Quick answer: a pelvic ultrasound in women can be done in two ways, and many exams use both. In a transabdominal ultrasound, the probe moves over your lower belly, and you usually need a full bladder. In a transvaginal ultrasound, a slim, covered probe is placed about 2 to 3 inches into the vagina, after you empty your bladder; it gives sharper images of the uterus and ovaries. Neither uses radiation. The transvaginal exam is usually more comfortable than a gynecologic exam with a speculum, and the whole visit usually takes under 30 minutes. You can always ask for a chaperone, ask questions, or ask to stop.
Many women are surprised, or uncomfortable, when they learn that their «pelvic ultrasound» includes an internal scan. Knowing why each method is used and what to expect makes it much easier.
What a pelvic ultrasound shows
In women, a pelvic ultrasound looks at the uterus, cervix, ovaries, fallopian tubes and bladder. It helps investigate:
- pelvic pain
- abnormal vaginal bleeding and other menstrual problems
- infertility
- ovarian cysts and uterine fibroids
- endometrial polyps and the lining of the uterus (endometrium)
- ovarian or uterine cancers
It is also used in early pregnancy and to guide some procedures. In men, a pelvic ultrasound looks at the bladder, seminal vesicles and prostate; a transrectal ultrasound gives detailed images of the prostate.
Transabdominal vs transvaginal at a glance
| Transabdominal | Transvaginal | |
|---|---|---|
| How it is done | Probe moves over the lower belly with gel | Slim, covered and lubricated probe placed about 2 to 3 inches into the vagina |
| Bladder | Full bladder usually needed | Empty bladder |
| Image detail | Wider overview of the pelvis | Sharper, closer images of the uterus, endometrium and ovaries |
| Best for | Large masses, overall view, when an internal exam is not appropriate | Lining of the uterus, ovaries, small cysts, early pregnancy, abnormal bleeding |
| Comfort | Pressure on a full bladder can be uncomfortable | Usually more comfortable than a speculum exam |
Many exams start with a transabdominal scan for an overview and then add a transvaginal scan for detail.
How to prepare
For a transabdominal scan: you may be asked to drink up to six glasses of water about two hours before the exam and not to urinate, so your bladder is full. A full bladder pushes the bowel aside and works as a window to the organs behind it.
For a transvaginal scan: you will empty your bladder just before.
For both: wear a two-piece outfit; you will usually change into a gown from the waist down. Tell the team if you have a latex allergy, so they use a latex-free probe cover. Follow any specific instructions from your center.
What happens during the scan
Transabdominal: you lie on your back. The sonographer applies warm gel to your lower belly and moves the probe over it, pressing gently. There is usually no discomfort, apart from pressure on a full bladder.
Transvaginal: after you empty your bladder, you lie on your back with your knees bent, sometimes with your feet in stirrups or a cushion under your hips, much like a gynecologic exam. The sonographer or doctor covers the probe with a protective sheath, adds lubricating gel and gently inserts the tip, which is smaller than a speculum. They angle it to get views of the uterus and ovaries. Some people prefer to insert the probe themselves; ask if you would like to.
If a Doppler study is done, you may hear pulsing sounds as blood flow is measured. The exam is usually completed within 30 minutes, and you can return to normal activities right away.
From the scanner room: [ESPACIO PARA UNA ECOGRAFISTA O GINECÓLOGA: cómo explica la ecografía transvaginal a pacientes nerviosas y qué hace para que sea cómoda.]
Does a transvaginal ultrasound hurt?
It should not be painful. Most women feel some pressure, and it is usually more comfortable than a manual gynecologic exam. If you are having the scan because of pelvic pain, pressure on a tender area may be uncomfortable; tell the person scanning, and they can adjust.
Your comfort and your choices
- Ask for a chaperone. You can ask for another staff member or a person you trust to be in the room.
- Ask questions about what is going to happen before it starts.
- You can say no or ask to stop at any time. If a transvaginal scan is not right for you, for example if you have never been sexually active, have had a traumatic experience or simply prefer not to, tell the team; a transabdominal scan may still give useful information.
- Ask about a female sonographer if that would make you more comfortable; many centers can arrange it.
Common questions about timing
- On your period: a transvaginal ultrasound can usually still be done. Some exams, for example to look at the lining of the uterus, are best timed to a certain part of the cycle, so ask your doctor or the center.
- Pregnancy: ultrasound uses no radiation and is the preferred imaging test in pregnancy. Transvaginal scans are commonly used in early pregnancy. See [link: Ultrasound in Pregnancy: Dating, Anatomy and 3D Scans].
Is it safe?
Yes. Standard diagnostic ultrasound has no known harmful effects and uses no radiation.
Limitations
Gas in the bowel can block the view, and in larger patients deeper structures are harder to see through the abdomen, which is one reason a transvaginal scan is often added. If more detail is needed, your doctor may order an MRI.
Results
A radiologist reviews the images and sends a signed report to your doctor. Sometimes the radiologist discusses the results with you after the exam. Reports about ovarian cysts or masses may use a scoring system called O-RADS to describe the level of concern.
Frequently asked questions
Do I need a full bladder for a transvaginal ultrasound?
No. You empty your bladder first. A full bladder is only needed for the transabdominal part.
How far does the transvaginal probe go in?
About 2 to 3 inches. The tip is smaller than a speculum.
Can I refuse a transvaginal ultrasound?
Yes. You can decline or stop at any time. Discuss the alternatives with your doctor, as a transabdominal scan may give less detail.
Is a transvaginal ultrasound safe in early pregnancy?
Yes. It is commonly used in early pregnancy and does not use radiation.
How long does a pelvic ultrasound take?
Usually under 30 minutes, including both types if needed.
For more on preparation, see [link: Abdominal Ultrasound: How to Prepare].
This article is for general information and does not replace advice from your doctor or imaging team.