Fertility investigations · 10 October 2026 · 7-minute guide

HyCoSy vs HSG: Which Fallopian Tube Test Do You Need?

Short answer: HyCoSy and HSG are both tests used to assess tubal patency—whether contrast fluid appears to pass through your fallopian tubes. HyCoSy uses ultrasound; HSG uses X-rays. The most appropriate test depends on your history and what your clinician needs to find out.

Why might the fallopian tubes need investigating?

During conception without IVF, sperm and egg usually meet in a fallopian tube, and the developing embryo then travels towards the uterus. Tubal narrowing or damage can make this process harder. A person's periods can be regular, and hormone tests can be reassuring, while important questions about the tubes remain unanswered.

That does not mean everyone needs a tubal test. The question is whether investigating tubal patency could change your understanding or the next step in your care. History can matter: previous pelvic inflammatory disease, ectopic pregnancy, abdominal or pelvic surgery, and suspected endometriosis may prompt a discussion about tubal factors. A clinician should also consider investigations of sperm-related factors where relevant.

What's the difference between HyCoSy and HSG?

Neither test is a pregnancy prediction or a complete check of reproductive health. Test quality and interpretation matter, and a finding that looks abnormal may need a second look.

Can a routine pelvic ultrasound show if my tubes are open?

Not reliably. A standard pelvic ultrasound is useful for assessing the uterus, ovaries and some structural concerns. But seeing ovaries and a uterus that look normal is not the same as showing fluid passing through each tube. A dedicated tubal patency investigation asks a different question. This is one reason why 'my ultrasound was normal' does not necessarily mean all relevant fertility investigations have been completed.

What happens during a HyCoSy or HSG appointment?

Both procedures generally involve a speculum examination, placing a small catheter through the cervix and introducing fluid or contrast. Some people experience period-like cramping or discomfort; experiences vary. Ask the clinic what pain-relief options are available, whether someone should accompany you afterwards, and when results will be discussed.

Testing is usually planned for a point in the cycle when an existing pregnancy is unlikely. Tell the clinic if you think you may be pregnant, have symptoms of a pelvic infection, have a history of infection or have had reactions to contrast agents. For HSG, relevant contrast allergies also need discussion. Your clinic may advise testing or other precautions before the procedure.

Mild spotting or cramping can occur afterwards. Seek prompt medical advice if you develop fever, heavy bleeding, foul-smelling discharge, or severe or worsening abdominal pain.

If the result says 'blocked tube', is that definitive?

Not always. A suspected obstruction, particularly near the uterus, may sometimes reflect transient muscular spasm or a technical issue such as catheter position rather than permanent blockage. The American Society for Reproductive Medicine recommends further evaluation for findings suggestive of blockage in both tubes close to the uterus before treating them as certain.

If a tube appears open, that is useful information too—but it does not prove that every aspect of tubal function is normal. Your clinician may review the images, compare them with your symptoms or history, and decide whether any additional investigation is worth considering. Avoid making an irreversible treatment decision from an unexplained single result.

How do I know whether this is the next test worth discussing?

Start by mapping the questions that have already been answered. Have you reviewed ovulation or menstrual patterns where relevant? Has a clinician considered pelvic anatomy? Is there a semen analysis or other assessment of the sperm-producing partner where applicable? Have you had previous tests but don't know what they actually rule in or rule out?

A proactive consultation can make sense whenever there are relevant risk factors or meaningful unanswered questions. You do not need to treat a fixed waiting period as a prerequisite to asking how investigations work. Equally, more tests are not automatically better: a useful test should answer a particular question or inform a decision.

Five questions for your appointment

1. Which specific part of my fertility history makes tubal testing useful now?
2. Would HyCoSy or HSG be preferable in my situation, and why?
3. What should I know about timing, discomfort, infection precautions and aftercare?
4. If the scan suggests a blockage, how will that finding be confirmed?
5. How would each possible result change the next step in my plan?

For more context, explore our guides to normal results with unanswered questions, choosing fertility tests, and investigations for couples.

Evidence and further reading

1. American Society for Reproductive Medicine: Fertility evaluation (2021) — tubal patency methods, interpretation and broader assessment.
2. American Society for Reproductive Medicine: Tubal surgery and assessment (2021) — possible obstruction and follow-up.
3. American College of Obstetricians and Gynecologists: Hysterosalpingography — preparation, discomfort and warning signs.
4. RadiologyInfo: Hysterosalpingography — radiation, contrast and scope of the procedure.

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Published 10 October 2026. Editorially researched educational guidance; no individual clinical review or approval is claimed.