Public Health Birth Defects Surveillance
Diana Valencia MS,
R.J Berry, MD, MPH
National Center on Birth Defects and Developmental Disabilities
Centers for Disease Control and Prevention
Atlanta, GA USA
Antiretroviral Therapy (ART) in Pregnancy, Breastfeeding and Beyond
Johannesburg, South Africa
18-20 June, 2012
Public Health Birth Defects Surveillance
The ongoing and systematic collection,
analysis, and interpretation of health data
essential to the planning, implementation, and
evaluation of public health practice
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What Are Birth Defects?

Abnormalities of structure or function, present at
birth with medical, social, or cosmetic consequences
(typically requiring intervention)

More than 4,000 birth defects are known

Mental or physical disabilities or death

Leading cause of death in children under 5 years of
age in many countries

~8 million babies are born/year worldwide with birth
defects
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Source: March of Dimes 2006
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Planning for Birth Defects Surveillance



Defining a public health problem
What are the real needs?
What is the perceived need or purpose for surveillance?
 Are there concerns about exposure to Efavirenz (EFV) ?
 What is the impact of Efavirenz therapy on neural tube defect
rates/birth defect rates?
 Who has a stake/interest in the solution or outcome?

Can surveillance help address the problem? How?
 Base-line data
 Serves as a sentinel system for birth defects vs. reassurance
 Implementation of prevention strategies
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Planning for Birth Defects Surveillance


Clear goals and objectives
Plan for implementation
 Procurement of resources: people, time, infrastructure
 Training of personnel
 Harmonization with MoH data systems and forms

Quality and value: relevant, recent, reliable




Focus on quality (accuracy, timeliness, completeness)
Focus on the needs/purpose of the system
Plans for supervision/evaluation
Plans for analysis and reporting/communicating
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Prevalence of Neural Tube Defects


Neural tube defects are rare
World estimate ~ 323,904 per year
 Prevalence of 2.5/1,000 live births

Small studies in African hospitals
 Prevalence 0.23/1,000 to 7/1,000 live births

Malawi: Queen Elizabeth Central Hospital
 Prevalence of NTDs (0.62 /1,000)
 Other birth defects
• Orofacial clefts (0.67/1,000)
• Hydrocephaly (0.23/1,000)
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Neural Tube Defects
Anencephaly
Spina bifida
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Hospital-based Birth Defects Surveillance Systems
Advantages:
 Requires fewer resources and simpler protocol
 Can generate high quality case data, including exposures
 Useful when trying to establish (approximate) baseline data
 Useful for documenting that a problem exists or not
 Useful for alerting health and government officials to the need for
investing further in surveillance and prevention strategies

Very useful in settings where
 Most births occur in hospitals
 Surveillance at lower level facilities or in community is not
feasible

Able to calculate a prevalence estimate for the condition in a
particular hospital(s) if there is an accurate estimate of the
source population/denominator for that hospital
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Hospital-based Birth Defects Surveillance Systems
Disadvantages:

Limited to prevalence estimates for hospital sites
 Target population is limited to those born in the hospital
sites where data are collected
 Hospital participation can change over time, making the
interpretation of findings and trends difficult

Prevalence estimates can be unreliable
 Referral/selection bias can be variable, significant, difficult
to estimate: extrapolation to entire population is uncertain
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Protocol for Data Collection

Standardize data collection
 Uniform examination of all deliveries
 Uniform identification of mothers on EFV-based ART
 Uniform classification of birth defects
 Uniform criteria for inclusion of cases
 Uniform coding (ICD-10)
 Use of structured abstraction form
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Inclusion Criteria

All Live Births and Fetal Deaths (stillbirths)
 Identified at participating hospital(s)

Birth defect must be diagnosed
 At birth, or within the first 12 hours after birth
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Example of
abstraction
form
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Protocol for Birth Defects Surveillance

Protocol will be standard for every country
 Hospitals will
•
•
•
•
Complete a reporting form for all deliveries
Make sure that forms are complete
Verify data
Send forms to a central office
 Central office will
•
•
•
•
Verify data
Assign a number to each individual
Analyze data
Report data to MoH and other stake holders
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Potential Uses of Birth Defects Surveillance
EFV-based ART Data

Surveillance for any increase in BD over and above
expected baseline prevalence

Reassurance vs. elevated concern

Can be used to look at more than one exposure of
concern: EFV, other ARVs, other new or commonly
used drugs
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Potential Uses of Birth Defects Surveillance Data

Case registry for case-control studies of possible
risk

Link cases to health services

Case registry for studies of outcomes (e.g., survival,
development)

Evaluate the impact of prevention interventions

Education, advocacy, and health promotion

Monitor trends
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Why is Surveillance Important?
Without a surveillance system, you cannot

Capture adverse birth outcomes

Capture rare conditions

Identify potential risk factors
 Efavirenz and NTDs

Estimate the prevalence of a condition in a population
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QUESTIONS?
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RJ Berry - rjb1@cdc.gov
Diana Valencia - ile9@cdc.gov
For more information please contact Centers for
Disease Control and Prevention
1600 Clifton Road NE, Atlanta, GA 30333
Telephone: 1-800-CDC-INFO (232-4636)/TTY: 1-888232-6348
E-mail: cdcinfo@cdc.gov Web: http://www.cdc.gov
The findings and conclusions in this report are those
of the authors and do not necessarily represent the
official position of the Centers for Disease Control and
Prevention.
National Center on Birth Defects and Developmental Disabilities
Division of Birth Defects and Developmental Disabilities
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