Fetal ultrasounds are used to produce images of a baby while it is still in the uterus. Ultrasounds work by using high frequency sound waves and can help your doctor to determine how your pregnancy is progressing by evaluating your baby’s growth and development.
Why are pregnancy ultrasounds performed?
The first fetal ultrasound is typically performed during the first trimester of pregnancy. During the second or third trimester, another ultrasound is usually performed at about 18 to 20 weeks. If there is a reason to monitor any other complications, other ultrasounds may be scheduled as well.
Here are the most common reasons for fetal ultrasounds:
- To confirm the pregnancy and its location: An ectopic pregnancy is a fetus that has developed outside of the uterus and inside the fallopian tubes. Ultrasounds help your doctor to make sure the fetus is developing inside the uterus where it should be.
- To determine the age of the fetus and set a due date: Knowing your baby’s gestational age helps your doctor to determine an exact due date for the birth and can also help to track various milestones throughout your pregnancy.
- To confirm the number of fetuses: If your doctor suspects you may have a multiple pregnancy, he or she may recommend an ultrasound to confirm the number of babies that are present.
- To evaluate the growth of the fetus: Ultrasounds help your doctor to evaluate your baby’s growth and ensure they are growing and developing at a normal rate. Ultrasounds also allow your doctor to monitor your baby’s movement, breathing, and heart rate to check for any abnormalities.
- To study the placenta and the levels of amniotic fluid: Amniotic fluid is the fluid that surrounds the baby while it is in the uterus during pregnancy. Since the placenta is what provides your baby with the necessary nutrients and oxygen-rich blood it needs for survival, if there is too much or too little amniotic fluid in the placenta, this could mean an increased risk for complications.
- To identify any birth defects: If you choose to screen for birth defects, an ultrasound is one way to do this.
- To investigate any complications that arise: If you are experiencing any complications from your pregnancy, such as unexplained bleeding, an ultrasound will help your doctor to determine the cause of the problems you are having.
- To perform any prenatal testing: There are certain prenatal tests that require your doctor to use an ultrasound to guide the placement of a needle.
- To determine the position of the fetus before delivery: Although most babies are positioned headfirst by the end of the third trimester, this is not always the case. Fetal ultrasounds help to confirm the position of the baby so that decisions can be made to ensure the smoothest possible delivery.
What happens during a pregnancy ultrasound?
There are two different types of fetal ultrasounds that are used depending on how far along you are in pregnancy. They include:
- Transvaginal ultrasound: This type of ultrasound is usually used during early pregnancy because the uterus and fallopian tubes are closer to the vagina than the abdominal surface. It in involve inserting a transducer inside the vagina to create images of the uterus, cervix, and fallopian tubes.
- Transabdominal ultrasound: This type of fetal ultrasound is typically used during the later part of pregnancy and involves moving a transducer over your abdomen. Gel is usually applied to the abdomen beforehand to prevent air bubbles that may form during the procedure from interfering with the images.
