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

Transfer of more than two embryos, regardless of the age of the female partner, is not beneficial for neither the mothers nor the babies: lessons from the Latin American Registry of Assisted Reproductive Techniques

Objective

ART has helped millions of infertile couples worldwide to overcome their childlessness. These successes have been accompanied by an increase in multiple deliveries, and perinatal complications associated. The explanation for this complication is the transfer of more than one embryo, to increase the odds of delivery. Our objective was to compare the outcome of elective dual embryo transfer (eDET) to that of the transfer of more than two embryos without embryo cryopreservation (TET), terms of delivery rate and multiple delivery.

Methods

We analyzed the data registered by 155 clinics members of the RLA: 11,024 eDET and 10,634 TET.

Results

The delivery rate was significantly higher when eDET was performed than when TET was performed (40.24% and 26.98%, p < 0.001). Also, the ratio of twin deliveries was higher in eDET (25.80% and 20.56%, p < 0.001). However, the ratio of triplets and more deliveries was higher in TET than in eDET (2.34%and 0.52%, p < 0.001). These findings were consistent across the different age categories of the female partner.

Conclusion

Our findings suggest that eDET was associated with a statistically significant better delivery rate per embryo transfer, and lower ratio of triplet-and-higher deliveries, regardless of the woman’s age. Therefore, there is no evidence that supports the transfer of more than two embryos.

Increasing The Number of Embryos Transferred from Two to Three, Does not Increase Pregnancy Rates in Good Prognosis Patients

BACKGROUND

To compare the pregnancy outcomes after two embryos versus three embryos transfers (ETs) in women undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles.

MATERIALS AND METHODS

This retrospective study was performed on three hundred eighty seven women with primary infertility and with at least one fresh embryo in good quality in order to transfer at each IVF/ICSI cycle, from September 2006 to June 2010. Patients were categorized into two groups according to the number of ET as follows: ET2 and ET3 groups, indicating two and three embryos were respectively transferred. Pregnancy outcomes were compared between ET2 and ET3 groups. Chi square and student t tests were used for data analysis.

RESULTS

Clinical pregnancy and live birth rates were similar between two groups. The rates of multiple pregnancies were 27 and 45.2% in ET2 and ET3 groups, respectively. The rate of multiple pregnancies in young women was significantly increased when triple instead of double embryos were transferred. Logistic regression analysis indicated two significant prognostic variables for live birth that included number and quality of transferred embryos; it means that the chance of live birth following ICSI treatment increased 3.2-fold when the embryo with top quality (grade A) was transferred, but the number of ET had an inverse relationship with live birth rate; it means that probability of live birth in women with transfer of two embryos was three times greater than those who had three ET.

CONCLUSION

Due to the difficulty of implementation of the elective single-ET technique in some infertility centers in the world, we suggest transfer of double instead of triple embryos when at least one good quality embryo is available for transfer in women aged 39 years or younger. However, to reduce the rate of multiple pregnancies, it is recommended to consider the elective single ET strategy.

Epidemiology of multiple pregnancy and the effect of assisted conception

Multiple pregnancy is one of the greatest perinatal challenges facing clinicians today. In a society of rising expectations among fertility and maternity service users, the potential for adverse outcomes associated with multiple pregnancy is a source of concern. This article examines the impact of assisted conception on the incidence of multiple pregnancies and associated complications. It explores some of the reasons for the strong association between assisted reproductive technology and multiple pregnancies and suggests possible ways of addressing this continuing problem.

Individual patient data meta-analysis: a promising approach for evidence synthesis in reproductive medicine

Systematic reviews and accompanying meta-analyses are the cornerstones of evidence-based medicine. Systematic reviews summarize clinical evidence; meta-analyses provide summary estimates of the treatment effect or the diagnostic test accuracy. Although deemed to provide the highest level of evidence, their clinical value is limited as they can only summarize aggregated data. In these meta-analyses the true variability of the treatment effects cannot be explored to the desired extent, because the meta-analyses cannot distinguish between patients with different clinical profiles. Systematic reviews and meta-analyses based on individual patient data (IPD), described as the 'gold standard' for systematic reviews are a promising approach that might overcome these limitations. IPD meta-analyses allow treatment effects and diagnostic accuracy to be estimated at the level of relevant patient subgroups. This enables researchers to investigate the effectiveness of treatment in patients with different profiles. In this article, we address the opportunities of systematic reviews and meta-analyses using IPD in reproductive medicine. We discuss its potential based on three clinical examples: single versus double embryo transfer in IVF, the diagnosis of tubal pathology and the prognostic value of ovarian reserve tests. We propose to show potential advantages of IPD systematic reviews and meta-analyses in providing stratified clinical evidence, which could improve medical care.

Vitrification with DMSO protects embryo membrane integrity better than solutions without DMSO

Vitrification has become common for cryopreservation of embryos. However, the most optimal protocol for vitrification is still to be found. Two vitrification protocols with similar osmolarities were compared: Protocol A, containing dimethyl sulphoxide (DMSO), propane-2-diol, and ethylene glycol, and Protocol B, containing propane-2-diol and ethylene glycol. Viability and the importance of specific incubation times for early embryo recovery, survival, and cleavage were studied. For assessment of cryodamage, embryos were labelled with Alexa Fluor 488-conjugated annexin V and propidium iodide. Vitrification studies on early mouse embryos were followed up with studies on human embryos. The two vitrification protocols did not differ in embryo survival rates and were equally efficient in both mouse and human embryo models. Morphological assessment of embryos directly after vitrification was not a useful tool for assessing survival in this study. Extended exposure of embryos with both vitrification protocols showed that the DMSO-containing vitrification solutions did not lead to cell membrane damage and death as quickly as the DMSO-free vitrification solutions. To assess embryo viability, the authors recommend that vitrification of early embryos should be combined with extended culture and assessment of normal blastocyst development before transferring to patients.

Infertility, assisted reproductive technology, and adverse pregnancy outcomes: executive summary of a National Institute of Child Health and Human Development workshop

The National Institute of Child Health and Human Development held a workshop on September 12-13, 2005, to summarize the risks for adverse pregnancy outcomes after assisted reproductive technology (ART), develop an approach to counseling couples regarding these risks, and establish a research agenda. Although the majority of ART children are normal, there are concerns about the increased risk for adverse pregnancy outcomes. More than 30% of ART pregnancies are twins or higher-order multiple gestations (triplets or greater) and more than one half of all ART neonates are the products of multifetal gestations, with an attendant increase in prematurity complications. Assisted reproductive technology singleton pregnancies also demonstrate increased rates of perinatal complications-small for gestational age infants, preterm delivery, and perinatal mortality-as well as maternal complications, such as preeclampsia, gestational diabetes, placenta previa, placental abruption, and cesarean delivery. Although it is not possible to separate ART-related risks from those secondary to the underlying reproductive pathology, the overall increased frequency of obstetric complications, including preterm birth and small for gestational age neonates, should be discussed with the couple. Significant gaps in knowledge were identified, and the basic science and clinical and epidemiologic research required to address these gaps is outlined.

Cerebral palsy among children born after in vitro fertilization: the role of preterm delivery--a population-based, cohort study

OBJECTIVE

Our aim was to assess the incidence of cerebral palsy among children conceived with in vitro fertilization and children conceived without in vitro fertilization.

METHODS

A population-based, cohort study, including all live-born singletons and twins born in Denmark between January 1, 1995, and December 31, 2000, was performed. Children conceived with in vitro fertilization (9255 children) were identified through the In Vitro Fertilization Register; children conceived without in vitro fertilization (394,713) were identified through the Danish Medical Birth Register. Cerebral palsy diagnoses were obtained from the National Register of Hospital Discharges. The main outcome measure was the incidence of cerebral palsy in the in vitro fertilization and non-in vitro fertilization groups.

RESULTS

Children born after in vitro fertilization had an increased risk of cerebral palsy; these results were largely unchanged after adjustment for maternal age, gender, parity, small-for-gestational age status, and educational level. The independent effect of in vitro fertilization vanished after additional adjustment for multiplicity or preterm delivery. When both multiplicity and preterm delivery were included in the multivariate models, preterm delivery remained associated strongly with the risk of cerebral palsy.

CONCLUSIONS

The large proportions of preterm deliveries with in vitro fertilization, primarily for twins but also for singletons, pose an increased risk of cerebral palsy.

Day 2 transfer improves pregnancy outcome in in vitro fertilization cycles with few available embryos

OBJECTIVE

Delaying ET to day 3 to optimize embryo selection is well accepted. However, in cases where there are not enough embryos to perform selection, it is not clear whether there is a difference in clinical outcomes with the day of ET.

DESIGN

Cohort study.

SETTING

Academic medical center.

PATIENT(S)

Two hundred forty-two fresh IVF/intracytoplasmic sperm injection (ICSI) cycles from 2002-2004, where all generated embryos were transferred irrespective of quality because of an extremely low number of available embryos.

INTERVENTION(S)

In time period 1, ET was on day 3. In time period 2, ET was on day 2.

MAIN OUTCOME MEASURE(S)

Patient response to stimulation was analyzed along with pregnancy outcome and implantation rate.

RESULT(S)

Miscarriage rates were decreased, and ongoing pregnancy rates were increased with a day 2 ET in patients <40 years of age.

CONCLUSION(S)

In women <40 years of age, the day of transfer is a significant predictor of clinical outcome in cases in which a low number of embryos are available for transfer. The evidence suggests that limiting embryo culture to only 2 days reduces the incidence of miscarriage and increases ongoing pregnancy rates.

Embryo transfer: factors involved in optimizing the success

PURPOSE OF REVIEW

Embryo transfer is arguably the most critical step in assisted reproduction. The purpose of this article is to review the different aspects of the procedure in the light of recent evidence.

RECENT FINDINGS

Randomized trials have shown that significantly higher pregnancy rates are obtained when embryo transfer is performed under ultrasound guidance, the embryos are deposited in the middle part of the uterine cavity, an atraumatic technique is used and when low-dose aspirin is routinely administered following the procedure. Blood in the catheter and leaving the embryos inside it for more than 120 s diminish the pregnancy rate significantly. Air in the catheter, immediate removal of the catheter, performing two transfers in the same cycle, prolonged bed rest, sexual intercourse after embryo transfer or the use of sildenafil do not affect the results. Based on currently available evidence, Cochrane reviews have concluded that the live birth rate is not increased by delaying embryo transfer from day two to three or to the blastocyst stage, and that single embryo transfer leads to lower live birth rates than the transfer of two embryos. The value of a mock transfer a few days before the actual procedure has been challenged as the position of the uterus may change. The effect of holding the cervix with a volsellum, routinely administering antibiotics and the superiority of one catheter over the others is still to be determined.

SUMMARY

Recent studies confirm the importance of the various aspects of embryo transfer. More randomized studies are needed to further evaluate them.

Evidence-based care of women with a multiple pregnancy

Women with a multiple pregnancy face greater risks for themselves and their infants than women pregnant with one child. Pre-pregnancy care should focus on avoiding multiple pregnancy. Early prenatal care centres on determining chorionicity and screening for fetal anomalies, with later care focusing on the presentation, prediction and management of preterm birth, and intrauterine growth restriction. The optimal timing and mode of birth are the focus of current multicentre, randomised, controlled trials. However, the data from such trials on care for women with a multiple pregnancy are limited. Many areas of care require better-quality information, including when using assisted reproductive techniques, the optimal number of embryos to be transferred, care after the diagnosis of chorionicity, and the benefits of specialised multiple pregnancy clinics. Better-quality information is required to inform clinical practice for women with complications of multiple pregnancy, including monoamniotic twin pregnancy, treatment of twin-to-twin transfusion syndrome, and care following single intrauterine fetal death.