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Updated: Jun 14, 2025
Long-term Behavioral and Reproductive Consequences of Embryonic Exposure to Low-dose Toxicants
Published on: March 6, 2018
Association between Exposure of Rare Earth Elements and Outcomes of In Vitro Fertilization-Embryo Transfer in Beijing
Yu Tong Wang1, Jing Li2, Shi Rong Xu2
1State Key Laboratory of Female Fertility Promotion, Center for Reproductive Medicine, Department of Obstetrics and Gynecology Peking University Third Hospital, Beijing 100191, China;Department of Medical Genetics, Peking University, Beijing 100191, China;National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China;Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing 100191, China;Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing 100191, China.
Objective:
The study aimed to investigate the impact of rare earth elements (REEs) exposure on pregnancy outcomes of in vitro fertilization-embryo transfer (IVF-ET) by analyzing samples from spouses.
Methods:
A total of 141 couples were included. Blood and follicular fluid from the wives and semen plasma from the husbands, were analyzed for REEs using inductively coupled plasma mass spectrometry (ICP-MS). Spearman's correlation coefficients and the Mann-Whitney U test were used to assess correlations and compare REE concentrations among three types of samples, respectively. Logistic models were utilized to estimate the individual REE effect on IVF-ET outcomes, while BKMR and WQS models explored the mixture of REE interaction effects on IVF-ET outcomes.
Results:
Higher La concentration in semen (median 0.089 ng/mL, P = 0.03) was associated with a lower fertilization rate. However, this effect was not observed after artificial selection intervention through intracytoplasmic sperm injection (ICSI) ( P = 0.27). In semen, the REEs mixture did not exhibit any significant association with clinical pregnancy.
Conclusion:
Our study revealed a potential association between high La exposure in semen and a decline in fertilization rate, but not clinical pregnancy rate. This is the first to report REEs concentrations in follicular fluid with La, Ce, Pr, and Nd found at significantly lower concentrations than in serum, suggesting that these four REEs may not accumulate in the female reproductive system. However, at the current exposure levels, mixed REEs exposure did not exhibit reproductive toxicity.
