Fertilization and neonatal outcomes after early rescue intracytoplasmic sperm injection: a retrospective analysis of 16,769 patients

Indications affect neonatal outcomes following early rescue ICSI: a retrospective study

PURPOSE

To investigate the impact of heterogeneity in patient indications or insemination protocols on neonatal outcomes of singletons following early rescue ICSI (rICSI) treatments.

METHODS

A retrospective study was conducted. Propensity score matching and multivariable logistic regression were used to adjust for confounders and biases.

RESULTS

A total of 9095 IVF patients, 2063 ICSI patients, and 642 early rICSI patients were included in the study. No differences were detected in neonatal outcomes except small for gestational age (SGA) which increased in early rICSI patients compared with both unmatched and matched IVF groups with the risk ratio (RR) of 1.31 (95% CI: 1.05, 1.64) and 1.49 (95% CI: 1.05, 2.12). Further analysis showed that SGA increased significantly in partial fertilization failure (PFF) cycles with RRs of 1.56 (95% CI: 1.08, 2.27) and 1.78 (95% CI: 1.22, 2.59) compared with both unmatched and matched IVF patients but not in TFF patients. A positive association between fertilization rate via IVF and birth weight z-score was revealed in the PFF patients.

CONCLUSION

Early rICSI in patients with total fertilization failure (TFF) appeared to be safe in terms of neonatal outcomes. However, when expanding the indications of rICSI to PFF patients, the SGA in the offspring increased, suggesting a potential effect on long-term health. Since other treatment options, such as using only the IVF-origin embryos still exist for these patients, further studies were needed to confirm the optimal decision for these patients.

Cumulative live birth rate and neonatal outcomes after early rescue ICSI: a propensity score matching analysis

STUDY QUESTION

Is early rescue ICSI (E-RICSI) an effective and safe technique compared to conventional ICSI?

SUMMARY ANSWER

Despite the higher multi-pronucleus (PN) rate compared to conventional ICSI, E-RICSI did not add extra risks to clinical and neonatal outcomes.

WHAT IS KNOWN ALREADY

Based on the finding that the second polar body was released in 80% of fertilized oocytes by 4 h after exposure to spermatozoa and in ∼90% of fertilized oocytes by 6 h, E-RICSI brings forward the timing of rescue ICSI to 6 h after initial insemination, and effectively prevents oocyte aging and embryo-uterus asynchrony. However, some researchers still voice concerns about the efficacy and safety of E-RICSI, and comparative studies are limited.

STUDY DESIGN SIZE DURATION

A retrospective cohort study was conducted on patients who underwent conventional ICSI or E-RICSI treatment between January 2015 and December 2020 at a university-affiliated hospital. Using 1:1 propensity score matching, 1496 cases entered each group.

PARTICIPANTS/MATERIALS SETTING METHODS

In total, 1496 couples undergoing conventional ICSI oocyte retrieval cycles and 1496 undergoing E-RICSI oocyte retrieval cycles were enrolled in this study, and basic clinical characteristics, embryologic data, clinical outcomes and neonatal data were compared between groups. The embryos in the E-RICSI group were divided into two subgroups: those fertilized by iIVF (IVF subgroup) and those fertilized by E-RICSI (E-RICSI subgroup); the embryologic data, clinical outcomes, and neonatal data for these subgroups were also compared with the conventional ICSI group. Logistic regression was used for statistical analysis with potential confounder adjustment.

MAIN RESULTS AND THE ROLE OF CHANCE

The 2PN rate, blastocyst formation rate, and viable blastocyst formation rate of the E-RICSI group were significantly lower compared to the conventional ICSI group (2PN rate: P < 0.001; blastocyst formation rate: P < 0.001; viable blastocyst formation rate: P = 0.004), and the multi-PN rate in the E-RICSI group was significantly higher than the conventional ICSI group (P < 0.001). However, the number of 2PN embryos, normal cleavage embryo rate, Day 3 high-quality cleavage embryo rate, and high-quality blastocyst rate were similar between groups. When considering the IVF embryos and E-RCSI embryos in the E-RICSI group independently, the 2PN rate of the conventional ICSI group was significantly lower than E-RICSI subgroup but higher than the IVF subgroup, whereas the blastocyst formation rate and viable blastocyst formation rate were higher than E-RICSI embryos but comparable to IVF embryos. As for the clinical and neonatal outcomes, the implantation rate of the E-RICSI subgroup was significantly lower than the IVF subgroup but comparable to the conventional ICSI group, while the low birthweight (LBW) rate was significantly lower compared with the conventional ICSI group but similar with the IVF subgroup. No other differences were observed among the three groups for cumulative clinical pregnancy rate, cumulative live birth rate, and the pregnancy outcomes per transfer including clinical pregnancy, ectopic pregnancy, miscarriage, and live birth, either in fresh or frozen embryo transfer cycles. Furthermore, neonatal outcomes, including cesarean section, sex ratio, LBW, preterm birth, and macrosomia, were similar among groups.

LIMITATIONS REASONS FOR CAUTION

This study is limited by the retrospective design, limited sample size, and short follow-up period. However, our study underlies the need for large-scale, multi-center randomized controlled trials with long-term follow-up.

WIDER IMPLICATIONS OF THE FINDINGS

Short-term insemination (3 h) combined with E-RICSI may be a safe and effective method to prevent the occurrence of total fertilization failure, and patients with normal or borderline sperm could be encouraged to try IVF first.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by grants from the National Key & Development Program of China (No. 2021YFC2700603) and the National Natural Science Foundation of China (No. 81801443). The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Comparing the pregnancy outcomes of Re‑ICSI and ICSI embryos in fresh ET and FET cycles

Early rescue intracytoplasmic sperm injection (Re-ICSI) can prevent total fertilization failure (TFF) during conventional in vitro fertilization (IVF). However, the implantation rate of Re-ICSI embryos is lower than that of direct ICSI during fresh embryo transfer (ET). The aim of the present study was to investigate the effect of frozen ET (FET) after Re-ICSI. In the present retrospective study, primary infertility patients that underwent the first Re-ICSI and ICSI treatment, were studied. The clinical pregnancy rate, implantation rate, ectopic pregnancy, abortion rate and live birth rate were analyzed between the Re-ICSI and ICSI groups in fresh ET and FET cycles. The average age of patients between Re-ICSI and ICSI groups in fresh ET and FET cycles was (29.0±3.2 vs. 29.1±3.1, and 29.1±3.3 vs. 28.9±3.0), respectively (P>0.05). Compared with ICSI embryos, the clinical pregnancy, implantation and live birth rates of Re-ICSI embryos were lower in fresh ET cycles. By contrast, there were no significant differences in the pregnancy, implantation and live birth rates between the Re-ICSI and ICSI embryos during the FET cycles. Re-ICSI coupled with FET may overcome the impaired outcomes in fresh ET.

Safety of early cumulus cell removal combined with early rescue ICSI in the prevention of fertilization failure

RESEARCH QUESTION

What are the clinical outcomes and safety implications of early cumulus cell removal after short-term insemination combined with early rescue intracytoplasmic sperm injection (ICSI) in preventing fertilization failure?

DESIGN

In this retrospective study, a total of 14,360 cycles were divided into four groups based on insemination method and fertilization ability: conventional IVF group (n = 5519); early cumulus cell removal group (n = 4107); conventional ICSI group (n = 4215); and early rescue ICSI group (where failed or low fertilization was predicted, n = 519). Fertilization outcomes, pregnancy outcomes, neonatal outcomes and birth defects were analysed by comparing the early cumulus cell removal group with the conventional IVF group, and the early rescue ICSI group with the conventional ICSI group.

RESULTS

There were no significant differences in the outcomes of fertilization, pregnancy, neonates or birth defects between the conventional IVF group and the early cumulus cell removal group (P > 0.05). When compared with the conventional ICSI group, the early rescue ICSI group had similar rates of two pronuclei (2PN) at fertilization, clinical pregnancy, miscarriage, ectopic pregnancy, live birth, sex, mean gestational age, very low birthweight, macrosomia and birth defects (P > 0.05) but a higher polyploidy rate, lower high-quality embryo rate (both P < 0.001), lower twin pregnancy rate (P < 0.01), lower rate of low birthweight, and a higher rate of normal birthweight (both P = 0.024).

CONCLUSIONS

Early cumulus cell removal combined with early rescue ICSI led to good pregnancy and neonatal outcomes without an increase in birth defects. This approach could therefore be an effective and safe method for patients with fertilization failure in conventional IVF.

A novel frameshift mutation in DNAH6 associated with male infertility and asthenoteratozoospermia

Introduction

Asthenoteratozoospermia is one of the most common causes of male infertility. Several genes have been identified as genetic causative factors, but there is a considerable genetic heterogeneity underlying asthenoteratozoospermia. In this study, we performed a genetic analysis of two brothers from a consanguineous Uighur family in China to identify gene mutations causative for asthenoteratozoospermia-related male infertility.

Methods

Two related patients with asthenoteratozoospermia from a large consanguineous family were sequenced by whole-exome sequencing and Sanger sequencing to identify disease-causing genes. Scanning and transmission electron microscopy analysis revealed ultrastructural abnormalities of spermatozoa. Quantitative real-time PCR (qRT-PCR) analysis and immunofluorescence (IF) analysis were used to assess the expression of the mutant messenger RNA (mRNA) and protein.

Results

A novel homozygous frameshift mutation (c.2823dupT, p.Val942Cysfs*21) in DNAH6 was identified in both affected individuals and was predicted to be pathogenic. Papanicolaou staining and electron microscopy revealed multiple morphological and ultrastructural abnormalities of affected spermatozoa. qRT-PCR and IF analysis showed abnormal expression of DNAH6 in affected sperm, probably due to premature termination code and decay of abnormal 3' untranslated region (UTR) region of mRNA. Furthermore, intracytoplasmic sperm injection could achieve successful fertilization in infertile men with DNAH6 mutations.

Discussion

The novel frameshift mutation identified in DNAH6 may contribute to asthenoteratozoospermia. These findings expand the spectrum of genetic mutations and phenotypes associated with asthenoteratozoospermia and may be useful for genetic and reproductive counseling in male infertility.

The role of maternal physical activity on in vitro fertilization outcomes: a systematic review and meta-analysis

PURPOSE

This systematic review is designed to summarize the evidence concerning the impact of maternal physical activity on the reproductive outcomes following assisted reproduction techniques (ART), namely in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI).

METHODS

We searched for eligible studies on PubMed, EMBASE databases and the Cochrane Library from their inception until September 2021. Our primary outcomes were live birth rate and miscarriage, while secondary ones included clinical pregnancy and implantation rates. The quality of the evidence was evaluated using a study-specific adaptation of the Robins I tool.

RESULTS

Quantitative data from 10 cohort studies (CS) and 2 randomized control trials (RCT), involving 3431 women undergoing ART treatments, were included in the analyses. The pooled results exhibited uncertainty regarding the effect of physical activity on live birth rate per woman (OR 1.15, 95% CI 0.92-1.43, p = 0.23, I² = 61%, 9 studies) and miscarriage rates (OR 0.79, 95% CI 0.44-1.43, p = 0.43, I² = 44%, 6 studies). However, physical activity was associated with significantly improved clinical pregnancy rate after ART (OR 1.39, 95% CI 1.08-1.79, p = 0.0009, I² = 68%, 10 studies), whereas implantation rate after ART almost reached statistical significance (OR = 1.95, 95% CI 0.99-3.82, p = 0.05, I² = 77%).

CONCLUSION

The current evidence is still insufficient to firmly conclude on the effect of maternal physical activity on live birth, miscarriage and implantation rates. Although clinical pregnancy rates favored physical activity in this group of patients, these results must be undertaken with caution due to the low quality and the high heterogeneity of the studies included.