Ultrasound, also called sonography, is an imaging tool that uses sound waves to construct an image of the baby inside the womb.Why Ultrasound is Done During Pregnancy
Ultrasound can be very useful during pregnancy. It can aid your OBGYN in monitoring your baby’s health and development. Specific uses for ultrasound during pregnancy include:
- Determining fetal age and sex
- Confirming the location of the placenta
- Observing the amount of amniotic fluid present in the uterus
- Identifying the number of fetuses
- Analyzing developmental defects or possible health problems in the fetus
- Detecting of suspected pregnancy complications such as ectopic pregnancy
- Determining the position of the fetus and monitoring movement, breathing and heart rate
- Providing guidance during certain procedures such as chorionic villus sampling and amniocentesis.
When is Ultrasound Performed During Pregnancy?
Most expectant mothers undergo at least one ultrasound during pregnancy. When done for routine purposes, ultrasound is typically scheduled during the second trimester, around the 16th to 20th weeks of pregnancy.
Ultrasound may also be performed in the first trimester to establish an approximate due date, to identify multiples or to screen for potential problems. Late in pregnancy, ultrasound may be used to estimate your baby’s size prior to birth.
Additional ultrasounds may be scheduled to help identify the cause of pregnancy complications such as bleeding.
Types of Ultrasound Done During Pregnancy
The most commonly performed ultrasound is 2D. Specialized ultrasound includes three-dimensional (3D), four-dimensional (4D), and Doppler ultrasound. Your obstetrician may order Doppler ultrasound during pregnancy to measure fetal blood flow, fetal growth, to evaluate fetal heartbeat, or in conjunction with other tests if fetal anemia is suspected.
How is an Ultrasound Performed During Pregnancy?
There are two types of ultrasound exams that may be performed during pregnancy:
- Transvaginal ultrasound
- Transabdominal ultrasound
The type of ultrasound you have will be determined by how far along you are in your pregnancy, why the ultrasound is being done and in some cases, your weight.
Transvaginal ultrasound is often performed in early pregnancy. After 10 weeks of pregnancy, transabdominal ultrasound is used more commonly.
Before, During and After Ultrasound During Pregnancy
Prior to a sonogram (ultrasound) exam, you may be asked to drink several glasses of water to fill the bladder. This helps with sound wave transmission.
During a transabdominal ultrasound exam, you will be asked to lie on a table with your abdomen exposed. A gel is applied to help the transducer glide smoothly over the skin and improve sound wave transmission. If you are scheduled for a transvaginal ultrasound, your feet will be positioned in stirrups and a lubricated, wand-like transducer will be inserted into your vagina.
Afterwards, you can immediately return to your normal activities.
Ultrasound is considered very safe for both you and your baby, but should only be performed when ordered by your OBGYN or appropriate health care provider.