Assisted reproductive technology and neurodevelopment in children at 1 year of age: a longitudinal birth cohort study

BACKGROUND

With remarkable advancements in assisted reproductive technology (ART), the number of ART-conceived children continues to increase. Despite increased research investigating the outcomes of ART children, evidence on neurodevelopment remains controversial.

OBJECTIVE

The aim of this study was to investigate the association between ART use and neurodevelopment in children at 1 year of age and to determine whether the characteristics of parental infertility and specific ART procedures affect neurodevelopment in children.

STUDY DESIGN

The Jiangsu Birth Cohort enrolled couples who received ART treatment and who conceived spontaneously (2014-2020) in Jiangsu Province, China. In this study, we included 3531 pregnancies with 3840 cohort children who completed neurodevelopment assessment at 1 year of age, including 1906 infants conceived by ART (including 621 twins). Poisson regressions were fitted to estimate unadjusted and adjusted risk ratios (RRs) and 95% confidence intervals (CIs) for ART use with neurodevelopmental outcomes (cognition, receptive communication, expressive communication, fine motor, and gross motor) in children.

RESULTS

Among singletons, ART use was associated with a 24% to 34% decrease in the risk for noncompetent development in 3 domains (cognition, adjusted RR, 0.66; 95% CI, 0.53-0.82; receptive communication, 0.76; 0.64-0.91; expressive communication, 0.69; 0.51-0.93) after adjustment for conventional covariates. However, an inverse association was observed in the gross motor domain, with ART singletons having a greater risk of being noncompetent in gross motor development than their non-ART counterparts (adjusted RR, 1.41; 95% CI, 1.11-1.79). Compared with singletons, twins resulting from ART treatment demonstrated compromised neurodevelopment in several domains. Furthermore, we continued to observe that the transfer of 'poor' quality embryos was associated with greater risks for noncompetent development in receptive communication (adjusted RR, 1.50; 95% CI, 1.05-2.14) and gross motor domains (1.55; 1.02-2.36) among ART singletons.

CONCLUSION

These results generally provide reassuring evidence among singletons born after ART in the cognition, communication, and fine motor domains, but drawn attention to their gross motor development. The quality of transferred embryos in ART treatment might be associated with offspring neurodevelopment; however, the potential associations warrant further validation in independent studies, and the clinical significance needs careful interpretation.

Clinical Benefits of Decreased Photo-Oxidative Stress on Human Embryo Development

OBJECTIVE

Early embryonic development is characterized by rapid cell division and gene activation, making the embryo extremely sensitive to environmental influences. Light exposure can affect embryonic development through a direct toxic effect on the embryo via the generation of reactive oxygen species. In a previous study, we demonstrated the positive effect of improved light-protected embryo culture conditions implemented in our laboratory. This study aimed to investigate the changes in human embryo development under light protection during the conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

MATERIALS AND METHODS

We tested the potential beneficial effect of light filters to reduce the risk of toxic effects of light. IVF outcomes were compared between two experimental conditions, light protection with red light filters versus no light protection as a control.

RESULTS

Blastocyst development rate in IVF was significantly higher in the light-protected group than in the group treated under conventional conditions (46.6 vs. 26.7%). In the case of ICSI, we obtained a similar result (44.5 vs. 31.6%). The rate of cryopreservation with at least one embryo was higher in the light-protected phase (32.8%) than in the conventionally manipulated phase (26.8%). The abortion rate was also significantly lower during the light-protected period in IVF, resulting in a higher live birth rate.

CONCLUSIONS

The implementation of light protection to reduce the embryotoxic wavelengths of light in IVF centers may improve the blastocyst development rate and embryo quality while maintaining embryo safety.

Bridging the Gap: Animal Models in Next-Generation Reproductive Technologies for Male Fertility Preservation

This review aims to explore advanced reproductive technologies for male fertility preservation, underscoring the essential role that animal models have played in shaping these techniques through historical contexts and into modern applications. Rising infertility concerns have become more prevalent in human populations recently. The surge in male fertility issues has prompted advanced reproductive technologies, with animal models playing a pivotal role in their evolution. Historically, animal models have aided our understanding in the field, from early reproductive basic research to developing techniques like artificial insemination, multiple ovulation, and in vitro fertilization. The contemporary landscape of male fertility preservation encompasses techniques such as sperm cryopreservation, testicular sperm extraction, and intracytoplasmic sperm injection, among others. The relevance of animal models will undoubtedly bridge the gap between traditional methods and revolutionary next-generation reproductive techniques, fortifying our collective efforts in enhancing male fertility preservation strategies. While we possess extensive knowledge about spermatogenesis and its regulation, largely thanks to insights from animal models that paved the way for human infertility treatments, a pressing need remains to further understand specific infertility issues unique to humans. The primary aim of this review is to provide a comprehensive analysis of how animal models have influenced the development and refinement of advanced reproductive technologies for male fertility preservation, and to assess their future potential in bridging the gap between current practices and cutting-edge fertility techniques, particularly in addressing unique human male factor infertility.

Genetics of infertility: a paradigm shift for medically assisted reproduction

The field of reproductive genetics has undergone significant advancements with the completion of the Human Genome Project and the development of high-throughput sequencing techniques. This has led to the identification of numerous genes involved in both male and female infertility, revolutionizing the diagnosis and management of infertility patients. Genetic investigations, including karyotyping, specific genetic tests, and high-throughput sequencing, have become essential in determining the genetic causes of infertility. Moreover, the integration of genetics into reproductive medicine has expanded the scope of care to include not only affected individuals or couples but also their family members. Genetic consultations and counselling play a crucial role in identifying potentially affected relatives and offering tailored therapy and the possibility of fertility preservation. Despite the current limited therapeutic options, an increasing understanding of genotype-phenotype correlations in infertility genes holds promise for improved treatment outcomes. The availability of genetic diagnostic tools has reduced the number of idiopathic infertility cases by providing accurate aetiological diagnoses. The transition from research to clinical practice in reproductive genetics requires the establishment of genetic consultations and data warehousing systems to provide up-to-date information on gene-disease relationships. Overall, the integration of genetics into reproductive medicine has brought about a paradigm shift, emphasizing the familial dimension of infertility and offering new possibilities for personalized care and family planning.

Day-3-embryo fragmentation is associated with singleton birth weight following fresh single blastocyst transfer: A retrospective study

BACKGROUND

Previous studies have arguably associated poor embryo morphology with low birth weight in singletons following single embryo transfer. However, the association between birth weight and specific morphological features in the cleavage stage remains less known. The purpose of the study was to investigate whether morphological features of embryos at the cleavage stage affect birth weight following blastocyst transfer.

METHODS

The single-center retrospective cohort study included 4,226 singletons derived from fresh single cleavage-stage embryo transfer (ET; n = 1,185), fresh single blastocyst transfer (BT; n = 787), or frozen-thawed single blastocyst transfer (FBT; n = 2,254) between 2016 and 2019. Morphological parameters including early cleavage, day-3 fragmentation, symmetry, blastomere number, and blastocyst morphology were associated with neonatal birth weight and birth weight z-score in multivariate regression models. The models were adjusted for maternal age, body mass index (BMI), parity, peak estradiol level, endometrial thickness, insemination protocol, female etiologies, order of transfer, mode of delivery, and year of treatment.

RESULTS

Adjusted for confounders, day-3 fragmentation was the only morphological feature associated with birth weight and birth weight z-score, while early cleavage, symmetry, blastomere number, and blastocyst morphology were not. Day-3 fragmentation increased the birth weight in both the ET (115.4 g, 95% CI: 26.6-204.2) and BT groups (168.8 g, 95% CI: 48.8-288.8) but not in the FBT group (7.47 g, 95% CI: -46.4 to 61.3). The associations between birth weight and these morphological parameters were confirmed through birth weight z-score analyses. The adjusted odds of large for gestational age (LGA) and high birth weight were also significantly greater in singletons following the transfer of fragmented embryos in the BT group [odds ratio (OR) 3, 95% CI: 1.2-7.51 and OR 3.65, 95% CI: 1.33-10, respectively]. The presence of fragmentation at the cleavage stage also affected the association between the blastocyst morphology and birth weight. Inner cell mass grades were negatively associated with birth weight in blastocysts with day-3 fragmentation but not in blastocysts without.

CONCLUSIONS

The birth weight following blastocyst transfer was found to be positively associated with fragmentation at the cleavage stage. The data did not support the argument that transferring a poor-looking embryo may increase the risks of low birth weight. However, concerns for LGA infants remain.