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Association of the levels of heavy metals and trace elements during pregnancy with congenital heart defects in offspring: a prospective cohort study.

OBJECTIVES
To study the association of the levels of heavy metals and trace elements during pregnancy with congenital heart defects (CHD) in offspring, and to establish a model for predicting the probability of CHD based on the levels of heavy metals and trace elements during pregnancy.


METHODS
Based on the prospective birth cohort study in Gansu Provincial Maternal and Child Health Hospital in 2010-2012, a nested case-control study was conducted for the follow-up observation of 14 359 pregnant women. Among the pregnant women, 97 pregnant women whose offspring were diagnosed with CHD during follow-up were enrolled as the CHD group, and 194 pregnant women whose offspring had no CHD were selected as the control group. Inductively coupled plasma mass spectrometry was used to measure the levels of heavy metals and trace elements in maternal blood samples and fetal umbilical cord blood samples. A multivariate logistic regression analysis was used to evaluate the association between heavy metal and trace elements and CHD in offspring. A nomogram model for predicting the probability of CHD in offspring was established based on the levels of heavy metals and trace elements during pregnancy.


RESULTS
Compared with the control group, the CHD group had significantly higher levels of aluminum (Al), natrium (Na), calcium (Ca), titanium (Ti), selenium (Se), strontium (Sr), stannum (Sn), stibium (Sb), barium (Ba), and thorium (Th) in maternal blood samples (P<0.05), as well as significantly higher levels of Al, zinc (Zn), magnesium (Mg), kalium (K), Ca, Ti, chromium (Cr), copper (Cu), arsenic (As), Se, Sr, argentum (Ag), cadmium (Cd), Sn, and plumbum (Pb) in umbilical cord blood (P<0.05). The multivariate logistic regression analysis showed that the increase in the Sb level in maternal blood was associated with the increase in the risk of CHD in offspring [adjusted odds ratio (aOR)=4.81, 95% confidence interval (CI): 1.65-14.07, P=0.004], while in umbilical cord blood, the high levels of Al (aOR=4.22, 95%CI: 1.35-13.16, P=0.013), Mg (aOR=8.00, 95%CI: 1.52-42.08, P=0.014), and Pb (aOR=3.82, 95%CI: 0.96-15.23, P=0.049) were significantly associated with the risk of CHD in offspring. The levels of Al, Th, and Sb in maternal blood and levels of Al, Mg, and Pb in umbilical cord blood were included in the predictive model for CHD in offspring based on the levels of heavy metals and trace elements during pregnancy, and the calibration curve of the nomogram predictive model was close to the ideal curve.


CONCLUSIONS
Increases in the levels of Al, Th, Sb, Mg, and Pb during pregnancy may indicate the increase in the risk of CHD in offspring, and the nomogram predictive model based on these indices can be used to predict the probability of CHD in offspring.