Impact of Zinc on Birth and Placental Weight inCadmium and Lead Exposure during Pregnancy

Background: Exposure to toxic metals in the prenatal period may have a negative impact onbirthweightandplacental weight (BW/PW). Low birth weight is an important etiological factor for chronic diseasesinadvancedages. The levels of essential elements are also important for healthy progress of pregnancy, but abnormal levelsmaybe harmful, such as excessive zinc (Zn) in the body increases BW/PW. Placental tissue directlyprovidesinformationto clinician about maternal and foetal exposure. Aims: To investigate the impact of cadmium(Cd), lead(Pb)andzinc (Zn) levels on birth weight. Methods: This study involved the measurement of metal levels in150participantsby inductively coupled plasma mass spectrometry (ICP-MS). Results: There were positive significant correlationswith BW/PW ratio and gestational age (r=0.205, p = 0.012), number of births (r=0.182, p =0.025), birthweight(r=0.505, p<0.001), and birth size (r=0.296, p < 0.001). Maternal blood Cd levels positively correlatedwithplacentalweight (r=0.256, p=0.002) and negatively correlated with BW/PWratio (r=-0.188 p =0.021). Foetal placentaPblevels were positively correlated with BW/PW ratio (r=0.198, p=0.015). Differences betweenmaternal andfoetalplacenta Zn levels were found to be statistically significant (23.90 ± 3.26 and 25.50 ± 4.69, respectively, p<0.001). Furthermore, Zn maternal levels of healthy births were found to be statistically different (p =0.014) whencomparedwith pregnancies with curettages and stillbirths. Conclusion: The findings are consistent withthehypothesisthatincreased Pb and Cd levels in pregnancy results in a low birth weight and these effects cannot be reversedbyZn, thelevels of which are positive related with healthy births. Environmental heavy metal exposure inpregnancyshouldbe routinely examined for baby health.