Enhancement of outcome from intracytoplasmic sperm injection: does co-culture or assisted hatching improve implantation rates?

Assisted hatching on assisted conception (in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI))

BACKGROUND

Failure of implantation and conception may result from inability of the blastocyst to escape from its outer coat, which is known as the zona pellucida. Artificial disruption of this coat is known as assisted hatching and has been proposed as a method for improving the success of assisted conception by facilitating embryo implantation.

OBJECTIVES

To determine effects of assisted hatching (AH) of embryos derived from assisted conception on live birth and multiple pregnancy rates.  SEARCH METHODS: We searched the Cochrane Gynaecology and Fertility Group Specialised Register (until May 2020), the Cochrane Central Register of Controlled Trials (CENTRAL; until May 2020), in the Cochrane Library; MEDLINE (1966 to May 2020); and Embase (1980 to May 2020). We also searched trial registers for ongoing and registered trials (http://www.clinicaltrials.gov - a service of the US National Institutes of Health; http://www.who.int/trialsearch/Default.aspx - The World Health Organization International Trials Registry Platform search portal) (May 2020).

SELECTION CRITERIA

Two review authors identified and independently screened trials. We included randomised controlled trials (RCTs) of AH (mechanical, chemical, or laser disruption of the zona pellucida before embryo replacement) versus no AH that reported live birth or clinical pregnancy data.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. Two review authors independently performed quality assessments and data extraction.

MAIN RESULTS

We included 39 RCTs (7249 women). All reported clinical pregnancy data, including 2486 clinical pregnancies. Only 14 studies reported live birth data, with 834 live birth events. The quality of evidence ranged from very low to low. The main limitations were serious risk of bias associated with poor reporting of study methods, inconsistency, imprecision, and publication bias. Five trials are currently ongoing. We are uncertain whether assisted hatching improved live birth rates compared to no assisted hatching (odds ratio (OR) 1.09, 95% confidence interval (CI) 0.92 to 1.29; 14 RCTs, N = 2849; I² = 20%; low-quality evidence). This analysis suggests that if the live birth rate in women not using assisted hatching is about 28%, the rate in those using assisted hatching will be between 27% and 34%. Analysis of multiple pregnancy rates per woman showed that in women who were randomised to AH compared with women randomised to no AH, there may have been a slight increase in multiple pregnancy rates (OR 1.38, 95% CI 1.13 to 1.68; 18 RCTs, N = 4308; I² = 48%; low-quality evidence). This suggests that if the multiple pregnancy rate in women not using assisted hatching is about 9%, the rate in those using assisted hatching will be between 10% and 14%. When all of the included studies (39) are pooled, the clinical pregnancy rate in women who underwent AH may improve slightly in comparison to no AH (OR 1.20, 95% CI 1.09 to 1.33; 39 RCTs, N = 7249; I² = 55%; low-quality evidence). However, when a random-effects model is used due to high heterogeneity, there may be little to no difference in clinical pregnancy rate (P = 0.04). All 14 RCTs that reported live birth rates also reported clinical pregnancy rates, and analysis of these studies illustrates that AH may make little to no difference in clinical pregnancy rates when compared to no AH (OR 1.07, 95% CI 0.92 to 1.25; 14 RCTs, N = 2848; I² = 45%). We are uncertain about whether AH affects miscarriage rates due to the quality of the evidence (OR 1.13, 95% CI 0.82 to 1.56; 17 RCTs, N = 2810; I² = 0%; very low-quality evidence).

AUTHORS' CONCLUSIONS

This update suggests that we are uncertain of the effects of assisted hatching (AH) on live birth rates. AH may lead to increased risk of multiple pregnancy. The risks of complications associated with multiple pregnancy may be increased without evidence to demonstrate an increase in live birth rate, warranting careful consideration of the routine use of AH for couples undergoing in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI). AH may offer a slightly increased chance of achieving a clinical pregnancy, but data quality was of low grade. We are uncertain about whether AH influences miscarriage rates.

Revisiting embryo assisted hatching approaches: a systematic review of the current protocols

Zona pellucida (ZP) manipulation, termed "assisted hatching" (AH), has been introduced in order to favor embryo hatching and ultimately improve assisted reproductive technology success but with poor proofs of safety and biological plausibility. We herein provide a systematic review of clinical outcomes following the application of different methods of ZP manipulation on fresh or frozen/thawed embryos at different developmental stages in different groups of patients. Out of the 69 papers that compared the clinical outcomes deriving from hatched versus non-hatched embryos, only 11 considered blastocysts while the rest referred to cleavage stage embryos. The ZP thinning of fresh embryos either by chemical or laser approach was shown to provide very limited benefit in terms of clinical outcomes. Better results were observed with procedures implying a higher degree of zona manipulation, including zona removal. Studies comparing the mechanical or chemical procedures to those laser-mediated consistently reported a superiority of the latter ones over the former. Literature is consistent for a benefit of ZP breaching in thawed blastocysts. This review provides the current knowledge on the AH procedure in order to improve its efficacy in the appropriate context. Embryologists might benefit from the approaches presented herein in order to improve Assisted Reproduction Technologies (ART) outcomes.

Effect of assisted hatching on pregnancy outcomes: a systematic review and meta-analysis of randomized controlled trials

Emerging evidence suggests that assisted hatching (AH) techniques may improve clinical pregnancy rates, particularly in poor prognosis patients; however, there still remains considerable uncertainty. We conducted a meta-analysis to verify the effect of AH on pregnancy outcomes. We searched for related studies published in PubMed, Web of Science, and Cochrane library databases from start dates to October 10, 2015. Totally, 36 randomized controlled trials with 6459 participants were included. Summary odds ratios (ORs) with 95% confidence intervals (CIs) for whether by AH or not were estimated. We found a significant increase in clinical pregnancy (OR = 1.16, 95% CI = 1.00–1.36, I² = 48.3%) and multiple pregnancy rates (OR = 1.50, 95% CI = 1.11–2.01, I² = 44.0%) with AH when compared to the control. Numerous subgroup analyses stratified by hatching method, conception mode, extent of AH, embryos transfer status, and previous failure history were also carried out. Interestingly, significant results of clinical pregnancy as well as multiple pregnancy rates were observed among women who received intracytoplasmic sperm injection, and who received AH which the zona were completely removed. In summary, this meta-analysis supports that AH was associated with an increased chance of achieving clinical pregnancy and multiple pregnancy. Whether AH significantly changes live birth and miscarriage rates needs further investigations.

A Prospective Randomized Controlled Study of Laser-Assisted Hatching on the Outcome of First Fresh IVF-ET Cycle in Advanced Age Women

There is no sufficient data to conclude the benefit of assisted hatching (AH) for advanced age patients. However, AH is routinely performed for advanced age patients undergoing in vitro fertilization (IVF) in China based on some retrospective evidence. It is important to assess the benefit of AH procedure for advanced age patients, especially by analyzing the data from China. This is a prospective randomized controlled trial to evaluate the effect of laser AH in the advanced age patients undergoing IVF. A total of 256 patients conformed to the inclusion criteria, and 78 were excluded by exclusion criteria. A total of 178 patients were eligible and randomized to 2 groups (82 AH group and 96 control group). Laser AH (zona thinning) was performed in the AH group. There were no statistical significance in basic clinical parameters between the 2 groups. No difference was found in implantation rate (AH vs control, 32.45% vs 39.29%) and clinical pregnancy rate (AH vs control, 48.78% vs 59.38%). Our data did not find any benefit of laser AH in improving implantation or pregnancy rates in advanced age women. Due to the potential risk and increasing financial burden, AH should not be routinely performed in first fresh IVF embryo transfer cycle for advanced age women.

Assisted hatching on assisted conception (in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI)

BACKGROUND

Failure of implantation and conception may result from an inability of the blastocyst to escape from its outer coat, which is known as the zona pellucida. Artificial disruption of this coat is known as assisted hatching and has been proposed as a method for improving the success of assisted conception by facilitating embryo implantation.

OBJECTIVES

To determine the effect of assisted hatching (AH) of embryos from assisted conception on live birth and multiple pregnancy rates. 

SEARCH METHODS

We searched the Cochrane Menstrual Disorders and Subfertility Group Specialised Register (August 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (August 2012), MEDLINE (1966 to August 2012) and EMBASE (1980 to August 2012).

SELECTION CRITERIA

Three authors identified and independently screened trials. We included randomised controlled trials (RCTs) of AH (mechanical, chemical or laser disruption of the zona pellucida prior to embryo replacement) versus no AH that reported live birth or clinical pregnancy.

DATA COLLECTION AND ANALYSIS

Three authors independently performed quality assessments and data extraction.

MAIN RESULTS

Thirty-one trials reported clinical pregnancy data, including 1992 clinical pregnancies in 5728 women. There was no significant difference in the odds of live birth in the AH group compared with the control group (9 RCTs; odds ratio (OR) 1.03, 95% confidence interval (CI) 0.85 to 1.26, moderate quality evidence), with no evidence of significant heterogeneity (P = 0.38) or inconsistency (I(2) = 6%). Analysis of the clinical pregnancy rates from the nine studies which reported live birth showed a non-significant result (OR 1.03, 95% CI 0.85 to 1.25 ).Analysis of all of the studies included in this update (31 RCTs) showed that the clinical pregnancy rate in women who underwent AH was slightly improved, but the level only just reached statistical significance (OR 1.13, 95% CI 1.01 to 1.27, moderate quality evidence). However, it is important to note that the heterogeneity for this combined analysis for clinical pregnancy rate was statistically significant (P = 0.001) and the I(2) was 49%. Subgroup analysis of women who had had a previous failed attempt at IVF found improved clinical pregnancy rates in the women undergoing AH compared with the women in the control group (9 RCTs, n = 1365; OR 1.42, 95% CI 1.11 to 1.81) with I(2) = 20%. Miscarriage rates per woman were similar in both groups (14 RCTs; OR 1.03, 95% CI 0.69 to 1.54, P = 0.90, moderate quality evidence). Multiple pregnancy rates per woman were significantly increased in women who were randomised to AH compared with women in the control groups (14 RCTs, 3447 women; OR 1.38, 95% CI 1.11 to 1.70, P = 0.004, low quality evidence).

AUTHORS' CONCLUSIONS

This update has demonstrated that whilst assisted hatching (AH) does appear to offer a significantly increased chance of achieving a clinical pregnancy, the extent to which it may do so only just reaches statistical significance. The 'take home' baby rate was still not proven to be increased by AH. The included trials provided insufficient data to investigate the impact of AH on several important outcomes. Most trials still failed to report on live birth rates.

Assisted reproductive technologies and monozygous twins: implications for future study and clinical practice

That the zona pellucida (ZP) plays a prominent role in the physiology of some human twinning is an attractive, albeit incompletely proven, medical hypothesis. Indeed, an association has been proposed between manipulation of the ZP and/or native ZP microarchitecture and monozygotic (MZ) twins. Ovulation induction also has been theoretically linked to in vivo ZP alterations facilitating MZ twin development. In vitro fertilization (IVF) relies on necessary (and, in some cases extended) embryo culture techniques potentially creating subtle ZP changes and subsequent MZ twinning. With growing experience in the assisted reproductive technologies and particularly IVF, some preliminary reports have noted an increased frequency of MZ twins after procedures that artificially breach the ZP (i.e., intracytoplasmic sperm injection [ICSI], or ‘assisted hatching’). Such ZP manipulations ostensibly enhance oocyte fertilization or facilitate blastocyst hatching, thus improving pregnancy rates for couples undergoing fertility treatment. Evidence exists both to challenge and support the connection between these phenomena and MZ twins. This report outlines the fundamental embryological processes believed responsible for these conflicting observations; the current literature on the subject of human ZP micro-manipulation and MZ twins is also discussed. Twin Research (2000) 3, 217–223.

Stimulation of the endometrium with high-grade blastocyst culture supernatant (SEHB) can improve pregnancy outcome for couples undergoing intracytoplasmic sperm injection (ICSI): a randomized clinical trial

PURPOSE

To evaluate the impact of stimulating the endometrium with high-grade blastocyst culture supernatant (SEHB) perfusion before blastocyst transfer (BT) on implantation rate, pregnancy rate, and pregnancy outcome in ICSI cycles.

MATERIALS AND METHODS

Ninety-four infertile couples who were referred to the Valiasr department of Imam Hospital complex between January 2010 and March 2011 enrolled in this randomized clinical trial. They were randomly divided into only BT or SEHB groups. Implantation rates, pregnancy rates, abortion, preterm and term delivery rates were compared between the two groups.

RESULTS

Implantation rates and pregnancy rates did not differ significantly between the two groups. The abortion rate was significantly higher in the BT only group while term delivery was significantly higher in SEHB group. Odds ratios of term delivery and abortion were 4.5 (p = 0.001) and 0.3 (p = 0.04), respectively.

CONCLUSION

The SEHB application may improve pregnancy outcome in infertile couples who are candidates for the ICSI reproductive method.

Assisted hatching in assisted reproduction: a state of the art

The World Health Organization estimates that one in six couples experience some delay in conception and an increasing number require treatment by the assisted conception (AC) procedures of in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI).The implantation rate of embryos resulting from in vitro fertilization cycles is generally less than 20%. The exposure of oocytes and embryos to the artificial conditions of in vitro culture may have negative effects on the embryo's ability to undergo normal hatching, resulting in low rates of implantation following IVF and embryo transfer. Human embryos resulting from superovulation develop more slowly in vitro compared to embryos in vivo, manifest a relatively high degree of cytogenetic abnormalities and undergo cellular fragmentation. Artificially disrupting the zona pellucida is known as assisted hatching (AH) and there is some evidence that embryos that have undergone zona manipulation for assisted hatching tend to implant one day earlier than unhatched embryos. A variety of techniques have since been employed to assist embryo hatching, including partial mechanical zona dissection, zona drilling and zona thinning, making use of acid tyrodes, proteinases, piezon vibrator manipulators and lasers. This review will consider the impact of IVF conditions on zona pellucida physiology, zona hardening, different techniques of assisted hatching, who may benefit from assisted hatching and potential hazards.

Assisted hatching on assisted conception (IVF and ICSI)

BACKGROUND

Failure of implantation and conception may result from an inability of the blastocyst to escape from its outer coat, known as the zona pellucida. Artificial disruption of this coat is known as assisted hatching (AH) and has been proposed as a method for improving the success of assisted conception.

OBJECTIVES

To determine whether assisted hatching (AH) of embryos facilitates live births and clinical pregnancy.

SEARCH STRATEGY

We previously searched the Cochrane Menstrual Disorders and Subfertility Group Specialsed Register (February 2007), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2007), MEDLINE (1966 to February 2007) and EMBASE (1980 to February 2007).

SELECTION CRITERIA

Two authors identified and independently screened trials. We included randomised controlled trials (RCTs) of AH (mechanical, chemical or laser disruption of the zona pellucida prior to embryo replacement) versus no AH, which reported live birth or clinical pregnancy rates.

DATA COLLECTION AND ANALYSIS

Two authors independently performed qualitative assessments and data extraction.

MAIN RESULTS

Twenty-eight trials reported clinical pregnancy data, including 1228 clinical pregnancies in 3646 women. There was no significant difference in the odds of live births in the AH compared with control groups (seven RCTs; OR 1.13, 95% CI 0.83 to 1.55; 255 births from 719 women, with no heterogeneity (P = 0.37) or inconsistency I(2) = 8%)). We also analysed the clinical pregnancy rate from the seven studies that reported live births, which was non-significant (OR 1.13, 95% CI 0.83 to 1.54). Inclusion of studies which were more robust in methodology showed an increase in clinical pregnancy rate which was just statistically significant (16 RCTs; OR 1.20, 95% CI 1.00 to 1.45, P = 0.05). Analysis of all the studies included in this update (28 RCTs) showed a marked increase in clinical pregnancy rate (OR 1.29, 95% CI 1.12 to 1.49).Miscarriage rates per women were similar in both groups (14 RCTs; OR 1.13, 95% CI 0.74 to 1.73). Multiple pregnancy rates per woman were significantly increased in women who were randomised to AH compared with women in control groups (12 RCTs; OR 1.67, 95% CI 1.24 to 2.26).

AUTHORS' CONCLUSIONS

The improvement in clinical pregnancy rate (CPR) with AH means that a clinic with a success rate of 25% could anticipate improving the CPR to between 29% and 49%, all things being equal. The included trials provided insufficient data to investigate the impact of assisted hatching on several important outcomes.

[Laser assisted hatching: Rouen University Hospital outcomes]

OBJECTIVE

Despite technical progress in In Vitro Fertilisation (IVF) procedure, embryo implantation rate remains low. Assisted hatching has been proposed to facilitate natural embryo hatching and implantation.

PATIENTS AND METHODS

Our study has evaluated whether laser assisted hatching improves implantation, pregnancy and live birth rates in different cases. We studied retrospectively 143 IVF cycles concerning more than 38 years old women, 166 IVF cycles after two previous implantation failures and 180 frozen-thawed embryo transfers.

RESULTS

Population characteristics were comparable in hatched and control groups. Implantation, pregnancy and live birth rates in women more than 38 years old were comparable with or without assisted hatching. Concerning repeated implantation failures, even if implantation, pregnancy and live birth rates were higher in assisted hatching group (FIV or ICSI), the differences were not significant. After frozen-thawed embryo transfers, implantation rate was significantly better with assisted hatching (19.14% vs 8.84% [p=0.02]).

DISCUSSION AND CONCLUSION

Assisted hatching improves embryo implantation rate after frozen-thawed embryo transfer.

The effect of condition/state of testicular spermatozoa injected to the outcome of TESE-ICSI-ET cycles

OBJECTIVE

The effect of state/condition of spermatozoa (fresh/motile, fresh/immotile, frozen/motile and frozen/immotile) to fertilization, embryo formation/development, implantation and pregnancy/delivery and abortion rates were studied.

STUDY DESIGN

The data of a total of 167 TESE-ICSI-ET cycles with fresh and cryopreserved, motile and immotile testicular spermatozoa collected with testicular biopsy from patients suffering from non-obstructive azoospermia were analyzed retrospectively. Analysis of variance (ANOVA) was used to distinguish the group effects in fertilization, embryo formation, and implantation ratio. The group effect was evaluated by using non-parametric statistics and the independent grouping variable was also the "semen state/condition". "Semen state/condition" groups were created according to fresh or frozen, and motile or non-motile (immotile) characteristics. For comparing the four groups, Kruskal-Wallis ANOVA and Median-test was applied. The analysis was carried out using Statistica for Windows (StatSoft, Inc., Chicago, USA).

RESULTS

Independently of state/condition of testicular spermatozoa injected into oocytes, no differences were found in fertilization and implantation/pregnancy rates. No difference was obtained in embryo development of oocytes injected with fresh/immotile or frozen/motile spermatozoa. However, difference was found in embryo development of oocytes injected with fresh/motile or frozen/immotile testicular spermatozoa (87% vs. 73%; P<0.04). Comparing embryo development of oocytes injected with fresh vs. frozen spermatozoa difference was also found (83% vs. 74%; P<0.01). No difference was found in the abortion rates between the groups. Differences were observed in the implantation rates, however, these differences could not be verified statistically.

CONCLUSION

The presented data show that condition of injected testicular spermatozoa has influence to embryo development and even frozen/immotile testicular spermatozoa is able to induce/support fertilization and early embryo development.

Impact of assisted hatching on fresh and frozen-thawed embryo transfer cycles: a prospective, randomized study

The aim of this study was to determine if assisted hatching (AH) could improve the rates of pregnancy and implantation for both fresh and frozen-thawed embryo transfer cycles. A total of 760 fresh embryo transfer cycles and 200 frozen-thawed embryo transfer cycles were randomly assigned to either the treatment group (AH) or the control group (no AH). Zona thinning by laser was performed just before embryo transfer. In fresh embryo transfer cycles, the AH group and control group results were comparable. There were no significant differences in the rates of positive human chorionic gonadotrophin (HCG; 47.5 versus 48.8%), clinical pregnancy (42.4 versus 42.6%), or implantation (26.3 versus 25.2%) between the two groups. However, in frozen-thawed embryo transfer cycles, the rates of positive HCG (32.0 versus 17.0%), clinical pregnancy (25.0 versus 14.0%) and implantation (16.7 versus 7.3%) were significantly greater in the AH group than in the control group (P &lt: 0.05). The results of this investigation show that in the fresh embryo transfer cycles, laser-assisted hatching by zona thinning has no impact on the rates of positive HCG, clinical pregnancy and implantation, whereas in frozen-thawed cycles, assisted hatching by zona thinning significantly increases all three of these rates.

Beneficial effect of long zona dissection on frozen-thawed blastocysts at a young age

Aim:  To assess the appropriateness of assisted hatching using long zona dissection of human frozen-thawed blastocysts at the time of warming, especially in women over 35 years of age or with repeated implantation failures. Methods:  Of 177 frozen-thawed blastocyst transfer cycles, 89 control cycles had an intact zona and 88 cycles had assisted hatching using long zona dissection of human thawed blastocyst at the time of warming. These two groups were further subdivided by age to a total of four subgroups: ≤34 years (assisted hatching, n = 39; controls, n = 39) and ≥35 years (assisted hatching, n = 49; controls, n = 50). Twenty-seven cycles in the control group and 28 cycles in the assisted-hatching group had repeated implantation failures. The clinical and ongoing pregnancy rates and the implantation rate between the two groups were analyzed retrospectively. Results:  The clinical pregnancy and implantation rates in women ≤34 years were significantly higher after the application of assisted hatching compared with the control group (87.2% and 71.2%vs 56.4% and 46.6%, P < 0.001). The clinical pregnancy and implantation rates of women with repeated implantation failures were higher after the application of assisted hatching compared with the control group (64.3% and 46.3%vs 48.1% and 34.1%), but this difference was not statistically significant. Conclusions:  Routine assisted hatching using long zona dissection at the time of warming on frozen-thawed blastocysts is a safe and easy method to perform and is extremely beneficial for increasing the pregnancy rate in young women ≤34 years of age, but not in women ≥35 years of age. Despite increased pregnancy and implantation rates in patients with repeated implantation failures, statistical significance was not achieved. (Reprod Med Biol 2007; 6: 211-218).

Effect of laser zona pellucida opening on clinical outcome of assisted reproduction technology in patients with advanced female age, recurrent implantation failure, or frozen-thawed embryos

OBJECTIVE

To determine whether laser-assisted hatching can improve clinical outcome of assisted reproductive techniques in patients with advanced female age, with recurrent implantation failure, or who are using frozen-thawed embryos.

DESIGN

A prospective randomized study.

SETTING

The infertility and IVF unit at a research facility in Iran.

PATIENT(S)

Four hundred ten patients with advanced female age (> or =37 y), 796 patients with recurrent implantation failure (for > or =2 cycles), and 180 patients with frozen-thawed embryos.

INTERVENTION(S)

Patients were divided equally into test and control groups. On the day of embryo transfer, the zona pellucida of the selected embryos in the test group were opened about 40 mum by using an infrared optical laser system, whereas in the control group they were all intact.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rates and implantation rates.

RESULT(S)

In the patients with advanced female age or recurrent implantation failure, the clinical pregnancy and implantation rates were similar for the test and control groups. However, in the patients with frozen-thawed embryos, the rates were statistically significantly higher in the test group as compared with those of the control group (31.2% and 12.8% vs. 11.1% and 4.2%, respectively).

CONCLUSION(S)

The laser-assisted hatching improved the pregnancy and implantation rates in patients with frozen-thawed embryos but had no effect in patients with advanced female age or recurrent implantation failure.

Laser assisted hatching in good prognosis patients undergoing in vitro fertilization-embryo transfer: a randomized controlled trial

OBJECTIVE

To evaluate whether assisted hatching improves clinical outcomes of embryo transfers to good prognosis patients, defined as patients < or =39 years with normal follicle-stimulating hormone (FSH) and E(2) levels, no more than one previous unsuccessful cycle of in vitro fertilization (IVF)-embryo transfer, and good embryo quality.

DESIGN

Prospective randomized controlled trial.

SETTING

Private assisted reproductive technology (ART) center.

PATIENT(S)

One hundred ninety-nine good prognosis patients undergoing IVF-embryo transfer.

INTERVENTION(S)

In vitro fertilization followed by embryo transfer on day 3 after oocyte retrieval with or without assisted hatching using a 1,480-nm wavelength infrared laser.

MAIN OUTCOME MEASURE(S)

Clinical intrauterine pregnancy, spontaneous pregnancy loss, and live birth.

RESULT(S)

Rates of clinical intrauterine pregnancy with fetal cardiac activity (53% vs. 54% per cycle), spontaneous pregnancy loss (13% vs. 16% per pregnancy), and live birth (47% vs. 46% per cycle) were very similar between treatment cycles with laser-assisted hatching and control cycles in which embryos were transferred without assisted hatching. There were no significant differences between treatment and control groups in any measured clinical outcome parameters.

CONCLUSION(S)

Assisted hatching does not improve clinical outcomes among good prognosis patients.

Evidence of improving quality of reporting of randomized controlled trials in subfertility

BACKGROUND

The quality of randomized controlled trials (RCTs) in subfertility and their suitability for inclusion in meta-analyses have been assessed in the past and found to be insufficient. Our aim was to assess whether this quality has improved over time, particularly since the publication of the Consolidated Standards of Reporting Trials (CONSORT) statement, and to assess what proportion of trials could be included in the meta-analyses of pregnancy outcomes such as those included in Cochrane Reviews.

METHODS

A selection of subfertility trials published in 1990, 1996 and 2002 was collected from the Cochrane Menstrual Disorder and Subfertility Group (MDSG) database. Only trials published in English as full journal articles, claiming to be randomized and reporting on pregnancy outcomes, were included.

RESULTS

One hundred and sixty-four trials met our inclusion criteria. Twenty-four (15%) were found not to be randomized, despite claims, and only 10 trials (6%) provided adequate details on the methods of randomization and allocation concealment. Of these, only three had sufficient details extractable to allow for an intention-to-treat analysis of the outcome 'live birth'.

CONCLUSIONS

Although an improvement in some subfertility-specific issues was observed, the quality of reporting of RCTs still needs to improve to make them suitable for inclusion in meta-analyses such as those in the Cochrane Library.

A randomized double-blind controlled study on the efficacy of laser zona pellucida thinning on live birth rates in cases of advanced female age

BACKGROUND

It is conceivable that defective embryo hatching plays a part in the mechanisms involved in the decrease of embryo implantation rates with advancing age. In an effort to test this hypothesis, we tested the effectiveness of assisted hatching (AH) in women > or =37 years of age.

METHODS

We prospectively studied 103 IVF-embryo transfer patients undergoing 103 embryo transfers. All of them were > or =37 years of age and had <3 previous IVF-embryo transfer attempts. Laser-AH of transferred embryos was either performed (AH group, n = 49) or not (control group, n = 54) according to randomized and double-blind methodology. Primary outcome was live birth rate.

RESULTS

Population characteristics were comparable in AH and control groups as well as the mean number of embryos transferred (2.7 +/- 0.6 versus 2.7 +/- 0.6) and the prevalence of top quality embryos transferred (65 versus 59%, respectively). We failed to find any statistically significant difference between AH and control groups with regard to implantation (16.1 versus 16.7%, respectively) and live birth rates (22.4 versus 29.6%, respectively).

CONCLUSION

The present study indicates that AH does not improve IVF-embryo transfer outcome in women aged > or =37 years.

Impact of assisted hatching on the outcome of intracytoplasmic sperm injection: a prospective, randomized clinical trial and pregnancy follow-up

OBJECTIVE

To evaluate the overall effect of assisted hatching (AH) on the implantation, pregnancy, and live birth rates in women undergoing intracytoplasmic sperm injection (ICSI) cycles; and to determine the effect of AH on the cytogenetic outcome (chromosomal constitution) of pregnancy.

DESIGN

Prospective, randomized study.

SETTING

Academic research environment.

PATIENT(S)

A total of 172 couples were enrolled in the study.

INTERVENTION(S)

Assisted hatching was carried out on day-3 ICSI embryos.

MAIN OUTCOME MEASURE(S)

Implantation, clinical pregnancy, and live birth rates; cytogenetic analysis of abortuses and umbilical cord blood samples from newborns.

RESULT(S)

Biochemical, clinical, and ongoing pregnancy rates were not significantly different between the AH and control groups. The implantation rate was higher in the AH group than in the control group (16% vs. 8%), especially in women aged > or =35 years. Postnatal umbilical cord blood samples were collected and cytogenetically analyzed from 39 live births (20 from the AH group, 19 from the control group). Two abnormal karyotypes were found (one AH, one control). There were seven spontaneous losses during the study interval. Six of the abortuses underwent cytogenetic study (five AH, one control), and four were found to have an abnormal karyotype (three AH, one control).

CONCLUSION

We found that AH improves implantation rates of ICSI cycles and seems to be most effective in women aged > or =35 years. A larger sample size is needed to determine whether AH improves the take-home-baby rate. Assisted hatching did not affect the rate of chromosomal abnormalities in live births in this study.

Assisted hatching on assisted conception (IVF & ICSI)

BACKGROUND

Failure of implantation and conception may result from an inability of the blastocyst to escape from its outer coat, know as the zona pellucida. In vitro culture conditions and/or advancing maternal age may alter the architecture of the zona pellucida and result in hatching difficulties. Artificial disruption of this coat is known as assisted hatching (AH) has been proposed as a method of improving the success of assisted conception.

OBJECTIVES

To determine whether assisted hatching (AH) of embryos facilitates live births and clinical pregnancy and whether it impacts on negative outcomes (such as multiple pregnancy and miscarriage).

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group trials register (1 June 2005), the Cochrane Controlled Trials Register (Cochrane Library Issue 2, 2005), MEDLINE (1996 to June 2003), EMBASE (1980 to June 2005) and reference lists of articles. Authors were contacted for missing and/or unpublished data.

SELECTION CRITERIA

Trials were identified and independently screened by two reviewers. Randomised controlled trials of AH (mechanical, chemical or laser disruption of the zona pellucida prior to embryo replacement) versus no AH that reported live birth, clinical pregnancy or implantation rates were included.

DATA COLLECTION AND ANALYSIS

Qualitative assessments and data extraction were performed independently by two reviewers. Outcomes were extracted as rates and combined using random effects meta-analysis, sensitivity analysis, sub grouping and meta-regression where appropriate.

MAIN RESULTS

Twenty-three randomised controlled trials consisting of 2668 women reported on 849 pregnancy outcomes. There was no significant difference in the odds of live births in the AH compared with control groups (6 RCTs; OR 1.19 95% CI 0.81 to 1.73; 163 births from 516 women). Women undergoing assisted hatching were significantly more likely to achieve clinical pregnancy (23 RCTs, OR 1.33, 95% CI 1.12 to 1.57). Miscarriage rates per woman were similar in both groups (12 RCTs OR 1.23 (95% CI 0.73 to 2.05). Multiple pregnancy rates per woman was increased in women who were randomised to AH compared with control women (9 RCTs OR 1.83 (95% CI 1.19 to 2.83). The improvement in clinical pregnancy rate means for a clinic with a success rate of 25% could anticipate improving the CPR to between 28 and 39%, all things being equal. The trials provided insufficient data to investigate the impact of assisted hatching on several important outcomes, including monozygotic twinning, embryo damage, congenital and chromosomal abnormalities, and in vitro blastocyst development.

AUTHORS' CONCLUSIONS

Despite significantly improved odds of clinical pregnancy, there is insufficient evidence to determine any effect of AH on live birth rates. The increased multiple pregnancy rate is of concern although it likely that with a policy of single embryo transfer this may be lowered. Currently, there is insufficient evidence to recommend assisted hatching.

Is there still a place for co-cultures in the era of sequential media?

Co-cultures have been advocated in assisted reproduction owing to the inadequacy of simple media to support embryo development beyond the cleavage stage. Different human and non-human cells and cell lines have been used for co-cultures. High rates of blastocyst formation have been reported with the use of co-cultures, and they have been proposed as a salvage treatment option in couples with repeated implantation failures. Since the advent of complex sequential media, which yield very high blastocyst formation and blastocyst implantation rates, the need for co-cultures has been questioned. Upon review of the literature, it is evident that well-designed randomized studies that compare co-cultures with simple or sequential media do not exist. Progression to the blastocyst stage for cleavage stage embryos appears to be similar, if not better, for embryos that are cultured in modern sequential media, rendering the use of co-cultures obsolete. Furthermore, there is no consensus regarding the necessity of sequential media, as similar results have been obtained with a single medium formulation that supports all stages of the preimplantation period. Whether co-cultures are beneficial in patients with repeated implantation failures, however, should be investigated in randomized trials. Co-cultures still serve as powerful tools for understanding embryo metabolism. Furthermore, co-cultures may be instrumental in studying expression of implantation-related genes and embryo-endometrium interaction.

[Assisted hatching: procedure and effectiveness]

Assisted hatching (AH) has been proposed to improve the implantation rate in patients with poor prognosis for pregnancy. This systematic review of randomized controlled trials addresses primary outcomes of clinical pregnancy and embryo implantation. Several different methods for AH have been introduced over the years but comparative studies are lacking. AH using laser technology is probably the best technique. Assisted hatching increases the pregnancy and implantation rates significantly in patients with a poor prognosis undergoing IVF or ICSI, particularly in older women. More randomized trials are required to confirm any positive effects on the take-home-baby rate and to compare the different techniques.

Assisted hatching--a meta-analysis of randomized controlled trials

PURPOSE

To conduct a meta-analysis of randomized controlled trials (RCTs) on assisted hatching.

METHODS

One hundred sixty-five studies were retrieved from the literature, but only 13 of them fitted our selection criteria. The meta-analysis was conducted using the RevMan software with the Peto-modified Mantel-Haenszel method.

RESULTS

Assisted hatching increases the pregnancy [OR (+/-95% CI) = 2.51 (1.91-3.29)], implantation [OR (+/-95% CI) = 2.38 (1.87-3.03)], and ongoing pregnancy rates [OR (+/-95% CI) = 2.65 (1.85-3.79)] significantly in poor prognosis patients undergoing IVF or ICSI. For patients with repeated IVF failures, the OR (+/-95% CI) were 2.84 (1.99-4.06) for pregnancy, 2.53 (1.85-3.47) for implantation, and 3.51 (2.12-5.82) for ongoing pregnancy rates, in favor of assisted hatching.

CONCLUSIONS

Assisted hatching increases the pregnancy, implantation, and ongoing pregnancy rates significantly in patients with a poor prognosis undergoing IVF or ICSI, particularly those with repeated failures.

Transfer of frozen-thawed blastocysts that underwent quarter laser-assisted hatching at the day 3 cleaving stage before freezing

OBJECTIVE

To examine the pregnancy potential of frozen-thawed blastocysts that underwent quarter laser-assisted hatching (AH) at the cleaving stage before freezing and to compare clinical and embryo characteristics between the groups that succeeded in and failed to achieve pregnancy.

DESIGN

Prospective observational study.

PATIENT(S)

Thirty-four of 112 patients with frozen blastocysts requiring transfer of thawed embryos between January 2000 and December 2001.

SETTING

Assisted reproductive technology unit in a tertiary medical center.

INTERVENTION(S)

Embryos of patients undergoing blastocyst transfers routinely underwent quarter AH using a nontouch 1.48-microm diode laser. Blastocysts not transferred were cryopreserved using a six-step freezing protocol with glycerol as the cryoprotectant.

MAIN OUTCOME MEASURE(S)

Postthaw embryo survival and zona pellucida (ZP) maintenance, implantation rate, and clinical pregnancy rate per transfer of thawed blastocysts.

RESULT(S)

A total of 118 frozen blastocysts was thawed. Of these, 89 (75.4%) embryos survived and were transferred in 35 cycles. Assisted hatching-manipulated ZP tolerated the freeze-thaw procedures without shape distortion in surviving embryos. Eleven (31.4%) clinical pregnancies with 15 intrauterine gestational sacs occurred, for an implantation rate of 16.9%. Those who succeeded in pregnancy tended to have more embryos available before freezing, more original blastocysts of good quality for freezing, and more surviving blastocysts after thawing for transfer than did those who failed to achieve pregnancy.

CONCLUSION(S)

An acceptable clinical pregnancy rate was obtained from transfer of thawed blastocysts that underwent laser AH on the ZP at the day 3 cleaving embryo stage in fresh cycles in selected patients. Embryo characteristics before freezing played major roles in determining implantation potential of thawed embryos.

Advanced embryo development during extended in vitro culture: observations of formation and hatching patterns in non-transferred human blastocysts

Human embryos not chosen for fresh transfer or cryopreservation were maintained in extended in vitro culture for up to 9 days after fertilization to observe blastocyst formation and hatching features. These non-transferred embryos were derived from 64 consecutive IVF cycles, and were not cryopreserved either because of compromised morphology or because the patients did not consent to cryopreservation for personal reasons. Embryos were cultured individually to monitor daily growth until developmental arrest, and differential blastocyst formation and hatching were analysed among groups of patients and embryos. In the population studied, hatching occurred most commonly on day 7 after fertilization (range 5-9 days). A total of 301 blastocysts was observed, of which 116 (38.5%) eventually hatched in vitro irrespective of day of formation. A trend towards earlier blastocyst formation and a greater likelihood of hatching was noted in this population. Both blastocyst formation and hatching appeared negatively correlated with increasing maternal age and higher basal serum FSH concentrations on day 3 of development, although these trends did not reach statistical significance. Comparison of intracytoplasmic sperm injection (ICSI) (n = 25) and conventional insemination (n = 39) cycles showed a similar rate of blastocyst formation in both groups (54 and 52%, respectively; P > 0.05), but hatching patterns varied significantly between these groups (4.1 versus 61.6%, respectively; P < 0.0001). The discovery of marked impairment of hatching among non-transferred ICSI embryos supports the case for reconsideration of the appropriateness of assisted blastocyst hatching in selected cases.

An analysis of spontaneous hatching in a human endometrial epithelial coculture system: is assisted hatching justified?

PURPOSE

To evaluate spontaneous embryo hatching in an endometrial epithelial coculture system, and compare it with cases where coculture was performed because of maternal age, previous repeated implantation failures, or both. To clarify in which cases assisted hatching would be appropriate.

METHODS

Individual human embryos were cocultured on an endometrial epithelial cell monolayer until Day 6.

RESULTS

Blastocyst hatching rate at Day 6, depending on maternal age, was 9.1% (age <37 years) and 3.4% (age > or = 37 years). However, blastocyst hatching rates depending on number of previous IVF failures were similar.

CONCLUSIONS

Maternal age and previous implantation failures are factors affecting the ability of human embryos to reach the blastocyst stage in coculture. However, assisted hatching is not justified in these populations because of the absence of hatching rate differences between blastocysts obtained from these two groups and the control group.

Evaluation and treatment of low responders in assisted reproductive technology: a challenge to meet

PURPOSE

To investigate the various methods of evaluation and treatment of patients with a low response to controlled ovarian hyperstimulation in assisted reproductive technologies (ART).

METHODS

Review and analysis of relevant studies published in the last decade, identified through the literature and Medline searches.

RESULTS

While a universally accepted definition for low responders is still lacking, these patients are reported to represent about 10% of the ART population. Several ovarian reserve screening techniques have been proposed; however, currently the best-characterized and most sensitive screening tools available are the basal day 3 serum follicle-stimulating hormone level and the clomiphene citrate challenge test. When abnormal, these tests allow physicians to counsel patients that their prognosis for conception is poor. Although the presence of a normal result does indicate better long-term chances for conception, on age-related decline in fecundity remains and patient age should still be considered when counseling patients with normal screening results. Several stimulation protocols have been applied in the low-response group with varying success. Recent studies show that the use of a minidose gonadotropin-releasing hormone-agonist protocol may result in significantly decreased cycle cancellations as well as increased clinical and ongoing pregnancies, and thus is proposed as a first-line therapy. Studies evaluating supplementary forms of treatment to the ovulation induction regimen show improved outcome when pretreating with oral contraceptives, whereas there seems to be no benefit from cotreatment with growth hormone or glucocorticoids. Blastocyst culture and transfer and assisted hatching in low responders are still under evaluation, whereas natural cycle in vitro fertilization may be used in cases of repeated failures as a last option before resorting to oocyte donation or adoption. Future possible forms of treatment like in vitro maturation of immature human oocytes, cytoplasm, and nuclear transfer currently are experimental in nature and their efficacy has still to be proven.

CONCLUSIONS

The evaluation and treatment of low responders in ART remains a challenge. Understanding of the underlying etiology and pathophysiology of this disorder may help the clinician to approach it successfully.

Does assisted hatching pose a risk for monozygotic twinning in pregnancies conceived through in vitro fertilization?

OBJECTIVE

To examine the association between assisted hatching and monozygotic (MZ) twinning.

DESIGN

Case-control.

SETTING

Population-based sample of IVF-ET cycles initiated in U.S. clinics, 1996.

PATIENT(S)

The IVF-ET (n = 35,503) cycles and 11,247 resultant pregnancies.

INTERVENTION(S)

Use of an assisted hatching procedure on embryos transferred.

MAIN OUTCOME MEASURE(S)

Cases were pregnancies for which number of fetal hearts observed on ultrasound exceeded number of embryos transferred. These pregnancies were considered to contain at least one MZ set of twins. Cases were compared with two control groups: other multiple-gestation pregnancies (>/=2 fetal hearts but number of fetal hearts </= number of embryos transferred); and singleton pregnancies (1 fetal heart).

RESULT(S)

Women with a case pregnancy were more likely to have received embryos treated with assisted hatching procedures than were women in either control group. After adjustment for patient age, number of embryos transferred, prior cycles, infertility diagnosis, intracytoplasmic sperm injection, and whether embryos from the current cycle were cryopreserved for later use, odds ratios and 95% CIs for use of assisted hatching were 3.2 (1.2-8.0), compared with other multiple-gestation pregnancies, and 3.8 (1.8-9.8), compared with singleton pregnancies.

CONCLUSION(S)

Assisted hatching may pose a risk for MZ twinning.

Coculture of human embryos with autologous human endometrial epithelial cells in patients with implantation failure

We have developed a coculture system with autologous human endometrial epithelial cells (AEEC) that retained many features of human endometrial epithelium. Implantation failure (IF; >3 previous cycles failed with 3-4 good quality embryos transferred) is a distressing condition in which 2-day embryo transfer repetition is the routine option. The objective of this study was to investigate the basics and to evaluate prospectively the clinical value of embryo coculture on AEEC and blastocyst transfer with their own oocytes [in vitro fertilization (IVF) patients] or with donated oocytes (oocyte donation patients) compared to a routine day 2 embryo transfer for patients with IF. Scanning electron microscopy and mouse embryo assays demonstrate that EEC from fertile and IF patients were morphologically and functionally similar; similar findings were observed in EEC obtained from fresh or frozen endometria. Clinically, 168 IVF cycles were performed in 127 patients with 3.8+/-0.2 previously failed cycles, and 80 cycles were performed in 57 patients undergoing oocyte donation with 3.0+/-0.2 previously failed cycles. Twenty IVF patients and 15 ovum donation patients with 3 previously failed cycles in whom a 2-day embryo transfer was performed were used as controls. In 88% of ovum donation cycles, at least 2 blastocysts were available for transfer, with 60.1% blastocyst formation; 2.2+/-0.1 blastocysts were transferred/cycle, and 36 pregnancies (determined by fetal cardiac activity) were obtained (32.7% implantation and 54.5% pregnancy rates). In 168 IVF cycles, 8.1+/-0.2 embryos/cycle started coculture, resulting in 49.2% blastocyst formation; 2.3+/-0.2 blastocysts were transferred/cycle, and 29 clinical pregnancies were obtained (11.8% implantation and 20.2% pregnancy rates). Fifteen cycles were canceled (9%). In oocyte donation patients with IF undergoing 2-day embryo transfer, implantation and pregnancy rates were significantly lower (4.5% and 13.3%; P < 0.01) than with coculture; however, in IVF patients with IF, results with day 2 transfer (10.7% and 35%) were similar to those with coculture. The present study demonstrates that coculture of human embryos with AEEC and blastocyst transfer is safe, ethical, and effective and constitutes a new approach to improve implantation in patients with IF undergoing ovum donation, but not in IVF patients.

Multiple pregnancy rate and embryo number transferred during in vitro fertilization

OBJECTIVE

Our goal was to achieve a good pregnancy rate after in vitro fertilization; more than one embryo, if available, is transferred to the uterine cavity. This is a recognition of the low implantation rates of embryos from in vitro fertilization. A consequence of this can be high-order multiple implantation with obstetric complications.

STUDY DESIGN

Retrospectively, we reviewed 42 months' in vitro fertilization experience; we related the number of embryos transferred and the pregnancy outcome. During this period 2173 fresh and frozen-thawed embryo transfers were performed. One to six embryos were transferred to women whose average age was 34.4 years (range 21 to 49).

RESULTS

A total of 734 delivered pregnancies (33.8% per embryo transfer) was analyzed according to whether they were single or multiple, and this was related to the original number of embryos transferred. The overall multiple pregnancy rate was 31.3% (24.7% twins, 5.8% triplets, 0.8% quadruplets).

CONCLUSIONS

There was a trend toward a higher pregnancy rate with more embryos transferred. The embryonic implantation rate, which reflects the number of embryos that implant per total transferred, was not significantly different in any one group, except in older women in whom more than one embryo was transferred. Whereas greater numbers of embryos (more than three) were transferred in couples with a poorer prognosis for successful in vitro fertilization (e.g., older women [> 36 years old], previous failure of in vitro fertilization, poor embryo quality, or severe male factor causing infertility), there still remained a significant trend toward a higher pregnancy rate when more embryos were transferred. The embryonic implantation rate did not decline in the poorer-prognosis groups (more than three embryos transferred), yet the multiple pregnancy rate was increased. Technologic procedures such as embryo biopsy for aneuploidy screening are proposed as one means to reduce embryo numbers transferred without decreasing the overall pregnancy rate.