1. Different Methods for Different Reasons
There are two ways to perform a prenatal ultrasound. Technicians perform transvaginal ultrasounds by inserting a round wand into the vagina. This method is most common in the first trimester when the date of the mother's last menstrual period is unknown with certainty. Transabdominal ultrasounds require the technician to put gel on the woman's stomach. The technician then moves a transducer over the gel. Both methods are usually painless for the mother and the fetus.
2. Results May Vary
Prenatal ultrasounds are subject to human error because a human performs and interprets the results. Because of this, false positive and false negative results can sometimes occur when the technician is checking the fetus for abnormalities. A false negative is when everything seems right with the fetus, but there is actually an abnormality. More commonly, the prenatal ultrasound gives a false positive result, which is when a fetal abnormality is detected when the fetus is actually fine. When a possible fetal abnormality is detected, more tests will be ordered to verify the results. In the mean time, try to relax and remember that there is a chance that everything is fine with your baby.
3. Fill It Up
A first trimester ultrasound requires a full bladder. Because the fetus and uterus are still small, a full bladder pushes the uterus toward the front of the stomach. This makes it easier for the ultrasound technician to see the fetus and the placenta. You may feel slight discomfort during the ultrasound because of your full bladder. The ultrasound should be relatively short, so try to relax and enjoy seeing a sneak peak of your baby. A full bladder is usually not necessary in ultrasounds performed after the first trimester.
4. The Sounds of an Ultrasound
Ultrasounds use high-pitched sonar waves that bounce off the fetus to produce a picture of the baby. The pitch is so high that humans cannot hear it. Sometimes, once the pregnancy is past the eighteenth gestational week, the fetus can hear secondary vibrations from the sonar waves. These secondary vibrations sound like pings. They are not loud and will not cause the fetus any harm. Sometimes, a fetus is asleep when the ultrasound starts and then begins to move and squirm in response to these pings.
5. A Change of Heart
Once you reach the sixth week of your pregnancy, you can usually see and hear your baby's heartbeat during a prenatal ultrasound. Before the sixth gestational week, you may be able to see your baby's heartbeat on an ultrasound. It will look like a flicker in the baby's chest. Even though you can see the heartbeat earlier than your sixth week of pregnancy, it beats too soft to be heard even with amplification.
