calmodulin-dependent protein kinase 1D; GSTA4: glutathione S-transferase alpha 4; GSR: glutathione reductase; PGR: progesterone receptor; AMHR2: anti-Müllerian hormone receptor 2; LIF: leukemia inhibitory factor; sHLA-G: soluble human leukocyte antigen G.

One Plus One Is Better Than Two: Cumulative Reproductive Outcomes Are Better after Two Elective Single Blastocyst Embryo Transfers Compared to One Double Blastocyst Embryo Transfer

Aims

The aim of this study is to compare cumulative in vitro fertilization-intracytoplasmic sperm injection outcomes following two elective single embryo transfer (eSET) versus one double embryo transfer (DET) using blastocyst(s).

Settings and Design

This was retrospective observational study.

Study Period

The study was conducted during January 2015-December 2015.

Subjects and Methods

Forty-one fresh + 25 frozen eSET versus 123 DET using self-oocytes and 68 fresh + 35 frozen eSET versus 184 DET using donor-oocytes were included in the study. All failing to achieve live birth after first eSET underwent frozen embryo transfer cycle with second blastocyst. Cumulative outcome after two eSET were compared with one DET.

Statistical Analysis Used

The analysis was performed by Chi-square and t-test.

Results

In self-oocytes group, higher but statistically nonsignificant cumulative clinical pregnancy rate (CPR) (58.5% vs. 57.7%, P = 0.92) and live birth rate (LBR) (48.7% vs. 44.7%, P = 0.65) with significantly lower multiple pregnancy rate (MPR) (4.2% vs. 45%, P = 0.0002) were obtained; whereas in donor-oocytes group, comparable cumulative CPR (73.5% vs. 65.7%, P = 0.24), significantly higher LBR (64.7% vs. 48.9%, P = 0.02) and significantly lower MPR (4% vs. 51.2%, P = 0.00005) were obtained after two eSET vs. one DET. In self-oocytes group, the incidence of prematurity (10% vs. 21.4%, P > 0.05) and low birth weight (25% vs. 45.6%, P > 0.05) were lower but statistically nonsignificant, whereas in donor-oocytes group, incidence of prematurity was lower but statistically nonsignificant (26.7% vs. 38.8%, P > 0.05) while of low birth weight was significantly lower (32.7% vs. 51.2%, P = 0.0038) after two eSET versus one DET.

Conclusion

Cumulative LBR was higher with lower incidence of multiple births, prematurity and low birth weight after two eSET versus one DET using self- or donor-oocytes. Higher use of eSET improves reproductive outcomes in patients with good prognosis.

The addition of a low-quality embryo as part of a fresh day 3 double embryo transfer does not improve ongoing pregnancy rates

STUDY QUESTION

Does the addition of a low-quality embryo in fresh Day 3 double embryo transfer (DET) affect the ongoing pregnancy rate (OPR) and multiple gestation rate in patients with only one or no high-quality embryos available?

SUMMARY ANSWER

In patients with only one- or no high-quality embryo available, the addition of a low-quality embryo in fresh Day 3 DET does not improve the OPR but increases multiple gestation rates in fresh DET.

WHAT IS KNOWN ALREADY

Pregnancy rates after DET are considered to be higher compared to single embryo transfer (SET) when analyzed per first embryo transfer only. However, these conclusions are based on RCTs in which mostly patients with two or more high-quality embryos were included, and can therefore not be applied to patients with only one or no high-quality embryo available. This is particularly relevant since it has been suggested that low-quality embryos could impair the implantation of simultaneously transferred embryos by paracrine signaling. Hence, we investigated in patients with only one or no high-quality embryo available whether the addition of a low-quality embryo in DET affects the OPR, multiple gestation rate and miscarriage rate.

STUDY DESIGN SIZE DURATION

This was a retrospective cohort study of 5050 patients receiving 7252 fresh embryo transfers on Day 3 after fertilization in IVF/ICSI cycles from 2012 to 2015 in two academic hospitals.

PARTICIPANTS/MATERIALS SETTING METHODS

We included all women that received fresh SET or DET with any combination of high-quality embryos (7, 8 or 9 blastomeres, with equal to or <20% fragmentation) or low-quality embryos (all other embryos). Outcomes were OPR (primary outcome, defined as a positive fetal heartbeat by transvaginal ultrasound at least 10 weeks after oocyte retrieval), miscarriage rate and multiple gestation rate. We used a generalized estimating equations model adjusting for maternal age, number of oocytes retrieved, center of treatment and the interaction between maternal age and number of oocytes retrieved. Other baseline characteristics, including infertility diagnosis, fertilization method and the number of consecutive fresh embryo transfers per patient, did not contribute significantly to the GEE model and were therefore excluded, and not adjusted for.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared to SET with one high-quality embryo, DET with two high-quality embryos resulted in a higher OPR (adjusted odds ratio (OR) 1.38, 95% CI 1.14-1.67), while DET with one high- and one low-quality embryo resulted in a lower OPR (adjusted OR 0.65, 95% CI 0.49-0.90). However, SET in patients with only one high-quality embryo available resulted in a lower OPR compared to SET in patients with two or more high-quality embryos available (adjusted OR 0.52, 95% CI 0.39-0.70). After adjusting for this confounding factor, we found that both DET with two high-quality embryos (adjusted OR 0.99, 95% CI 0.74-1.31) and DET with one high- and one low-quality embryo (adjusted OR 0.78, 95% CI 0.47-1.27) resulted in a not significantly different OPR compared to SET with one high-quality embryo. If only low-quality embryos were available, DET did not increase the OPR as compared to SET with one low-quality embryo (adjusted OR 0.84, 95% CI 0.55-1.28). Multiple gestation rates were higher in all DET groups compared to SET (DET with ≥1 high-quality embryo(s) compared to SET with one high-quality embryo; DET with two low-quality embryos compared to SET with one low-quality embryo; all comparisons P < 0.001). Miscarriage rates were not different in all DET groups compared to SET (DET with ≥1 high-quality embryo(s) compared to SET with one high-quality embryo; DET with two low-quality embryos compared to SET with one low-quality embryo; all comparisons P > 0.05).

LIMITATIONS REASONS FOR CAUTION

Limitations to this study include the retrospective design and possible bias between study groups related to embryo transfer policies between 2012 and 2015. Consequently, we may have underestimated pregnancy chances in all DET groups. Furthermore, the OPR was calculated as a percentage of the number of fresh embryo transfers in each study group, and not the total number of started IVF/ICSI cycles. Therefore, the reported pregnancy outcomes may not truly reflect the pregnancy chances of couples at the start of treatment. A possible confounding effect of maternal age in our study is acknowledged but we could not compare clinical outcomes in different age groups separately owing to small sample sizes. Analysis of pregnancy outcomes in lower prognosis patients (higher maternal age, fewer oocytes retrieved) separately is an avenue for future research.

WIDER IMPLICATIONS OF THE FINDINGS

The decision to perform DET rather than SET in order to increase the OPR per fresh embryo transfer seems not to be justified for those patients with only one or no high-quality embryo(s) available. However, owing to the limitations of this study, prospective RCTs are needed that specifically investigate pregnancy outcomes in patients with only one or no high-quality embryo(s) available in SET and DET.

STUDY FUNDING/COMPETING INTERESTS

This study was funded by a grant from the joint Amsterdam Reproduction & Development Institute of the Academic Medical Center and VU University Medical Center (www.amsterdam-reproduction-and-development.org). The authors have no conflicts of interest to declare.

Mixed double-embryo transfer: A promising approach for patients with repeated implantation failure

Objective

The purpose of this study was to evaluate the efficacy of frozen mixed double-embryo transfer (MDET; the simultaneous transfer of day 3 and day 5 embryos) in comparison with frozen blastocyst double-embryo transfer (BDET; transfer of two day 5 blastocysts) in patients with repeated implantation failure (RIF).

Methods

A total of 104 women with RIF who underwent frozen MDET (n=48) or BDET (n=56) with excellent-quality embryos were included in this retrospective analysis. All frozen embryo transfers were performed in natural cycles. The main outcome measures were the implantation rate, clinical pregnancy rate, multiple pregnancy rate, and miscarriage rate. These measures were compared between the patients who underwent MDET or BDET using the chi-square test or the Fisher exact test, as appropriate.

Results

The implantation and clinical pregnancy rates were significantly higher in patients who underwent MDET than in those who underwent BDET (60.4% vs. 39.3%, p=0.03 and 52.1% vs. 30.4%, p=0.05, respectively). A significantly lower miscarriage rate was observed in the MDET group (6.9% vs. 10.7%, p=0.05). In addition, the multiple pregnancy rate was slightly, but not significantly, higher in the MDET group (27.1% vs. 25.0%).

Conclusion

MDET was found to be significantly superior to double blastocyst transfer. It could be regarded as an appropriate approach to improve in vitro fertilization success rates in RIF patients.

Cost-effectiveness of embryo transfer strategies: a decision analytic model using long-term costs and consequences of singletons and multiples born as a consequence of IVF

STUDY QUESTION

What is the cost-effectiveness of elective single embryo transfer (eSET) versus double embryo transfer (DET) strategies from a societal perspective, when applying a time horizon of 1, 5 and 18 years?

SUMMARY ANSWER

From a short-term perspective (1 year) it is cost-effective to replace DET with single embryo transfer; however when intermediate- (5 years) and long-term (18 years) costs and consequences are incorporated, DET becomes the most cost-effective strategy, given a ceiling ratio of €20 000 per quality-adjusted life years (QALY) gained.

WHAT IS ALREADY KNOWN

According to previous cost-effectiveness research into embryo transfer strategies, DET is considered cost-effective if society is willing to pay around €20 000 for an extra live birth. However, interpretation of those studies is complicated, as those studies fail to incorporate long-term costs and outcomes and used live birth as a measure of effectiveness instead of QALYs. With this outcome, both multiple and singletons were valued as one live birth, whereas costs of all children of a multiple were incorporated.

STUDY DESIGN, SIZE, DURATION

A Markov model (cycle length: 1 year; time horizon: 1, 5 and 18 years) was developed comparing a maximum of: (i) three cycles of eSET in all patients; (ii) four cycles of eSET in all patients; (iii) five cycles of eSET in all patients; (iv) three cycles of standard treatment policy (STP), i.e. eSET in women <38 years with a good quality embryo, and DET in all other women; and (v) three cycles of DET in all patients.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Expected life years (LYs), child QALYs and costs were estimated for all comparators. Input parameters were derived from a retrospective cohort study, in which hospital resource data were collected (n=580) and a parental questionnaire was sent out (431 respondents). Probabilistic sensitivity analysis (5000 iterations) was performed.

MAIN RESULTS AND THE ROLE OF CHANCE

With a time horizon of 18 years, DETx3 is most effective (0.54 live births, 10.2 LYs and 9.8 QALYs) and expensive (€37 871) per couple starting IVF. Three cycles of eSET are least effective (0.43 live births, 7.1 LYs and 6.8 QALYs) and expensive (€25 563). We assumed that society is willing to pay €20 000 per QALY gained. With a time horizon of 1 year, eSETx3 was the most cost-effective embryo transfer strategy with a probability of being cost-effective of 99.9%. With a time horizon of 5 or 18 years, DETx3 was most cost-effective, with probabilities of being cost-effective of 77.3 and 93.2%, respectively.

LIMITATIONS, REASONS FOR CAUTION

This is the first study to use QALYs generated by the children in the economic evaluation of embryo transfer strategies. There remains some disagreement on whether QALYs generated by new life should be used in economic evaluations of fertility treatment. A further limitation is that treatment ends when it results in live birth and that only child QALYs were considered as measure of effectiveness. The results for the time horizon of 18 years might be less solid, as the data beyond the age of 8 years are based on extrapolation.

WIDER IMPLICATIONS OF THE FINDINGS

The current Markov model indicates that when child QALYs are used as measure of outcome it is not cost-effective on the long term to replace DET with single embryo transfer strategies. However, for a balanced approach, a family-planning perspective would be preferable, including additional treatment cycles for couples who wish to have another child. Furthermore, the analysis should be extended to include QALYs of family members.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by a research grant (grant number 80-82310-98-09094) from the Netherlands Organization for Health Research and Development (ZonMw). There are no conflicts of interest in connection with this article.

TRIAL REGISTRATION NUMBER

Not applicable.

Population trends and live birth rates associated with common ART treatment strategies

STUDY QUESTION

Have ART live birth rates improved in Australia over the last 12 years?

SUMMARY ANSWER

There were striking improvements in per-cycle live birth rates observed for frozen/thaw embryo transfers, blastocyst transfer and single embryo transfer (SET), while live birth rates following ICSI were lower than IVF for non-male factor infertility in most years.

WHAT IS ALREADY KNOWN

ART and associated techniques have become the predominant treatment of infertility over the past 30 years in most developed countries. However, there are differences in ART laboratory and clinical practices, and success rates worldwide. Australia has one of the highest ART utilization rates and lowest multiple birth rates in the world, thus providing a unique setting to investigate the contribution of common ART strategies in an unrestricted population of patients to ART success rates.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of 585 065 ART treatment cycles performed in Australia between 2002 and 2013 using the Australian and New Zealand Assisted Reproduction Database (ANZARD).

PARTICIPANTS MATERIALS, SETTING, METHOD

An unrestricted population of all women who underwent autologous ART treatment between 2002 and 2013. Visual descriptive analysis was used to assess the trends in ART procedures by the calendar years. Adjusted odds ratios (aORs) of a live birth for four common ART techniques were calculated after controlling for important confounders including female age, infertility diagnosis, stage of the embryo (blastocyst versus cleavage stage), type of embryo (fresh versus thawed), fertilization method (IVF versus ICSI) and number of embryos transferred (SET versus multiple embryos).

MAIN RESULTS AND THE ROLE OF CHANCE

The overall live birth rate per embryo transfer increased from 19.2% in 2002 to 23.3% in 2013 (21.9-24.3% for fresh embryo transfers and 14.6-23.3% for frozen/thaw embryo transfers). This occurred concurrently with an increase in SET from 29.7% to 78.9%, and an increase in the average age of women undergoing treatment from 35.0 to 35.9 years. Individuals who had a frozen/thaw embryo transfer cycle in 2002 had 43% (aOR: 0.57, 95% CI: 0.53-0.61) reduced odds of a live birth compared with a fresh embryo transfer cycle. This contrasted with 16% (aOR: 0.84, 95% CI: 0.80-0.98) reduced odds of a live birth from frozen/thaw embryo transfer cycles in 2013. In 2013, the odds of blastocyst transfer resulting in a live birth were more than twice as great as for cleavage stage transfer (aOR 2.01, 95% CI: 1.92-2.11). The adjusted odds of live birth per SET compared with multiple embryo transfer increased significantly over the last 12 years, from a 38% reduced odds of a live birth follow SET in 2002 (aOR: 062, 95% CI: 0.57-0.67) compared to an 8% reduced odds in 2013 (aOR: 0.92, 95% CI: 0.87-0.98). The aOR of a live birth using ICSI compared to IVF in non-male factor patients was lower in most years bringing into question its widespread use.

LIMITATION, REASONS FOR CAUTION

This is a retrospective cohort analysis and cannot confirm causality. High-level evidence on the effectiveness of particular ART techniques, particularly ICSI and blastocyst culture, requires prospective randomized controlled trials or detailed statistical analysis using large-scale data that counts for fertilization failure, embryo loss, prognostic factors and cycle characteristics.

WIDER IMPLICATION OF THE FINDINGS

The most striking improvements in ART success rates in Australia have been observed for frozen/thaw embryo transfers, blastocyst transfer and SET. Further studies of the role of ICSI in non-male factor infertility and blastocyst transfer success rates that take into account embryo loss are needed.

STUDY FUNDING/COMPETING INTERESTS

No funding was received to undertake this study. The authors declare that they do not have competing interests with this study.

TRIAL REGISTRATION NUMBER

NA.

Cost Implications for Subsequent Perinatal Outcomes After IVF Stratified by Number of Embryos Transferred: A Five Year Analysis of Vermont Data

BACKGROUND

In states in the USA without in vitro fertilzation coverage (IVF) insurance coverage, more embryos are transferred per cycle leading to higher risks of multi-fetal pregnancies and adverse pregnancy outcomes.

OBJECTIVE

To determine frequency and cost of selected adverse perinatal complications based on number of embryos transferred during IVF, and calculate incremental cost per IVF live birth.

METHODS

Medical records of patients who conceived with IVF (n = 116) and delivered at >20 weeks gestational age between 2007 and 2011 were evaluated. Gestational age at delivery, low birth weight (LBW) term births, and delivery mode were tabulated. Healthcare costs per cohort, extrapolated costs assuming 100 patients per cohort, and incremental costs per infant delivered were calculated.

RESULTS

The highest prematurity and cesarean section rates were recorded after double embryo transfers (DET), while the lowest rates were found in single embryo transfers (SET). Premature singleton deliveries increased directly with number of transferred embryos [6.3 % (SET), 9.1 % (DET) and 10.0 % for ≥3 embryos transferred]. This trend was also noted for rate of cesarean delivery [26.7 % (SET), 36.6 % (DET), and 47.1 % for ≥3 embryos transferred]. The proportion of LBW infants among deliveries after DET and for ≥3 embryos transferred was 3.9 and 9.1 %, respectively. Extrapolated costs per cohort were US$718,616, US$1,713,470 and US$1,227,396 for SET, DET, and ≥3 embryos transferred, respectively.

CONCLUSION

Attempting to improve IVF pregnancy rates by permitting multiple embryo transfers results in sharply increased rates of multiple gestation and preterm delivery. This practice yields a greater frequency of adverse perinatal outcomes and substantially increased healthcare spending. Better efforts to encourage SET are necessary to normalize healthcare expenditures considering the frequency of very high cost sequela associated with IVF where multiple embryo transfers occur.

Clinical outcomes of frozen-thawed single blastocyst transfer in patients requiring whole embryo freezing

We compared clinical outcomes amongst frozen-thawed cleavage-stage embryo, double and single blastocyst transfers in patients requiring whole embryo freezing. Data of infertile patients undergoing in-vitro fertilization and embryo transfer (IVF-ET) in our Reproductive Medicine Center from January 2010 to December 2012 were retrospectively analyzed. According to patients' wishes, patients were divided into cleavage-stage embryo transfer groups (group A, n = 456), double blastocyst transfer group (group B, n = 106), and single blastocyst transfer group (group C, n = 402). We found that the number of frozen embryos was significantly less in groups B and C than in group A (all p < 0.05), but the implantation rate was significantly higher in groups B and C as compared to group A (all p < 0.05). The clinical pregnancy rate and pregnancy rate per included cycle were significantly higher in group B than in groups A and C (all p < 0.05). The multiple pregnancy rate was significantly lower in group C than in groups A and B (all p < 0.05). The rate of early abortion was significantly lower in group C as compared to group A (p < 0.05). The data support the view that it may be the best clinical strategy for patients who require whole embryo freezing and have four or more Day 3 embryos available, to incubate Day 3 embryos into blastocysts, which are then vitrified for elective single blastocyst transfer.

Assisted Reproductive Technologies in Alberta: An Economic Analysis to Inform Policy Decision-Making

OBJECTIVE

Regulation and public funding of assisted reproductive technologies (ARTs) vary across the Canadian provinces. In Alberta, neither of these exists. We conducted this study to evaluate the cost effectiveness and budget impact of providing ARTs in Alberta under three different policy scenarios (a "restrictive" policy, a policy based on Quebec's model, and a "permissive" policy) in comparison with the status quo.

METHODS

To predict the cost effectiveness and budget impact of three policy options for publicly funded ARTs in Alberta, we developed an economic model by combining a state transition Markov model and a decision tree. The primary outcome was cost per healthy singleton. Probabilistic and one-way sensitivity analyses were conducted.

RESULTS

The restrictive policy was the most cost effective option for two subgroups of age (< 35 years and 35 to 39 years), while the Quebec policy option was most cost-effective for the ≥ 40 years subgroup. Budget impact analysis extending up to the age of 18 years for the children in the model showed the cost savings of $8.33 million for the restrictive policy for the < 35 years subgroup. For the ≥ 40 years subgroup, the Quebec policy option resulted in total cost savings of $3.75 million. Sensitivity analyses showed that the model results were robust.

CONCLUSION

This economic modelling study shows that publicly funded and scientifically regulated ARTs could provide treatment access and save health care expenditures for the province.

Is mandating elective single embryo transfer ethically justifiable in young women?

Compared with natural conception, IVF is an effective form of fertility treatment associated with higher rates of obstetric complications and poorer neonatal outcomes. While some increased risk is intrinsic to the infertile population requiring treatment, the practice of multiple embryo transfer contributes to these complications and outcomes, especially concerning its role in higher order pregnancies. As a result, several jurisdictions (e.g. Sweden, Belgium, Turkey, and Quebec) have legally mandated elective single-embryo transfer (eSET) for young women. We accept that in very high-risk scenarios (e.g. past history of preterm delivery and poor maternal health), double-embryo transfer (DET) should be prohibited due to unacceptably high risks. However, we argue that mandating eSET for all young women can be considered an unacceptable breach of patient autonomy, especially since DET offers certain women financial and social advantages. We also show that mandated eSET is inconsistent with other practices (e.g. ovulation induction and intrauterine insemination-ovulation induction) that can expose women and their offspring to risks associated with multiple pregnancies. While defending the option of DET for certain women, some recommendations are offered regarding IVF practice (e.g. preimplantation genetic screening and better support of IVF and maternity leave) to incentivise patients to choose eSET.

Costs of achieving live birth from assisted reproductive technology: a comparison of sequential single and double embryo transfer approaches

OBJECTIVE

To assess treatment and pregnancy/infant-associated medical costs and birth outcomes for assisted reproductive technology (ART) cycles in a subset of patients using elective double embryo (ET) and to project the difference in costs and outcomes had the cycles instead been sequential single ETs (fresh followed by frozen if the fresh ET did not result in live birth).

DESIGN

Retrospective cohort study using 2012 and 2013 data from the National ART Surveillance System.

SETTING

Infertility treatment centers.

PATIENT(S)

Fresh, autologous double ETs performed in 2012 among ART patients younger than 35 years of age with no prior ART use who cryopreserved at least one embryo.

INTERVENTION(S)

Sequential single and double ETs.

MAIN OUTCOME MEASURE(S)

Actual live birth rates and estimated ART treatment and pregnancy/infant-associated medical costs for double ET cycles started in 2012 and projected ART treatment and pregnancy/infant-associated medical costs if the double ET cycles had been performed as sequential single ETs.

RESULT(S)

The estimated total ART treatment and pregnancy/infant-associated medical costs were $580.9 million for 10,001 double ETs started in 2012. If performed as sequential single ETs, estimated costs would have decreased by $195.0 million to $386.0 million, and live birth rates would have increased from 57.7%-68.0%.

CONCLUSION(S)

Sequential single ETs, when clinically appropriate, can reduce total ART treatment and pregnancy/infant-associated medical costs by reducing multiple births without lowering live birth rates.

Reduction of multiple pregnancies in the advanced maternal age population after implementation of an elective single embryo transfer policy coupled with enhanced embryo selection: pre- and post-intervention study

STUDY QUESTION

Is an elective single-embryo transfer (eSET) policy an efficient approach for women aged >35 years when embryo selection is enhanced via blastocyst culture and preimplantation genetic screening (PGS)?

SUMMARY ANSWER

Elective SET coupled with enhanced embryo selection using PGS in women older than 35 years reduced the multiple pregnancy rates while maintaining the cumulative success rate of the IVF programme.

WHAT IS KNOWN ALREADY

Multiple pregnancies mean an increased risk of premature birth and perinatal death and occur mainly in older patients when multiple embryos are transferred to increase the chance of pregnancy. A SET policy is usually recommended in cases of good prognosis patients, but no general consensus has been reached for SET application in the advanced maternal age (AMA) population, defined as women older than 35 years. Our objective was to evaluate the results in terms of efficacy, efficiency and safety of an eSET policy coupled with increased application of blastocyst culture and PGS for this population of patients in our IVF programme.

STUDY DESIGN, SIZE, DURATION

In January 2013, a multidisciplinary intervention involving optimization of embryo selection procedure and introduction of an eSET policy in an AMA population of women was implemented. This is a retrospective 4-year (January 2010–December 2013) pre- and post-intervention analysis, including 1161 and 499 patients in the pre- and post-intervention period, respectively. The primary outcome measures were the cumulative delivery rate (DR) per oocyte retrieval cycle and multiple DR.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Surplus oocytes and/or embryos were vitrified during the entire study period. In the post-intervention period, all couples with good quality embryos and less than two previous implantation failures were offered eSET. Embryo selection was enhanced by blastocyst culture and PGS (blastocyst stage biopsy and 24-chromosomal screening). Elective SET was also applied in cryopreservation cycles.

MAIN RESULTS AND THE ROLE OF CHANCE

Patient and cycle characteristics were similar in the pre- and post-intervention groups [mean (SD) female age: 39.6 ± 2.1 and 39.4 ± 2.2 years; range 36–44] as assessed by logistic regression. A total of 1609 versus 574 oocyte retrievals, 937 versus 350 embryo warming and 138 versus 27 oocyte warming cycles were performed in the pre- and post-intervention periods, respectively, resulting in 1854 and 508 embryo transfers, respectively. In the post-intervention period, 289 cycles were blastocyst stage with (n = 182) or without PGS (n = 107). A mean (SD) number of 2.9 ± 1.1 (range 1–4) and 1.4 ± 0.8 (range 1–3) embryos were transferred pre- and post-intervention, respectively (P < 0.01) and similar cumulative clinical pregnancy rates per transfer and per cycle were obtained: 26.8, 30.9% and 29.7, 26.3%, respectively. The total DR per oocyte retrieval cycle (21.0 and 20.4% pre- and post-intervention, respectively) defined as efficacy was not affected by the intervention [odds ratio (OR) = 0.8, 95% confidence interval (CI) = 0.7–1.1; P = 0.23]. However, a significantly increased live birth rate per transferred embryo (defined as efficiency) was observed in the post-intervention group 17.0 versus 10.6% (P < 0.01). Multiple DRs decreased from 21.0 in the preintervention to 6.8% in the post-intervention group (OR = 0.3. 95% CI = 0.1–0.7; P < 0.01).

LIMITATIONS, REASONS FOR CAUTION

In this study, the suitability of SET was assessed in individual women on the basis of both clinical and embryological prognostic factors and was not standardized. For the described eSET strategy coupled with an enhanced embryo selection policy, an optimized culture system, cryopreservation and aneuploidy screening programme is necessary.

WIDER IMPLICATIONS OF THE FINDINGS

Owing to the increased maternal morbidity and perinatal complications related to multiple pregnancies, it is recommended to extend the eSET policy to the AMA population. As shown in this study, enhanced embryo selection procedures might allow a reduction in the number of embryos transferred and the number of transfers to be performed without affecting the total efficacy of the treatment but increasing efficiency and safety.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

None.

Prevention of multiple pregnancies in couples with unexplained or mild male subfertility: randomised controlled trial of in vitro fertilisation with single embryo transfer or in vitro fertilisation in modified natural cycle compared with intrauterine insemination with controlled ovarian hyperstimulation

OBJECTIVES

To compare the effectiveness of in vitro fertilisation with single embryo transfer or in vitro fertilisation in a modified natural cycle with that of intrauterine insemination with controlled ovarian hyperstimulation in terms of a healthy child.

DESIGN

Multicentre, open label, three arm, parallel group, randomised controlled non-inferiority trial.

SETTING

17 centres in the Netherlands.

PARTICIPANTS

Couples seeking fertility treatment after at least 12 months of unprotected intercourse, with the female partner aged between 18 and 38 years, an unfavourable prognosis for natural conception, and a diagnosis of unexplained or mild male subfertility.

INTERVENTIONS

Three cycles of in vitro fertilisation with single embryo transfer (plus subsequent cryocycles), six cycles of in vitro fertilisation in a modified natural cycle, or six cycles of intrauterine insemination with ovarian hyperstimulation within 12 months after randomisation.

MAIN OUTCOME MEASURES

The primary outcome was birth of a healthy child resulting from a singleton pregnancy conceived within 12 months after randomisation. Secondary outcomes were live birth, clinical pregnancy, ongoing pregnancy, multiple pregnancy, time to pregnancy, complications of pregnancy, and neonatal morbidity and mortality

RESULTS

602 couples were randomly assigned between January 2009 and February 2012; 201 were allocated to in vitro fertilisation with single embryo transfer, 194 to in vitro fertilisation in a modified natural cycle, and 207 to intrauterine insemination with controlled ovarian hyperstimulation. Birth of a healthy child occurred in 104 (52%) couples in the in vitro fertilisation with single embryo transfer group, 83 (43%) in the in vitro fertilisation in a modified natural cycle group, and 97 (47%) in the intrauterine insemination with controlled ovarian hyperstimulation group. This corresponds to a risk, relative to intrauterine insemination with ovarian hyperstimulation, of 1.10 (95% confidence interval 0.91 to 1.34) for in vitro fertilisation with single embryo transfer and 0.91 (0.73 to 1.14) for in vitro fertilisation in a modified natural cycle. These 95% confidence intervals do not extend below the predefined threshold of 0.69 for inferiority. Multiple pregnancy rates per ongoing pregnancy were 6% (7/121) after in vitro fertilisation with single embryo transfer, 5% (5/102) after in vitro fertilisation in a modified natural cycle, and 7% (8/119) after intrauterine insemination with ovarian hyperstimulation (one sided P=0.52 for in vitro fertilisation with single embryo transfer compared with intrauterine insemination with ovarian hyperstimulation; one sided P=0.33 for in vitro fertilisation in a modified natural cycle compared with intrauterine insemination with controlled ovarian hyperstimulation).

CONCLUSIONS

In vitro fertilisation with single embryo transfer and in vitro fertilisation in a modified natural cycle were non-inferior to intrauterine insemination with controlled ovarian hyperstimulation in terms of the birth of a healthy child and showed comparable, low multiple pregnancy rates.Trial registration Current Controlled Trials ISRCTN52843371; Nederlands Trial Register NTR939.

Status of sperm morphology assessment: an evaluation of methodology and clinical value

OBJECTIVE

To characterize methodological changes in sperm morphology assessment and to correlate sperm morphology with clinical outcome.

DESIGN

In this observational study, sperm morphology profiles of patients were analyzed. The percentages of morphologically normal spermatozoa were evaluated with respect to changes in morphology assessment criteria; male aging; and prognostic value for outcomes after in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI).

SETTING

Diagnostic and clinical laboratories.

PATIENT(S)

A total of 8,846 men who visited the diagnostic laboratory; 133 samples from a sperm bank; and 3,676 IVF/ICSI couples.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The percentage of morphologically normal spermatozoa in semen samples. The regression of the individual morphologically normal cell profiles. The relation between the percentage of normal forms with pregnancy outcome after IVF/ICSI.

RESULT(S)

The percentage of morphologically normal spermatozoa showed a decrease from roughly 30%-80% in 1984 to 0%-10% since 2004. With added evidence from sperm bank samples, this decrease was found to be attributable mainly to changes in morphology assessment criteria. Furthermore, an intraindividual aging effect of 0.51% per year was observed. A statistically significant relationship was found between decreases in percentage of normal forms and a lower probability of ongoing pregnancies after IVF, although the area under the curve was only 54%.

CONCLUSION(S)

Methodological changes had a strong effect on the percentage of morphologically normal spermatozoa over the past few decades. In addition, male aging results in decreasing sperm morphology. The percentage of morphologically normal spermatozoa has no prognostic value for individual IVF/ICSI patients.

The economic implications of multiple pregnancy following ART

The clinical risks to mothers and babies associated with assisted reproductive technology (ART) multiple birth pregnancies are well described and widely recognized. In contrast, the long-term economic consequences that follow are less appreciated. The few economic analyses that do exist consistently demonstrate the greater patient, healthcare and societal costs associated with twins and higher-order multiples when compared with singleton infants, and convincingly add to the argument that single embryo transfer should be standard practice in most patient groups. Several recent studies have shown that the relative price paid by patients for ART treatment not only has implications for who can afford to access treatment, but also plays an important role in incentivizing embryo transfer practices and thus ART multiple birth rates. This review summarizes the current literature on the costs and consequences of ART multiple births, the contribution of ART multiple births to the economic burden associated with preterm birth, the evidence for the cost-effectiveness of single embryo transfer, and the association between the cost of treatment and the downstream costs associated with multiple births.

The impact of consumer affordability on access to assisted reproductive technologies and embryo transfer practices: an international analysis

OBJECTIVE

To systematically quantify the impact of consumer cost on assisted reproduction technology (ART) utilization and numbers of embryos transferred.

DESIGN

Ordinary least squared (OLS) regression models were constructed to measure the independent impact of ART affordability-measured as consumer cost relative to average disposable income-on ART utilization and embryo transfer practices.

SETTING

Not applicable.

PATIENT(S)

Women undergoing ART treatment.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

OLS regression coefficient for ART affordability, which estimates the independent effect of consumer cost relative to income on utilization and number of embryos transferred.

RESULT(S)

ART affordability was independently and positively associated with ART utilization with a mean OLS coefficient of 0.032. This indicates that, on average, a decrease in the cost of a cycle of 1 percentage point of disposable income predicts a 3.2% increase in utilization. ART affordability was independently and negatively associated with the number of embryos transferred, indicating that a decrease in the cost of a cycle of 10 percentage points of disposable income predicts a 5.1% increase in single-embryo transfer cycles.

CONCLUSION(S)

The relative cost that consumers pay for ART treatment predicts the level of access and number of embryos transferred. Policies that affect ART funding should be informed by these findings to ensure equitable access to treatment and clinically responsible embryo transfer practices.

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

BACKGROUND

Multiple embryo transfer during in vitro fertilisation (IVF) increases multiple pregnancy rates causing maternal and perinatal morbidity. Single embryo transfer is now being seriously considered as a means of minimising the risk of multiple pregnancy. However, this needs to be balanced against the risk of jeopardising the overall live birth rate.

OBJECTIVES

To evaluate the effectiveness and safety of different policies for the number of embryos transferred in couples who undergo assisted reproductive technology (ART).

SEARCH METHODS

We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE, from inception to July 2013. We handsearched reference lists of articles, trial registers and relevant conference proceedings and contacted researchers in the field.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing different policies for the number of embryos transferred following IVF or intra-cytoplasmic sperm injection (ICSI) in subfertile women. Studies of fresh or frozen and thawed transfer of one, two, three or four embryos at cleavage or blastocyst stage were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias and extracted the data. The overall quality of the evidence was graded in a summary of findings table.

MAIN RESULTS

Fourteen RCTs were included in the review (2165 women). Thirteen compared cleavage-stage transfers (2017 women) and two compared blastocyst transfers (148 women): one study compared both. No studies compared repeated multiple versus repeated single embryo transfer (SET). DET versus repeated SETDET was compared with repeated SET in three studies of cleavage-stage transfer. In these studies the SET group received either two cycles of fresh SET (one study) or one cycle of fresh SET followed by one frozen SET in a natural or hormone-stimulated cycle (two studies). When these three studies were pooled, the cumulative live birth rate after one cycle of DET was not significantly different from the rate after repeated SET (OR 1.22, 95% CI 0.92 to 1.62, three studies, n=811, I(2)=0%, low quality evidence). This suggests that for a woman with a 40% chance of live birth following a single cycle of DET, the chance following repeated SET would be between 30% and 42%. The multiple pregnancy rate was significantly higher in the DET group (OR 30.54, 95% CI 7.46 to 124.95, three RCTs, n = 811, I(2) = 23%, low quality evidence), suggesting that for a woman with a 15% risk of multiple pregnancy following a single cycle of DET, the risk following repeated SET would be between 0% and 2%. Single-cycle DET versus single-cycle SETA single cycle of DET was compared with a single cycle of SET in 10 studies, nine comparing cleavage-stage transfers and two comparing blastocyst-stage transfers. When all studies were pooled the live birth rate was significantly higher in the DET group (OR 2.07, 95% CI 1.68 to 2.57, nine studies, n = 1564, I(2) = 0%, high quality evidence). This suggests that for a woman with a 40% chance of live birth following a single cycle of DET, the chance following a single cycle of SET would be between 22% and 30%. The multiple pregnancy rate was also significantly higher in the DET group (OR 8.47, 95% CI 4.97 to 14.43, 10 studies, n = 1612, I(2) = 45%, high quality evidence), suggesting that for a woman with a 15% risk of multiple pregnancy following a single cycle of DET, the risk following a single cycle of SET would be between 1% and 4%. The heterogeneity for this analysis was attributable to a study with a high rate of cross-over between treatment arms. Other comparisons Other fresh cycle comparisons were evaluated in three studies which compared DET versus transfer of three or four embryos. Live birth rates did not differ significantly between the groups for any comparison, but there was a significantly lower multiple pregnancy rate in the DET group than in the three embryo transfer (TET) group (OR 0.36, 95% CI 0.13 to 0.99, two studies, n = 343, I(2) = 0%).

AUTHORS' CONCLUSIONS

In a single fresh IVF cycle, single embryo transfer is associated with a lower live birth rate than double embryo transfer. However, there is no evidence of a significant difference in the cumulative live birth rate when a single cycle of double embryo transfer is compared with repeated SET (either two cycles of fresh SET or one cycle of fresh SET followed by one frozen SET in a natural or hormone-stimulated cycle). Single embryo transfer is associated with much lower rates of multiple pregnancy than other embryo transfer policies. A policy of repeated SET may minimise the risk of multiple pregnancy in couples undergoing ART without substantially reducing the likelihood of achieving a live birth. Most of the evidence currently available concerns younger women with a good prognosis.

The paediatric consequences of Assisted Reproductive Technologies, with special emphasis on multiple pregnancies

Paediatricians will encounter many babies and children who are the result of assisted reproductive technologies. Although in most cases, there are no adverse health consequences, assisted reproductive technologies (ART) are associated with some risks that are reviewed in this article.

CONCLUSION

ART has had a major impact on multiple gestation and the incidence of prematurity in many countries. Among singletons, there are also increases in prematurity, small for gestational age, congenital anomalies and perinatal mortality.

[Reduction of multiple pregnancies in ART with large SET procedures over the period 2001-2010]

OBJECTIVE

To evaluate delivery rate and multiple pregnancy rates in ART (assisted reproductive techniques) following introduction of an elective single embryo tranfer (eSET) policy. This strategy was started in 2002 including transfer of one embryo for women less than 35 years with a least two good quality embryo during their first or second attempts.

PATIENTS AND METHODS

Retrospective study including all IVF cycles performed in the IVF centre of Clermont-Ferrand University Hospital from 01/01/2001 to 31/12/2010. Main outcome measures were number of embryos transferred, cumulative delivery and multiple pregnancy rates (including fresh and frozen embryo transfers). A subgroup analysis including patients' age was done.

RESULTS

Cumulative delivery rate reached 27,3% in 2010 with a significant drop in multiple pregnancy rate: from 30% in 2001 to 7,9% in 2010. The average number of transferred embryo decreased from 2.29 to 1.55 in the same period. In our centre, eSET was performed in 85% of first IVF attempt and in 34,4% of second attempts for women less than 35 years.

CONCLUSION

The implementation of an eSET policy does not change the delivery rate but significantly decrease the number of multiple pregnancies compared to double embryo transfer. eSET should be carried out during the 1st and 2nd attempts in patients under 35 years when at least two good quality embryos were obtained.

Reducing multiples: a mathematical formula that accurately predicts rates of singletons, twins, and higher-order multiples in women undergoing in vitro fertilization

OBJECTIVE

To develop a mathematical formula that accurately predicts the probability of a singleton, twin, and higher-order multiple pregnancy according to implantation rate and number of embryos transferred.

DESIGN

A total of 12,003 IVF cycles from a single center resulting in ET were analyzed. Using mathematical modeling we developed a formula, the Combined Formula, and tested for the ability of this formula to accurately predict outcomes.

SETTING

Academic hospital.

PATIENT(S)

Patients undergoing IVF.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Goodness of fit of data from our center and previously published data to the Combined Formula and three previous mathematical models.

RESULT(S)

The Combined Formula predicted the probability of singleton, twin, and higher-order pregnancies more accurately than three previous formulas (1.4% vs. 2.88%, 4.02%, and 5%, respectively) and accurately predicted outcomes from five previously published studies from other centers. An online applet is provided (https://secure.ivf.org/ivf-calculator.html).

CONCLUSION(S)

The probability of pregnancy with singletons, twins, and higher-order multiples according to number of embryos transferred is predictable and not random and can be accurately modeled using the Combined Formula. The embryo itself is the major predictor of pregnancy outcomes, but there is an influence from "barriers," such as the endometrium and collaboration between embryos (embryo-embryo interaction). This model can be used to guide the decision regarding number of embryos to transfer after IVF.

Clinical factors associated with live birth after single embryo transfer

OBJECTIVE

To identify patient, cycle, and retrieval characteristics associated with embryo implantation and live birth in patients undergoing single embryo transfer (SET).

DESIGN

Analysis of prospectively collected IVF database.

SETTING

Academic IVF program.

PATIENT(S)

All patient cycles meeting criteria for SET between June 2004 and September 2010.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy and live birth.

RESULT(S)

Single embryo transfer was performed in 438 cycles, resulting in a clinical pregnancy rate of 76.2% and a live birth rate of 66.8% per transfer. Clinical pregnancy was associated with younger female age, ≥ 58% mature (metaphase II) oocytes at the time of retrieval, and increasing blastocyst expansion. Ongoing pregnancy was associated with younger female age and more advanced blastocysts. A diagnosis of uterine factor was negatively associated with live birth.

CONCLUSION(S)

Even in a favorable prognosis population, younger female age is associated with clinical pregnancy and live birth. Although all patients underwent blastocyst transfer, expanded and hatching blastocysts were strongly associated with pregnancy and live birth. A diagnosis of uterine factor was the only infertility diagnosis found to affect live birth after SET. Obesity did not negatively affect SET outcome. These findings may assist physicians in determining the best candidates for SET.

Comparable clinical outcomes and live births after single vitrified-warmed and fresh blastocyst transfer

Selective single-blastocyst transfer (SBT) in fresh cycles has been effective in reducing multiple pregnancies. However, we do not know whether this successful strategy of fresh transfer cycles is suitable for cryopreserved cycles. The present study was undertaken to evaluate the feasibility and value of SBT in vitrified-warmed cycles. Clinical pregnancy rate (CPR) was similar with vitrified and fresh SBT (46.61% versus 52.15% respectively). Of the pregnant patients, monozygotic twin, miscarriage and ectopic pregnancy rates were similar with vitrified and fresh SBT. For the newborns, no significant difference was observed in live birth, low birthweight, premature delivery and birth defects rates between vitrified and fresh SBT. With respect to the quality of transferred blastocysts (from BB to AA), a similar CPR and miscarriage rate was obtained for both vitrified and fresh SBT when a similar blastocyst cohort graded ≥ 3BB was transferred. The data show that vitrified SBT is an effective means of reducing multiple pregnancy and that comparable clinical outcomes and live births are achieved if single blastocysts graded ≥ 3BB are transferred for both vitrified and fresh SBT. These data should encourage clinics to evaluate their embryo transfer policy and adopt vitrified SBT as everyday practice. Selective single-blastocyst transfer in fresh cycles has been an effective method to reduce the multiple pregnancies. However, due to a lack of adequate studies, we do not know whether this successful strategy in fresh transfer cycles is suitable in cryopreserved cycles. The present study was undertaken to explore the feasibility and value of single-blastocyst transfer in vitrified-warmed cycles. We found that single-blastocyst transfer in vitrified-warmed cycles is an effective means of reducing multiple pregnancy, and comparable clinical outcomes and live births were achieved if single blastocysts graded ≥ 3BB were transferred for both vitrified-warmed and fresh blastocyst transfer. These data should encourage clinics to evaluate their embryo transfer policy and adopt single-blastocyst transfer in cryopreserved cycles as their everyday practice.