Screening for Elevated Blood Lead Levels in Pregnancy [Entered Retrospectively]

Project Summary Title and Description

Title
Screening for Elevated Blood Lead Levels in Pregnancy [Entered Retrospectively]
Description
Structured Abstract Background: In 2006, the United States Preventive Services Task Force (USPSTF) recommended against routine screening for elevated blood lead levels in asymptomatic pregnant women (D recommendation). Purpose: To synthesize evidence on the effects of screening, testing, and treatment for elevated blood lead level in pregnant women, in order to update a 2006 USPSTF systematic review. Data Sources: Cochrane CENTRAL and Cochrane Database of Systematic Reviews (through June 2018), and Ovid MEDLINE (1946 to June 2018), reference lists, and surveillance through December 5, 2018. Study Selection: English-language trials and observational studies of screening effectiveness, test accuracy, benefits and harms of screening and interventions in asymptomatic pregnant women. Data Extraction: One investigator abstracted details about study design, patient population, setting, screening method, follow up, and results. Two investigators independently applied prespecified criteria to rate study quality using methods developed by the USPSTF. Discrepancies were resolved through consensus. Data Synthesis: No studies directly evaluated clinical benefits and harms of screening pregnant women for elevated lead levels versus no screening, or how effectiveness of screening varies according to the gestational age at which screening is performed. One fair quality study (N = 314) evaluated the diagnostic accuracy of using a version of the CDC screening questionnaire for lead exposure in children, modified for identifying pregnant women with elevated lead levels. The study used four out of five of the questions from the CDC questionnaire and found a sensitivity of 75.7 percent and specificity of 46.2 percent. The most predictive single item was living in a home built before 1960. One fair quality RCT from Mexico found calcium supplementation in healthy pregnant women (N = 670; mean baseline lead levels ~ 4 µg/dL) associated with a reduction in serum lead levels compared with placebo (difference 11%, p=0.004). No studies reported health outcomes or harms associated with interventions to reduce blood levels in asymptomatic pregnant women. Limitations: Limited to English-language articles; quality and applicability of studies were limited due to flawed study design, poor reporting of statistical outcomes, and loss to follow up. Two studies addressed the key questions, with no evidence on effects of screening or interventions for elevated lead levels in pregnant women on health outcomes. Conclusions: Evidence on the benefits and harms of screening pregnant women for elevated blood lead levels is extremely limited, with no evidence on effects of screening or interventions for lowering elevated blood lead levels in pregnant women on health outcomes.
Attribution
N/A
Authors of Report
N/A
Methodology description
Study Selection: English-language trials and observational studies of screening effectiveness, test accuracy, benefits and harms of screening and interventions in asymptomatic pregnant women. Data Extraction: One investigator abstracted details about study design, patient population, setting, screening method, follow up, and results. Two investigators independently applied prespecified criteria to rate study quality using methods developed by the USPSTF. Discrepancies were resolved through consensus.
PROSPERO
N/A
DOI
10.26300/ezcd-z525
Notes
Data was entered retrospectively via the upload of the evidence and quality appendix tables in Word. The files uploaded for this project include: Appendix B1. Data Abstraction of Pregnancy Lead Diagnostic Accuracy Study Appendix B2. Data Abstraction of Pregnancy Lead Treatment Trial Appendix C1. Quality Assessment of Pregnancy Lead Diagnostic Accuracy Study Appendix C2. Quality Assessment of Pregnancy Lead Treatment Trial
Funding Source
Agency for Healthcare Research and Quality (AHRQ), Rockville, MD (Prepared by the Pacific Northwest Evidence-based Practice Center under Contract No HHSA290201500009I Task Order No. 7)

Key Questions

1. Key Question 1a. Is there direct evidence that screening for elevated blood lead levels in asymptomatic pregnant women improves health outcomes (i.e., reduced cognitive problems in offspring, adverse perinatal outcomes, and adverse maternal outcomes)? 1b. Does the effectiveness of screening in asymptomatic pregnant women vary by gestational age?
2. Key Question 2. What is the accuracy of questionnaires or clinical prediction tools that identify pregnant women who have elevated blood lead levels?
3. Key Question 3. What are the harms of screening for elevated blood lead levels (with or without screening questionnaires) in asymptomatic pregnant women?
4. Key Question 4. Do counseling and nutritional interventions, residential lead hazard control techniques, or chelation therapy reduce blood lead levels and rates of gestational hypertension in asymptomatic pregnant women with elevated blood lead levels?
5. Key Question 5. Do counseling and nutritional interventions, residential lead hazard control techniques, or chelation therapy improve health outcomes in asymptomatic pregnant women with elevated blood lead levels?
6. Key Question 6. What are the harms of interventions in asymptomatic pregnant women with elevated blood lead levels?

Associated Extraction Forms

Downloadable Data Content

Files
  • XLSX Project Data