Information obtained from a manual pelvic exam alone may be incomplete. With a pelvic sonogram, the uterus and ovaries are visualized. The sonogram can help explain findings from the manual exam or provide additional information. Common indications for a pelvic ultrasound examination include pelvic pain, abnormal vaginal bleeding and suspicion of an abnormality on a manual gynecologic examination.
There are two methods of performing an ultrasound examination of the pelvis: (1) abdominal or transabdominal and (2) vaginal, also called transvaginal or endovaginal. The same principles of high-frequency sound described previously apply in each technique. For abdominal or transabdominal sonography, a sonographer or doctor places a transducer on the surface of your lower abdomen. A small amount of gel is used on the skin to ensure good transducer contact. Vaginal sonography involves the insertion of a transducer into your vagina. The tip of the transducer can be circular or oblong but is usually smaller than the standard speculum used when obtaining a routine Pap smear. A protective cover is placed over the transducer, which is then lubricated to ease insertion and provide better contact with your body. The transducer is inserted into your vagina either by the doctor or sonographer, or you could be asked to insert it yourself in a similar manner as you would a tampon.
A typical pelvic sonogram requires less than 30 minutes. However, the length of time can vary greatly depending on how easily the necessary information is obtained and on the complexity of the findings.
Abdominal scanning is usually done with you lying flat on an examination table. Garments are elevated or pulled down to expose the lower abdomen from the navel to the pubic bone. Abdominal scanning may or may not require a full bladder. A full bladder provides a "window" through which the pelvic organs can be seen. Your doctor could ask you to drink a large quantity of water and/or refrain from urinating just prior to the examination. Preparations for vaginal scanning are similar to those for a routine manual pelvic examination. You will be asked to empty your bladder prior to the exam and to disrobe from the waist down. You will need to assume a position similar to the one used for a Pap smear. If necessary, your buttocks could be elevated by a thick cushion.
This will depend on the reason the exam has been requested. In some instances, it might be necessary to perform only a pelvic sonogram transabdominally (possibly with a full bladder). In other cases, a vaginal exam alone will be adequate. In still other cases, both transabdominal and transvaginal scans will be necessary. The examiner will decide which types of scans will be necessary.
Each has its advantages. The abdominal approach offers a panoramic view of the entire pelvis. This shows where one internal structure is in relation to another. Improved visualization of some structures can be achieved using the vaginal approach because the transducer is brought closer to the area being examined. Thus, this approach can be very helpful in seeing the fetal heartbeat in an early pregnancy, evaluating the internal lining of the uterus or measuring a cyst in an ovary. The doctor or sonographer performing your sonogram will decide whether one approach or a combination of approaches is best for your particular case.
Although the examination is often performed to look for a cause of pelvic pain, the sonogram itself should not be painful or significantly increase your discomfort. A vaginal sonogram is usually more comfortable then a manual examination performed by your gynecologist or family doctor. If you have been experiencing vaginal bleeding, whether pregnant or not, a careful vaginal sonogram will not be harmful and could be helpful in determining the cause of the bleeding.