Approximately 6.2 million women in the U.S. become pregnant each year, and most of those who seek prenatal care are offered at least one ultrasound. According to the Wall Street Journal, data compiled by FAIR Health Inc. showed the average number of ultrasounds per delivery was 5.2 in 2014.
However, some patients tell us they’d prefer not to have routine ultrasounds performed during their pregnancy. They cite a range of reasons, from not wanting to know if the baby might have a birth defect to concerns about the safety of ultrasound technology.
I trained in an era in which routine ultrasounds were not a standard of care during pregnancy. The technology wasn’t as readily available or advanced as it is today. Currently, the American College of Obstetricians and Gynecologists (ACOG) suggests that pregnant women have at least one ultrasound exam during pregnancy, usually between 18 and 22 weeks of gestation. This scan is an opportunity to look for abnormal fetal development or other problems with the placenta, uterus, or amniotic fluid.
But some doctors around the U.S. consider fetal ultrasounds mandatory, asking that all women have them in order to deliver at their centers. That strikes me as extreme. While ultrasounds are useful, they aren’t perfect, and some findings may lead to interventions and anxiety during pregnancy that ultimately aren't necessary.
ACOG considers mandatory ultrasounds discriminatory, and says a pregnant woman’s decision to refuse a therapy should be respected. This controversy highlights the need for a balance between patients' beliefs, education provided by doctors, and medical standards of care. Let’s look at the role ultrasound plays at different points in pregnancy.
First trimester ultrasound
ACOG suggests that ultrasounds in the first trimester should not be standard because it’s hard to see the parts of the baby to determine whether they have formed normally. But other reasons for doing an ultrasound in the first trimester include determining the gestational age of the pregnancy or evaluating a patient who has bleeding or pain
In our practice, we started offering early ultrasounds to all when we noticed a trend in young women being uncertain when their last menstrual period began. After a couple years, we went back and looked at the data. Our suspicions were confirmed – almost one in four women had their due date adjusted by the first trimester ultrasound, which can also affect the delivery date. Also, some tests require accurate knowledge of gestational age to perform them at the right time. However, we’d support a patient’s choice to not have an ultrasound at that time.
The 20-week ultrasound
An ultrasound performed in the second trimester can help reduce concerns about the development of the fetus. Many patients tell us they are eager to have the ultrasound – they want this reassurance. This can be particularly important to older mothers and women with health conditions that are associated with a higher risk of a congenital anomaly. (If the baby is in a favorable position, the 20-week ultrasound can also help us determine the sex of the child.)
If the ultrasound reveals a concern, some parents appreciate knowing in advance that the delivery or the baby’s care might be complex. While birth defects are not rare – the Centers for Disease Control and Prevention estimate that 3% of babies in the U.S. have a birth defect – it can take time to find a hospital that is prepared to handle your pregnancy and delivery, as well as to find a specialized pediatrician and daycare, if needed.
An ultrasound at this time can also identify other situations that are high risk, such as identifying the presence of twins or a placenta previa. These situations can be dangerous for the mother and babies – for example, placenta previa can cause significant maternal hemorrhage, and you’d be advised to choose a hospital over a birth center or home birth.
So given these advantages, why would a woman choose not to have ultrasounds?
Understanding your fetal ultrasounds
Dr. Robyn Horsager describes some of the movements of a baby that can be seen on ultrasound during the various stages of pregnancy, including tiny movements at nine weeks, big kicks at 20 weeks, and when a baby has hiccups in the womb.
Sometimes ultrasounds create unnecessary stress
We see this frequently in the first trimester. Women come in for an ultrasound thinking they are farther along in the pregnancy than they are, and we can't see the heartbeat in the fetus. My experience is that patients and their partners immediately focus on the worst possible outcome – that the pregnancy has failed. In these cases, they have to come back for another ultrasound in a few weeks, and very frequently the pregnancy is fine. But they’ve had many days of anxiety and concern before we can give them the good news.
We also must acknowledge that ultrasounds in the second and third trimester aren’t perfect. A 2014 study from France found that among 526 pregnancies, ultrasounds at this time showed false positive results for fetal anomaly in 8.8% of cases and misclassification of potential anomalies in 9.2% of cases.
Some patients opt out due to this uncertainty, saying they don’t want suspicious ultrasound findings adding to their stress level. Others say they would rather avoid having to make decisions about advanced testing or procedures – or feel obligated to defend their choices to loved ones. Some patients say no ultrasound findings will affect their feelings about the pregnancy.
In any scenario, your Ob/Gyn will offer information to help you make the best choice for your health and your family.
Ultrasound is safe
For those women who avoid sonograms because of concerns they pose risk to their baby, I do want to emphasize that we believe ultrasound is a very safe technology to use during pregnancy. ACOG states, “No links have been found between ultrasound birth defects, childhood cancer, or developmental problems later in life.” That said, there is no way to prove this point – we only have the decades of experience to support this position.
Experienced ultrasonographers perform studies with a goal of minimizing exposure to the developing fetus. The FDA also recommends avoiding keepsake ultrasounds and home ultrasound machines for the same reason.
The decision to have ultrasounds is personal. Doctors should provide the information you need to make your own informed decision and keep open lines of communication about your preferences and concerns.
If you are unsure about using ultrasound during your pregnancy, talk with your doctor about the risks and benefits. Our goal is the same as yours – a healthy mother and baby.