Key Findings: Racial and Ethnic Differences in the Occurrence of Major Birth Defects

3 pregnant women making a heart with their hands over there stomach

The American Journal of Public Health published a new study that examined the occurrence of major birth defects across multiple racial and ethnic groups. Using 12 state-based birth defects tracking systems, this is to date the largest study conducted to look at racial and ethnic differences in the United States for a range of birth defects. Read the abstract for the study here .

Main Findings from this Study

Compared with non-Hispanic whites, American Indians/Alaska Natives had a significantly higher occurrence of:
- Anotia/Microtia (ear defects)
- Cleft lip with or without cleft palate
- Trisomy 18
- Encephalocele (serious defect of the skull and brain)
- Limb deficiency (when part or all of the arm or leg fails to form completely during pregnancy)
Cubans and Asians, especially Chinese and Asian Indians, had significantly lower occurrence of many of the studied birth defects, compared to non-Hispanic whites.
Some of the studied birth defects had very different rates of occurrence across the racial and ethnic groups (either much higher or much lower occurrence compared to non-Hispanic whites). Conditions that showed substantial variation across the racial and ethnic groups include anotia/microtia, spina bifida (a defect of the spine), and Down syndrome.
The researchers recommend further investigation to determine why there appeared to be a relatively high occurrence of certain birth defects in American Indians/Alaska Natives.

Birth defects that have significantly higher or lower occurrence in selected racial and ethnic groups, compared to non-Hispanic white:
	Much higher occurrence1	Much lower occurrence2
Non-Hispanic American Indian/Alaskan Native	Encephalocele Anotia/Microtia Cleft lip with or without cleft palate Upper limb deficiency Lower limb deficiency Any limb deficiency Trisomy 18	Hypospadias
Non-Hispanic Asian		Spina bifida without anencephaly Truncus arteriosus Aortic valve stenosis Hypoplastic left heart syndrome Coarctation of the aorta Esophageal atresia Pyloric stenosis Hypospadias Gastroschisis Omphalocele
Non-Hispanic Black	Encephalocele Trisomy 18	Aortic valve stenosis Cleft lip with or without cleft palate Pyloric stenosis Gastroschisis
Hispanic	Anencephaly Encephalocele Anotia/Microtia	Hypospadias

1 These conditions were found to have statistically significantly higher occurrences in the noted races and ethnicities compared to non-Hispanic white
2 These conditions were found to have statistically significantly lower occurrences in the noted races and ethnicities compared to non-Hispanic white.
Note: Even though programs try to collect information on all occurrences, some birth defects might not be captured by programs if the outcome is not a live birth. This could underestimate the occurrences of some birth defects.

About this Study

Researchers used data from 12 population-based birth defects tracking programs. Population-based means that the researchers look at all babies with birth defects who live in a defined study area, in order to get a complete picture of what is happening among all of the people (the population) living in the study area. Participating states were: Arizona, Colorado, Florida, Georgia (some counties), Illinois, Massachusetts, New York, North Carolina, and Texas. This study included 13.5 million live U.S. births from 1999 to 2007, meaning 1 of every 3 births in the United States during that time period was included in the study.
This is the most comprehensive study to date to examine racial and ethnic variation for a wide range of birth defects in the United States, particularly among under-studied racial and ethnic groups including American Indians/Alaska natives, Hispanic subgroups, and Asian subgroups.

Reference for Key Findings

Canfield MA, Mai CT, Wang Y, O’Halloran M, Marengo LK, Olney RS, Borger CL, Rutkowski R, Fornoff J, Irwin N, Copeland G, Flood TJ, Meyer RE, Rickard R, Alverson CJ, Sweatlock J, Kirby RS. The Association Between Race/Ethnicity and Major Birth Defects in the United States, 1999-2007. American Journal of Public Health. 2014 [epub ahead of print].

Birth Defects: CDC’s Activities

CDC works to identify causes of birth defects, find opportunities to prevent them, and improve the health of those living with birth defects.

Tracking: CDC tracks birth defects through several state tracking systems and regional programs. CDC also supports and collaborates with the National Birth Defects Prevention Network (NBDPN), as well as representatives from local, state, and national groups working on birth defects. For this study, researchers collaborated through the NBDPN to collect the data from the 12 different states.
Research: CDC funds the Centers for Birth Defects Research and Prevention, which collaborate on large studies such as the National Birth Defects Prevention Study (births 1997-2011) and the Birth Defects Study To Evaluate Pregnancy exposures (started with births in 2014). These studies work to identify factors that increase the risk for birth defects.