Ultrasound Assessment in Infertility: Causes, AFC, Ovarian Reserve and Pelvic Ultrasound
Infertility is influenced by hormonal, anatomical, genetic, lifestyle and male-factor contributors. Pelvic ultrasound helps assess the uterus, ovaries, endometrium and antral follicle count, supporting fertility planning and onward investigations.
What is the role of ultrasound in infertility assessment?
Pelvic ultrasound is one of the key imaging tests used in female fertility assessment. It can assess ovarian reserve through antral follicle count, ovarian morphology, follicular development, endometrial thickness, uterine structure, fibroids, polyps, adenomyosis, ovarian cysts and some signs of endometriosis. Ultrasound cannot diagnose every cause of infertility, but it provides important information that can guide hormone testing, semen analysis, tubal investigations and fertility specialist planning.
What can cause infertility?
For natural conception to occur, ovulation, egg quality, tubal function, sperm quality, fertilisation, embryo transport and implantation all need to work together. A problem at any stage may reduce the chance of pregnancy.
Ovulatory disorders
PCOS, thyroid disease, hyperprolactinaemia, hypothalamic dysfunction and premature ovarian insufficiency can affect ovulation and cycle regularity.
Diminished reserve
Egg number and egg quality decline with age, with a more noticeable fertility decline often seen after the mid-30s. AFC and AMH are commonly used to support ovarian reserve assessment.
Uterine and pelvic causes
Fibroids, polyps, adenomyosis, endometriosis, ovarian cysts and congenital uterine differences may affect implantation or fertility treatment planning.
Fertility pelvic ultrasound in Harley Street, London
London Private Ultrasound provides fertility-focused pelvic ultrasound at 27 Welbeck Street, London W1G 8EN, in the Harley Street medical district. The scan can support assessment of ovarian reserve, antral follicle count, ovarian morphology, endometrial thickness and structural findings such as fibroids, polyps, cysts or adenomyosis features.
Patients commonly travel from Marylebone, Mayfair, Fitzrovia, Soho, Bond Street, Oxford Circus, Baker Street and across Greater London for private women’s health and fertility ultrasound appointments.
Why pelvic ultrasound is important in fertility assessment
A fertility-focused pelvic ultrasound provides detailed information about the uterus, endometrium and ovaries. It is often used early in the fertility pathway because it is non-invasive, does not use radiation and can identify many structural findings that may affect conception.
Ultrasound can assess
- Ovarian reserve and antral follicle count.
- Ovarian morphology, cysts and possible PCOS appearances.
- Endometrial thickness and appearance.
- Fibroids, polyps, adenomyosis and congenital uterine differences.
- Endometriomas and selected signs of advanced endometriosis.
Ultrasound cannot assess everything
- It cannot confirm whether the fallopian tubes are open unless a specific tubal test is performed.
- It does not assess sperm quality.
- It cannot measure egg quality directly.
- It may need to be combined with AMH, FSH, LH, thyroid tests, prolactin and other investigations.
How ultrasound fits into an infertility assessment
Ultrasound is usually one part of a broader fertility assessment. It is most useful when combined with cycle history, ovulation assessment, hormone testing, semen analysis and, where indicated, tubal patency testing or specialist fertility review.
History and symptoms
Cycle regularity, pelvic pain, previous pregnancies, surgery, infection history, age and duration of trying are reviewed.
Pelvic ultrasound
Uterus, endometrium, ovaries, AFC, cysts, fibroids, polyps and other visible pelvic findings are assessed.
Blood and semen tests
AMH, ovulation hormones, thyroid, prolactin and semen analysis may be needed to complete the picture.
Specialist planning
Results can guide fertility clinic review, IVF planning, ovulation support or further investigations such as HyCoSy or HSG.
What is AFC and why does it matter?
Antral follicle count, or AFC, is the number of small visible follicles in the ovaries, usually measuring around 2–10 mm. It is a key ultrasound marker used to estimate ovarian reserve and potential response to ovarian stimulation.
Reduced ovarian reserve
A low AFC may suggest reduced ovarian reserve and potentially lower response to fertility treatment. Interpretation should consider age and hormone testing.
Expected range
A mid-range AFC is generally reassuring for ovarian reserve, although it does not guarantee pregnancy or confirm egg quality.
PCOS-type pattern
A high AFC may be seen in PCOS or increased ovarian responsiveness. It should be interpreted with cycle pattern, androgen symptoms and blood tests.
Antral follicle count interpretation table
AFC ranges vary between clinics, ultrasound technique and patient factors. The table below is a general patient guide only; results should be interpreted with age, AMH, cycle day, symptoms and fertility specialist advice.
| AFC pattern | Typical finding | Possible meaning | Important limitation |
|---|---|---|---|
| Low AFC | Often fewer than approximately 5–7 antral follicles in total. | May suggest reduced ovarian reserve or a lower response to ovarian stimulation. | Does not measure egg quality and does not rule out natural conception. |
| Mid-range AFC | Often around 8–24 follicles in total. | May be consistent with expected ovarian reserve for many patients. | Must still be interpreted with age, AMH and clinical history. |
| High AFC | Often above approximately 25 follicles. | May be associated with PCOS-type ovarian morphology or higher ovarian responsiveness. | PCOS diagnosis requires clinical and biochemical context, not ultrasound alone. |
Conditions considered during infertility assessment
PCOS
PCOS may involve irregular ovulation, raised androgen features and polycystic ovarian morphology. Ultrasound can assess ovarian size and follicle pattern.
Premature ovarian insufficiency
POI may present with irregular periods, menopausal-type symptoms and reduced follicle numbers on ultrasound.
Endometriosis
Endometriosis can affect fertility through inflammation and altered pelvic anatomy. Ultrasound may identify endometriomas and some advanced features.
Fibroids and polyps
Submucosal fibroids and endometrial polyps may distort the uterine cavity and affect implantation or fertility treatment planning.
Adenomyosis
Adenomyosis may affect menstrual symptoms and implantation. Ultrasound can identify features suggestive of adenomyosis in some patients.
Tubal factors
Standard pelvic ultrasound cannot confirm tubal patency, but it may detect indirect findings such as hydrosalpinx or pelvic pathology.
Concise answers for common fertility ultrasound searches
What happens during a fertility ultrasound?
A fertility pelvic ultrasound usually takes around 20–30 minutes. Transvaginal ultrasound often provides the clearest view for AFC and endometrial assessment, but consent and suitability are always considered.
The scan may include
- Uterus and endometrial assessment.
- Ovarian volume and morphology.
- Antral follicle count in both ovaries.
- Assessment for cysts, fibroids, polyps or adenomyosis features.
- Recommendations for onward fertility review if needed.
When to book
- After 12 months trying to conceive if under 35.
- After 6 months if aged 35 or over.
- Earlier if periods are irregular, absent or very painful.
- Earlier if there is known PCOS, endometriosis, fibroids or previous pelvic surgery.
- Before IVF or fertility treatment planning.
How to prepare for a fertility pelvic ultrasound
If AFC is required, many clinics prefer early-cycle scanning, commonly around days 2–5. If your cycles are irregular, your clinician or fertility clinic may advise alternative timing.
What to bring
Bring previous pelvic scans, fertility clinic letters, blood test results such as AMH or FSH, menstrual dates and any history of surgery, endometriosis, fibroids or PCOS.
Transvaginal or transabdominal?
Transvaginal ultrasound usually gives the best detail for AFC and endometrium, but it is only performed with consent. Transabdominal scanning may be used when more appropriate.
Read next: fertility and pelvic ultrasound pages
These links help patients move from infertility education to the most relevant ultrasound and women’s health services.
Ultrasound assessment in infertility — FAQs
Can ultrasound diagnose infertility?
Ultrasound can identify or suggest several factors that may contribute to infertility, such as ovarian reserve, cysts, fibroids, polyps, adenomyosis, endometriomas and uterine differences. It cannot diagnose every cause of infertility and should be combined with clinical assessment and other tests.
What is the best scan for antral follicle count?
Transvaginal ultrasound is usually preferred because it provides higher-resolution views of the ovaries and small follicles. Transabdominal ultrasound may be considered if transvaginal ultrasound is not suitable or not consented to.
Does a normal AFC mean I will get pregnant?
No. AFC estimates egg quantity and likely response to stimulation, but it does not confirm egg quality, tubal patency, sperm quality or implantation success.
Can ultrasound show blocked tubes?
Standard pelvic ultrasound cannot confirm tubal patency. A specific tubal test such as HyCoSy or HSG may be required. Ultrasound may sometimes identify indirect signs such as hydrosalpinx.
Do I need blood tests as well?
Often yes. AMH, FSH, LH, oestradiol, progesterone, prolactin, thyroid function and other blood tests may be used depending on symptoms and fertility-clinic advice.
Article preparation and clinical review
Clinical references and guidance
- World Health Organization. Infertility fact sheet.
- NICE. Fertility problems: assessment and treatment. NG257.
- ASRM. Fertility evaluation of infertile women: committee opinion.
- ASRM. Testing and interpreting measures of ovarian reserve.
- ESHRE. International evidence-based guideline for PCOS.
Article preparation and clinical review: Prepared with AI-assisted editorial support and reviewed for clinical accuracy by Dr Pedram Aghaei and Dr Hosna Rashidi. This article is for general patient information only and does not replace consultation with a qualified healthcare professional.
Book an ultrasound assessment in infertility in London
A dedicated fertility pelvic ultrasound can assess ovarian reserve, antral follicle count, endometrial health, ovarian morphology and structural causes that may affect fertility planning.