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Frequently Asked Questions - Birth Defects

What is birth defects tracking?

Birth defects tracking, or surveillance, is the ongoing collection, analysis, and interpretation of birth defects data in a population of children from birth up to age one.  Massachusetts law requires the reporting of birth defects to the Massachusetts Department of Public Health (MDPH). The Massachusetts Center for Birth Defects Research and Prevention was established in 1996 within MDPH as an active state-wide, population-based birth defects registry. The EPHT portal allows users to review both birth defects data and environmental data to help determine the need for follow-up investigations.

Why is the EPHT Program 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.

How is information collected on birth defects in Massachusetts?

The Massachusetts Birth Defects Monitoring Program (MBDMP) is an active, statewide surveillance program.  It is part of the Massachusetts Center for Birth Defects Research and Prevention within the Massachusetts Department of Public Health/Bureau of Family Health and Nutrition. Birthing hospitals and other pediatric care centers across the state regularly submit birth defect diagnoses to the Center. These diagnoses are verified through medical record abstraction conducted by Center staff; during the abstracting process additional important demographic information is collected. Also, vital records, including birth certificates, fetal death reports, and infant death certificates are reviewed for qualifying diagnoses. The diagnoses are reviewed by a clinical geneticist and entered into a secure confidential electronic database maintained by the MBDMP.

If my child was born with a birth defect, will information on my child or family be available to the public?

No.  Only summary statistics on the occurrence of birth defects in Massachusetts will be available through the EPHT network.  No personally-identifying information on your child or your family will ever be disclosed. Extensive procedures are in place to guarantee the confidentiality of the birth defects data and to protect the privacy of families. These procedures uphold MDPH ethical and legal obligations to safeguard confidentiality and they fully comply with the strict requirements of state and federal laws.

What statistic is used to measure the number of birth defects in a county or the state of Massachusetts as a whole?

The occurrence of birth defects in an area is estimated by calculating a statistic called prevalence. Prevalence is defined generally as the number of individuals with a disease or condition over a specified period of time divided by the number of individuals at risk during the same period. For birth defects, prevalence is defined as the number of infants less than one year of age with a birth defect divided by the number of live births over a specified period of time, typically over a one-year period. 

Prevalence is usually expressed as the number of birth defect births per 10,000 live births.  It is calculated using the formula: 

number of infants with birth defect(s)
total number of live births
   x 10,000

The number of live births in the denominator of the prevalence estimate is an approximation of the number of total pregnancies during the time period of interest.  Because the number of pregnancies cannot be determined, the number of total births is used as an approximation.

How are prevalence estimates interpreted?

To best interpret the prevalence estimate for a county or the state a statistic referred to as a confidence interval (CI) is used.  Confidence intervals are commonly used to assess the magnitude and stability of disease rates or, in this case, the prevalence of birth defects. The CI can also help determine if the prevalence estimate for a county is statistically significantly different from the statewide experience for that birth defect. That is, does the difference between the two prevalence estimates most likely represent normal random variation in prevalence estimates or is it a statistically significant difference?

The CI represents a range of values that has a 95% probability of including the true prevalence. The width of the confidence interval reflects the size of the population and the number of birth defects. The prevalence estimate for a smaller population with fewer birth defects, such as that of a more sparsely populated county in the state, will lead to a wider confidence interval.  In contrast, the confidence interval for the prevalence of a birth defect for the state as a whole will be narrower. 

As mentioned, one method for determining if a given prevalence estimate is statistically significantly different from another is to compare their confidence intervals. The prevalence of birth defects in a county can be compared to the prevalence of birth defects in the state as a whole using the two CIs.  If the CI for one county does not overlap the CI of the state, then it can be concluded that the prevalence estimates are statistically significantly different from each other.  If they do overlap, then it can be concluded that the birth defect prevalence estimates are not likely to be statistically significantly different. 

What is the relationship between birth defects and the environment?

Some research on environmental hazards and associations with birth defects is available; however, much more work is needed to more fully understand the relationship between the environment and birth defects.

Environmental substances that can cause birth defects are called teratogens. These include alcohol, certain drugs/medications, infections and certain chemicals.

Some endocrine-disrupting chemicals, including polychlorinated biphenyls (PCBs), dioxins, and pesticides, have been linked to nervous system defects and developmental problems such as reduced muscle tone and response.

The CDC has reported that living near a hazardous waste site has been identified as a possible risk factor for birth defects such as neural tube defects. Neural tube defects are defects in the development of the brain and spinal cord. Exposure to disinfection by-products in drinking water such as trihalomethanes, or THM, may increase the risk of some types of birth defects.

Most experts believe that the majority of birth defects are likely to be the result of a complex interaction between genetic predisposition and environmental factors.

Are there other known risk factors for birth defects?

Some birth defects are caused by genetic problems. Sometimes, these birth defects run in families, but other times they will occur even when there is no one else in the family who has this problem.

If a woman takes certain drugs during her pregnancy, the chance of birth defects in her offspring is increased. Also, women who smoke and use alcohol while pregnant have a higher risk of having a baby with certain birth defects.

Folic acid (vitamin B9) deficiency is related to certain birth defects.  Studies have shown that the presence of adequate amounts of folic acid in the mother’s system during the period around conception may help prevent defects of the brain and spinal cord. 

Women over the age of 35 years have a higher chance of having a child with Down syndrome than women who are younger.  Teenage mothers are more likely to have a baby born with gastroschisis —a defect in the abdominal wall.

It is important to note, however, that the Massachusetts Center for Birth Defects Research and Prevention estimates that approximately 80% of birth defects in the state have unknown causes.

What are the limitations of the data?

  • Defects related to early fetal deaths and/or terminations are not included in prevalence estimates. Furthermore, defects that are not diagnosed at birth, do not need hospitalization, or are diagnosed after age one may be underreported.
  • There is the possibility of misclassification due to a vague or miscoded diagnosis which may affect birth defect prevalence measures. Quality control measures such as careful medical record abstraction minimize this error.
  • It is important to note that prevalence estimates are based on the residential location of the mother at the time of the child’s diagnosis.
  • Counts and prevalence estimates may differ slightly from those contained in other publications. These differences may be due to file updates, differences in calculation methods (such as grouping ages differently or rounding off numbers at different points in calculations), updates or differences in population estimates, and differences in birth defects definitions.
  • Only diagnoses confirmed before one year of age are included.

What types of birth defects are included on the EPHT network?

Twelve birth defects are included on the EPHT network. They include: 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. Definitions of these birth defects can be found in the glossary.

What are the Codes and Exclusions for each birth defect category?

The following coding schme is derived from the National Birth Defects Prevention Network (NBDPN) Case Definitions, revised 2015.
Birth Defect ICD-9-CM1 CDC/BPA2 ICD-10-CM3
Birth Defect Anencephaly ICD-9-CM1 740.0-740.1 CDC/BPA2 740.00-740.10 ICD-10-CM3 Q00.0 - Q00.1
Birth Defect Cleft Lip with Cleft Palate ICD-9-CM1 749.2 CDC/BPA2 749.20-749.29 ICD-10-CM3 Q37.0-Q37.9
Birth Defect Cleft Lip without Cleft Palate ICD-9-CM1 749.1 CDC/BPA2 749.10-749.19 ICD-10-CM3 Q36.0-Q36.9
Birth Defect Cleft Palate without Cleft Lip ICD-9-CM1 749.0 CDC/BPA2 749.00-749.09 ICD-10-CM3 Q35.1 – Q35.9
Birth Defect Gastroschisis (prior to 10/01/2009) ICD-9-CM1 756.79 (This is a shared code with omphalocele. If your state uses ICD-9 codes, please indicate in your metadata if you have another method to distinguish these two conditions.  If not, you do not have to report the data.) CDC/BPA2 756.71 ICD-10-CM3 NA
Birth Defect Gastroschisis (starting on 10/01/2009) ICD-9-CM1 756.73 CDC/BPA2 756.71 ICD-10-CM3 Q79.3
Birth Defect Hypoplastic Left Heart Syndrome ICD-9-CM1 746.7 CDC/BPA2 746.7 ICD-10-CM3 Q23.4
Birth Defect Hypospadias ICD-9-CM1 752.61 CDC/BPA2 752.60 – 752.62 (excluding 752.61 and 752.621) ICD-10-CM3 Q54.0 – Q54.9 (excluding Q54.4)
Birth Defect Limb Deficiencies ICD-9-CM1 755.2 – 755.4 CDC/BPA2 755.20 – 755.49 ICD-10-CM3 Q71.0 – Q71.9, Q72.0 – Q72.9, Q73.0 – Q73.8
Birth Defect Spina Bifida (w/out anencephaly) ICD-9-CM1 741.0, 741.9 without 740.0-740.10 CDC/BPA2 741.00-741.99 without 740.0-740.10 ICD-10-CM3 Q05.0 - Q05.9, Q07.01, Q07.03 without Q00.0 - Q00.1
Birth Defect Tetralogy of Fallot ICD-9-CM1 745.2 CDC/BPA2 745.20 – 745.21, 747.31 ICD-10-CM3 Q21.3
Birth Defect Transposition of the Great Arteries ICD-9-CM1 745.10, 745.12, 745.19 (Note: for CCHD, 745.10 only (d-TGA only)) CDC/BPA2 745.10 – 745.12, 745.18 – 745.19 (Note: for CCHD, 745.10 (TGA complete, no VSD), 745.11 (TGA incomplete, with VSD), 745.18 (other specified TGA), 745.19 (unspecified TGA) ICD-10-CM3 Q20.3, Q20.5 (Note: for CCHD, Q20.3 only)
Birth Defect Trisomy 21 ICD-9-CM1 758.0 CDC/BPA2 758.00-758.09 ICD-10-CM3 Q90.0 – Q90.9

1International Classification of Diseases, 9th Revision, Clinical Modification

2Centers for Disease Control/ British Pediatric Association

3International Classification of Diseases, 10th Revision, Clinical Modification