Objective To describe serum arsenic levels in peripheral blood during first or second trimester and umbilical cord blood of pregnant women in Ma′anshan city of Anhui province and to explore correlations between the arsenic levels and hypertensive disorder complicating pregnancy (HDCP).

Methods A total of 3 474 pregnant women were consecutively recruited in Ma′anshan Birth Cohort study between May 2013 and September 2014. Demographic information were collected at the first prenatal examination in first trimester. Maternal serum arsenic in the early and second trimester, and arsenic level in umbilical cord blood at delivery were detected via inductively coupled plasma mass spectrometry (ICP-MS). Logistic regression models were established to evaluate the association of arsenic levels during pregnancy and in umbilical cord blood with HDCP.

Results The incidence of HDCP was 5.9% among all the pregnant woman. The median and interquartile ranges (25 percentage point – 75 percentage point) of serum arsenic in the first trimester, second trimester and umbilical cord blood were 1.74 (1.22 – 2.51), 1.77 (1.28 – 2.54), and 1.87 (1.27 – 2.88) μg/L, respectively. The serum arsenic level in umbilical cord blood was higher than that of peripheral blood during first and second trimester of pregnancy, with significant difference (both P < 0.001). Logistic regression analysis indicated that the pregnant women with higher serum arsenic during first trimester had a 1.63 (95% confidence interval: 1.08 – 2.48) times higher risk of HDCP compared to the women with low serum arsenic; but there was no significantly observed association of serum arsenic in peripheral blood during second trimester and in umbilical cord blood with HDCP (P > 0.05).

Conclusion Serum arsenic concentration in umbilical cord blood is higher than that in maternal peripheral blood during first and second trimesters. High exposure to serum arsenic in first trimester could increase the risk of HDCP.