Scientists are uncovering disturbing evidence that those sneak peeks at baby could damage a developing brain.
Toward the end of my first pregnancy, a doctor ordered an “emergency” ultrasound because she believed I was measuring small. She turned to go to her next client before I could talk to her about it, muttering that she suspected “intrauterine growth retardation.”
My husband and I sat in the waiting room, flooded with anxiety. The scan showed the baby was fine. It wasn’t until years later when I started researching and writing about pregnancy that I learned that ultrasound scans have not been shown to be any more effective in predicting intrauterine growth restriction (doctors these days try to avoid using the wordretardation) than palpation of the pregnant woman’s abdomen by an experienced clinician.
The same summer my daughter was born, Marsden Wagner, an obstetrician, scientist, and former director of Women’s and Children’s Health at the World Health Organization, wrote: “There is no justification for clinicians using routine ultrasound during pregnancy for the management of IUGR.”
Most women look forward to multiple ultrasounds because they are lulled into the assumption that this technology will catch potentially fatal abnormalities—such as a heart defect—early, so they can be fixed. When doctors tell pregnant women they will only get one or two scans, some are terribly disappointed, feeling that they won’t be able to bond as effectively with the baby or worrying that the doctor won’t know that the baby is growing normally. But one study of 15,151 pregnant women published in theNew England Journal of Medicineshowed that an ultrasound scan does not improve fetal outcome. The study, which was conducted by a team of six researchers over almost four years, compared pregnant women who received two scans to pregnant women who received scans only when some other medical indication suggested an ultrasound was necessary. The results showed no difference in fetal outcomes.
“This practice-based trial demonstrates that among low-risk pregnant women ultrasound screening does not improve perinatal outcome,” the authors conclude. Even when the ultrasound technology uncovered fetal abnormalities, the fetal survival or death rate was the same in both groups.
What the authors did find, however, was that routine ultrasounds led to more expensive prenatal care, adding more than $1 billion to the cost of caring for pregnant women in America each year.
Another study, of 2,834 pregnant women, published in theLancet, showed that the babies of the randomly chosen group of 1,415 women who received five ultrasounds (as opposed to the group of 1,419 women who had only one scan at eighteen weeks) were muchmore likelyto experience intrauterine growth restriction, a scary combination of words that means the fetus is not developing normally. Ironically, intrauterine growth restriction is one of the conditions that having multiple ultrasounds is supposed to detect.
Though the American College of Obstetricians and Gynecologists recommends that obstetricians discuss the advantages and disadvantages of having an ultrasound scan with pregnant patients, ACOG does not explicitly recommend the screening. ACOG explains that ultrasoundmayreduce fetal mortality rates because women who discover they are carrying fetuses that are incompatible with life will often choose abortion, but ACOG also specifies that ultrasoundhas not been proven to be effectivefor reducing infant mortality in any other way.