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Maternal Lead Exposure

Introduction

Pregnant women who have contact with lead can pass the lead to the developing fetus and breastfed infant. Children exposed to lead before and/or after birth are at increased risk for delays in development and growth. Lead exposure may result from contact with lead in the environment, including in lead-based paint, dirt, cosmetics, hobby products, occupational exposures, and other sources. Lead exposure occurs, generally, when contaminants with lead are inhaled or ingested. Lead exposure from water sources are less common but continue to occur occasionally in the United States. Among women ages 15-44, approximately 1% have blood lead levels (BLL) of 5 μg/dL or greater. [Centers: 2010] Risk assessments can be used to determine if pregnant women might have been exposed to lead and if a blood test is needed. Risk assessments can provide anticipatory guidance to prevent lead exposure from home renovations, occupational exposures, crafts, herbal products, or other avoidable sources. The first priority for treatment is removing the source of lead exposure. Guidelines, recommendations, and reviews of the literature are provided by the Centers for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists (ACOG) [Centers: 2010] [Committee: 2012]
The medical home is key in providing risk assessments, testing, care coordination, and anticipatory guidance for the mother and child.

ICD-10 Coding

Z77.011, Contact with and (suspected) exposure to lead
R78.71, Abnormal lead level in blood
Z13.88, Encounter for screening for disorder due to exposure to contaminants
See ICD10 related to lead exposure (icd10data.com) for further coding details.

Presentations

Symptoms of elevated lead levels and adverse outcomes in pregnant women may include:
  • Anemia
  • Gestational hypertension
  • Hypertension
  • Preeclampsia
  • Lead colic or abdominal pain
  • Peripheral neuropathy
  • Spontaneous abortion
  • Preterm delivery
  • Low birth weight, head circumference, and length
  • Delirium
  • Stupor
  • Coma
  • Seizures or tremors
  • Death
While prenatal lead exposure does not increase the risk of structural birth defects, it increases the risk of other poor outcomes. Signs and symptoms in infants and young children may include:
  • Constipation
  • Anorexia
  • Vomiting
  • Inattentiveness, distractibility, impulsivity
  • Anemia
  • Learning problems
  • Decreased growth
  • Neurodevelopmental delays
  • Intellectual disability (see the Portal’s module on Intellectual Disability for more information)
  • Attention deficit hyperactivity disorder [Daneshparvar: 2016] (see the Portal’s module on Attention Deficit Hyperactivity Disorder (ADHD) for more information)

Surveillance and Screening

Assess Risk Factors

Health risk assessments are an important step in screening for lead exposure. Symptoms will not usually present until very high blood lead levels are reached.
The prenatal history, at the first prenatal visit, should include a health risk assessment to determine possible exposure to lead from various sources including (but not limited to): [Committee: 2012] [Centers: 2010]
  • Residence (leaded gasoline, environmental sources, contaminate water, etc.)
  • Occupation (police officers, artists, construction workers, etc. See Jobs That May Have Lead Exposure (CDC) for more examples.) [Centers: 2010]
  • Pica
  • Imported cosmetics, foods, alternative health care products
  • Hobbies and housewares (stained glass, lead-glazed pottery, shooting/reloading)
  • Home remodeling in older homes
  • Previous lead exposure
  • Living with others with elevated lead levels
A complete list can be found in the Guidelines for the Identification and Management of Lead Exposure in Pregnant Women (CDC) (PDF Document 3.7 MB) (Table 4-1) and Lead Screening During Pregnancy and Lactation (ACOG) (Box 1).
The health risk assessment questions can be asked again at later prenatal visits especially if the woman’s situation has changed, such as engaging in new hobby, remodeling the home for the baby, etc. Pregnant women should be tested for lead with a blood test as required by state laws or, in the absence of such laws, according to the CDC guidelines.

Screening with a Blood Lead Test

ACOG and CDC do not recommend universal blood lead screening for pregnant women. [Committee: 2012] [Centers: 2010]

Testing

Labs
Venous blood lead testing is recommended to determine exposure levels. Universal blood lead testing is not recommended for pregnant women but testing is recommended based on the results of the health risk assessment. Due to changes during pregnancy, blood lead levels may be lower in the second trimester than in the first or third trimesters, following a “U-shaped curve”. [Centers: 2018] Testing should be done as early in the first trimester as possible and repeated in the third trimester. Women who have had lead exposure during their early years of life may have lead stored in their bones and may mobilize that into their bloodstreams during the later parts of pregnancy, particularly if they are calcium-deficient as bone calcium (and lead) may be released into the bloodstream to provide additional calcium to the fetus. [Centers: 2018] [Kosnett: 2007]
Check with the lab that will perform the test to ensure that blood samples are submitted in the correct tube (lead-free) and that the lab is familiar with blood lead testing. The CDC provides additional instructions for blood collection and storage. [Advisory: 2013]

Treatment & Management

There is no safe blood lead level. Recommended criteria and steps for treatment may differ by state. Determining the source of the exposure and eliminating or limiting the lead exposure is a key step in the treatment and management of a pregnant woman with lead exposure.
  • The health risk assessment is important in identifying the sources of exposure.
  • Remove or decontaminate exposed clothing, household items, and other sources of re-exposure during treatment.
  • Avoid the use of herbal products, particularly those from other countries, due to lack of regulation and possible contamination.
  • Avoid the release of lead dust from lead-based paint in older houses, before 1978.
  • Avoid hobbies that may result in lead exposure such as stained glass crafts, hunting, welding, etc.
  • Provide alternative behaviors in the event of pica.
  • Educate the pregnant or breastfeeding woman regarding the sources of lead exposure and strategies for avoiding or reducing exposure.

Frequency of Maternal Blood Lead Follow-up Testing During Pregnancy

Venous Blood Lead Level (micrograms/dL) Perform Follow-up Test(s)
Less than 5
  • None (no follow-up testing is indicated)
5-14
  • Within 1 month
  • Obtain a maternal blood lead level or cord blood level at delivery
15-24
  • Within 1 month and then every 2-3 months
  • Obtain a maternal blood lead level or cord blood lead level at delivery
  • More frequent testing may be indicated based on risk factors
25-44
  • Within 1-4 weeks and then every month
  • Obtain a maternal blood lead level or cord blood lead level at delivery
45 or more
  • Within 24 hours and then at frequent intervals depending on clinical interventions and trend in blood lead levels
  • Consultation with a clinician experienced in the management of pregnant women with blood lead levels in this range is strongly advised
  • Obtain a maternal blood lead level or cord blood level at delivery
Notes:
  • Venous blood sample is recommended for maternal blood lead testing
  • The higher the blood lead level on the screening test, the more urgent the need for confirmatory testing
  • If possible, obtain a maternal blood lead level before delivery because blood lead levels tend to increase over the course of pregnancy
See Acknowledgement 1 below. [Committee: 2012]

Maternal Treatment & Management

For pregnant and breastfeeding women, supplement with 1,200 mg/day calcium to reduce bone resorption and release of stored lead to reduce levels in breast milk. Calcium deficiency increases bone absorption of lead. Lead is released from the bone as fetal and breastfeeding demand for calcium is increased. Calcium supplementation reduces resorption, the release of calcium and lead from the bone, and decreases absorption of lead in the intestines. [Centers: 2018] Releasing lead from the bone increases fetal exposure to lead. [Kosnett: 2007] [Committee: 2012] Supplement with iron to address or prevent iron deficiency. [Centers: 2018] Monitor blood pressure. Identify renal dysfunction by monitoring serum creatinine. [Kosnett: 2007]
The CDC recommends “case management services for pregnant women with blood lead levels >15 μ/dl”. [Centers: 2010] The medical home can provide care coordination including anticipatory guidance; care planning; identification of resources and specialists; appointment coordination; collection and coordination of testing and treatment results; and other care coordination activities.

Fetal and Child Treatment & Management

Assess for growth restriction in the fetus and child. Screen for developmental and other neurodevelopmental delays. See Developmental Screening.

Recommendations for Initiating Breastfeeding

  • Measurement of levels of lead in breast milk is not recommended.
  • Mothers with BLLs <40 μg/dL should breastfeed.
  • Mothers with confrmed BLLs ≥40 μg/dL should begin breastfeeding when their blood lead levels drop below 40 μg/dL. Until then, they should pump and discard their breast milk. Repeat blood lead levels every 1-2 weeks after removal of the exposure source.
See Acknowledgement 2 below. [Centers: 2010] [Committee: 2012]

Medications Used to Treat Lead Exposure

Common treatment interventions, including removal from the source of the exposure and nutritional interventions, are attempted before medications are considered due to the risks of using the medications.
Oral chelation may improve blood lead levels and reduce symptoms of acute lead intoxication but may have limited usefulness in reducing other existing symptoms such as neurodevelopmental delays. [Kosnett: 2007] Chelation is generally not recommended during pregnancy, since it releases lead from the bone, increases blood lead levels, and increases fetal exposure, except in cases where the life of the mother is at risk. [Centers: 2010]
Chelation is considered when blood lead levels are greater than 45 μg/dL, when the individual has been removed from the lead exposure, and based on the individual situation of the exposed mother. An expert in lead poisoning should be consulted for chelation. Chelation medications bind to and release lead and other essential minerals from bone and other tissues. The blood lead level may drop immediately after chelation treatment but usually increases about two weeks after treatment. [Centers: 2010] [Lowry: 2010] Blood lead levels may remain high for years even after chelation therapy, particularly if there has been longstanding exposure, and chelation may not affect long-term neurodevelopmental outcomes in children. [Cantor: 2018] In pregnant women, the loss of other minerals from the therapy may increase risks of complications for the fetus. [Centers: 2010]
Recommendations for chelation therapy:
  • Chelation therapy should be considered for pregnant women with confirmed blood lead levels ≥45 μg/dL on a case-by-case basis, in consultation with an expert in lead poisoning. In most cases, chelation will not be performed unless the pregnant woman has a blood lead level >70 μg/dL.
  • Pregnant women with confirmed BLLs ≥45 μg/dL should be considered as having high-risk pregnancies and should be managed in consultation with an expert in high-risk pregnancy.
  • Pregnant women with life-threatening lead encephalopathy should be chelated regardless of trimester.
  • Insufficient data exist regarding the advisability of chelation for pregnant women with BLLs <45 μg/dL.
  • Before considering chelation therapy for a pregnant woman (or infant), blood lead levels should be repeated and confirmed using an additional venous blood lead sample collected within 24 hours.
  • Chelation therapy must occur in a lead-safe environment; therefore, prior to initiating chelation therapy, the patient should be removed from further lead exposure.
See Acknowledgement 3 below. [Centers: 2010]
Limited case reports are available that describe the use of chelating agents in pregnancy. For a list of chelating agents, see Childhood Lead Exposure.

Consultation

Local health department, occupational health, and other experts will perform important roles depending upon the source of the lead exposure. OSHA-acceptable exposure levels that trigger action are higher than CDC levels, with a medical evaluation required at 40 μ/dL and removal from the exposure required at 50 μ/dL. The physician examining the pregnant or breastfeeding woman may, however, recommend stronger actions at lower levels based upon the clinical presentation or other situational information. [Centers: 2010] Those actions would include identification of the source of lead, removal from further exposure, and blood testing frequency based on the BLL.
An expert in lead poisoning should be consulted for chelation. [Centers: 2010] See the section above, Medications Used to Treat Lead Exposure, for details on chelation.

Acknowledgements

  1. Table and notes adapted from Table 1 from ACOG. Committee Opinion: Lead screening during pregnancy and lactation. Number 533. Washington D.C. ACOG; 2012 and Reaffirmed 2016. Available at Lead Screening During Pregnancy and Lactation (ACOG). [Committee: 2012] and modified from Table 5-3 from CDC. Guidelines for the identification and management of lead exposure in pregnant and lactating women. Atlanta (GA): CDC; 2010. Available at Guidelines for the Identification and Management of Lead Exposure in Pregnant Women (CDC) (PDF Document 3.7 MB). [Centers: 2010]
  2. Recommendations adapted from Chapter 5. Blood Lead Testing in Pregnancy and Early Infancy and Chapter 9. Breastfeeding. CDC. Guidelines for the identification and management of lead exposure in pregnant and lactating women. Atlanta (GA): CDC; 2010. Available at Guidelines for the Identification and Management of Lead Exposure in Pregnant Women (CDC) (PDF Document 3.7 MB). And adapted from ACOG. Committee Opinion: Lead screening during pregnancy and lactation. Number 533. Washington D.C. ACOG; 2012 and Reaffirmed 2016. Available at Lead Screening During Pregnancy and Lactation (ACOG). [Centers: 2010] [Committee: 2012]
  3. Recommendations adapted from Chapter 8. Chelation of Pregnant Women, Fetuses, and Newborn Infants. CDC. Guidelines for the identification and management of lead exposure in pregnant and lactating women. Atlanta (GA): CDC; 2010. Available at Guidelines for the Identification and Management of Lead Exposure in Pregnant Women (CDC) (PDF Document 3.7 MB). [Centers: 2010]

Resources

Information & Support

For Professionals

Lead Screening During Pregnancy and Lactation (ACOG)
Committee Opinion (policy) on screening, testing, and treatment for lead exposure in women from the American College of Obstetricians and Gynecologists.

Sample Recommendations for Follow-up Blood Lead Level (BLL) Testing in Pregnant and Lactating Women (PDF Document)
Sample guidelines and local contact information from the New York State Department of Health.

Jobs That May Have Lead Exposure (CDC)
List of various jobs where workers may be exposed to lead, from the Centers for Disease Control and Prevention.

Practice Guidelines

Centers for Disease Control and Prevention.
Guidelines for the Identification and Management of Lead Exposure in Pregnant and Lactating Women.
Center for Disease Control and Prevention; (2010) https://www.cdc.gov/nceh/lead/publications/leadandpregnancy2010.pdf. Accessed on 10/2/2018.

Patient Education

Frequently Asked Questions About Lead During Pregnancy and Breastfeeding (MTB)
Brief answers to questions about lead exposure from the Organization of Teratology Information Specialists / MotherToBaby.

Healthy Eating (ACOG)
Answers to questions about nutrition during pregnancy.

Lead Poisoning: Are You Pregnant? (CDC) (PDF Document 128 KB)
Risks of lead poisoning, where lead can be found, and what to do from the Centers for Disease Control and Prevention.

Lead in Pregnancy (MTB)
Fact sheet describing common sources of lead exposure and risks in pregnancy and breastfeeding from the Organization of Teratology Information Specialists / MotherToBaby.

Natural Remedies, Fertility and Lead (MTB)
Blog describing sources of lead and risks in pregnancy from the Organization of Teratology Information Specialists / MotherToBaby.

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Authors & Reviewers

Initial publication: January 2019; last update/revision: March 2019
Current Authors and Reviewers:
Author: Alfred N. Romeo, RN, PhD
Reviewers: Stanley Schaffer, MD, MS, FAAP
Beth Conover, MS, APRN, LCGC
Funding: Developed by the Organization of Teratology Information Specialists / MotherToBaby in collaboration with and funding from the Association of Maternal & Child Health Programs (AMCHP) Cooperative Agreement #UJ9MC31105, U.S. Department of Health and Human Services’ Health Resources and Services Administration, Maternal and Child Environmental Health (MCEH) Collaborative Improvement and Innovation Network (CoIIN) for $849,999. This information or content and conclusions are those of the author and should not be construed as the official position or policy of, nor should any endorsements be inferred by, HRSA, HHS or the US government.

Page Bibliography

Advisory Committee on Childhood Lead Poisoning Prevention.
Guidelines for Measuring Lead in Blood Using Point of Care Instruments.
Centers for Disease Control and Prevention; (2013) https://www.cdc.gov/nceh/lead/ACCLPP/20131024_POCguidelines_final.pdf. Accessed on 10/31/2018.

Cantor A, Hendrickson R, Blazina I, Griffin J, Grusing S, McDonagh M.
Screening for Elevated Blood Lead Levels in Children: A Systematic Review for the U.S. Preventive Services Task Force.
Agency for Healthcare Research and Quality. 174; October 2018. / https://www.uspreventiveservicestaskforce.org/Home/GetFile/1/16900/lea...

Centers for Disease Control and Prevention.
Guidelines for the Identification and Management of Lead Exposure in Pregnant and Lactating Women.
Center for Disease Control and Prevention; (2010) https://www.cdc.gov/nceh/lead/publications/leadandpregnancy2010.pdf. Accessed on 10/2/2018.

Centers for Medicaid & CHIP Services.
CMCS Informational Bulletin: Coverage of Blood Lead Testing for Children Enrolled in Medicaid and the Children’s Health Insurance Program.
Centers for Medicare & Medicaid Services; (2018) https://www.medicaid.gov/federal-policy-guidance/downloads/cib113016.p.... Accessed on 10/2/2018.

Committee on Obstetric Practice.
Committee opinion No. 533: Lead screening during pregnancy and lactation.
Obstet Gynecol. 2012;120(2 Pt 1):416-20. PubMed abstract / Full Text
American College of Obstetricians and Gynecologists Committee Opinion.

Kosnett MJ, Wedeen RP, Rothenberg SJ, Hipkins KL, Materna BL, Schwartz BS, Hu H, Woolf A.
Recommendations for medical management of adult lead exposure.
Environ Health Perspect. 2007;115(3):463-71. PubMed abstract / Full Text

Lowry JA.
Oral Chelation Therapy for Patients with Lead Poisoning.
Children's Mercy Hospitals and Clinics; (2010) https://www.who.int/selection_medicines/committees/expert/18/applicati.... Available on the World Health Organization's website. Accessed on 10/31/2018.