Internal or belly ultrasound? How early pregnancy scans are done
By the mybaby4D teamUpdated 13 min read
The short answer
Early pregnancy scans are more likely to be internal (transvaginal): a thin, covered probe goes about 2 to 3 inches into the vagina, closer to the uterus. Cleveland Clinic says providers use belly (abdominal) scans after about 12 weeks, and the U.S. guideline allows either method, or both, in the first trimester. An internal scan may be uncomfortable but shouldn’t be painful, and you can ask for a chaperone or ask to stop. A belly scan may need a full bladder; an internal one, an empty or partly full one.
This guide walks through an internal scan step by step, bladder prep for each method, your choices in the room, and common myths.
Belly (transabdominal) scan. Gel goes on your belly and pelvis area, and a handheld probe moves over it (MedlinePlus).
Internal (transvaginal) scan. A probe in a protective cover, with gel, goes a short way into the vagina (MedlinePlus).
Why the earliest scans are often internal
Distance. “At this early stage in the pregnancy a vaginal scan gets closer to your uterus and gives a better picture than an abdominal scan,” says an NHS unit in Norwich, England (Norfolk and Norwich). A belly scan is less sensitive. It shows the first landmarks of a pregnancy “about one week after they are visible transvaginally,” says a review for family doctors (AAFP). How early can an ultrasound see a pregnancy? shows what appears when, and When can you see the heartbeat on an ultrasound? does the same for the heartbeat.
What the U.S. guideline says
The U.S. practice guideline for obstetric ultrasound says first-trimester scanning “may be performed transabdominally, transvaginally, or a combination of both.” If a belly scan “is not definitive, a transvaginal scan is recommended” (ACR–ACOG–AIUM–SMFM–SRU).
What can make a belly scan harder
Body size, for one: RadiologyInfo.org says larger patients are harder to image by ultrasound “because greater amounts of tissue weaken the sound waves.” Gas in the bowel can block the view too, since ultrasound waves “are disrupted by air or gas” (RadiologyInfo.org). Sometimes it’s the reverse. NICE, which advises the NHS in England, says to consider a belly scan for women with an enlarged uterus or other pelvic problems, “such as fibroids or an ovarian cyst” (NICE).
Which scan at which week
Clinics set their own rules, so treat these as rough guides, counted from the first day of your last period.
About 6 to 12 weeks
Internal scans are “more likely in early pregnancy,” says MedlinePlus (MedlinePlus). The Norwich unit, which sees people with early pregnancy problems such as bleeding or pain, recommends one at 6 to 12 weeks, with your permission.
Around 10 to 14 weeks, in England
The NHS medical dating scan (NHS). The probe moves over your tummy, and you might be offered an internal scan as well (GOV.UK).
After about 12 weeks
Over the belly. Cleveland Clinic, a U.S. academic medical center, says providers use belly scans “after about 12 weeks of pregnancy” (Cleveland Clinic). The Norwich unit does a belly scan at 12 to 16 weeks.
Around 20 to 24 weeks
Sometimes internal again. MedlinePlus says many women have the length of the cervix measured on a medical vaginal ultrasound around then.
Bladder prep for each kind of scan
The two methods want opposite things from your bladder.
For a belly scan: full, if you’re asked
Early on, a full bladder helps a belly scan: the NHS says it “makes the ultrasound image clearer” (NHS). How much to drink, and when, varies:
MedlinePlus (U.S.): you may be asked to drink 2 to 3 glasses of liquid an hour before, and not to pee beforehand (MedlinePlus).
Gateshead Health, England, for its dating scan: a pint of water about an hour before (Gateshead Health).
Leeds Teaching Hospitals, England, for an early scan over the belly only: about 500 to 1,000 milliliters (17 to 34 ounces) an hour before (Leeds Teaching Hospitals).
For an internal scan: empty or partly full
MedlinePlus says an internal scan “is done with your bladder empty or partly filled” (MedlinePlus). Several guides ask you to empty it first. “A full bladder may prevent a clear view of your pelvic organs during an internal scan,” explains Leicester’s Hospitals in England (Leicester’s Hospitals).
Not sure which you’ll have?
Follow your clinic’s instructions, or ask when you book. Some clinics do both in one visit. At Leeds, you’ll normally have the belly scan before being offered an internal one, and you’re asked to empty your bladder before the internal scan.
Undress, usually from the waist down. You may wear a gown, and the NHS says you may have a sheet or paper towel to cover yourself.
Lie back with your knees bent, sometimes with your feet in stirrups. The NHS says you might lie on your side instead.
The probe is covered and lubricated. MedlinePlus calls the cover a condom. Lubricant is used “to make this more comfortable,” says the NHS.
Only part of it goes in: about 2 to 3 inches (5 to 7.6 centimeters), says RadiologyInfo.org.
The probe is moved gently to see the uterus and ovaries. The person scanning might press on your tummy too.
The U.S. guideline says vaginal probes “should be covered by a protective sheath prior to insertion” (ACR–ACOG–AIUM–SMFM–SRU). Covers can be plastic or latex (GOV.UK). If you’re allergic to latex, say so first: the NHS says they can then use an alternative.
How it feels
In most cases it doesn’t hurt, says MedlinePlus, though some women may have mild discomfort from the pressure of the probe. Cleveland Clinic says it may be uncomfortable, “but it shouldn’t be painful” (Cleveland Clinic). If it hurts, tell the person scanning: the NHS says they “will help you feel more comfortable.”
At an early pregnancy unit in Preston, England, researchers surveyed 425 women who had an internal scan for problems in the first trimester. Of the 425, 419 (98.6%) said it wasn’t painful, and 378 (88.9%) said it wasn’t embarrassing (Basama and colleagues, 2004). It’s one unit, more than 20 years ago, so it can’t predict your experience.
Bleeding or spotting afterward
Cleveland Clinic’s general guide to the test says a little bleeding or cramping afterward is “temporary and uncommon.” If you were already bleeding, one NHS trust says the probe may dislodge blood, which “could result in heavier vaginal loss” (University Hospitals Sussex). In early pregnancy, new bleeding or pain can be a sign of a problem, so don’t put it down to the scan.
Severe pain, heavy bleeding, pain in the tip of your shoulder, or feeling faint?
These can be signs of an ectopic pregnancy, which is an emergency. Call 911 or go to the emergency room now. For milder pain or spotting, call your doctor or midwife today. A keepsake scan can’t check on your health.
Consent, chaperones and comfort
An internal scan is an intimate exam, and you stay in charge.
A chaperone. In England, the NHS says to tell the person scanning if you’d like someone else in the room, “someone you know, or a member of staff” (NHS). In the U.S., the American Medical Association’s ethics code tells doctors to “always honor a patient’s request to have a chaperone” (AMA). From January 1, 2027, California hospitals and licensed clinics that do ultrasounds involving the genital area must tell patients a chaperone is available on request (California health department).
Stopping, or doing it yourself. “You’re in control of the scan and can ask the person doing your scan to stop at any time,” says the NHS in England. It adds that you can ask to insert the probe yourself.
Saying no. In the U.S., the AMA’s code says a patient who can make their own decisions “may accept or refuse any recommended medical intervention” (AMA). NICE says to offer a belly scan if an internal one is unacceptable, and to explain its limits (NICE). It may not give as clear a view, the Leeds leaflet says, so you may be offered another scan later.
If internal exams are hard for you
For some people, an internal exam stirs up past trauma. For others, the body tightens on its own: the NHS describes vaginismus as the vagina suddenly tightening when you try to insert something. It “is an automatic reaction, which you do not have control over,” and it can be treated (NHS).
The Australasian Sonographers Association’s 2024 consent guide asks sonographers for “heightened awareness and sensitivity” with survivors of sexual abuse or assault. It also notes that conditions such as vaginismus can make an intimate exam difficult (ASA). These can help:
Tell the clinic before the day, or at the start. In its leaflet for internal pelvic scans, which doesn’t mention pregnancy, one NHS hospital asks people who “are unable to tolerate internal examinations” to contact its booking team first (Princess Alexandra Hospital).
Ask for time. The ASA guide calls for “more time to explain the examination and process of ongoing consent.”
Insert the probe yourself, and speak up. The ASA guide tells sonographers to ask if you’d prefer to insert it, and to invite you to say if you feel pain or want to stop.
Know there are other options. If a scan has to stop, the guide suggests talking it through once you’re dressed, including trying another day or booking a different exam.
In the U.S., RAINN’s National Sexual Assault Hotline is free, confidential and open 24/7 at 800-656-HOPE (4673) (RAINN). If you’re pregnant after a loss, Pregnant after a loss: seeing your baby early has ideas for asking for what you need in the scan room.
ACOG says ultrasound is “not associated with risk,” but should be used only to answer a clinical question or bring a medical benefit (ACOG Committee Opinion 723). The FDA and the American Institute of Ultrasound in Medicine (AIUM) discourage keepsake-only scans (FDA, AIUM). Safety, in plain words has their statements.
Can you have one while you’re bleeding?
Yes. “Vaginal bleeding does not affect the scan,” says Cambridge University Hospitals, and the Norwich unit is “used to scanning women who are bleeding.” Still, call your doctor or midwife today about any bleeding. For heavy bleeding, severe pain, shoulder-tip pain or feeling faint, call 911 (999 in the UK) or go to the emergency room now.
Is it like putting in a tampon?
A little. Cleveland Clinic says it “may feel like you’re inserting a larger-than-normal tampon.” RadiologyInfo.org says the tip of the probe is smaller than the speculum used for a Pap test.
What if you’ve never had penetrative sex?
It can come up after IVF or donor insemination. Policies differ. The ASA guide says that when there’s a medical reason for one, an internal scan “should be offered to all consenting patients, regardless of penetrative sexual experience,” though it may be more uncomfortable. But one NHS trust’s general leaflet for internal pelvic scans, which doesn’t mention pregnancy, says it won’t do one if you haven’t had sexual intercourse (Sherwood Forest Hospitals). Tell the clinic when you book, and ask about a belly scan.
A first look with us, in Glendale
Our Pregnancy Check is a short, private 2D ultrasound in the first 10 weeks, at our studio in Glendale, Los Angeles County. It takes a few minutes: you watch a big screen, we point out what you’re looking at, and we tell you what we could and couldn’t see. You take home 8 black-and-white prints, for one price of $100, with no referral and no insurance.
Before booking, call (818) 243-7010 with the first day of your last period, and we’ll let you know whether it’s a good day to come. If it’s too early to see, you come back for a second look, almost always at no charge. Seeing little or nothing can simply mean it’s early. It can also be a sign of a problem, and only your doctor or midwife can tell which, so tell your doctor or midwife, even if you feel well.
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Questions
Is a transvaginal ultrasound painful?
It shouldn’t be. MedlinePlus says that in most cases there is no pain, though some women may have mild discomfort from the pressure of the probe. If it hurts, say so; in England, the NHS says you can ask to stop at any time.
Do I need a full bladder for an early pregnancy ultrasound?
For a belly scan, you may: the NHS says a full bladder makes the image clearer, and MedlinePlus says you may be asked to drink 2 to 3 glasses of liquid an hour before. An internal scan is done with the bladder empty or partly filled. Clinics differ, so check when you book.
At what week do they stop doing internal ultrasounds?
There’s no set week. Cleveland Clinic says providers use belly scans after about 12 weeks, and one NHS early pregnancy unit switches at 12 weeks. A medical internal scan can still be used later, for example to measure the cervix around 20 to 24 weeks.
Can a transvaginal ultrasound cause a miscarriage?
NHS hospital guidance says an internal scan doesn’t increase the risk of miscarriage. ACOG says ultrasound is not associated with risk but should be used only to answer a clinical question or provide medical benefit, and the FDA and AIUM discourage keepsake-only scans. For heavy bleeding, severe pain, shoulder-tip pain or feeling faint, call 911 (999 in the UK) or go to the emergency room now.
Can I refuse an internal ultrasound?
Yes. In the U.S., the AMA’s ethics code says a patient who can make their own decisions may refuse any recommended medical intervention. In England, NICE guidance says to offer a belly scan instead and to explain its limits. One NHS hospital’s leaflet says a belly scan may not give as clear a view, so you may be offered another scan later.
Can I have a transvaginal ultrasound on my period or while bleeding?
Yes. NHS hospital leaflets say a period or bleeding doesn’t stop an internal scan. In pregnancy, call your doctor or midwife today about any bleeding. For heavy bleeding, severe pain, shoulder-tip pain or feeling faint, call 911 (999 in the UK) or go to the emergency room now.
Is an ultrasound at 8 or 10 weeks internal or external?
Either, depending on the clinic. One NHS early pregnancy unit, which sees people with problems such as bleeding or pain, recommends an internal scan from 6 to 12 weeks. Cleveland Clinic says providers use belly scans after about 12 weeks. In England, the medical dating scan at around 10 to 14 weeks is over the tummy, sometimes with an internal scan too.
An early look can help after a loss, but no scan can promise how a pregnancy will go. The care you may be offered, what to ask for at a scan, and support.
On an internal medical scan, two sacs can show from about 5 weeks and two heartbeats from about 6. Early scans can miss a twin; later medical scans settle it.
No harm to babies reported in over 40 years of medical use, says the WFUMB. The FDA says long-term effects are unknown and discourages keepsake-only scans.
Updated October 13, 2026
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