Ultrasounds have become a helpful, regular part of prenatal care, and all women should receive more than one ultrasound during pregnancy. A prenatal ultrasound test uses a small amount of gel on your abdomen and a device called a transducer to emit high-frequency sound waves into your abdomen. The echoes are recorded and transformed into video or photographic images of your baby as well as your placenta, ovaries, and amniotic sac.
Early in pregnancy, ultrasounds are used to confirm the fetal heartbeat and the baby’s position in the uterus. Ultrasounds also screen for fetal growth and weight, amount of amniotic fluid, placenta and umbilical cord location, as well as the baby’s general health and anatomy. Later on in your pregnancy, any abnormalities or birth defects could be visible on an ultrasound.
During the first trimester, your physician may perform an internal ultrasound, where a small transducer wand is inserted directly into the vagina. The practitioner will move the wand within the vaginal cavity to scan your uterus. This allows your practitioner to see the fetus even before it’s detectable on a transabdominal ultrasound. A gestational sac can be visualized on ultrasound as early as 4 1/2 weeks after your last period; a heartbeat can be detected as early as 5 to 6 weeks.
Both procedures can last from five to 30 minutes and are painless. That said, if the sonographer needs to press hard on your abdomen to see a particular part of your baby more clearly, you may experience discomfort.
Usually, a woman gets a minimum of two ultrasounds during her pregnancy. In the first trimester of pregnancy it can be done anytime. A first trimester ultrasound is used to confirm the fetal heartbeat, date a pregnancy, determine if the pregnancy is uterine, and discover the number of fetuses. Midway through your pregnancy, a trained sonographer will perform a detailed anatomy scan. Sometimes a mom-to-be will have additional ultrasounds over the course of her pregnancy if she is considered high-risk.
Ultrasounds are noninvasive and very low-risk. However, medical professionals caution against unnecessary exposure and using 4-D ultrasounds, which private businesses offer (i.e. at your local mall). While ultrasounds are usually relatively accurate at estimating a baby’s size, they can under- or over-estimate weight, especially if they’re overused or administered by untrained personnel, which may occasionally result in unnecessary C-sections or premature deliveries. The American Congress of Obstetricians and Gynecologists urges practitioners and patients to use ultrasounds only if they’re medically necessary.