Birth Defects
What Is A Birth Defect?
A birth defect is an abnormality in the structure or function of an organ that develops in a baby before birth. They are also called congenital anomalies. Birth defects can affect almost any part of the body. Usually, the abnormality involves a body part that is missing or malformed. Other times, it may involve problems with metabolism, or how the organs work. Babies born with birth defects often need special care to thrive. In the United States, about 3% or one out of every 33 babies is born with a birth defect.
What Are Known Risk Factors For Birth Defects?
The cause of about 70% of birth defects in the state is unknown. Most are likely due to a mix of genetic, behavioral, and environmental factors.
Some known risk factors include:
- Having someone in your family with a birth defect. Sometimes birth defects are caused by genetic mutations that are inherited (passed down from a parent to a child).
- Smoking, drinking alcohol, and/or taking certain drugs or medications during pregnancy.
- Not getting enough folic acid (vitamin B9) on a daily basis during the time around conception through the first several months of pregnancy. This can increase the risk of neural tube defects, which affect the brain and/or spinal cord.
- Age. Having a child after age 35 increases the risk of Down syndrome. Teenage mothers are more likely to have a baby born with gastroschisis – a defect in the abdominal wall.
What Is The Relationship Between Birth Defects And The Environment?
It is not clear how many birth defects are related to environmental exposure to teratogens (substances that cause developmental malformations). Researchers are looking at a wide variety and much more work is needed.
Current research indicates:
- Living near a hazardous waste site has been studied and is a possible risk factor for birth defects.
- Studies looking at whether exposure to disinfection byproducts in drinking water, such as trihalomethanes (THM), may increase the risk of birth defects have had mixed results. Some find exposure may increase the risk of heart defects, but others have not.
- Exposure to ionizing radiation can cause birth defects. For this reason, radiology technicians ask about pregnancy before giving x-rays to minimize risk to the developing baby.
How Does MA EPHT Track Birth Defects?
Birth defects surveillance tracks what type of birth defects are occurring, how often they are occurring, and where they are occurring.
The Massachusetts Birth Defects Monitoring Program (MBDMP) is a statewide surveillance program that is a part of the Massachusetts Center for Birth Defects Research and Prevention within the DPH Bureau of Family Health and Nutrition. By law, hospitals and other medical facilities must report structural birth defects to the Massachusetts Department of Public Health (DPH) when diagnosed before age 1. The MA EPHT portal allows users to review both birth defects data and environmental data to help determine the need for follow-up investigations.
Why Is MA EPHT Tracking Birth Defects?
In 2002, Massachusetts was one of seven states across the U.S. to be awarded funds from the U.S. Centers for Disease Control and Prevention (CDC) to track health conditions thought to be impacted by the environment. By sharing data about the occurrence of birth defects in Massachusetts, the EPHT Program hopes to better understand the potential for environmental factors to play a role.
Available Data On Birth Defects
Use the Explore Maps & Tables link to access the following measures for birth defects:
- Annual prevalence per 10,000 live births by birth defect statewide
- Prevalence per 10,000 live births by birth defect during a 5-year period for each county and statewide
The most current available data will be shown. Be sure to check the site periodically as new data is added. To protect privacy, only summary statistics are available, and no information is shown that could identify an individual.
Data are provided for the following 12 birth defects: anencephaly, spina bifida (without anencephaly), hypoplastic left heart syndrome, tetralogy of Fallot, transposition of the great arteries (vessels), cleft lip with cleft palate, cleft lip without cleft palate, cleft palate without cleft lip, hypospadias, gastroschisis, limb deficiencies, and trisomy 21.
Data considerations
When reviewing and interpreting birth defects data, it is important to consider the following:
- Birth defects prevalence is the number of infants (babies younger than one year old) with a birth defect divided by the number of live births over a period of time (typically one year). It is usually expressed as the number of birth defects per 10,000 live births. Estimates are based on the residential location of the birthing parent at the time of the child’s diagnosis.
- Confidence intervals (CI) are commonly used to assess the magnitude and stability of disease rates. The CI can also be used to determine if the estimate for a county is statistically significantly different from the statewide experience.
- In this case, if the CI for a county does not overlap the CI of the state, then the prevalence estimates are statistically significantly different. If the CIs do overlap, then the difference in the birth defect prevalence estimates may be due to natural variation or random chance.
- Beginning in 2012, the MA Birth Defects Monitoring Program began to collect data on birth defects among pregnancies that ended in other types of losses, including terminations at any gestational age and miscarriages less than 20 weeks gestation. Diagnoses of cases made after age one are not included in this dataset.
- Potential cases are identified through reports from delivery and specialty hospitals, prenatal diagnostic centers, vital records, and other sources.
Birth Defect Descriptions
Anencephaly
Anencephaly is a birth defect that affects the closing of the neural tube during pregnancy. The neural tube is a narrow channel that folds and closes during the third and fourth weeks of pregnancy to form the brain and spinal cord. Anencephaly occurs when the part of the neural tube that forms the brain does not close. This results in the baby lacking parts of the brain, skull, and scalp.
Cleft Lip
A cleft lip is a congenital defect of the upper lip in which there is incomplete closure. The opening in the lip can be a small slit in the lip or a large opening that goes through the lip into the nose.
Cleft Palate
A cleft palate is an opening in the roof of the mouth, called the palate. A cleft palate can occur when the two sides of the palate do not come together correctly.
Gastroschisis
A birth defect in which a portion of an infant’s intestines stick out of the body through a small hole in the body wall beside the umbilical cord. The body wall defect can be small or large and other organs such as the liver can be involved.
Hypoplastic Left Heart Syndrome
A type of congenital heart defect that affects normal blood flow through the heart. Several parts of the left side of the heart do not fully develop.
Hypospadias
A birth defect among boys in which the opening of the urethra is located somewhere along the underside of the penis instead of at the tip. The urethra is the tube that carries urine from the bladder to the outside of the body. This defect occurs when the urethra does not complete its development during the pregnancy.
Limb Deficiency
Upper limb deficiency defects occur when a part of or the entire arm (upper limb) of a fetus fails to form completely during pregnancy. Lower limb deficiency defects occur when a part of or the entire leg (lower limb) of a fetus fails to form completely during pregnancy.
Spina Bifida (without Anencephaly)
The neural tube is a narrow channel that folds and closes during the third and fourth weeks of pregnancy to form the brain and spinal cord. Spina bifida is a neural tube defect that happens if part of the neural tube does not close all the way.
Tetralogy of Fallot
A type of congenital heart defect that changes the normal flow of blood through the heart. Tetralogy of Fallot is a combination of four defects: (1) a hole in the wall between the ventricles (two lower chambers of the heart), called a ventricular septal defect; (2) narrowing of the tube that carries blood from the heart to the lungs, called pulmonary stenosis; (3) the aorta (the tube that carries oxygen-rich blood to the body) grows from both ventricles, rather than from the left ventricle only; and (4) a thickened muscular wall of the right ventricle, called right ventricular hypertrophy.
Transposition of the Great Arteries
A type of congenital heart defect that occurs when the two main arteries going out of the heart—the pulmonary artery and the aorta—are switched in position, or “transposed.”
Trisomy 21 (Down Syndrome)
Down syndrome is a condition in which a baby is born with an extra chromosome, chromosome 21. This extra copy changes the normal development of the body and brain and can cause developmental and physical problems for the baby.
Source: CDC Specific Birth Defects and Other Health Conditions, 2024
Related Links
National Sources
- U.S. CDC Birth Defects: Centers for Disease Control (CDC) website that provides birth defects information and resources
- National Environmental Public Health Tracking: National Environmental Public Health Tracking website
- National Birth Defects Prevention Network: National standards for birth defects surveillance, reports, and other information.
- March of Dimes: Non-profit organization providing information on pregnancy, prematurity, birth defects, and more
- International Clearinghouse for Birth Defects Surveillance and Research: WHO-affiliated global birth defects initiative
- Eunice Kennedy Shriver National Institute of Child Health and Human Development: National Institute of Health center for birth defects information and research
- National Birth Defects Prevention Study: A collaboration between CDC and birth defects programs across the U.S. to find the causes of birth defects
Massachusetts Sources
- Massachusetts Birth Defects Monitoring Program: Information on birth defect monitoring in Massachusetts
- Massachusetts Center for Birth Defects Research and Prevention: Information on the Massachusetts Birth Defects Registry
- Massachusetts Birth Defects Surveillance Reports: Reports (with birth defects coding) and fact sheets
- Massachusetts Department of Public Health Zika Virus Information: Information about the Zika Virus
- Care Coordination for Children with Special Health Care Needs: Information on and referrals to community services