For decades, OB-GYNs have offered prenatal tests to expectant moms to uncover potential issues, including Down syndrome, before they give birth. However, some tests, such as amniocentesis and chorionic villus sampling, carry health risks, including miscarriage. For some women, the risks can be greater than the potential benefits from information they would gain.
Evidence now suggests that women who are well-informed about the pros and cons are more likely to decline testing, even when the tests are free, indicating that the average mother-to-be might not have all the facts.
In a study published in JAMA, the Journal of the American Medical Association, researchers worked with 710 women at medical centers around San Francisco. Half of them received standard care, including a focus on testing for women over age 35. The others were offered a computerized guide to prenatal testing and presented with the choice of having prenatal tests free of charge.
The guide, complete with bilingual narrator, talked through the information about the tests, including screenings such as blood tests and ultrasounds that don't carry a physical risk. The guide also covered diagnostic tests like amniocentesis that do.
The guide was personalized for each woman, using her birthday and expected delivery day to say which tests were still available for that stage of pregnancy and what the risk of Down syndrome was (the risk increases with maternal age).
The guide also highlighted a choice that women frequently overlooked: opting out. "We already knew that a lot of women do not understand that the screening tests are optional," says Miriam Kuppermann, professor of obstetrics and gynecology at the University of California, San Francisco School of Medicine and lead author of the study. "We told them it was totally reasonable to have no testing at all," she tells Shots. "It's not a medical question — it's really a values question."
The guide pushed women to think about their values, asking whether they wanted to be tested, whether they would want screenings before the more invasive testing, and which tests in particular they were interested in. All of the women in the study were quizzed on their knowledge of prenatal tests.
The researchers found that only 5.9 percent of women who used the guide underwent invasive testing, while 12.3 percent of the normally treated group did. The group that got a personalized guide was also more likely to avoid testing altogether, knew more about the risks of invasive testing and had a better handle on their likelihood of carrying a fetus with Down syndrome.
Reproductive geneticist Debbie Driscoll, at the Hospital of the University of Pennsylvania in Philadelphia, says having women think about their values and beliefs is important before diving in. She tells Shots there's variability across the country among women who choose prenatal screenings. Those differences, she says, are "probably not so surprising when you think about people's political and religious beliefs."
Kuppermann says prenatal testing can be a wonderful thing, particularly with advances in safer blood tests that can give definitive answers. However, she says the millions of women having babies each year in the U.S. need to understand what they're signing up for. The women should make the decision, she says, not their doctors. "I'm not trying to get women to test, and I'm not trying to get women to not test," says Kuppermann. "My goal is to have all women get the information they need."
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