A pelvic ultrasound is something many women will have at some point in their lives. It might be arranged because of pregnancy, pelvic pain, changes to your periods, concerns about fertility, unexpected bleeding or simply to investigate symptoms that don’t feel quite right.
But how much can an ultrasound actually tell you?
For some people, there is an assumption that an ultrasound is just a quick look at the uterus. Others may believe that if a condition such as endometriosis is suspected, it’s pointless and an MRI scan will always be needed to get a proper answer.
The reality is much more interesting.
Gynaecological ultrasound has developed considerably. Modern equipment, advanced imaging techniques and, importantly, the experience of the person performing the examination mean that ultrasound can provide detailed information about a range of gynaecological conditions.
In the right hands, it can do much more than simply produce a basic picture of the pelvis.
So, let’s look at what a pelvic ultrasound can show, where its limitations lie and why the skill of the person carrying out the scan matters.
What is a pelvic ultrasound?
A pelvic ultrasound uses high-frequency sound waves to create images of the reproductive organs and surrounding structures.
It allows us to examine the uterus, cervix, ovaries and other areas within the pelvis. Depending on the reason for the scan, it can help investigate symptoms, identify abnormalities and guide decisions about further investigations or treatment.
There are two main approaches.
Transvaginal ultrasound involves placing a slim ultrasound probe into the vagina. Because the probe is closer to the pelvic organs, it generally provides more detailed images of the uterus, ovaries and surrounding structures. This type of scan is often used to help investigate concerns about pelvic pain, fertility and bleeding. It would also be used in very early pregnancy scans.
Transabdominal ultrasound involves placing an ultrasound probe on the lower abdomen. This can provide a broader overview of the pelvis and if mostly used in pregnancy scans or when a transvaginal examination is not something you wish to have.
In some circumstances, both approaches may be used to provide additional information.
The type of scan recommended will depend on your symptoms, medical history and individual circumstances. A transvaginal scan should always be explained beforehand and only performed with your consent.
What can an ultrasound identify?
One of the most useful aspects of pelvic ultrasound is that it can investigate several possible causes of symptoms during the same examination.
Depending on the findings, a scan may identify:
- Fibroids: non-cancerous growths within the muscle of the uterus, including their size, number and location.
- Adenomyosis: changes within the muscle of the uterus that may be associated with heavy, painful periods and pelvic discomfort.
- Ovarian cysts: including their size, appearance and whether they have features that require further assessment.
- Endometriomas: ovarian cysts associated with endometriosis, which can often be recognised by their characteristic ultrasound appearance.
- Endometrial changes: assessment of the lining of the uterus, including its thickness and appearance, interpreted in the context of your age, menstrual cycle and symptoms.
- Pelvic masses: identifying abnormalities that may need further investigation.
- Structural causes of bleeding or pain: including some changes within the uterus that may help explain your symptoms.
Ultrasound can also assess the position and appearance of the uterus and ovaries, and whether there are signs of reduced movement or changes in the relationship between pelvic structures.
This is important because the value of a scan is not simply in identifying an abnormality. It is about understanding what the findings might mean in the context of your symptoms.
Endometriosis: what can advanced ultrasound show?
Endometriosis is a particularly good example of how much gynaecological ultrasound has developed.
Endometriosis occurs when tissue similar to the lining of the uterus grows elsewhere in the body, commonly within the pelvis. It can affect the ovaries and other pelvic structures, including the bowel, bladder and areas behind the uterus.
A detailed transvaginal ultrasound, performed by someone with appropriate training and experience in endometriosis imaging, can identify features of the condition and assess how extensive it may be.
This is sometimes referred to as advanced or specialist endometriosis ultrasound.
Rather than simply looking at the uterus and ovaries, the examination takes a systematic approach to assessing the pelvis. This may include:
- Looking for ovarian endometriomas.
- Assessing the position and mobility of the uterus and ovaries.
- Examining the spaces behind the uterus and around the pelvic organs.
- Assessing the relationship between the uterus, bowel and surrounding structures.
- Looking for features of deep endometriosis, including possible involvement of the bowel, bladder or ureters.
- Identifying areas where organs may appear less mobile or joined together by adhesions.
These findings can help build a clearer picture of the possible location and extent of endometriosis.
Importantly, advanced ultrasound is not simply about having a more sophisticated machine. It requires an understanding of the condition, a structured examination technique and the ability to recognise and interpret sometimes subtle findings.
The skill and experience of the person performing the scan are fundamental.
Does endometriosis always need an MRI?
No. And this is an important point.
MRI has a valuable role in the assessment of endometriosis, particularly when further information is needed about the location and extent of deep disease or when findings need clarification for treatment planning.
However, it is not automatically the next step for everyone with suspected endometriosis.
NICE recommends transvaginal ultrasound for people with suspected endometriosis and advises that specialist transvaginal ultrasound or pelvic MRI can be considered to diagnose deep endometriosis and assess its extent.
Both examinations should be planned and interpreted by a healthcare professional with specialist expertise in gynaecological imaging.
In other words, specialist ultrasound is a recognised and valuable imaging investigation in its own right. It should not be thought of simply as a less detailed alternative to MRI.
The most appropriate investigation depends on the individual, the symptoms, the clinical question and the expertise available.
There are also limitations. A normal ultrasound does not rule out endometriosis, particularly superficial disease, which may not be visible on imaging. If symptoms remain suggestive, further assessment is still appropriate.
The important thing is that imaging findings are considered alongside your symptoms and clinical history, rather than in isolation.
Why does the experience of the person scanning matter?
This is one of the most important things to understand about gynaecological ultrasound.
An ultrasound machine produces images, but those images need to be obtained, assessed and interpreted by a skilled operator.
Two scans are not necessarily the same simply because they use similar equipment.
A routine pelvic scan may focus on the size, position and general appearance of the uterus and ovaries. A specialist examination may involve a more detailed assessment of specific structures, using additional techniques and a systematic approach based on the condition being investigated.
For example, when assessing possible endometriosis, the operator needs to know which areas to examine, what features to look for and how to interpret the movement and relationship of pelvic organs.
The same principle applies to conditions such as adenomyosis and fibroids, where recognising the pattern, location and extent of changes can make a real difference to the information provided.
This is why specialist knowledge and experience are so important.
What happens during the appointment?
Before your scan, it is helpful for the clinician to understand why the examination has been requested.
Your symptoms, menstrual history, previous investigations, medical history and any previous surgery can all help guide the assessment.
The scan itself will usually involve looking at the uterus and ovaries, with additional assessment depending on your symptoms and the reason for the appointment.
You may be asked about areas of discomfort or tenderness during the examination. This information can sometimes help the operator understand the findings and identify areas that need closer assessment.
A scan should not be a one-size-fits-all examination. It should be guided by symptoms and tailored to the individual.
You should have the opportunity to ask questions, understand what is happening and discuss any concerns before the examination begins.
What if my ultrasound is normal?
A normal ultrasound can be reassuring, but it does not always provide the complete answer.
Pelvic pain for example, can have several possible causes, some of which may not be identified through ultrasound alone.
Further assessment, alternative investigations or referral to a specialist may be appropriate depending on your circumstances.
A normal scan should never be used as a reason to dismiss persistent symptoms.
Why consultant-led ultrasound can make a difference
An ultrasound is most useful when the findings are considered alongside a persons symptoms, medical history and their concerns, ideas and expectations.
A scan may identify a fibroid, an ovarian cyst or features that suggest adenomyosis. But what does that mean for you? Could it explain your symptoms? Does it need monitoring? Are further investigations appropriate? What treatment options might be available?
These are the questions that matter.
When ultrasound is performed by a clinician with specialist knowledge of gynaecology, there is an opportunity to bring the imaging findings and clinical history together.
At West Wales Women’s Wellbeing, our approach is consultant-led meaning your symptoms, medical history and ultrasound findings can be considered together, helping to provide a clearer understanding of what may be happening and what the next steps could be.
The bigger picture
Ultrasound is a valuable part of modern gynaecological care.
It can help monitor pregnancy, investigate symptoms, identify a range of conditions and provide detailed information that may guide diagnosis, treatment and onward referral.
For conditions such as endometriosis, specialist ultrasound has an increasingly important role. It can identify ovarian and deep endometriosis, assess pelvic structures and help establish the extent of disease in many cases. MRI remains an important complementary investigation when clinically indicated, but it is not the only way to obtain detailed imaging.
Ultimately, the most useful scan is one that is appropriate to your symptoms, performed with the right expertise and interpreted in the context of your overall health.
You should not have to feel that a scan is simply a picture or that a normal result means your concerns are over.
The purpose of imaging is to help answer questions, guide decisions and support the next stage of your care.
Trusted sources and further reading
- NICE: Endometriosis – diagnosis and management (NG73)
- ESHRE: Guideline on Endometriosis (2022)
- NICE: Heavy menstrual bleeding – assessment and management (NG88)
This article is intended for general information and does not replace individual medical advice, assessment or diagnosis.