Nickel and Reproductive/Developmental Toxicity

Congenital Heart Defects (CHDs)#

A Chinese case-control study (n=889) found dose-dependent association between maternal nickel exposure and CHD risk.^{[1]Metal nickel exposure increase the risk of congenital heart defects occurrence in offspringZhang N, Chen W, Dong Y et al. · 2019Open reference 1 ↓}

Hair nickel: median 0.629 ng/mg in CHD cases vs 0.443 ng/mg in controls (P<.001). Placental nickel: 0.178 ng/mg in cases vs 0.148 ng/mg (P=.039). Highest hair nickel (Ni) tertile: aOR 1.326 (95% CI 1.003-1.757) for total CHDs.

Strongest associations: left ventricular outflow tract obstruction (aOR 1.549), right ventricular outflow tract obstruction (aOR 1.543). "Other heart defects" with highest placental nickel: aOR 11.280 (dramatic but wide CI: 1.621-78.512).

Proposed mechanisms: ROS generation, epigenetic alterations (DNA methylation, histone acetylation changes), direct embryotoxicity.

Placental Barrier Dysfunction#

The placenta normally acts as a barrier to nickel transfer, but pregnancy complications weaken this barrier.^{[2]Pregnancy complications effect on the nickel content in maternal blood, placenta blood and umbilical cord blood during pregnancyDing R, Ruan Y, He X et al. · 2021Open reference 2 ↓}

Cord blood nickel (Ni) was elevated in women with gestational diabetes (GDM) and hypertensive disorders (HDCP) vs controls. Barrier function ranking: Control > GDM > Disease combination > HDCP (weakest). Maternal blood:cord blood nickel ratio >1 indicates good barrier—85% of controls vs 50-60% of disease groups met this threshold.

Birth weight and length significantly reduced in HDCP group. Nickel induces lipid peroxidation in placenta → decreased placental vitality → potential IUGR.

Effects on Growth and Development#

High nickel in placenta negatively correlated with birth weight.^{[3]Nickel Exposure from Food and Levels in Children's Blood and Tissues: Health ImplicationsDobrzyńska MM, Gajowik A, Jankowska-Steifer EA et al. · 2025Open reference 3 ↓} Nickel targets endocrine system: hypothalamus, pituitary, adrenal gland, thyroid, gonads. Can cause dysfunction of hormone secretion (growth, cortisol, thyroid hormones).

Associated with depression, autism, schizophrenia in animal models at high doses.

Animal studies: dietary NiCl₂ at 300 mg/kg causes immunotoxicity, cytotoxicity, genotoxicity; at 1200 mg/kg reduces food intake and body weight.