Childhood lead screening and testing are critical for identifying children exposed to lead and addressing exposure for the future, but in utero exposure remains unaddressed by such efforts. Prenatal exposure may be independently neurotoxic to the developing fetus1 and can contribute to the overall body burden in childhood because of placental transfer, which occurs unencumbered because of lack of a barrier to placental–fetal lead transport.2 In addition to fetal effects, lead in blood during pregnancy appears to be associated with preterm birth, impaired fetal growth, and hypertensive complications of pregnancy. These toxic effects have been observed across a range of exposures, including blood lead levels (BLLs) as low as 2.3 μg/dL.3–5 Pregnant people are identified as an “at-risk” group by the Centers for Disease Control and Prevention with respect to lead exposure, and yet universal blood lead testing in this population is not currently recommended because of insufficient evidence of benefits and harms.3,6,7
Clinicians caring for pregnant people nevertheless are supposed to perform risk-factor–based screening for lead during all pregnancies and then expected to obtain a BLL on their pregnant patients should they meet certain criteria (Table 1).6 Unfortunately, lead screening based on prenatal risk factors appears underused in practice and does not adequately discriminate between those with and without lead in their blood.8 This underutilization is not surprising because translating risk factors into simple screening questions is not straightforward, as evidenced by Table 1. Given the complexity of the risk-factor–based approach and its underusage in practice, the benefits and cost-effectiveness of universal lead testing are critical knowledge gaps.7 In lieu of additional data demonstrating clear benefit, we detail 5 good reasons to consider a universal testing approach regardless:
Risk-factor–based screening paradigms inadequately predict the BLL during pregnancy.9,10 Sources of lead in blood in pregnancy include not only exposure to home renovation projects, occupational sources, contaminated imported spices, and other items (Table 1), but also past exposures. Lead is stored in bone, and during pregnancy, there is increased bone turnover, releasing lead into the circulation.3,11 Current risk factors may not identify previous exposures nor lead body burden. Determination of a BLL during pregnancy, rather than solely an assessment of risks, is critical.
Universal blood testing for other conditions, such as hepatitis C or HIV is routine in pregnancy. Furthermore, risk-factor–based approaches to screen for conditions like gestational diabetes or group B streptococcus carriage have been abandoned in favor of universal testing for a variety of reasons including underascertainment of those at risk, potential for biased screening, and simplicity in implementation.12 Adding a BLL test to the prenatal panel would be easy to operationalize.
Pregnancy offers a unique opportunity for health promotion. Many people have health insurance coverage during pregnancy and are very motivated to make positive changes in their own health to benefit their families. Testing also provides an opportunity to increase awareness about the sources and risks of lead to an entire family.
The BLL assay is a relatively inexpensive test. Universal testing has been mandated for children for families on Medicaid, and in some states, for all children aged <3. Similar point-of-care testing utilized for the pediatric population could be used in pregnancy, with costs comparable to a complete blood count.
Identifying lead in the blood of a pregnant individual offers an opportunity to intervene earlier and at a vulnerable time period for the fetus. Effective interventions are available. Calcium supplementation during pregnancy has been shown to lower BLL compared to placebo in 1 study.13 Furthermore, identification of the source of lead hazard, followed by abatement, can reduce the risk of further exposure. If needed, lead inspectors, lead abatement contractors, other community resources, and programs focused on reducing lead exposure can be leveraged.
Risk Factors for Lead Exposure in Pregnant and Lactating People, as Outlined by the American College of Obstetricians and Gynecologists
| Risk Factors . |
|---|
| Recent emigration from or residency in areas where ambient lead contamination is high, people from countries where leaded gasoline is still being used (or was recently phased out) or where industrial emissions are not well controlled. |
| Living near a point source of lead; examples include lead mines, smelters, or battery recycling plants (even in the establishment is closed). |
| Working with lead or living with someone who does; people who work in or who have family members who work in an industry that uses lead (eg, lead production, battery manufacturing, paint manufacturing, ship building, ammunition production, or plastic manufacturing) and do not practice OSHA-recommended guidance in industrial hygiene. |
| People who work in security or as police officers or in the military and engage in target practice using firearms in improperly cleaned or ventilated indoor ranges without appropriate gloves and other personal protective clothing. |
| Using lead-glazed ceramic pottery; people who cook, store, or serve food in lead-glazed ceramic pottery made in a traditional process and usually imported by individuals outside the normal commercial channels. |
| Eating nonfood substances (pica); people who eat or mouth nonfood items that may be contaminated with lead, such as soil or lead-glazed ceramic pottery. |
| Using alternative or complementary substances, herbs or therapies; people who use imported home remedies or certain therapeutic herbs traditionally used by East Indian, Indian, Middle Eastern, West Asian, and Hispanic cultures that may be contaminated with lead. |
| Using imported cosmetics or certain food products; people who use imported cosmetics, such as tiro, kohl, or surma. or certain imported foods or spices that may be contaminated with lead. Lead-acetate–containing hair dyes can also be sources of contamination. |
| Engaging in certain high-risk hobbies or recreational activities; people who engage in high-risk activities (eg, stained glass production or pottery making with certain leaded glazes and paints or amateur firearms marksmanship activities using indoor gun ranges) or have family members who do. |
| Consumption of lead-contaminated drinking water; people whose homes have leaded pipes or sources lines with lead. |
| Having a history of previous lead exposure or evidence of elevated body burden of lead; people who have high body burdens of lead from past exposure, particularly those who have deficiencies in certain key nutrients (calcium or iron). |
| Living with someone identified with an elevated lead level; people who may have exposure in common with a child, close friend, or other relative living in the same environment. |
| Risk Factors . |
|---|
| Recent emigration from or residency in areas where ambient lead contamination is high, people from countries where leaded gasoline is still being used (or was recently phased out) or where industrial emissions are not well controlled. |
| Living near a point source of lead; examples include lead mines, smelters, or battery recycling plants (even in the establishment is closed). |
| Working with lead or living with someone who does; people who work in or who have family members who work in an industry that uses lead (eg, lead production, battery manufacturing, paint manufacturing, ship building, ammunition production, or plastic manufacturing) and do not practice OSHA-recommended guidance in industrial hygiene. |
| People who work in security or as police officers or in the military and engage in target practice using firearms in improperly cleaned or ventilated indoor ranges without appropriate gloves and other personal protective clothing. |
| Using lead-glazed ceramic pottery; people who cook, store, or serve food in lead-glazed ceramic pottery made in a traditional process and usually imported by individuals outside the normal commercial channels. |
| Eating nonfood substances (pica); people who eat or mouth nonfood items that may be contaminated with lead, such as soil or lead-glazed ceramic pottery. |
| Using alternative or complementary substances, herbs or therapies; people who use imported home remedies or certain therapeutic herbs traditionally used by East Indian, Indian, Middle Eastern, West Asian, and Hispanic cultures that may be contaminated with lead. |
| Using imported cosmetics or certain food products; people who use imported cosmetics, such as tiro, kohl, or surma. or certain imported foods or spices that may be contaminated with lead. Lead-acetate–containing hair dyes can also be sources of contamination. |
| Engaging in certain high-risk hobbies or recreational activities; people who engage in high-risk activities (eg, stained glass production or pottery making with certain leaded glazes and paints or amateur firearms marksmanship activities using indoor gun ranges) or have family members who do. |
| Consumption of lead-contaminated drinking water; people whose homes have leaded pipes or sources lines with lead. |
| Having a history of previous lead exposure or evidence of elevated body burden of lead; people who have high body burdens of lead from past exposure, particularly those who have deficiencies in certain key nutrients (calcium or iron). |
| Living with someone identified with an elevated lead level; people who may have exposure in common with a child, close friend, or other relative living in the same environment. |
Adapted from the American College of Obstetricians and Gynecologists committee opinion No. 533, August 2012, reaffirmed 2016. This table was modified by American College of Obstetricians and Gynecologists from the Centers for Disease Control and Prevention, guidelines for the identification and management of lead exposure in pregnant and lactating women.6 OSHA, Occupational Safety and Health Administration.
Although there are several reasons to pursue universal lead testing, there remain areas of uncertainty. Less is known about whether addressing lead in blood in pregnancy could decrease pregnancy complications associated with lead; nonetheless, there is no known safe level of lead and no amount is physiologically normal.14 Theoretically, universal lead testing in pregnancy and the increased resources required to respond to high levels may reduce resources available for testing and management of lead in blood in children. However, enlightened health policy can allocate sufficient resources; such a potential harm is far outweighed by the benefit of earlier identification and treatment of lead exposure.
Although efforts to reduce exposure to lead have decreased lead in blood in the population, pregnancy represents a time of increased risk because of bone turnover and a developing neurologically vulnerable fetus. This presents us with a tremendous opportunity to shift lead screening to earlier in the life cycle. Universal prenatal lead testing would be another step toward addressing the generational disparities associated with lead exposure.
Dr Johnson drafted the initial manuscript, and critically reviewed and revised the final manuscript; Drs Woolf and Hauptman critically reviewed and revised the final manuscript; Dr Wylie cowrote and critically reviewed and revised the manuscript for important intellectual content; and all authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.
References
Competing Interests
CONFLICT OF INTEREST DISCLOSURES: The authors have indicated they have no conflicts of interest relevant to this article to disclose.
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