Ultrasound and Your Pregnancy
A fetal ultrasound, or sonogram, is an imaging technique that uses high-frequency sound waves to produce images of a baby in the uterus. Diagnostic ultrasound has been used during pregnancy for many years and is considered safe when used appropriately. The lowest amount of ultrasound energy that provides an accurate assessment should be used – obstetric providers and ultrasonographers are trained in appropriate use of ultrasound energy. Our practice is certified by the American Institute of Ultrasound in Medicine (AIUM).
Ultrasound Schedule During Pregnancy
Ultrasound during pregnancy is used for several reasons, including the following:
- Confirmation and dating of a pregnancy (first trimester).
- Determination of placental location and development (second and/or third trimester).
- Evaluation of fetal anatomy (second trimester).
- Evaluation of fetal position and/or growth, and approximate amount of amniotic fluid surrounding the fetus (second and/or third trimester).
First Trimester Ultrasound
First trimester ultrasound is done to evaluate the presence, size, number and location of the pregnancy. This test may be done over the belly (transabdominally) or internally (transvaginally). For the transabdominal ultrasound we may ask that you hold your urine – it helps us see through skin and muscle tissues. If a transvaginal ultrasound is performed, we will ask you to empty your bladder to optimize visualization.
Second Trimester Ultrasound
Second trimester ultrasound is typically done at approximately 20 weeks to evaluate fetal anatomy, however, it may also be used to monitor your pregnancy more closely (e.g. placental location, approximate amount of amniotic fluid, etc.). Your bladder does not need to be full for this exam, however, if you can hold your urine without discomfort, it may help us to visualize your cervix better at the beginning of the exam. A transvaginal exam may be performed for evaluation of your cervix and/or placenta.
Third Trimester Ultrasound
Third trimester ultrasound may or may not be performed – If your medical provider determines that ultrasound evaluation is medically necessary, this exam can help us to evaluate fetal well-being, fetal position, placental location, and fetal growth. A transvaginal exam may be performed for evaluation of your cervix and/or placenta.
How to prepare for your ultrasound
Wear comfortable, loose-fitting clothing. Please bring another adult with you if you are bringing young children, and if one is not available, please schedule your appointment when you can arrange for childcare. Ultrasound evaluation of your pregnancy can be very involved (exams can last from 30-60 minutes), and we want to make sure that there are no distractions to make it the best possible experience for you. We ask that you turn off your cell phones during the exam. No recording devices of any type are allowed during the ultrasound.
For transabominal ultrasounds, you will be asked to recline on an exam table, and gel is applied to your abdomen. This gel is non-staining, and allows the sound waves to travel through your skin and muscle. For transvaginal ultrasounds, you will be asked to urinate if there is urine in your bladder, then disrobe from the waist down. The probe is placed in your vagina (just like a tampon). This is the best way to evaluate early pregnancies, and also examine your cervix and placenta.