Effect of using an echogenic catheter for ultrasound-guided embryo transfer in an IVF programme: a prospective, randomized, controlled study

Sperm cryopreservation does not affect live birth rate in normozoospermic men: analysis of 7969 oocyte donation cycles

STUDY QUESTION

Does sperm cryopreservation influence the reproductive outcomes of normozoospermic patients in oocyte donation cycles?

SUMMARY ANSWER

After controlling for confounders, the use of cryopreserved semen from normozoospermic patients does not affect pregnancy and live birth rates after elective ICSI.

WHAT IS KNOWN ALREADY

Sperm cryopreservation by slow freezing is a common practice in ART. While frozen-thawed semen typically presents reduced motility and vitality, its use for ICSI is generally considered adequate in terms of reproductive outcomes. Nevertheless, most studies comparing reproductive outcomes between fresh and cryopreserved sperm include patients with severe male factor (testicular sperm, oligo-, and/or asthenozoospermia) or women of advanced maternal age, where the altered quality of the gametes can partially mask the full effect of freezing/thawing.

STUDY DESIGN, SIZE, DURATION

The study included a retrospective cohort of 7969 couples undergoing their first oocyte donation cycle between January 2013 and December 2019 in one large clinic, using normozoospermic semen from the male partner. All cycles involved elective ICSI, fresh oocytes, and a fresh embryo transfer, either at cleavage or blastocyst stage. Two study groups were established based on the sperm status: fresh (n = 2865) and cryopreserved (n = 5104).

PARTICIPANTS/MATERIALS, SETTING, METHODS

A slow freezing protocol was used for all sperm cryopreservation. Sperm washing, capacitation, and selection prior to ICSI were performed identically for fresh and frozen-thawed samples, using pellet swim-up. Fertilization rate (FR), pregnancy (biochemical and ongoing), and live birth rates were compared between study groups using univariate and multivariate regression analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

Male and female age, sperm concentration and motility after ejaculation, and number of oocytes inseminated were similar between cycles using fresh or cryopreserved sperm. Analysis by Student's t-test did not indicate a significant difference in FR between fresh and cryopreserved sperm (P = 0.0591); however, after adjusting for confounders, this difference reached statistical significance: 74.65% FR for fresh (CI 95%: 73.92-75.38) versus 73.66% for cryopreserved sperm (CI 95%: 73.11-74.20), P = 0.0334. The adjusted regression analysis revealed higher odds of biochemical pregnancy when using fresh sperm (odds ratio (OR): 1.143, P = 0.0175), but no significant effects of sperm cryopreservation were observed for ongoing pregnancy (OR: 1.101, P = 0.0983) and live birth (OR: 1.082, P = 0.1805).

LIMITATIONS, REASONS FOR CAUTION

Caution should be exerted when extrapolating these results to different protocols for sperm cryopreservation and selection, or to IVM, advanced maternal age and classical IVF cycles, which were excluded from analysis. Owing to the retrospective nature of the study, some uncontrolled for variables may affect the results.

WIDER IMPLICATIONS OF THE FINDINGS

Sperm cryopreservation does not affect pregnancy and live birth rates in normozoospermic patients, and although it may lower FR s slightly, this would not be clinically relevant. In line with previous studies that included patients with an apparent male or female factor, sperm cryopreservation is a safe and convenient technique.

STUDY FUNDING/COMPETING INTEREST(S)

The study received no external funding and all authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Embryo transfer success: It is in our hands

Embryo transfer (ET) is considered as a critical step in the process of in vitro fertilization. Interestingly, studies have consistently shown significant outcome differences between physicians. Although the outcome of ET is not related to the physician's experience and specifically not different between fellows and attending physicians, certain techniques have been found to affect the success rate. This review summarizes the existing evidence regarding the impact of the individual physician performing ET and the techniques used.

Interventions to optimize embryo transfer in women undergoing assisted conception: a comprehensive systematic review and meta-analyses

BACKGROUND

Several interventions and techniques are suggested to improve the outcome of embryo transfer (ET) in assisted conception. However, there remains no consensus on the optimal practice, with high variations among fertility specialists.

OBJECTIVE AND RATIONALE

We conducted a comprehensive systematic review and meta-analyses of randomized controlled trials (RCTs) aiming to identify effective interventions that could be introduced around the time of ET to improve reproductive outcomes.

SEARCH METHODS

We searched the electronic databases (MEDLINE, EMBASE and Cochrane CENTRAL) from inception until March 2021 using a multi-stage search strategy of MeSH terms and keywords, and included all RCTs that evaluated an intervention in the 24-h period before/after ET in women undergoing IVF/ICSI. Our primary outcome was clinical pregnancy rate post-ET confirmed as viable pregnancy on ultrasound scan. We assessed the risk of bias in included trials and extracted data in duplicate. We pooled data using a random-effect meta-analysis and reported using risk ratio (RR) with 95% CI. We explored publication bias and effect modifiers using subgroup analyses.

OUTCOMES

Our search yielded 3685 citations of which we included 188 RCTs (38 interventions, 59 530 participants) with a median sample size of 200 (range 26-1761). The quality of included RCTs was moderate with most showing a low risk of bias for randomization (118/188, 62.8%) and attrition (105/188, 55.8%) but there was a significant risk of publication bias (Egger's test P = 0.001). Performing ET with ultrasound guidance versus clinical touch (n = 24, RR 1.265, 95% CI 1.151-1.391, I2 = 38.53%), hyaluronic acid versus routine care (n = 9, RR 1.457, 95% CI 1.197-1.261, I2 = 46.48%) and the use of a soft versus hard catheter (n = 27, RR 1.122, 95% CI 1.028-1.224, I2 = 57.66%) led to higher clinical pregnancy rates. Other pharmacological add-ons also showed a beneficial effect including granulocyte colony-stimulating factor (G-CSF: n = 4, RR 1.774, 95% CI 1.252-2.512, I2 = 0), Atosiban (n = 7, RR 1.493, 95% CI 1.184-1.882, I2 = 68.27%) and hCG (n = 17, RR 1.232, 95% CI 1.099-1.382, I2 = 57.76%). Bed rest following ET was associated with a reduction in clinical pregnancy (n = 6, RR 0.857, 95% CI 0.741-0.991, I2 = 0.01%). Other commonly used interventions, such as non-steroidal anti-inflammatory drugs, prophylactic antibiotics, acupuncture and cervical mucus removal, did not show a significant benefit on reproductive outcomes. Our effect estimates for other important outcomes, including miscarriage and live birth, were limited by the varied reporting across included RCTs.

WIDER IMPLICATIONS

Using ultrasound guidance, soft catheters and hyaluronic acid at the time of ET appears to increase clinical pregnancy rates. The use of Atosiban, G-CSF and hCG showed a trend towards increased clinical pregnancy rate, but larger trials are required before adopting these interventions in clinical practice. Bed rest post-ET was associated with a reduction in clinical pregnancy and should not be recommended.

How long can the sperm wait? Effect of incubation time on ICSI outcomes

In sperm processing for IVF/ICSI incubation times differ considerably both between and within assisted reproduction facilities. There is no established consensus on the optimal sperm incubation timings to maximize pregnancy rates, and the few studies addressing this association rely on manual and operator-dependent methods for time recording. The present retrospective cohort study includes 1169 ICSI cycles using fresh semen processed by swim-up. An operator-independent, radiofrequency-based system was used to record sperm incubation times: from sample collection to swim-up (T1, 0.35 ± 0.26); from swim-up to ICSI (T2, 3.30 ± 2.2); and total time from sample collection to ICSI (T, 3.66 ± 2.26). In oocyte donation cycles, we observed a significant negative effect of T1 on fertilization rate (FR; generalized linear modelling regression, coeff. -0.20, p = 0.001); however, after analysing all times by deciles and by adjusted logistic regression, none of the time intervals had a significant effect on pregnancy (biochemical, clinical, and ongoing) and live birth (LB) rates (p > 0.05 for all outcomes). In cycles using the patient's oocytes, we observed a negative effect of T2 (ordinal regression, coeff. -0.25, p = 0.011) and T (-0.33, p = 0.005) on the mean morphological score of the embryo cohort. In these cycles, a trend associating longer values of T with higher LB rates was identified (OR = 1.47, p = 0.050), although this difference is likely not clinically significant. In conclusion, while longer sperm incubation in vitro may impact slightly both FRs and embryo morphology after ICSI, no adverse effects were detected on the reproductive outcomes.

Efficiency and efficacy of vitrification in 35 654 sibling oocytes from donation cycles

STUDY QUESTION

Is oocyte vitrification/warming as efficient and effective as using fresh oocytes in donation cycles?

SUMMARY ANSWER

IVF with vitrified donor oocytes is less efficient than using fresh oocytes, but its efficacy remains comparable to that of fresh cycles.

WHAT IS KNOWN ALREADY

Oocyte vitrification is used to preserve the reproductive potential of oocytes. A small number of randomized controlled trials carried out by experienced groups have shown that this technique provides fertilization, pregnancy, implantation and ongoing pregnancy rates comparable to those of fresh oocytes. However, large registry-based analyses have consistently reported lower live birth rates (LBRs) in cycles using vitrified oocytes. It is not clear whether this decrease may be due to the effect of vitrification per se on the oocytes or to the lower efficiency of the technique, as some of the oocytes do not survive after warming.

STUDY DESIGN, SIZE, DURATION

Retrospective cohort analysis of 1844 cycles of oocyte donation (37 520 oocytes), each donor in the study provided enough oocytes for at least one reception cycle with fresh oocytes (2561 cycles) and one reception cycle with vitrified oocytes (2471 cycles) from the same ovarian stimulation (sibling oocytes). Overall, 35 654 oocytes were considered in the analysis. All embryo transfers (n = 5032) were carried out between 2011 and 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Differences in reproductive outcomes after the first embryo transfer were evaluated using Pearson's Chi-squared test and regression analysis adjusted for recipient's age, BMI, sperm origin and state, day of embryo transfer, morphological score and number of transferred embryos. We performed two additional sub-analyses, to test whether the efficiency and/or effectiveness of vitrification/warming impacts reproductive results. One analysis included paired cycles where the same number of fresh and vitrified oocytes were available for ICSI (SAME sub-analysis), while the second analysis included those cycles with a 100% survival rate post-warming (SAME100 sub-analysis).

MAIN RESULTS AND THE ROLE OF CHANCE

Baseline and cycle characteristics of participants were comparable between groups. Overall, fertilization rates and embryo morphological scores were significantly lower (P < 0.001) when using vitrified oocytes; moreover, vitrified oocytes also resulted in lower reproductive outcomes than sibling fresh oocytes using both unadjusted and adjusted analyses: ongoing pregnancy (32.1% versus 37.5%; P < 0.001; OR 0.88, 95% CI 0.77, 1.00) and live birth (32.1% versus 31.9%; P = 0.92; OR 1.16, 95% CI 0.90, 1.49). However, when the efficiency of warming was taken into account, reproductive outcomes in recipients became comparable: ongoing pregnancy (33.5% versus 34.1%; P = 0.82; OR 1.11, 95% CI 0.87, 1.43) and LBR (32.1% versus 32%; P = 0.97; OR 1.15, 95% CI 0.89, 1.48). Moreover, after selecting only cycles that, in addition to having the same number of oocytes available for ICSI, also had 100% post-warming survival rate in the vitrified group, reproductive outcomes were also comparable between fresh and vitrified oocytes: ongoing pregnancy (34.8% versus 32.4%; P = 0.42; OR 1.32, 95% CI 0.98, 1.77) and live birth (32.9% versus 31.0%; P = 0.52; OR 1.27, 95% CI 0.95, 1.71), indicating that reproductive outcomes of these cycles are affected by the efficiency of the vitrification/warming technique performed rather than the oocyte damage due to the fast cooling process to which oocytes are subjected.

LIMITATIONS, REASONS FOR CAUTION

An open vitrification system was used for all cases, and oocyte vitrification/warming was performed by experienced embryologists with consistently high survival rates; caution must be exerted when extrapolating our results to data obtained using other open vitrification systems, closed vitrification systems or to IVF units with survival rates <90%.

WIDER IMPLICATIONS OF THE FINDINGS

This is the largest cohort study comparing reproductive outcomes of vitrified and fresh sibling donor oocytes to date. We found that, when the number of oocytes available after warming is equal to the number of fresh oocytes, reproductive results including live birth are comparable. Consequently, the efficiency of vitrification must be taken into account to achieve the same reproductive outcomes as with fresh oocytes. We recommend implementing strict indicators of vitrification/warming efficiency in clinics and refining vitrification/warming protocols to maximize survival.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by intramural funding of Clínica EUGIN and by the Secretary for Universities and Research of the Ministry of Economy and Knowledge of the Government of Catalonia (GENCAT 2015 DI 048). The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Assisted oocyte activation effects on the morphokinetic pattern of derived embryos

OBJECTIVE

Assisted oocyte activation (AOA) can restore fertilization rates after IVF/ICSI cycles with fertilization failure. AOA is an experimental technique, and its downstream effects remain poorly characterized. Clarifying the relationship between AOA and embryo, morphokinetics could offer complementary insights into the quality and viability of the embryos obtained with this technique. The aim of this study is to compare the preimplantation morphokinetic development of embryos derived from ICSI-AOA (experimental group) vs. ICSI cycles (control group).

METHODS

A retrospective cohort study was carried out with 141 embryos from fresh oocyte donation cycles performed between 2013 and 2017; 41 embryos were derived from 7 ICSI-AOA cycles and 100 embryos from 18 ICSI cycles. Morphokinetic development of all embryos was followed using a time-lapse system.

RESULTS

We show that embryos from both groups develop similarly for most milestones, with the exception of the time of second polar body extrusion (tPB2) and the time to second cell division (t3).

CONCLUSIONS

We conclude that ionomycin mediated AOA does not seem to affect the morphokinetic pattern of preimplantation embryo development, despite the alterations found in tPB2 and t3, which could directly reflect the use of a Ca²⁺ ionophore as a transient and quick non-physiologic increase of free intracytoplasmic Ca²⁺.

Comparison of two different oocyte vitrification methods: a prospective, paired study on the same genetic background and stimulation protocol

STUDY QUESTION

Can two different methods for oocyte vitrification, one using an open tool and the other a closed tool, result in similar oocyte survival rates?

SUMMARY ANSWER

The oocyte survival rate was found to be higher in the closed method.

WHAT IS KNOWN ALREADY

Open vitrification is performed routinely in oocyte donation cycles. Closed oocyte vitrification may result in slower cooling rates and thus it is less used, even though it has been recommended in order to avoid the risk of cross-contamination between material from different patients.

STUDY DESIGN, SIZE, DURATION

This is a prospective cohort study with sibling oocytes carried out in a fertility center between July 2014 and January 2016. The study included 83 oocyte donors each providing a minimum of 12 mature oocytes (metaphase II: MII) at oocyte retrieval. Oocyte survival rate and fertilization rate, as well as reproductive outcomes (biochemical, clinical, ongoing pregnancy and live birth rates) per embryo transfer and also cumulatively between the two methods were compared by Chi2 tests.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Donor oocytes were denuded and six MII oocytes from each donor were vitrified using an open method and later assigned to one recipient, while another six MII oocytes were vitrified using a closed method and assigned to a different recipient (paired analysis). ICSI was used in all cases and embryo transfer was performed on Day 2-3 in all cases.

MAIN RESULTS AND THE ROLE OF CHANCE

Oocyte donors were 24.8 years old on average (SD 4.7). Recipient age (average 41.2 years, SD 4.7) and BMI (mean 23.8 kg/m2, SD 4.0) were similar between recipient groups. Oocytes vitrified using the closed method had higher survival rate (94.5% versus 88.9%, P = 0.002), but lower fertilization rate (57.1% versus 69.8%, P < 0.001) compared to the open method. The number of fresh embryos transferred in the two groups was 1.8 on average (SD 0.4). Biochemical (45% closed versus 50% open), clinical (40% versus 50%) and ongoing (37.5% versus 42.5%) pregnancy rates were not different between groups (P > 0.05) and neither were live birth rates (37.5% versus 42.5%, P > 0.05). Cumulative reproductive results (obtained after the transfer of all the embryos) were also similar between groups.

LIMITATIONS, REASONS FOR CAUTION

The participants of this study were oocyte donors, i.e. young women in good health, and care should be exerted in extending our results to other populations such as infertility patients, oncofertility patients and women freezing oocytes to delay childbearing.

WIDER IMPLICATIONS OF THE FINDINGS

Our results suggest that, in spite of different survival and fertilization rates, closed and open oocyte vitrification methods should offer similar reproductive outcomes up to cumulative live birth rates.

STUDY FUNDING/COMPETING INTEREST(S)

The authors report no conflict of interest. Vitrolife provided the media and the closed method tool needed for the study at no cost.

Medroxyprogesterone acetate versus ganirelix in oocyte donation: a randomized controlled trial

STUDY QUESTION

Is oral medroxiprogesterone acetate (MPA) non-inferior compared to ganirelix with respect to the number of mature oocytes (MII) retrieved at ovum pick-up (OPU) in oocyte donation cycles?

SUMMARY ANSWER

MPA is comparable to ganirelix in terms of number of MII retrieved at OPU in oocyte donation cycles.

WHAT IS KNOWN ALREADY

Oral treatment with MPA inhibits the pituitary LH surge during ovarian stimulation in infertile patients. Because of its negative effect on the endometrium, MPA suppression is combined with freeze-all. Published reports indicate that both the number of MII retrieved and pregnancy rates from these oocytes are comparable to short protocol of GnRH agonists during IVF cycles with freeze-all. MPA might allow for more comfortable and cost-effective ovarian stimulation.

STUDY DESIGN, SIZE, DURATION

Randomized clinical trial, open-label, single center, to assess the non-inferiority of MPA (10 mg/day) versus ganirelix (0.25 mg/day) from Day 7, in ovarian stimulation cycles triggered with triptoreline acetate. Trigger criterion was ≥3 follicles of diameter >18 mm.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Overall, 252 oocyte donors were selected (eligible), 216 were randomized and 173 reached OPU: 86 under MPA and 87 under ganirelix. The main outcome was the number of MII retrieved at OPU. Secondary outcomes were embryological laboratory outcomes and reproductive outcomes in recipients. The study was powered to test that the lower limit of the 95% confidence interval of the difference in retrieved MII between groups will be above the non-inferiority limit of -3. Differences were tested using a two-sided Student's t-test or a Pearson's Chi2 test, as appropriate.

MAIN RESULTS AND THE ROLE OF CHANCE

All participants were in their first cycle of oocyte donation. On average, donors were 24 (SD 4.5) years old and with a BMI of 23 (SD 2.9) kg/m2. Duration of stimulation was similar in both groups (11.2 days), as well as the total gonadotropin dose up to trigger (2162 IU in MPA and 2163 IU in ganirelix). The number of MII retrieved was no different: 15.1 (SD 8.3) with MPA and 14.6 (SD 7.0), 95% CI of the difference -2.78, -1.83 excluding the pre-defined non-inferiority limit (-3). Recipients and embryo transfer (ET) characteristics were also similar between groups. The average age of recipients was 42 (SD 4.8) years and the BMI was 24 (SD 4.4) kg/m2. The mean number of MII assigned to each recipients was 6.7 (SD 1.2) in MPA and 6.6 (SD 1.2) in ganirelix (P = 0.58). MII were fertilized with partner sperm in 84% cycles overall and fertilization rate was 76% in MPA versus 74% in ganirelix (P = 0.34). Overall, there was 54% of double ET and 46% of single ET, with 40% of ETs were performed in D5. In spite of similar recipients and cycle characteristics, reproductive outcomes were unexpectedly lower with MPA. Biochemical pregnancy rate was 44 versus 57% (P = 0.023); clinical pregnancy rate 31 versus 46% (P = 0.006); ongoing pregnancy rate 27 versus 40%, (P = 0.015) and live birth rate 22 versus 31%, (P = 0.10).

LIMITATIONS, REASONS FOR CAUTION

Although oocyte recipient and ET characteristics are similar among groups, this RCT has been designed under a hypothesis of non-inferiority in the number of MII obtained and recipients were not randomized; therefore, the reproductive outcomes in recipients should be evaluated with extreme caution.

WIDER IMPLICATION OF THE FINDINGS

Ovarian stimulation using MPA for prevention of LH surge yields comparable number of MII oocytes compared to ganirelix in oocyte donation cycles. The unexpected finding in reproductive outcomes should be further investigated.

STUDY FUNDING/COMPETING INTEREST(S)

None to report.

TRIAL REGISTRATION NUMBER

EudraCT number: 2015-004328-73; ClinicalTrials.gov Identifier: NCT02796105.

TRIAL REGISTRATION DATE

29 September 2015 (EudraCT); 9 June 2016 (ClinicalTrials.gov).

DATE OF FIRST PATIENT’S ENROLLMENT

The date of enrollment of the first participant was 07 July 2016, and the last participant last visit in the study was on 10 July 2017.

Could fertility clinics offer a sizable improvement of live birth rates by maturing post-GVBD oocytes in vitro?

PURPOSE

The objective of this study is to analyze the potential of immature, denuded, post-GVBD (germinal vesicle breakdown) oocytes (including prometaphase I, metaphase I, and prometaphase II stages) to result live birth after in vitro maturation. Furthermore, we compared two culture media to identify which of them provides better reproductive outcomes when used for in vitro maturation.

METHODS

We performed a retrospective cohort study including 4022 IVF-ICSI (in vitro fertilization-intracytoplasmic sperm injection) cycles between 2011 and 2015. A total of 4450 immature post-GVBD oocytes from 1442 cycles were cultured in vitro; of these, 2364 oocytes reached MII (metaphase II) stage (IVMC oocytes, in vitro meiotic completion) and were fertilized. Overall, 3933 embryo transfers were performed: 3579 were embryos derived from MII oocytes (ET-MII); 264 were embryos derived from MII + IVMC oocytes (ET-MIX), and 90 embryos from IVMC oocytes (ET-IVMC). In total, 399 IVMC embryos were transferred.

RESULTS

Maturation rate for immature post-GVBD oocytes was 54.1%. G-2™PLUS (Vitrolife) medium provided significantly higher maturation rate (p < 0.001) than G-IVF™PLUS (Vitrolife) (65.7% vs. 42.5%, p < 0.001). Embryos in ET-IVMC in cleavage stage had an average morphological score of 6.8/10 (7.7 in ET-MII; p < 0.001). Regarding reproductive outcomes, ET-IVMC gave 11.1% biochemical pregnancy rate, 10.0% clinical pregnancy rate, 7.8% ongoing pregnancy rate, and 5.6% live birth rate.

CONCLUSIONS

Embryos arising from IVMC oocytes resulted in a live birth rate of 5.6%. We suggest that in vitro maturation of denuded immature post-GVBD oocytes should be performed at the very least when few MII are collected, and likely in all patients, as they provide acceptable maturation and fertilization rates, and a sizeable increase in live birth.

Oocyte developmental competence is independent of ovarian reserve in women younger than 35 years

RESEARCH QUESTION

Is higher antral follicle count (AFC) in healthy young women associated with higher oocyte developmental competence?

DESIGN

Retrospective study of 1985 first oocyte donation cycles, corresponding to 3210 fresh embryo transfers in oocyte recipients, conducted between January 2010 and May 2014.

RESULTS

Donors with higher AFC who underwent ovarian stimulation, produced both more cumulus-oocyte complexes (COC) (B coefficient = 0.47, 95% CI 0.41 to 0.53;P ≤ 0.001) and MII oocytes (B coefficient = 0.36, 95% CI 0.32 to 0.41;P ≤ 0.001) at linear regression analysis. Donors with low AFC had a higher risk of cancellation (OR 4.79, 95% CI 2.99 to 7.69;P < 0.001) or obtaining fewer than four metaphase II (MII) at ovum retrieval (OR 3.87, 95% CI 2.38 to 6.27;P < 0.001). No association was found between AFC and biochemical (OR 1.13, 95% CI 0.93 to 1.36), clinical (OR 1.05, 95% CI 0.87 to 1.28), ongoing pregnancy (OR 1.00, 95%, CI 0.82 to 1.21) or live birth rates (OR 0.97, 95% CI 0.8 to 1.19), when at least four MII were obtained at ovum retrieval.

CONCLUSIONS

AFC does not relate to the developmental competence of oocytes in women younger than 35 years.

High reliability of morphokinetic annotations among embryologists

STUDY QUESTION

Are morphokinetic measurements of time lapse-videos of human embryos comparable among operators?

SUMMARY ANSWER

There is little variation among morphokinetic measurements taken by different operators when analyzing the same time lapse-videos of human embryos.

WHAT IS KNOWN ALREADY

Morphokinetic analysis of preimplantation embryo development is a complementary method of embryo assessment increasingly used in IVF laboratories. Time-lapse videos of embryo development are normally viewed by trained embryologists and annotated with the times when specific developmental events occur. Such annotations form the basis of embryo selection algorithms, used to rank the embryos for transfer. It is unknown whether the reliability of morphokinetic annotations is related to the morphological characteristics of the analyzed embryo or to the ability of the embryologists performing the annotation. One study so far reported the reliability of morphokinetic annotations among three embryologists using the time-lapse system (TLS), but larger studies with different setups are needed to address this issue further.

STUDY DESIGN SIZE DURATION

A prospective study was carried out between October 2015 and June 2016. Six embryologists with various degrees of experience in static, morphology-based evaluation, individually annotated the same 93 videos of preimplantation development, corresponding to 18 IVF/ICSI cycles, recorded with a TLS.

PARTICIPANTS/MATERIALS SETTING METHODS

Times of second polar body extrusion, appearance and disappearance of pronuclei, and embryo cleavages (times from 2-cell to 5-cell stage: t2, t3, t4, t5) were annotated. Each embryologist was blinded to the annotations of the others. Intra- and inter-observer agreement was evaluated by computing intra-class correlation coefficients (ICCs).

MAIN RESULTS AND THE ROLE OF CHANCE

In the inter-observer analysis, most ICCs obtained were higher than 0.80, indicating a high level of agreement: t2: 0.93; t3: 0.80; t4: 0.89; t5: 0.89; disappearance of two pronuclei: 0.98. However, the ICCs obtained for second polar body extrusion and the appearance of two pronuclei annotations was lower: 0.51 and 0.63, respectively, indicating an average level of agreement. The ICCs obtained from the intra-observer analysis were also higher than 0.80 (t2: 0.96; t3: 0.89; t4: 0.88; t5: 0.86; disappearance of two pronuclei: 0.96). The ICCs obtained from second polar body extrusion and the appearance of two pronuclei annotations were 0.77 and 0.66, respectively. These results indicate that developmental timings, annotated in time-lapse videos, are highly reliable both within and among observers.

LIMITATIONS REASONS FOR CAUTION

The events at the developmental stages from 6-cells to blastocyst were not evaluated; since some morphokinetic algorithms use times past the 6-cell stage in their calculations, further studies should be carried out to understand the variations among observers in these cases.

WIDER IMPLICATIONS OF THE FINDINGS

Time-lapse measurement should be as objective as possible, especially for the first embryo cleavages, because they are often measured to define algorithms to assess the embryonic implantation potential. Our results show that measurements using this particular TLS are consistent and reliable both within and among operators.

STUDY FUNDING/COMPETING INTERESTS

None.

TRIAL REGISTRATION NUMBER

Not applicable.

Transition from blastomere to trophectoderm biopsy: comparing two preimplantation genetic testing for aneuploidies strategies

Shortly after the implementation of comprehensive chromosome screening (CCS) techniques for preimplantation genetic testing for aneuploidies (PGT-A), the discussion about the transition from day 3 to blastocyst stage biopsy was initiated. Trophectoderm biopsy with CCS is meant to overcome the limitations of cleavage-stage biopsy and single-cell analysis. The aim of this study was to assess the results obtained in our PGT-A programme after the implementation of this new strategy. Comparisons between the results obtained in 179 PGT-A cycles with day 3 biopsy (D+3) and fresh embryo transfer, and 204 cycles with trophectoderm biopsy and deferred (frozen–thawed) embryo transfer were established. Fewer embryos were biopsied and a higher euploidy rate was observed in the trophectoderm biopsy group. No differences in implantation (50.3% vs. 61.4%) and clinical pregnancy rate per transfer (56.1% vs. 65.3%) were found. Although the mean number of euploid embryos per cycle did not differ between groups (1.5 ± 1.7 vs. 1.7 ± 1.8), the final number of euploid blastocysts available for transfer per cycle was significantly higher in the trophectoderm biopsy group (1.1 ± 1.3 vs. 1.7 ± 1.8). This factor led to an increased cumulative live birth rate in this last group (34.1% vs. 44.6%). Although both strategies can offer good results, trophectoderm biopsy offers a more robust diagnosis and the intervention is less harmful for the embryos so more euploid blastocysts are finally available for transfer and/or vitrification.

Sperm telomere length in donor samples is not related to ICSI outcome

PURPOSE

Variations in sperm telomere length (STL) have been associated with altered sperm parameters, poor embryo quality, and lower pregnancy rates, but for normozoospermic men, STL relevance in IVF/ICSI is still uncertain. Moreover, in all studies reported so far, each man's STL was linked to the corresponding female partner characteristics. Here, we study STL in sperm donor samples, each used for up to 12 women, in order to isolate and determine the relationship between STL and reproductive outcomes.

METHODS

Relative STL was determined by qPCR in 60 samples used in a total of 676 ICSI cycles. Univariable and multivariable statistical analyses were used to study the STL effect on fertilization rate; embryo morphology; biochemical, clinical, and ongoing pregnancy rates; and live birth (LB) rates.

RESULTS

The average STL value was 4.5 (relative units; SD 1.9; range 2.4-14.2). Locally weighted scatterplot smoothing regression and the rho-Spearman test did not reveal significant correlations between STL and the outcomes analyzed. STL was not different between cycles resulting or not in pregnancy and LB (Mann-Whitney U test, p > 0.05). No significant effect of STL on reproductive outcomes was found, with the OR for each unit increase in STL (95% CI) of 0.94 (0.86-1-04), 0.99 (0.9-1.09), 0.98 (0.89-1.09), and 0.93 (0.8-1.06) for biochemical, clinical, and ongoing pregnancy and LB, respectively. The multilevel analysis confirmed that the effect of STL on fertilization; biochemical, clinical, and ongoing pregnancy; and LB was not significant (p > 0.05).

CONCLUSION

After addressing STL independently from female variables, results show that STL measurement is not useful to predict reproductive outcomes in ICSI cycles using donor semen.

WBP2NL/PAWP mRNA and protein expression in sperm cells are not related to semen parameters, fertilization rate, or reproductive outcome

PURPOSE

WBP2NL/PAWP, a protein found in the post-acrosomal region of mammalian spermatozoa, has been proposed as a sperm-borne oocyte-activating factor (SOAF) contributing to Ca²⁺ release within the oocyte and subsequent fertilization and embryo development. However, its relevance as either a diagnostic or a prognostic marker of fertilization failure has been questioned in the recent literature. We analyzed WBP2NL/PAWP gene and protein expression level and localization in patients without previous intracytoplasmic sperm injection (ICSI) cycles in order to assess its association with both sperm characteristics and ability to fertilize.

METHODS

Raw frozen-thawed semen samples from 33 couples referred for oocyte donation were included in the study during 2015. Relative protein expression versus α-tubulin (western blot, WB), proportion of post-acrosomal WBP2NL/PAWP-positive spermatozoa over the total number of sperm cells (immunofluorescence), and WBP2NL/PAWP gene expression (RT-qPCR) were analyzed and correlated with semen analysis parameters (number, motility, and morphology) and with reproductive outcomes.

RESULTS

WBP2NL/PAWP protein was expressed in all samples with high variability: relative protein expression (1.77 ± 0.8, range [0.4-3.7]), proportion of positive cells (49.6% ± 16.1, range [22-89]), and relative gene expression (7.3 ± 8.2). No significant correlation (R ² < 0.1) was found between gene and protein expression, neither between WBP2NL/PAWP gene or protein expression, and fertilization rate or other reproductive outcomes (i.e., pregnancy). In contrast, we found significant correlation between sperm morphology and WBP2NL/PAWP semiquantitative analysis in WB (r = -0.42, p < 0.05) and for sperm motility and WBP2NL/PAWP expression in IF (r = 0.52, p < 0.05).

CONCLUSION

Taken into account that WBP2NL/PAWP gene and protein levels and distribution did not correlate with fertilization rates, this study questions the interest of WBP2NL/PAWP protein and gene expression analysis in sperm cells as a prognostic factor for the outcome of ICSI cycles. Larger studies focusing on WBP2NL/PAWP protein and gene expression are needed in order to evaluate the role of WBP2NL/PAWP as a prognostic factor for ART.

Usefulness of oocyte accumulation in low ovarian response for PGS

This is an observational study of the response to ovarian stimulation and preimplantational genetic screening (PGS) cycles of 188 patients with a foreseen high aneuploid rate, undergoing two or three stimulation cycles (2SC and 3SC) and oocyte vitrification to accumulate oocytes (Accumulation group = 112 patients) compared to patients undergoing one stimulation cycle (1SC Group= 76 patients) and fresh embryo transfer, between January 2011 and July 2014. Accumulation was performed when <10 MII oocytes were retrieved. Oocytes were vitrified for later warming and IVF, when the planned number of oocytes was achieved. After PGS, euploid embryos were transferred. Comparing 2SC Group with 3SC Group, AMH, AFC, number of oocytes retrieved per pick-up and total number of biopsied embryos were significantly higher in the 2SC Group. After chromosome analysis, 18.5% of biopsied embryos were euploid and 58.9% patients reached embryo transfer. There were no differences in pregnancy rates per patient between the 1SC, 2SC and 3SC Groups (36.8%, 34.9% and 31.0%, respectively) or per embryo transfer (59.6, 56.8 and 60%, respectively). In patients with <10 MII oocytes after ovarian stimulation undergoing PGS, accumulating oocytes can render a pregnancy rate per patient and per embryo transfer comparable to those of fresh PGS cycles.

Endometrial preparation: effect of estrogen dose and administration route on reproductive outcomes in oocyte donation cycles with fresh embryo transfer

STUDY QUESTION

Is there a difference in live birth rates following endometrial preparation with either a constant or increasing estrogen dose in fresh embryo transfer from oocyte donation cycles?

SUMMARY ANSWER

There is no difference in live birth rates between a constant dose versus an increasing dose of estrogen after fresh embryo transfer in oocyte donation cycles with oral or transdermal supplementation.

WHAT IS KNOWN ALREADY

Endometrial preparation (EP) with estrogen and progesterone, and embryo-endometrial synchronicity are determinant for adequate embryo implantation. Estrogen is crucial and different exogenous administration patterns could imply variations on EP. Moreover, estrogen undergoes metabolization by the intestines and liver when administered orally, an effect that is bypassed by transdermal administration. Information on the effect of replacement patterns and route of administration of E on reproductive outcomes of women undergoing fresh embryo transfer from oocyte donation cycles is scarce.

STUDY DESIGN, SIZE, DURATION

Retrospective cohort study including 8362 embryo transfers following ICSI, corresponding to 8254 patients, between October 2010 and March 2015. A total of 5593 (66.9%) patients received an increasing E dose (ID) (oral: 2 mg/day day(d)1-7, 4 mg days d8-12, 6 mg d13-embryo transfer; transdermal: 75 µg/3 days on d1-6, 150 µg/3 days d7-embryo transfer) while 2769 (33.1%) received a constant dose (CD) of estrogen (oral: 6 mg/day 1-embryo transfer; transdermal: 150 µg/3 days d1-embryo transfer). Embryos were generated by ICSI with fresh or vitrified donor oocytes fertilized with either fresh or frozen sperm from either the couple partner or donor.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Cohort allocation was not related to patient characteristics; instead it reflected an internal policy change in E administration. Effect of estrogen dose (ID versus CD) on biochemical, clinical, ongoing and live birth rates, stratified by administration route, was analyzed by univariate and multivariate analysis adjusted by donor and recipient demographic and cycle characteristics.

MAIN RESULTS AND THE ROLE OF CHANCE

No difference in live birth rate was found between CD and ID for oral (33.0 versus 32.5%, P = 0.81) and transdermal (35.3 versus 33.5%, P = 0.33) supplementation. Biochemical pregnancy rate was higher in CD than ID (53.7 versus 47.5%, P < 0.001) when patients received oral supplementation. Adjusted analysis confirmed that oral administration had a greater impact on biochemical pregnancy rates than transdermal (odds ratio (OR) 1.28; 95% confidence interval (CI) 1.11-1.48, P = 0.001 versus OR 1.13; 95% CI 1.00-1.30, P = 0.055). Sub-analysis of transfers between day 12 and 15 of estrogen supplementation showed no difference between CD and ID in pregnancy outcomes. Demographic variables and cycle characteristics were comparable between both groups. Moreover, the use of the oocyte donation model reduces confounding factors related to oocyte age, embryo aneuploidy, and embryo quality.

LIMITATIONS, REASONS FOR CAUTION

The greatest limitation of this study is its retrospective nature. On the other hand, this study was performed using donated oocytes; although this is unlikely to affect the results, we cannot exclude the possibility that a high quality female gamete responds differently to endometrial state in comparison to a patient's own oocytes.

WIDER IMPLICATIONS OF THE FINDINGS

In fresh embryo transfer from oocyte donation cycles, changes in the protocol of E replacement do not seem to have an impact on clinical outcomes and performance; for this reason estrogen replacement protocols can be adjusted to the patient's characteristics and preferences as well as to the most cost effective strategy.

STUDY FUNDING/COMPETING INTERESTS

None.

Oxidative stress level in fresh ejaculate is not related to semen parameters or to pregnancy rates in cycles with donor oocytes

PURPOSE

The purpose of the present study is to study the relationship between oxidative stress (OS) in semen, semen characteristics, and reproductive outcomes in oocyte donation intracytoplasmic sperm injection (ICSI) cycles.

METHODS

OS was measured in 132 semen samples.

RESULTS

OS levels were as follows: very high (1.5 %), high (43.2 %), low (30.3 %), and very low (25.0 %). Overall seminal parameters were as follows: volume (ml) = 4.2 (SD 2.1), concentration (millions/ml) = 61.6 (SD 59.8), motility (a+b%) = 47.4 (SD 18.0), and normal spermatozoa (%) = 8.2 (SD 5.1). Of the 101 cycles that reached embryo transfer, 55.4 % evolved in biochemical, 46.5 % in clinical, and 43.6 % in ongoing pregnancy. OS level does not relate to seminal parameters, fertilization rate, or pregnancy outcomes.

CONCLUSIONS

OS testing by nitro blue tetrazolium (NBT) in fresh ejaculate might not be useful for all patients. Reproductive results with young oocytes and ICSI do not seem to be affected by OS-level semen.

Paternal age and assisted reproductive outcomes in ICSI donor oocytes: is there an effect of older fathers?

STUDY QUESTION

Does paternal age affect semen quality and reproductive outcomes in oocyte donor cycles with ICSI?

SUMMARY ANSWER

Paternal age is associated with a decrease in sperm quality, however it does not affect either pregnancy or live birth rates in reproductive treatments when the oocytes come from donors <36 years old and ICSI is used.

WHAT IS KNOWN ALREADY

The weight of evidence suggest that paternal age is associated with decreasing sperm quality, but uncertainty remains as to whether reproductive outcomes are affected. Although developed to treat severe sperm factor infertility, ICSI is gaining popularity and is often used even in the presence of mild male factor infertility.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study spanning the period between February 2007 and June 2010. A total of 4887 oocyte donation cycles were included.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Fertilization was carried out by ICSI in all cycles included, and the semen sample used was from the male partner in all cases. The association of male age with semen parameters (volume, concentration, percentage of motile spermatozoa) was analyzed by multiple analysis of covariance. The association of male age with reproductive outcomes (biochemical pregnancy, miscarriage, ongoing pregnancy and live birth rate) was modeled by logistic regression, where the following covariates were introduced: donor age, recipient age, semen state (fresh versus frozen) and number of transferred embryos (3 and 2 versus 1).

MAIN RESULTS AND THE ROLE OF CHANCE

We identified a significant relationship between paternal age and all sperm parameters analyzed: for every 5 years of age, sperm volume decreases by 0.22 ml (P < 0.001), concentration increases by 3.1 million sperm/ml (P = 0.003) and percentage motile spermatozoa decreases by 1.2% (P < 0.001). No differences were found in reproductive outcomes (biochemical pregnancy, miscarriage, clinical pregnancy, ongoing pregnancy and live birth) among different male age groups.

LIMITATIONS, REASONS FOR CAUTION

The use of donor oocytes, while extremely useful in highlighting the role of male age in reproductive outcomes, limits the generalization of our results to a population of young women with older male partners. No data were available on perinatal and obstetrical outcomes of these pregnancies. Most (75%) cycles used frozen/thawed sperm samples which might have introduced a bias owing to loss of viability after thawing. ICSI was performed in all cycles to control for fertilization method; this technique could mask the natural fertilization rate of poorer sperm samples. Furthermore, we did not use stringent ICSI indications; and our data are therefore not generalizable to cases where only severe male factor is considered. However, male patients were of different racial background, thus allowing generalizing our results to a wider patient base.

WIDER IMPLICATIONS OF THE FINDINGS

Our study suggests that paternal age does not affect reproductive outcomes when the oocyte donor is <36 years of age, indicating that ICSI and oocyte quality can jointly overcome the lower reproductive potential of older semen.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported in part by Fundació Privada EUGIN. The authors have no conflicts of interest to declare.