Neonatal heavy metals levels are associated with the severity of neonatal respiratory distress syndrome: a case–control study

This case–control study aimed to compare lead (Pb), cadmium (Cd), and arsenic (As) levels in neonates with respiratory distress syndrome (NRDS) with those levels in normal neonates and tested their associations with the severity of NRDS indicated by the levels of serum surfactant protein D (SP-D) and cord blood cardiac troponin I (CTnI), and high-sensitive C-reactive protein (hs-CRP). The study included two groups: G1 (60 healthy neonates) and G2 (100 cases with NRDS). Cord blood Pb, erythrocytic Cd (E-Cd), neonatal scalp hair As (N-As), maternal urinary Cd (U-Cd), and arsenic (U-As) were measured by a Thermo Scientific iCAP 6200, while CTnI, hs-CRP, and SP-D by their corresponding ELISA kits. The levels of cord blood Pb, E-Cd, N-As, U-Cd, U-As, SP-D, CTnI, and hs-CRP were significantly higher in G2 than G1 (p = 0.019, 0.040, 0.003, 0.010, 0.011, < 0.001, 0.004, < 0.001, respectively). While the birth weight, and APGAR score at 1, 5 and 10 min were significantly lower in G2 than G1 (p = 0.002, < 0.001, < 0.001, < 0.001, respectively). The levels of the studied heavy metals correlated positively with the levels of SP-D, CTnI, and hs-CRP. Heavy metals toxicity may be accused to be one of the causes of NRDS especially if other apparent causes are not there. Measuring and follow-up of heavy metal levels should be considered during pregnancy.