Pregnancy outcomes in a university hospital after legal requirement for single-embryo transfer

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.

Time lapse microscopy is useful for elective single-embryo transfer

The aim of our study was to evaluate time lapse microscopy (TLM) as a selection tool for single-embryo transfer (SET) on day 5, blastocyst stage. An observational cohort study was conducted. Patients who had SET were compared to patients who had double embryo transfer (DET). A total of 108 patients were included in analysis, 83 had SET, and 25 underwent DET. Embryos were incubated and evaluated using TLM. The pregnancy rates were similar between the groups (42.2% in SET and 48.0% in DET). However, the multiple pregnancy rate was significantly higher in the DET group compared to the SET group (41.7% versus 2.9%, respectively; p < 0.001). This study concludes that SET with TLM do not decrease pregnancy rates compared to DET. However, transfers of two embryos increase the rate of multiple pregnancies.

Elective single embryo transfer- the power of one

Despite the highest historical live birth success rates for couples undergoing in vitro fertilization (IVF), there has been an epidemic of iatrogenic twin and higher order gestation conceived from this treatment. Continued improvement in cryopreservation techniques have allowed preservation of supernumerary embryos for use in future cycles, and refinements in culture systems and embryo selection have resulted in the transfer of fewer embryos while maintaining favorable pregnancy rates. The voluntary transfer of a single high quality embryo, elective single embryo transfer (eSET), has significantly reduced multiple gestation rates and maximized the rate of singleton pregnancy without compromising overall success rates. Although eSET is the standard of care in several developed countries, utilization in the United States has been slow. States with mandated IVF insurance have seen decreases in preterm birth rates yielding down stream health care savings. Herein, the evolution and future applications of this practice to reduce the risk of iatrogenic twins is reviewed.

Obstetric outcome and incidence of congenital anomalies in 2351 IVF/ICSI babies

PURPOSE

The aim of this study was to provide a comprehensive follow-up of fetal and perinatal outcome and the incidence of congenital anomalies in babies born after fresh embryo transfers compared to those conceived spontaneously in infertile couples.

METHODS

Retrospective comparative analysis of all clinical pregnancies from fresh cleavage-stage embryo transfer cycles (IVF and ICSI) compared with infertile patients who conceived spontaneously in the same time period (control). Congenital anomalies were classified following the European Surveillance of Congenital Anomalies (EUROCAT) classification.

RESULTS

A total of 2414 assisted reproductive technology (ART) pregnancies were compared to 582 spontaneous conceptions in the control infertile group representing 2306 deliveries. No significant differences were found in pregnancy outcome between the two groups (delivery rate, abortion rate, ectopic pregnancies, medical abortions for fetal anomalies, single and twins mean gestational age, and weight at delivery). A significant difference (p < 0.001) was found in the twin (21.3 vs 2.3 %) and triplet rates (2.3 vs 0 %). A total of 2351 babies were delivered in the ART group and 449 in the control group. A total of 90 babies (3.8 %) were diagnosed with a major congenital anomaly in the ART group and 15 (3.3 %) in the control group (p = ns). The overall rate of major congenital anomalies (105/2800) in ART and spontaneous pregnancies in infertile couples was significantly higher when compared to the EUROCAT 2.0 versus 3.75 % (p = 0.0002).

DISCUSSION

Babies born after ART treatments and from spontaneous conception in infertile couples had rates of congenital anomalies higher than those recorded by the EUROCAT. However, the rates of anomalies were not different within the infertile population whether conceived by ART or spontaneously. These data suggest that the diagnosis of infertility in itself is the common denominator for the increase in the rates of anomalies seen in both ART and spontaneous conceptions.

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.

Preliminary trials of a specific gravity technique in the determination of early embryo growth potential†

STUDY QUESTION

Can a modified specific gravity technique be used to distinguish viable from nonviable embryos?

SUMMARY ANSWER

Preliminary data suggests a modified specific gravity technique can be used to determine embryo viability and potential for future development.

WHAT IS KNOWN ALREADY

Single embryo transfer (SET) is fast becoming the standard of practice. However, there is currently no reliable method to ensure development of the embryo transferred.

STUDY DESIGN, SIZE, DURATION

A preliminary, animal-based in vitro study of specific gravity as a predictor of embryo development using a mouse model.

PARTICIPANTS/MATERIALS, SETTING, METHODS

After a brief study to demonstrate embryo recovery, experiments were conducted to assess the ability of the specific gravity system (SGS) to distinguish between viable and nonviable embryos. In the first study, 1-cell mouse embryos were exposed to the SGS with or without previous exposure to an extreme heat source (60°C); measurements were repeated daily for 5 days. In the second experiment, larger pools of 1-cell embryos were either placed directly in culture or passed through the SGS and then placed in culture and monitored for 4 days.

MAIN RESULTS AND THE ROLE OF CHANCE

In the first experiment, viable embryos demonstrated a predictable pattern of descent time over the first 48 h of development (similar to previous experience with the SGS), while embryos that were heat killed demonstrated significantly altered drop patterns (P < 0.001); first descending faster. In the second experiment, average descent times were different for embryos that stalled early versus those that developed to blastocyst (P < 0.001). Interestingly, more embryos dropped through the SGS developed to blastocyst than the culture control (P < 0.01).

LIMITATIONS, REASONS FOR CAUTION

As this is a preliminary report of the SGS technology determining viability, a larger embryo population will be needed. Further, the current in vitro study will need to be followed by fecundity studies prior to application to a human population.

WIDER IMPLICATIONS OF THE FINDINGS

If proven, the SGS would provide a noninvasive means of assessing embryos prior to transfer after assisted reproductive technologies procedures, thereby improving fecundity and allowing more reliable SET.

STUDY FUNDING/COMPETING INTERESTS

The authors gratefully acknowledge the funding support of the U.S. Jersey Association, the Laura W. Bush Institute for Women's Health and a Howard Hughes Medical Institute grant through the Undergraduate Science Education Program to Texas Tech University. None of the authors have any conflict of interest regarding this work.

TRIAL REGISTRATION NUMBER

none.

Infertility care and the introduction of new reproductive technologies in poor resource settings

BACKGROUND

The overall prevalence of infertility was estimated to be 3.5-16.7% in developing countries and 6.9-9.3% in developed countries. Furthermore, according to reports from some regions of sub-Saharan Africa, the prevalence rate is 30-40%. The consequences of infertility and how it affects the lives of women in poor-resource settings, particularly in developing countries, has become an important issue to be discussed in reproductive health. In some societies, the inability to fulfill the desire to have children makes life difficult for the infertile couple. In many regions, infertility is considered a tragedy that affects not only the infertile couple or woman, but the entire family.

METHODS

This is a position paper which encompasses a review of the needs of low-income infertile couples, mainly those living in developing countries, regarding access to infertility care, including ART and initiatives to provide ART at low or affordable cost. Information was gathered from the databases MEDLINE, CENTRAL, POPLINE, EMBASE, LILACS, and ICTRP with the key words: infertility, low income, assisted reproductive technologies, affordable cost, low cost.

RESULTS

There are few initiatives geared toward implementing ART procedures at low cost or at least at affordable cost in low-income populations. Nevertheless, from recent studies, possibilities have emerged for new low-cost initiatives that can help millions of couples to achieve the desire of having a biological child.

CONCLUSIONS

It is necessary for healthcare professionals and policymakers to take into account these new initiatives in order to implement ART in resource-constrained settings.