UF researchers who studied all Florida births from 1996 through 2000 found multiples have a higher risk than babies born singly of developing 23 of 40 birth defects, such as spina bifida, according to results recently published online in the Maternal and Child Health Journal.
The same team of researchers, from UF's Maternal Child Health Education Research and Data Center, studied 4,768 pairs of opposite-sex twins and found that boys had a 29 percent higher risk for birth defects than girls. This could be because boys tend to develop at a slower pace, leaving a little more time for potential problems to arise, according to findings published this month in Birth Defects Research (Part A): Clinical and Molecular Teratology.
"In the past 20 years, multiple births have increased because of greater reliance on assistive reproductive technology, especially among women delaying childbirth until their 30s and 40s," said Yiwei Tang, M.D., an assistant professor of pediatrics and a lead researcher on both studies. "In offering these options to women, full disclosure of an increased risk of birth defects should be made."
Multiples had the highest risks of having certain brain, heart, bladder and liver defects.
Although the risks are greater for multiple-birth babies, the number of children born with birth defects is still small. About 3.5 percent of multiples are born with birth defects, whereas 2.5 percent of single-birth babies are, the research shows.
"Though birth defects are not a common occurrence, when they do occur within a family, it can be life-altering," said Jeffrey Roth, Ph.D., an associate professor of pediatrics, director of the data center and a study co-author
Contact: April Frawley Birdwell
University of Florida