Association between female circulating heavy metal concentration and abortion: a systematic review and meta-analysis.

Objective: This study aimed to evaluate the association between blood heavy metal (zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd)) concentrations and spontaneous abortion (SA) and recurrent pregnancy loss (RPL) and explore the possible endocrine dysfunction associated with it. Methods: A literature search was performed in the PubMed, Embase, Cochrane Library, and Web of Science databases up to April 2023. The overall effects were expressed as the standard mean difference (SMD). Subgroup analysis was performed according to the type of abortion (SA or RPL). Stata 16.0 was utilized for data analysis. Results: Based on the integrated findings, abortion women showed significantly lower Zn (SMD = -1.05, 95% CI: -1.74 to -0.36, p = 0.003) and Cu concentrations (SMD = -1.42, 95% CI: -1.97 to -0.87, p <0.001) and higher Pb (SMD = 1.47, 95% CI: 0.89-2.05, p <0.001) and Cd concentrations (SMD = 1.15, 95% CI: 0.45-1.85, p = 0.001) than normal pregnant women. Subgroup analysis showed that Zn and Cu deficiency and Cd and Pb exposure were significantly (p <0.05) associated with RPL, whereas Cu deficiency and Cd and Pb exposure were significantly (p <0.05) associated with SA. Conclusion: Zn and Cu deficiencies and Pb and Cd exposure were associated with abortion. Endocrine dysfunction, such as insulin resistance, vitamin D insufficiency, and abnormal thyroid and sex hormone concentrations, is thought to be involved in heavy metal-related abortion.

Effects of NGS-based PGT-a for idiopathic recurrent pregnancy loss and implantation failure: a retrospective cohort study.

To clarify the effect of next-generation sequencing (NGS)-based preimplantation genetic testing for aneuploidy (PGT-A) combined with trophectoderm (TE) biopsy on the pregnancy outcomes of idiopathic recurrent pregnancy loss (iRPL) and idiopathic recurrent implantation failure (iRIF), we conducted a retrospective cohort study of 212 iRPL couples and 66 iRIF couples who underwent PGT-A or conventional in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment. The implantation rate (IR) per transfer (64.2%), clinical pregnancy rate (CPR) per transfer (57.5%), and live birth rate (LBR) per transfer (45%) of iRPL couples of the PGT-A treatment group were significantly higher (p < 0.05) than those of the conventional IVF/ICSI group (IR per transfer,38.2%; CPR per transfer,33.3%; LBR per transfer, 28.4%), whereas the pregnancy loss rate (PLR) per transfer was similar between the two groups. These effects were also significant (p < 0.05) in iRPL couples with advanced maternal age (AMA, ≥35 years), whereas no significant differences were found in clinical outcomes between the PGT-A and conventional IVF/ICSI groups in younger iRPL couples (<35 years). The cumulative clinical outcomes of iRPL couples were comparable between the PGT-A and conventional IVF/ICSI groups. No significant differences were found in any clinical outcomes between the PGT-A and conventional IVF/ICSI groups for young or AMA couples with iRIF. In conclusion, NGS-based PGT-A involving TE biopsy may be useful for iRPL women to shorten the time to pregnancy and reduce their physical and psychological burden, especially for iRPL women with AMA; however, couples with iRIF may not benefit from PGT-A treatment. Considering the small sample size of the iRIF group, further investigations with a larger sample size are needed to verify our findings.