Much like a transvaginal ultrasound, a pelvic ultrasound is a diagnostic test that gives views of a patient’s uterus, fallopian tubes, ovaries, and the surrounding areas. The difference between the two tests is that a pelvic ultrasound gives a broader, more general view. Often, a pelvic test will be performed first, followed by a transvaginal test. Other times a pelvic ultrasound is all that is necessary.
The preparation for a pelvic ultrasound involves filling the bladder about an hour before test time. Clear liquids (water, tea without milk, clear juices) work best because they produce less gas, an enemy to the ultrasound image.
Reasons for a pelvic ultrasound include:
Pain/ Irregular Bleeding
One of the most common reasons for a pelvic ultrasound is pelvic pain. Many women experience pain from fibroid tumors, ovarian cysts, endometriosis, pelvic infections, and a host of other reasons.
The transducer can capture the image of fibroids, benign uterine tumors. These tumors cause pelvic muscular cramping, especially during menstruation. They can also cause excessive bleeding.
An ovarian cyst, usually uncomplicated (benign), is a result of an egg ripening and not releasing. It can grow to as large as 6 cm or more, causing pain and pelvic pressure. A pelvic ultrasound is often the first test to be done, and if the ovary is not seen clearly, a transvaginal ultrasound might be done to determinine whether it is truly a cyst or a solid mass.
Endometriosis, or the overgrowth of endometrial tissue, can be found in unusual pelvic places, including the regions beyond the ovaries (adnexal), adjacent to the uterus, and even outside of the pelvis. It is thought that the endometrial tissue somehow migrates outside of the uterus through the fallopian tubes instead of being expelled into the vagina during menstruation. A pelvic ultrasound works best for diagnosing endometriosis because it gives a broad view of the areas around the pelvic organs.
Although a doctor might specifically order renal (kidney) and bladder ultrasounds for suspected bladder problems, occasionally an anomaly will be seen on a pelvic ultrasound. Because a patient has filled her bladder for this test, it is well-defined and viewable on a pelvic ultrasound. Bladder wall thickening (infections), ureter obstruction(s), and/or possible kidney stones can be detected, clarifying the reason for vague pelvic symptoms.
2nd and 3rd Trimester Pregnancies
Usually termed “obstetrical” ultrasounds, 2nd and 3rd trimester exams are performed in the same way as pelvic ultrasounds. A mother might fill her bladder somewhat less for a second trimester exam, and not at all for a 3rd trimester ultrasound, depending on her comfort level and the technologist’s needs.
This type of pelvic ultrasound shows fetal parts, determines fetal age, can determine fetal sex, and checks for the overall health of the fetus.
For further reference: WebMD