Elective single-embryo transfer improves cumulative pregnancy outcome in young patients but not in women of advanced reproductive age

Single versus double blastocyst transfer in first and second frozen-thawed embryo transfer cycle in advance-aged women: a two-center retrospective cohort study

BACKGROUND

The present evidence is deficient for the trade-offs between the pros and cons of single blastocyst transfer (SBT) versus double blastocyst transfer (DBT) in frozen-thawed embryo transfer cycles for women in advanced reproductive age, especially in the second cycle. The current study aimed to investigate the impact of transferred blastocyst numbers on pregnancy outcomes in the first and second embryo transfer for women ≥ 35 years.

METHODS

This was a retrospective cohort study including 1284 frozen-thawed blastocyst transfer (FBT) cycles from two reproductive centers. We analyzed the pregnancy outcomes after SBT and DBT in the first and second FBT cycles. Moreover, stratified analysis was conducted by maternal age.

RESULTS

In the first FBT cycle, the LBR was higher in the DBT group than that in the SBT group [52.3% vs. 33.9%; adjusted odds ratio (aOR), 1.65; 95% confidence interval (CI), 1.26-2.15, P < 0.001]. However, the LBR of the DBT group showed no remarkable difference compared with that of the SBT group in the second cycle of FBT (44.3% vs. 33.3%; aOR, 1.30; 95% CI, 0.81-2.08; P = 0.271). Furthermore, stratified analysis by age showed a higher LBR for the DBT group than the SBT group in patients aged 38-42 years (43.1% vs. 33.9%; aOR, 2.27; 95% CI, 1.05-4.90; P = 0.036).

CONCLUSIONS

The present study demonstrated that the SBT regimen is a better choice for both, the first and second frozen-thawed embryo transfer cycles, for women aged 35-37 years. Additionally, the DBT regimen is still recommended to achieve a high LBR in women aged 38-42 years in the second FBT cycle. These findings may be beneficial for deciding the embryo transfer regimens in women of advanced reproductive age.

Blastocyst Transplantation Strategies in Women of Different Ages

(1) Background: Single blastocyst transfers (SBT) and double blastocyst transfers (DBT) are widely used in clinical practice. The objective of this study was to investigate the application of these two strategies in women of different ages. (2) Methods: Analysis was carried out on 5477 frozen embryo transfer cycles of women in different ages. All the cycles were divided into three groups according to the age of the included women: <35, 35-39, and >39. The live birth rate (LBR) and multiple birth rate (MBR) between the SBT and DBT among these groups, respectively, were compared. (3) Results: In the women < 35 group, the LBR was similar in SBT and DBT, but the MBR was higher in DBT than SBT. In women 35-39, with >10 oocytes retrieved, the MBR in DBT was significantly higher than SBT, but there was no significant difference in LBR between the two groups; with ≤10 oocytes retrieved, the LBR in DBT were significantly higher than SBT, but the MBT was not significantly different between the two groups. In women > 39, the LBR and MBR were lower in the SBT than DBT, but the differences were not statistically significant. (4) Conclusions: Selective SET is appropriate for most young women, whereas older women are advised to make individualized choices based on the number of oocytes retrieved and blastocyst quality.

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.

Outcomes After a Single Ovarian Stimulation Cycle in Women of Advanced Reproductive Age: A Retrospective Analysis

OBJECTIVES

Previous studies showed that age is the most important factor that determines the outcome after embryo transfer (ET), with either in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI), regardless whether fresh or frozen cycles. The average cumulative live birth rate (CLBR) following a single ovarian stimulation cycle in women of advanced reproductive age (≥38 years of age) has been reported to be 22.6-34.1%. The purpose of this study is to compare the CLBR after a single ovarian stimulation cycle in women of different advanced reproductive age bracket (38/39, 40/41, 42/43 years of age or older), and to explore the factors (e.g., age, type of infertility, body mass index (BMI), ovarian stimulation protocols) associated with CLBR.

METHODS

This retrospective analysis included all women of advanced reproductive age (38 years or older) undergoing IVF or ICSI at authors' institute during a period from January 1, 2016 to December 31, 2018. The study protocol was approved by the Ethics Committee of the Second Hospital of Hebei Medical University (No. 2021-P045). Subjects with underlying diseases were excluded from analysis. The last follow-up was conducted in December 2020, with minimal 2-year follow-up.

RESULTS

The final analysis included 826 women (40.00 ± 2.10 years of age at the time of ovarian stimulation; n = 633 and 193 for IVF-ET and ICSI-ET, respectively). The number of women in each age bracket was: 424 for 38/39 y, 226 for 40/41 y, 118 for 42/43 y, and 58 for ≥44 y. The number of transferable embryos was 2 (interquartile range: 2,4) for 38/39 y, 2 (2,3) for 40/41 y, 2 (2,3) for 42/43 y, and 2 (1.75,3) for ≥44 y. The rate of fresh embryo transfer was comparable (62.03-72.58%) among the 4 age brackets. The average CLBR following a single cycle was 26.27% in the overall study population, 32.31% for 38/39 y, 26.99% for 40/41 y, 14.4% for 42/43 y, and 3.44% for ≥44 y (P <0.001). In multivariate regression, CLBR was independently associated with younger age (OR for each year: 1.538, 95%CI: 1.193, 1.984) and higher number of transferable embryos (OR for each embryo: 1.495, 95%CI: 1.297, 1.722). CLBR differed significantly in the 38/39 group (P = 0.014), with higher rate in women receiving the Gonadotropin-releasing hormone agonist (GnRH-a) long or GnRH-a ultra-long protocols.

CONCLUSIONS

Forty-two years of age seemed to be a critical cutoff to achieve reasonable level of CLBR after a single ovarian stimulation cycle in women of advanced reproductive age.

Multivariate analysis of the factors associated with live births during in vitro fertilisation in Southeast Asia: a cross-sectional study of 104,015 in vitro fertilisation records in Taiwan

PURPOSE

To investigate the factors associated with live births and the interaction between age and the number of embryos transferred after in vitro fertilisation (IVF) treatment.

METHODS

This study analyses data from a population-based-assisted reproductive database of all registered artificial reproduction institutions (n = 80) from 2010 to 2016 in Taiwan. The probability of a live birth in correlation with the treatment parameters was measured with multivariate logistic regression analyses using the generalised additive model (GAM) and Pearson's chi-square exact test.

RESULTS

A total of 104,015 IVF treatments performed between 2010 and 2016 were included in our analysis. From these treatments, 31,467 (30.3%) were successfully delivered, and 40,565 test-tube babies were born. Pearson's chi-square exact test indicated that parents' age, cause of infertility, type of ovarian stimulation, additional assisted reproductive technology techniques, donated egg or sperm, fresh or frozen embryo, presence or absence of ovarian hyperstimulation syndrome, and day of embryo transfer were significantly associated with live births after an IVF cycle (p < 0.05). Multiple logistic regression analysis with the GAM revealed that the odds of a live birth with IVF treatment in patients < 34 years of age were 2.55 times higher than that in patients ≥ 45 years of age (odds ratio = 2.55, 95% confidence interval = 1.69-2.90) for patients who underwent a single-embryo transfer (SET); a similar pattern was observed when two or more embryos were transferred. Egg donation, the assisted hatching technique, oral ovarian stimulation agents, and implantation of frozen embryos during SET were shown to improve the chance of a live birth by 29-90%. Implantation of the embryo after the 5th day of culture yielded the highest odds of a live birth. The interaction plot revealed that maternal age, especially < 40 years, was associated with the probability of a live birth. SET and double-embryo transfer showed similar associations with the probability of a live birth across age groups. Transferring more than two embryos might reduce the probability of a live birth during IVF treatment for women ≥ 40 years of age.

CONCLUSIONS

Implanting a greater number of embryos did not improve the age-related decrease in fertility for patients undergoing IVF. Therefore, we suggested that ≤ 2 blastocysts could be transferred during IVF treatments for women ≥ 40 years. Transferring a blastocyst on day 5 of culture was associated with a significant increase in the odds of a live birth resulting from IVF.

Elective single blastocyst transfer in advanced maternal age

PURPOSE

The purpose of this study was to investigate reproductive outcomes following elective single blastocyst transfer (eSBT) compared with those of double blastocyst transfer (DBT) in advanced maternal age.

METHODS

This was a retrospective cohort study performed at an academic fertility center. All women aged 40 and over for whom in vitro fertilization (IVF) cycles were performed and in whom embryo culture was extended to the blastocyst stage were reviewed for possible inclusion. Exclusion criteria included the following: women with >3 previous IVF cycles, the use of donor or frozen oocytes, preimplantation genetic diagnosis/preimplantation genetic screening cycles, and cycles in which embryos did not reach the blastocyst stage on day 5. The study included 310 women; 148 were included in the eSBT group and 162 were included in the DBT group. Live birth rate (LBR) was the main outcome. Outcomes were analyzed using logistic regression, controlling for confounders. These confounders were embryo expansion, embryo quality, and the number of previous IVF cycles.

RESULTS

The mean age of the whole group was 41 ± 0.91 years, and the LBR was 21.6%. The eSBT group and the DBT group achieved similar clinical pregnancy rates (33 vs. 33%) (OR 1.04; 95%CI, 0.62-1.75) and LBRs (20 vs. 22.8%) (OR 1.43; 95% CI, 0.78-2.64). The multiple birth rate was lower in the eSBT group (0 vs. 16%, p = 0.02). The subgroup of women who had elective DBT (eDBT) achieved a higher LBR (20 vs. 30.6%) (OR 2.32; 95% CI, 1.16-4.68) and a higher multiple birth rate (0 vs. 22%, p = 0.001). Cycles with early blastocyst transfers were associated with lower LBRs compared with cycles with fully expanded blastocyst transfers (11 vs. 24%, p = 0.02).

CONCLUSION

The results of this study indicate that eSBT is associated with similar LBRs compared to the entire DBT cohort; however, when supernumerary blastocysts are available for cryopreservation, eDBT is associated with both higher LBRs and a higher number of multiple births. Studies assessing the cumulative LBR in advanced maternal age after single blastocyst transfer and subsequent frozen-thawed blastocyst transfers are needed.

[Pregnancy and obstetric outcomes of elective single versus double cleavage-stage embryo transfer]

OBJECTIVE

To compare the pregnancy and obstetric outcomes in elective single versus two cleavage-stage embryo transfer.

METHODS

Fresh cleavage-stage embryo transfer cycles between January, 2014 and October, 2015 were reviewed, including 39 single embryo transfer (eSET) cycles and 200 double embryo transfer (DET) cycles. The clinical pregnancy rates, implantation rates, multiple pregnancy rates, live birth rate, and obstetric outcomes (gestational age, preterm delivery rate and mean birth weight) were compared between the two groups.

RESULTS

The baseline characteristics were comparable between the two groups. The estradiol level on the day of trigger and the oocyte number were significantly higher in eSET group than in DET group (10654.4 pmol/L vs 8284.2 pmol/L and 8.4 vs 7.0, respectively). No significant difference was found in the pregnancy rate (56.4% vs 66.0%) or live birth rate (48.7% vs 51.5%) between the two groups, and their implantation rates differed significantly (56.4% vs 37.8%). No multiple pregnancies occurred in eSET group while the rate of multiple pregnancies was 22.7% in DET group. The gestational age and mean birth weight were significantly higher in eSET group (P<0.05), and the preterm delivery rate after DET was nearly three times of that after eSET, although this difference was not statistically significant.

CONCLUSIONS

Elective single embryo transfer can be performed without compromising the live birth rates. Multiple pregnancy rates can be significantly reduced with eSET, which also results in a higher chance of delivering a term singleton live birth compared with DET.