Early blastulation (EB) of day 4 embryo is predictive of outcomes in single embryo transfer (SET) cycles

Objective

The aim of this study was to assess whether the early blastulation (EB) of day 4 embryo is a useful predictor for outcomes in fresh elective single embryo transfer (eSET) cycles.

Clinical pregnancy rate following frozen embryo transfer is higher with blastocysts vitrified on day 5 than on day 6

Purpose

The aim of this study was to compare the pregnancy rates between good quality blastocysts vitrified on day 6 versus blastocysts vitrified on day 5 after fertilization.

Methods

This is a retrospective cohort study of 791 freeze-thaw cycles of blastocysts vitrified either on day 5 or on day 6 and transferred between January 2012 and October 2015. Five hundred and thirty-seven cycles included blastocysts vitrified on day 5, and 254 cycles included blastocysts vitrified on day 6.

Results

The age of the patients and the proportion of embryos that survived the thawing process were comparable between the two groups. More good quality embryos were transferred in the group in which blastocysts were vitrified on day 6 (1.2 vs. 1.3, p?=?0.005), but the clinical pregnancy rate (44 vs. 33 %, p?=?0.002) and the ongoing pregnancy rate (41 vs. 28 %, p?<?0.001) were higher in the group in which blastocysts were vitrified on day 5. Multivariate regression analysis adjusting for patient’s age, number of good quality embryos transferred (≥3BB), and treatment protocol demonstrated that the day 6 vitrified group had a significantly lower clinical pregnancy rate compared to the day 5 vitrified group (OR 0.54, 95 % CI 0.38–0.76).

Conclusions

The clinical pregnancy rate following frozen embryo transfer is significantly lower with blastocysts vitrified on day 6 compared to blastocysts vitrified on day 5.

     

Pregnancy after in vitro fertilization,cryopreservation, and embryo transfer

Summary We reported on the first pregnancy achieved in the Erlangen IVF program after cryopreservation and embryo transfer. After hMG stimulation in the first treatment cycle, nine oocytes were retrieved by laparoscopy from a 31-year-old woman and three embryos transferred. Fived other oocytes were fertilized and developed to four- to eight-cell embryos, which were subsequently cryopreserved. Transfer of these embryos two cycles later resulted in a singleton pregnancy and the birth of a healthy girl.     

Elective cryopreservation of all day 5 blastocysts is more effective than using day 6 blastocysts for improving pregnancy outcome in stimulated cycles

Aim:  To evaluate the efficacy of cryopreservation of all blastocysts for future transfers in stimulated cycles.
Methods:  We carried out fresh blastocyst transfer cycles on day 5 ( n  = 290) or day 6 ( n  = 119) and thawed blastocyst transfer cycles that were frozen on day 5 ( n  = 136), day 6 ( n  = 71) or day 6 electively ( n  = 21). We retrospectively compared the clinical outcome of fresh blastocyst transfers with thawed blastocyst transfers according to the day of blastocyst transfer or freezing.
Results:  The clinical implantation rates in women with stimulated cycles were significantly higher after the transfer of thawed blastocysts compared with the transfer of fresh blastocysts (day 5, P  < 0.0005; day 6, P  < 0.00005). Although the implantation rate of fresh day 6 transfer cycles was lower than that of elective day 6 frozen–thawed cycles, this difference was not statistically significant ( P  = 0.17).
Conclusions:  Thawed blastocysts demonstrated a better potential for implantation when compared with fresh blastocysts in stimulated cycles. We concluded that elective cryopreservation of all blastocysts on day 5 is an effective option to improve the clinical outcome in stimulated cycles. Additionally, with cryopreservation of all day 6 blastocysts, the implantation rates of first embryo transfers may increase by allowing the best-quality blastocysts to be transferred in thawed cycles. (Reprod Med Biol 2008; 7 : 75–83)     

Comparison of aneuploidy,pregnancy and live birth rates between day 5 and day 6 blastocysts

Comprehensive chromosome screening is typically used for aneuploidy analysis of blastocysts. It is believed that either day of blastocyst development is acceptable. Euploidy rates and outcomes were examined between day 5 and day 6 blastocysts in two studies. First, euploidy rates of day 5 and day 6 blastocysts were examined on a per-embryo and per-patient basis. Second, outcomes were compared when only euploid day 5 or day 6 blastocysts were transferred in a cryopreserved embryo transfer cycle. In cycles (n = 70) that had blastocysts biopsied on both day 5 and day 6, day 5 blastocysts had a higher chance of being euploid than day 6 blastocysts (125/229 [54.6%]) and (77/180 [42.8%]), respectively (P = 0.0231). Similarly, euploid rates in blastocysts from patients (n = 193) with day 5 biopsy, day 6 biopsy, or both, were significantly higher in day 5 (235/421 [55.8%]) compared with day 6 (184/413 [44.6%]) blastocysts (P = 0.0014). In the second study, 50 women (36.1 ± 4.3 years) and 39 women (35.1 ± 3.8 years) with only euploid day 5 or euploid day 6 blastocysts transferred during a cryopreserved embryo transfer had similar cycle outcomes. Although underpowered, these data suggest that euploid day 6 blastocysts are as capable of positive outcomes as their euploid day 5 counterparts.     

Pregnancy rates after transfer of cryopreserved blastocysts cultured in a sequential media

OBJECTIVE: This study was undertaken to determine the pregnancy rate after transfer of cryopreserved blastocysts. STUDY DESIGN: Retrospective review of 61 patients from January 1, 2002, to December 31, 2003, who were transferred with blastocyst embryos cryopreserved on day 5 or 6 after culture in a sequential media. The cryopreserved blastocysts were thawed by using a 7-step dilution process after rapid thawing half hour to 2 hours before embryo transfer. RESULTS: The pregnancy rate after transfer of 61 patients with cryopreserved blastocysts was 66%, with 49% having cardiac activity. The pregnancy rate after transfer of 3 blastocysts was 71% and after transfer of 2 blastocysts was 66%. The pregnancy rate of blastocysts cryopreserved after intracytoplasmic sperm injection was 56%. CONCLUSION: Cryopreservation and transfer of blastocysts appears to be a reliable procedure, and that the human blastocyst can be cryopreserved and thawed without a significant loss of viability.     

Increased live births after day 5 versus day 6 transfers of vitrified-warmed blastocysts

Purpose

An investigation into the clinical implications of delayed blastulation (day 5 versus day 6) was carried out for cryo cycles, as heterogeneous results persist in the current literature.

Methods

We performed a retrospective study comparing clinical pregnancies and live births between 178 blastocysts vitrified and warmed on day 5 versus 149 on day 6. The stage of blastocyst development was taken into account and adjustment for confounding factors was performed.

Results

Our results demonstrate a significant difference in clinical pregnancy (43 versus 23% p value <?0.001) and live birth rates (34 versus 16% p value <?0.001) regarding the day of vitrification, in favour of day 5. This difference persisted after adjustment for confounding factors. The adjusted odds ratio for clinical pregnancies and deliveries for the day 5 group compared to that of the day 6 group was 2.83 (95%CI, 1.48 to 5.41) and 2.94 (95%CI, 1.39 to 6.22), respectively. When the stage of development of the blastocyst was taken into consideration, we still observed a significant advantage of day 5 versus day 6 vitrification.

Conclusions

Day of vitrification (day 5 versus day 6) appears to be an independent predictor of clinical outcomes. Stratification of our cohort was carried out according to the developmental stage, and significant differences persisted. Although the transfer of day 6 cryopreserved embryos remains a viable option, giving priority to a day 5 embryo would reduce the time to pregnancy.

     

Early pregnancy loss is significantly higher after day 3 single embryo transfer than after day 5 single blastocyst transfer in GnRH antagonist stimulated IVF cycles

The current study aimed to investigate whether single day-3 embryo transfer (SET) results in higher early pregnancy loss (EPL) than single blastocyst transfer (SBET). A total of 896 patients underwent 1103 IVF cycles with a gonadotrophin-releasing hormone (GnRH) antagonist protocol. In 603 cycles (D3 group) a single embryo on day 3 of the embryo culture was transferred, whereas in the remaining 500 cycles a single blastocyst was transferred on day 5 (D5 group). Multifollicular ovarian stimulation was performed with a GnRH antagonist protocol starting on day 6. SET resulted in 209 pregnancies (34.7%), compared with 221 pregnancies (44.2%) for SBET. Early pregnancy loss rate was significantly higher with SET compared with SBET (26.8% versus 17.2%, P = 0.017) and ongoing implantation rate was also significantly higher with day 5 compared with day-3 embryo transfer (OR:1.68, 95% confidence interval:1.31-2.18). Sub-optimal embryo selection for transfer on day 3, in addition to asynchronization between altered endometrium and early exposure of cleavage-stage embryos, might explain the above difference. Nevertheless, the higher implantation potential of the blastocyst questions the rationale behind performing single embryo transfer on day 3 of embryo culture in women under 36 years old.     

Aneuploidy rates and blastocyst formation after biopsy of morulae and early blastocysts on day 5

Purpose

Studies have demonstrated high implantation rates after trophectoderm biopsy of day 5 expanded blastocysts. However, biopsy of cleavage stage embryos may adversely affect embryo development and implantation. No studies have assessed the utility of day 5 morulae and early blastocyst biopsy. This study sought to better understand these slower embryos’ aneuploidy rates and implantation potential.

Methods

This was a retrospective review of all autologous IVF cycles utilizing PGS at a single academic infertility center.

Results

The biopsy of day 5 morulae and early blastocysts provided 22 % additional euploid blastocysts available for fresh day 6 transfer compared to day 5 biopsy of only expanded blastocysts. Aneuploidy did correlate with embryo stage on day 5, even after controlling for maternal age, with 16 % of morulae and 35 % of blastocysts being euploid. The majority (83 %) of euploid morulae progressed to the blastocyst stage by day 6. Experience transferring slower developing embryos is limited, but preliminary pregnancy and implantation rates appear similar to euploid embryos biopsied as expanded blastocysts.

Conclusions

The biopsy of all non-arrested embryos on day 5 provides genetic information for all blastocysts on day 6, increasing the pool of euploid blastocysts available for fresh transfer and avoiding the need to cryopreserve developmentally competent embryos without genetic information.

     

Comparison of clinical outcomes between single and double vitrified-warmed blastocyst embryo transfer according to the day of vitrification

Purpose

To compare the efficacy of single vitrified-warmed blastocyst embryo transfer (SVBT) versus double vitrified-warmed blastocyst embryo transfer (DVBT) according to the day of vitrification.

Methods

This retrospective study included a total of 1,051 cycles in women less than 37 years of age with their autologous SVBT cryopreserved on day 5 (5d-SVBT, n = 737) or day 6 (6d-SVBT, n = 154) and DVBT on day 5 (5d-DVBT, n = 129) or day 6 (6d-DVBT, n = 31) from January 2009 to December 2011.

Results

The clinical pregnancy rate (41.8 % vs. 48.1 %, p = 0.184) and ongoing pregnancy rate (36.6 % vs. 45.0 %, p = 0.072) were not significantly different between the 5d-SVBT group and the 5d-DVBT group. However, the clinical pregnancy (29.9 % vs. 58.1 %, p = 0.003) and ongoing pregnancy rates (23.4 % vs. 51.6 %, p = 0.001) were significantly lower in the 6d-SVBT group compared with those in the 6d-DVBT group. The implantation rate (42.2 % vs. 34.5 %, p = 0.03) of the 5d-SVBT group was significantly higher than that of the 5d-DVBT group, while the implantation rate (29.9 % vs. 37.1 %, p = 0.303) of the 6d-SVBT group was not statistically different compared with that in the 6d-DVBT group. The multiple pregnancy rates (1.0 % in the 5d-SVBT group vs. 38.7 % in the 5d-DVBT group, p < 0.001 and 0 % in the 6d-SVBT group vs. 22.2 % in the 6d-DVBT group, p = 0.001) were statistically significantly lower in the SVBT group compared with those in the DVBT group regardless of the day of vitrification.

Conclusions

This study showed that the 5d-SVBT resulted in comparable clinical outcomes compared to the 5d-DVBT while the 6d-SVBT yielded significantly lower clinical outcomes compared to the 6d-DVBT.     

Prospective evaluation of the optimal time for selecting a single embryo for transfer: day 3 versus day 5

To determine the best day for the selection and transfer of a single embryo, a prospective, randomized study was undertaken that compared the ongoing pregnancy rate (PR) after single embryo transfer (SET) on day 3 with that after single blastocyst transfer (SBT) on day 5. Our results show an overall significantly higher PR after SBT (32.8%) compared with SET (23.2%), and a PR of 40.8% after SBT versus 25.6% after excellent-quality embryos became available.     

Early embryo cleavage and day 2 mononucleation after intracytoplasmatic sperm injection for predicting embryo implantation potential in single embryo transfer cycles

In this study we analyzed the outcome of 275 fresh single embryo transfer cycles of day 2, mononucleate four-cell preembryos that had either cleaved early (n = 175) or not cleaved early (n = 100) 25 to 28 hours after intracytoplasmatic sperm injection. Neither the implantation rate nor the delivery rate showed any difference between the two groups, indicating that when a top-quality preembryo (mononucleate four-cell preembryo on day 2) is transferred, the presence of early cleavage seems to add no additional advantage in predicting the implantation potential of the preembryo.     

Minimal ovarian stimulation (mini-IVF) for IVF utilizing vitrification and cryopreserved embryo transfer

Gentle ovarian stimulation protocols, such as ‘mini-IVF’, have several potential advantages over conventional IVF protocols, including less medication and fewer injections, producing fewer eggs, but eggs of higher quality. The particular ‘mild’ stimulation protocol called ‘mini-IVF’ is described. This protocol requires a reliable and cheap method for embryo cryopreservation such as vitrification, because of the negative impact of clomiphene citrate on the endometrium and since cryopreserved embryo transfers with this protocol have yielded much higher pregnancy rates than fresh transfers. In this series, patients were not denied treatment based on their day-3 FSH value or ovarian reserve. Yet very acceptable pregnancy rates were achieved (20% for fresh embryo transfers and 41% for cryopreserved embryo transfers). These results strengthen the argument for a mini-IVF protocol and vitrification as an alternative to standard conventional IVF stimulation protocols. Now a randomized control trial with cryopreserved single-embryo transfer is required.Gentle ovarian stimulation protocols have several potential advantages over conventional IVF protocols, including less medication and fewer injections, producing fewer eggs, but eggs of higher quality. ‘Mini-IVF’ is safe, patient friendly and physiologically more natural. It may be more cost effective if results are comparable to conventional protocols. Vitrification of embryos allows the transfer of warmed embryos in subsequent cycles when the endometrium is more receptive. In this series, patients were not denied treatment based on their day-3 FSH value or ovarian reserve. Yet very acceptable pregnancy rates were achieved (20% for fresh embryo transfers and 41% for cryopreserved embryo transfers). These results strengthen the argument for gentle stimulation protocols and vitrification in preference to standard conventional IVF stimulation protocols. Now a randomized control trial with cryopreserved single-embryo transfer is required.