Maternal and Umbilical Cord Blood Levels of Lead and Cadmium in Sudanese Women with Preeclampsia

Background/Objectives: Previous studies hypothesized that significant exposure to lead (Pb) and/or cadmium (Cd) induces preeclampsia in pregnant women with subsequent unfavorable obstetric outcomes. This study aimed to compare maternal (Pb and Cd) and umbilical cord (Pb and Cd) levels between patients with preeclampsia and healthy control pregnant women and investigate the variables that are associated with preeclampsia. In addition, the possible influences of these heavy metals on birth weight were assessed. Methods: A case–control study involving 60 women in each group was conducted at the Maternity Hospital in Omdurman, Sudan, between January and June 2021, and included pregnant women residing in Omdurman city, Khartoum state, Sudan. A structured questionnaire was used to gather clinical and medical history. Maternal and cord blood concentrations of Pb and Cd were measured using an atomic absorption spectrophotometer. Univariate and multivariate binary logistic regression analyses were conducted to identify variables associated with preeclampsia. Results: The average maternal age in cases was 25.2 (6.1) years, and in the control group, it was 27.7 (7.2) years. All included participants were residing in Omdurman city, Khartoum state. Preeclampsia patients exhibited significantly elevated mean (SD) levels of umbilical cord Pb [14.2 (5.3) vs. 10.2 (4.5) µg/L, p < 0.001], and median (25th–75th quartile) maternal Cd [3.5 (2.0─6.7) vs. 3.0 (2.0─ 4.0) µg/L, p = 0.021] and umbilical cord Cd [5.0 (3.0─8.1) vs. 2.5 (1.0─4.0) µg/L, p < 0.001] compared with healthy controls. Mean (SD) of umbilical cord Pb level was lower than maternal Pb [14.2 (5.3) vs. 15.7 (7.8) µg/L, p = 0.246), but not reached statistical significance, while median (25th–75th quartile) concentration of umbilical cord Cd and maternal Cd remained comparable [5.0 (3.0─8.1) vs. 3.5 (2.0─ 6.7) µg/L, p = 0.093], in patients with preeclampsia. Levels of umbilical cord Cd correlated inversely with birth weight [Sperman's correlation coefficient (rho) = −0.689, p = 0.013]. Umbilical cord Pb [aOR = 1.29; 1.09 to 1.54; p = 0.003], and Cd [aOR = 1.37; 1.08 to 1.73; p = 0.007], in addition to maternal Cd [aOR = 1.35; 1.06 to 1.72; p = 0.012], were among the variables that are significantly associated with preeclampsia in univariate and multivariate analysis. Conclusions: Umbilical cord Pb, maternal Cd, and umbilical cord Cd concentrations were elevated in pre-eclamptic patients compared with healthy parturient controls and associated with preeclampsia. The preferential higher availability of Cd, but not Pb, in fetal compared with maternal blood might explain why umbilical cord Cd, but not umbilical cord Pb, had a significant negative effect on birthweight.