Trace elements exposure affects the outcomes of in vitro fertilization embryo transfer, a cohort study in Northern China.

Purpose: With urbanization and industrialization process accelerated, humans are exposed more and more trace elements. This study aimed to explore the potential associations of trace elements with the outcomes of in vitro fertilization embryo transfer (IVF-ET).

Methods: Total 181 women who underwent IVF-ET were enrolled, among which 89 women underwent fresh ET after IVF. Trace elements were measured in the serum and follicular fluid (FF) samples by inductively coupled plasma-mass spectroscopy. The associations of the levels of different trace elements with IVF-ET outcomes, including normal fertilization, high-quality embryos, and clinical pregnancy (fresh ET) were analyzed.

Results: Twenty-five out of twenty-eight trace elements showed higher concentrations in the serum than those in the FF. Normal fertilization was positively associated with Cu and Mn in the FF. High-quality embryos was positively associated with Cu in the serum and FF, and Zn in the serum. Clinical pregnancy was positively associated with Ge in the serum, and inversely associated with Al, Ba, and Pb in the serum. Additionally, poor outcomes of IVF-ET should be noticed in women with FF level of Cu < 955.38 ng/mL, FF level of Mn < 3.42 ng/mL, serum level of Ge < 6.11 ng/mL, serum level of Al > 28.44 ng/mL, and serum level of Pb > 0.90 ng/mL.

Conclusions: IVF-ET outcomes were positively associated with Cu, Mn, Zn, and Ge, and inversely associated with Al and Pb. Properly controlling the exposure of relevant trace elements is necessary for patients with the need of IVF-ET.