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

To describe pregnant individuals with blood lead levels (BLLs) ≥ 45 mcg/dL and their pregnancy outcomes to inform clinical practice and public health policy.

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.

NYC, 2004 to 2023.

Pregnant individuals with BLLs ≥ 45 mcg/dL.

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.

Demographic characteristics, pregnancy outcome data, chelation of mother, and chelation of newborn.

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 CaNa₂EDTA 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.

Cultural practices, pica, and using traditional remedies were frequently identified in pregnant individuals with BLLs ≥ 45 mcg/dL.