If you have a child born with a birth defect, what are the chances it will happen again with your next baby?
This is a common and deeply personal question families ask, and a source of anxiety in their desire for healthy offspring without special needs. A team at (COPH) sheds new light on the topic in a study published in the journal Birth Defects Research.
The peer-reviewed paper, 鈥淪ibling Recurrence Risk of Non-Chromosomal Birth Defects: A Population-Based Study in Florida, 2000鈥2019,鈥 addresses these risks using statewide, population-based data.
鈥淏irth defects are one of the leading causes of infant mortality and can have lifelong impacts on children and families, so understanding them has always been a central focus of our work,鈥欌 said , professor in the , principal investigator for the Birth Defects Surveillance Program at USF, and senior author of the study.
鈥淥ne question a family may ask after having a child with a birth defect is 鈥渨hat does this mean for future pregnancies?鈥 he added. 鈥淲e wanted to provide clear, evidence-based answers to that question using real-world data from across Florida.鈥欌
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The USF team on the paper included lead author Rachel Rutkowski, a DrPH student in ; , assistant professor of epidemiology and Co-PI of the Birth Defects Surveillance Program; and , assistant professor, and , distinguished university professor, both in the .
The team sought to estimate sibling recurrence risk for non-chromosomal birth defects, which are structural or functional abnormalities present at birth that aren鈥檛 caused by extra, missing or rearranged chromosomes. They are often a result of environmental factors, chemicals or drugs. Examples are spina bifida, congenital heart defects, cleft palate and defects of the limbs.
Using linked surveillance data, they quantified recurrence risk across a range of
birth defects in a rigorous manner. The study is intended to provide families, clinicians
and with clearer, evidence-based estimates that can directly inform counseling and future
pregnancy planning.
鈥淭his work underscores the power of high-quality surveillance data 鈥 not only to monitor
prevalence and trends, but to answer clinically meaningful questions that matter to
families,鈥欌 Rutkowski said. 鈥淚t鈥檚 a powerful example of how our program translates
surveillance into actionable knowledge.鈥欌
The study population included 1,372,831 sibling pairs, of which 29,611 (2.2 percent) had an older sibling with a birth defect. Among sibling pairs in which the older sibling was affected, roughly 5 percent of younger siblings also had a birth defect. Younger siblings had over twice the odds of having any birth defect if their older sibling was affected compared to those with an unaffected older sibling.
About 1 in 33 babies in the U.S. are born with a major birth defect, making them the leading cause of infant deaths 鈭 responsible for 20% of all infant fatalities, according to the Centers for Disease Control and Prevention (CDC). Birth defects are structural changes that affect a baby鈥檚 appearance or function or both. They can range from mild to severe and arise from a mix of genetic, behavioral and environmental factors, and include heart defects, Down syndrome, cleft lip and palate, and spina bifida, among others.
In the United States, birth defects have accounted for about 140,000 hospital stays during a single year, resulting in $2.6 billion in hospital costs alone, notes the CDC.
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Birth defects registries seek to identify health issues in the first year of a child鈥檚 life, while other public health programs collect data on special needs, developmental disabilities and early intervention services. Because newborn screening programs are population-based, despite that many of the conditions screened for are also birth defects, these conditions are not typically included in birth defects registries.
鈥淥ur broader goal has always been to understand the epidemiology of birth defects 鈥 how often they occur, why they happen and how we can prevent them or better support affected families,鈥欌 Tanner said. 鈥淭his study adds an important piece by focusing on recurrence, which helps set expectations for families planning future pregnancies.鈥欌
The team鈥檚 findings provide contemporary, system-specific estimates of sibling recurrence that may inform family counseling, folic acid fortification, preconception care and clinical decision-making. The research builds directly on decades of work by USF teams and collaborators, including a recent paper by Kirby.
"This paper equips families of children with birth defects with critical information for future family planning,'' Elmore said. "As a mother, I understand the weight of the questions these families face: What is the likelihood that a second child will also be affected? Can our family sustain another child with a birth defect- financially, emotionally, and physically? These are deeply practical questions, and families deserve real data to help answer them.''
These studies are products of the and a long-standing partnership with the Florida Department of Health. Together, they keep one of the largest population-based birth defects registries in the country, tracking millions of births and linking multiple data sources to better understand outcomes. That infrastructure 鈥 supported in part by CDC cooperative agreements and state partnerships 鈥 makes possible this kind of large-scale research.