Blood Lead Levels ≥ 45 mcg/ dL in Pregnancy: An Observational Study

ABSTRACT Objective To describe pregnant individuals with blood lead levels (BLLs) ≥ 45 mcg/dL and their pregnancy outcomes to inform clinical practice and public health policy. Design Inclusion criteria required New York City (NYC) residence and a venous BLL ≥ 45 mcg/dL during pregnancy. BLL data were linked to case events notes, risk assessment findings, and newborn data. Setting: NYC, 2004 to 2023. Population: Pregnant individuals with BLLs ≥ 45 mcg/dL. Methods Characteristics of pregnant individuals and pregnancy outcomes were summarised using descriptive statistics. Birth outcomes were compared with WHO standards and across trimesters of referral. Fisher's exact and Z tests were used to assess the significance of differences. Main Outcomes Measures Demographic characteristics, pregnancy outcome data, chelation of mother, and chelation of newborn. Results There were 44 pregnant individuals identified with BLLs ≥ 45 mcg/dL during pregnancy. The majority of cases were foreign‐born, with 52% from Mexico and 25% from South Asia. The miscarriage rate (9%) was more than twice the citywide rate. Potential lead sources varied by region, with 50% from Mexico and the Caribbean reporting pica, and 71% from India using traditional remedies. Cases identified earlier were more likely to have newborns with BLLs ≤ 10 mcg/dL and less likely to require chelation. Those treated with CaNa 2 EDTA alone had newborns with significant BLL declines. For the newborns, the prevalence of birth lengths and head circumferences below 5% was higher than expected, and if chelated, the BLL took about 27 months to decline < 5 mcg/dL. Conclusions Cultural practices, pica, and using traditional remedies were frequently identified in pregnant individuals with BLLs ≥ 45 mcg/dL.