Patient selection criteria for blastocyst transfers in extended embryo culture programs

Positive Effect of 25-Hydroxyvitamin D (25(OH)D) Levels in Follicular Fluid on Embryonic Developmental Potential in Diminished Ovarian Reserve (DOR) Patients Undergoing Microstimulation

OBJECTIVE

This study aimed to explore the effect of 25-hydroxyvitamin D (25(OH)D) levels in follicular fluid (FF) on the embryo outcome with diminished ovarian reserve (DOR) patients undergoing in vitro fertilization (IVF) by microstimulation protocol.

METHODS

A prospective cohort study of 79 patients with DOR who underwent IVF using the microstimulation protocol was conducted. Based on the level of 25(OH)D in follicular fluid (25(OH)D-FF), the patients were divided into a high-value group (25(OH)D-FF>11.1, n = 50) and a low-value group (25(OH)D-FF>11.1, n = 29). Correlation analysis was conducted between the level of 25(OH)D-FF and the rate of high-quality embryos on day 3 (D3). Logistic regression analysis of factors affecting the presence or absence of D3-available embryos in patients with DOR was conducted.

RESULTS

The number of oocytes retrieved, mature oocytes (MII), normal fertilization rate, number of available embryos on D3, and high-quality embryo rate were lower in the low-value group than in the high-value group (p = 0.000, p = 0.000, p = 0.009, p = 0.000, p = 0.001). The clinical pregnancy rate of frozen embryo transfer (FET) between the two groups was no statistically significant difference (p > 0.05); correlation analysis between the 25(OH)D-FF level and the rate of high-quality embryos was performed using Spearman's rank-sum test, and there was a positive correlation (R = 0.271, P<0.01). Logistic analysis showed that 25(OH)D-FF level was a protective factor for embryonic outcome (odds ratio (OR) > 1, P<0.01).

CONCLUSION

The 25(OH)D level in FF has a positive effect on embryonic outcomes in DOR patients with IVF using the microstimulation protocol. Vitamin D (VD) supplementation can be used to increase the number of available embryos and improve the quality of embryos for patients with DOR who are undergoing microstimulation of IVF.

Maternal age and gonadotrophin elevation cooperatively decrease viable ovulated oocytes and increase ootoxicity, chromosome-, and spindle-misalignments: '2-Hit' and 'FSH-OoToxicity' mechanisms as new reproductive aging hypotheses

While there is consensus that advanced maternal age (AMA) reduces oocyte yield and quality, the notion that high FSH reduces oocyte quality and causes aneuploidy remains controversial, perhaps due to difficulties controlling the confounding variables of age and FSH levels. Here, contributions of age and gonadotrophin elevation were separately controlled using a mouse model of human female reproductive aging. Ovulated oocytes were collected from young and midlife mice after 0-, 2.6-, or 17-day treatment with the FSH analog equine chorionic gonadotrophin (eCG), to model both exogenous FSH elevation within a single treatment cycle (as in controlled ovarian stimulation (COS)), and chronic endogenous FSH elevation during multiple cycles (as in diminished ovarian reserve). After 17-day eCG, fewer total oocytes/mouse are ovulated in midlife than young mice, and a precipitous decline in viable oocytes/mouse is observed in midlife but not young mice throughout eCG treatment. eCG is potently ootoxic to ovulatory oocytes and strongly induces chromosome- and spindle-misalignments within 2.6 days of eCG in midlife, but only after 17 days in young mice. These data indicate that AMA increases susceptibility to multiple adverse effects of elevated FSH activity in ovulated oocytes, including declines in total and viable oocytes/mouse, and induction of ootoxicity and aneuploidy. Two hypotheses are proposed for underlying causes of infertility in women. The FSH OOToxicity Hypothesis ('FOOT Hypothesis') posits that high FSH is ootoxic to ovulatory oocytes and that FSH ootoxicity is a root cause of low pregnancy success rates in naturally cycling women with high FSH and IUI patients undergoing COS. The '2-Hit Hypothesis' posits that AMA increases susceptibility to FSH-induced ootoxicity and aneuploidy.

Effects of high-altitude hypoxia on embryonic developmental potential in women undergoing IVF/ICSI procedures

PURPOSE

In this study we examined the effects of long-term adaptation to hypoxia on embryonic developmental potential of oocytes collected from women who underwent IVF/ICSI procedures.

METHODS

We selected young infertile women who lived in a low-altitude normoxic environment (n = 80, altitude < 500 m) or high-altitude hypoxic environment (n = 100, altitude > 2500 m) for a lengthy period of time and who planned to undergo IVF/ICSI procedures. We then determined the baseline reproductive hormone levels, gonadotropin (Gn) dose and Gn treatment duration during controlled ovarian hyperstimulation (COH), number of oocytes retrieved, number of mature oocytes, oocyte maturation rate, fertilization rate, normal fertilization rate, day (D3) embryo-formation rate, blastocyst formation rate, good-quality formation rate, D5 blastocyst formation rate, and D6 blastocyst formation rate between the two groups.

RESULTS

Compared with the low-altitude normoxic group, the various reproductive hormone markers of women in the high-altitude hypoxia group were lower, with LH and T levels significantly reduced (P < 0.05) at 72.29 and 72.44% of the normoxic group, respectively (normoxic group vs. hypoxic group, 5.24 ± 1.61 vs. 3.79 ± 1.21; 0.61 ± 0.18 vs. 0.42 ± 0.15; P < 0.05). During ovarian hyperstimulation, a greater Gn dose and longer Gn treatment duration were required for the hypoxic group to complete COH (normoxic group vs. hypoxic group, 2152.08 IU ± 52.76 vs. 2622.09 IU ± 123.28; 9.96 days ± 1.27 vs. 11.54 days ± 1.34, respectively; P < 0.05). The fertilization, cleavage, and D3 embryo-formation rates tended to be higher in the normoxic group than in the hypoxic group (P > 0.05); while the normal fertilization rate tended to lower than in the hypoxic group (P > 0.05). When we conducted an analysis of blastocyst formation rates at different timepoints, we ascertained that the blastocyst formation rate, usable blastocyst rate, and good-quality blastocyst rate of the hypoxic group were all lower than in the normoxic group, with the difference in usable blastocyst rate the most highly significant (normoxic group vs. hypoxic group, 75.31 ± 5.53 vs. 56.04 ± 6.10%, respectively; P < 0.05). In addition, the D5 and D6 blastocyst-formation rates in the normoxic group were slightly higher than in the hypoxic group, revealing that not only were fewer blastocysts formed in the hypoxic group but that there was also a delay in blastocyst formation.

CONCLUSION

In young women undergoing IVF/ICSI treatment, long-term hypoxic adaptation required augmented Gn dose and Gn treatment duration during COH, and blastocyst developmental potential was also attenuated.

Estimating the causal effect of embryo transfer day on clinical in vitro fertilization outcomes using propensity score matching

BACKGROUND

For women undergoing in vitro fertilization (IVF), the clinical benefit of embryo transfer at the blastocyst stage (Day 5) versus cleavage stage (Day 3) remains controversial. The purpose of this study is to compare the implantation rate, clinical pregnancy rate and odds of live birth of Day 3 and Day 5 embryo transfer, and more importantly, to address the issue that patients were chosen to receive either transfer protocol due to their underlying clinical characteristics, i.e., confounding by indication.

METHODS

We conducted a retrospective cohort study of 9,090 IVF cycles collected by Lee Women's Hospital in Taichung, Taiwan from 1998 to 2014. We utilized the method of propensity score matching to mimic a randomized controlled trial (RCT) where each patient with Day 5 transfer was matched by another patient with Day 3 transfer with respect to other clinical characteristics. Implantation rate, clinical pregnancy rate, and odds of live birth were compared for women underwent Day 5 transfer and Day 3 transfer to estimate the causal effects. We further investigated the causal effects in subgroups by stratifying age and anti-Mullerian hormone (AMH).

RESULTS

Our analyses uncovered an evidence of a significant difference in implantation rate (p=0.04) favoring Day 5 transfer, and showed that Day 3 and Day 5 transfers made no difference in both odds of live birth (p=0.27) and clinical pregnancy rate (p=0.11). With the increase of gestational age, the trend toward non-significance of embryo transfer day in our result appeared to be consistent for subgroups stratified by age and AMH, while all analyses stratified by age and AMH were not statistically significant.

CONCLUSIONS

We conclude that for women without strong indications for Day 3 or Day 5 transfer, there is a small significant difference in implantation rate in favor of Day 5 transfer. However, the two protocols have indistinguishable outcomes on odds of live birth and clinical pregnancy rate.

A visualized clinical model predicting good quality blastocyst development in the first IVF/ICSI cycle

RESEARCH QUESTION

Is it possible to establish a visualized clinical model predicting good quality blastocyst (GQB) formation for patients in their first IVF/intracytoplasmic sperm injection (ICSI) cycle?

DESIGN

A total of 4783 patients in their first IVF/ICSI cycle between January 2015 and December 2019 were retrospectively included and randomly divided into the training set (n = 3826) and the testing set (n = 957) in an 8:2 ratio. The least absolute shrinkage and selection operator (LASSO) regression was adopted to select the most critical predictors for GQB formation to construct a visualized nomogram model based on the data of patients in the training set. Receiver operating characteristic and calibration curves were used to evaluate the predictive accuracy and discriminative ability. The performance of the model was also validated on independent data from patients treated in the testing set.

RESULTS

Maternal age, maternal serum anti-Müllerian hormone (MsAMH) concentration and the number of oocytes retrieved were highlighted as critical predictors of GQB development and were incorporated into the nomogram model. Based on the area under the curve (AUC) values, the predictive ability for ≥1, ≥3 and ≥5 GQB were 0.831, 0.734 and 0.748, respectively. The calibration curve also showed high concordance between the observed and predicted results. The AUC for predicting ≥1, ≥3 and ≥5 GQB in the testing set were 0.805, 0.695 and 0.707, respectively, which were similar to those for the training set.

CONCLUSIONS

The visualized nomogram model provides great predictive value for GQB development in patients in their first IVF/ICSI cycle and can be used to improve clinical counselling.

Cleavage Stage versus Blastocyst Stage Embryo Transfer in Oocyte Donation Cycles

Background and Objective: During the last few years, a trend has been noted towards embryos being transferred at the blastocyst stage, which has been associated with improved rates regarding implantation and clinical pregnancy in comparison to cleavage stage embryo transfers. There is a limited number of studies investigating this notion in oocyte donation cycles employing cryopreserved embryos. The aim of this study is to evaluate the implantation potential and clinical pregnancy rates between the day 3 cleavage stage and blastocyst stage embryo transfers in oocyte donation cycles employing vitrified embryos. Methods: This is a retrospective evaluation of oocyte donation frozen–thawed transfers completed in our clinic from January 2017 to December 2017. Intracytoplasmic sperm injection was conducted for all oocytes. Following fertilization, all embryos were cryopreserved either at the cleavage or blastocyst stage. Embryo transfer of two embryos was performed under direct sonographic guidance in all cases. Results: Our results confirmed a 55.6% clinical pregnancy (CP) resulting from day 3 embryo transfers, a 68.8% CP from day 5, and 71.4% CP from day 6. Significantly improved pregnancy rates were related to embryo transfers at the blastocyst stage when compared to cleavage stage transfers (68.9% and 55.6% respectively, p = 0.016). The risk with regards to multiple pregnancies was similar. Conclusion: Our findings indicate that in oocyte donation cycles employing vitrified embryos, embryo transfer at the blastocyst stage is accompanied with a significant improvement in pregnancy rates and merits further investigation.

Should the flexibility enabled by performing a day-4 embryo transfer remain as a valid option in the IVF laboratory? A systematic review and network meta-analysis

PURPOSE

The present systematic review and network meta-analysis aims to uniquely bring to literature data supporting the true place of the alternative practice of day-4 embryo transfer (D4 ET) in an IVF laboratory, beyond the one-dimensional option of facilitating a highly demanding program.

METHODS

A systematic search was conducted in the databases of PubMed/Medline, Embase, and Cochrane Central Library, resulting to six prospective along with nine retrospective cohort studies meeting eligibility criteria for inclusion. A comparison of D4 ET with day-2 (D2), day-3 (D3), and day-5 (D5) ET, respectively, was performed employing R statistics.

RESULTS

The sourced results indicate no statistically significant difference regarding clinical pregnancy rates, and ongoing pregnancy/live birth rates stemming from the comparison of D4 with D2, D4 with D3, and D4 with D5 ET, respectively. Additionally, no statistically significant difference could be established in respect to cancelation, and miscarriage rates, following the comparison of D4 with D3 and D4 with D5 ET. Interestingly, we report statistically significant lower preterm birth rates associated with D4 ET, in contrast with D5 ET (RR, 0.19; 95% CI, 0.05-0.67; p value = 0.01).

CONCLUSIONS

The aforementioned results may serve as advocates buttressing the option of D4 ET as a valid candidate in the ET decision-making process. Possible limitations of the current study are the publication bias stemming from the retrospective nature of certain included studies, along with various deviations among studies' design, referring to number and quality of transferred embryos, or different culture conditions referring to studies of previous decades.

Protein expression in human cumulus cells as an indicator of blastocyst formation and pregnancy success

PURPOSE

The goal for the present study was to implement a technique for protein extraction and identification in human cumulus cells (CCs).

METHODS

Forty samples of CCs were collected after ovum pick-up from patients undergoing intracytoplasmic sperm injection (ICSI). Samples were split into the blastocyst group (n = 10), including patients in which all embryos converted into blastocysts, and the non-blastocyst group (n = 10), including patients in which none of the embryos reached the blastocyst stage or the positive-pregnancy (n = 10) and negative-pregnancy group (n = 10). Proteins were extracted and injected into a liquid chromatography system coupled to a mass spectrometer. The spectra were processed and used to search a database.

RESULTS

There were 87 different proteins in samples from the blastocyst and non-blastocyst groups, in which 30 were exclusively expressed in the blastocyst group and 17 in the non-blastocyst group. Among the 72 proteins detected in the pregnancy groups, 19 were exclusively expressed in the positive, and 16 were exclusively expressed in the negative-pregnancy group.

CONCLUSIONS

CC proteomics may be useful for predicting pregnancy success and the identification of patients that should be included in extended embryo culture programs.

Is the presence of an uncleaved embryo on day 3 a useful predictor of outcomes following day 5 transfer?

PURPOSE

This study aimed to determine whether the presence of an uncleaved embryo on day 3 is predictive of cycle outcome after day 5 transfer (D5 ET).

METHODS

In vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles from January 2013 to November 2014 with D5 ET were analyzed for the presence of at least one uncleaved embryo on day 3 (D3). Each index cycle (n = 70) was compared with two matched control cycles without uncleaved embryos. The main outcome measures included embryo quality, implantation rate, and clinical pregnancy rate.

RESULTS

Fifty-nine of 3896 total embryos in this study were uncleaved on D3 (1.5 %). Cycles with uncleaved embryos had more oocytes retrieved (20.6 vs. 17.5), lower proportions of good quality embryos on D3 (52.4 vs. 66.1 %), and fewer usable embryos (transferred or frozen) on D5 (42.4 vs. 50.8 %). However, there were no significant differences in the incidence of cycles with a positive hCG, or in the rates of implantation, clinical pregnancy, or live birth.

CONCLUSIONS

Although an uncleaved embryo on D3 is associated with reduced conversion of sibling embryos to the blastocyst stage on D5, overall quality of those embryos forming blastocysts is not markedly decreased and clinical outcomes are not compromised.

The importance of the cleavage stage morphology evaluation for blastocyst transfer in patients with good prognosis

PURPOSE

To evaluate: (i) the influence of morphology at cleavage stage on blastocyst formation and implantation, and (ii) whether the transfer of low-quality embryos on day-three would be a better approach than the transfer at blastocyst stage.

METHODS

This study included 8,444 embryos obtained from 1,125 patients undergoing ICSI cycles between January/2011 and September/2013. The influence of the quality of the embryo on days-two and -three on blastocyst formation and implantation success was evaluated. Moreover, the implantation potential of low-quality embryos, at cleavage stage, transferred on day-three was compared with the implantation potential of low-quality embryos, at cleavage stage, transferred on day-five.

RESULTS

Low-quality embryos on day-two had an approximate 20 % decreased chance of achieving the blastocyst stage, and blastocysts derived from low-quality embryos on day-two had a nearly 40 % decrease in the implantation chance. Low-quality embryos on day-three had a 30 % decreased chance of achieving the blastocyst stage, and blastocysts derived from low-quality embryos on day-three had an almost 40 % decreased implantation chance. The implantation rate didn't differ when low-quality embryos on the cleavage stage were transferred on day-three or left in culture and transferred on day-five.

CONCLUSIONS

The transfer of low-quality embryos on day-three is a better approach than transfer at the blastocyst stage. In addition, the embryo morphology evaluation at the cleavage stage is still needed for the selection of the embryo with the best implantation potential in extended embryo culture programmes.