In brief
HyCoSy and HSG assess tubal patency: whether contrast fluid appears to pass through the fallopian tubes. HyCoSy uses ultrasound; HSG uses X-rays. Neither is automatically the better choice. Your history, the question being investigated and the team’s expertise determine which test is appropriate.
An open-tube result is useful information, but it is not a guarantee of pregnancy. A suspected blockage may need clarification. This guide builds on our Fertility Barrier Check article and connects the question to the wider ProFertility Library.
Key takeaways
- Regular periods, reassuring hormone results and a routine pelvic ultrasound do not establish that both tubes are open.
- Tubal testing should answer a specific question; it is not a compulsory check for everyone who wants to understand their fertility.
- Ask about preparation, pain relief, infection screening and how results will change your plan.
- A finding of blockage needs explanation, including its location and whether confirmation is needed.
Why might the fallopian tubes need investigating?
During conception without IVF, sperm and egg usually meet in a fallopian tube, and the developing embryo travels towards the uterus. Tubal damage or obstruction can interfere with that route. Ovulation and tubal patency are separate questions: regular periods do not show whether contrast can pass through each tube.
Useful context includes previous pelvic infection, ectopic pregnancy, abdominal or pelvic surgery, and suspected endometriosis. Bring that history to a consultation rather than choosing an investigation from a list. Include the sperm provider’s assessment where relevant; checking the tubes should not mean overlooking sperm-related questions.
What is the difference between HyCoSy and HSG?
Both introduce contrast through a small catheter placed through the cervix. The imaging method differs. HSG is hysterosalpingography; HyCoSy is hysterosalpingo-contrast sonography. Both can help investigate the uterine cavity as well as tubal passage, but neither replaces every other pelvic investigation.
| Question | HyCoSy | HSG |
|---|---|---|
| Imaging method | Internal ultrasound follows contrast through the uterus and tubes. | X-ray imaging follows contrast outlining the uterine cavity and tubes. |
| Ionising radiation | Ultrasound does not use ionising radiation. | Uses a small amount of ionising radiation. |
| Main question | Does contrast appear to pass through the tubes? | Does contrast pass through the tubes, and where might obstruction be suspected? |
| Choosing the test | Depends on the question, clinical history and available ultrasound expertise. | Depends on the question, clinical history and local imaging expertise. |
Which test is appropriate for you?
NICE NG257, published on 31 March 2026, recommends HSG for screening for tubal occlusion in people without relevant comorbidities. It considers HyCoSy an effective alternative where appropriate expertise is available. Where pelvic disease is suspected, such as endometriosis or a history of pelvic inflammatory disease, laparoscopy and dye may allow tubal and other pelvic assessment together.
These recommendations help explain the options; they are not a reason to choose surgery for every unanswered fertility question. Ask why the proposed test fits your history, what information it adds and what each possible result would change. A proactive conversation is available before you commit to an investigation. You do not need to treat a fixed waiting period as permission to learn or seek advice.
Can a normal pelvic ultrasound show that my tubes are open?
Not reliably. A routine pelvic ultrasound can assess the uterus, ovaries and some structural concerns. A dedicated tubal patency test observes contrast passing through the tubes. A reassuring routine scan and an open-tube result answer different questions.
The same distinction applies to blood tests. AMH provides ovarian-reserve information; it cannot establish tubal patency. Understanding the scope of each report helps you keep reassuring findings reassuring while identifying any meaningful unanswered question.
How do you prepare for HyCoSy or HSG?
Follow the instructions from the clinic performing your test. Timing is usually arranged after menstruation and before ovulation, with precautions to avoid an existing pregnancy. Irregular cycles need an individual plan rather than guessing a cycle day. Tell the team if pregnancy is possible, you have pelvic-infection symptoms, or you are using fertility medicines.
Ask what infection screening is required and whether antibiotics are indicated for your situation. Discuss previous contrast reactions and medicine allergies, particularly before HSG. Also ask which pain relief is suitable for you, whether a companion can attend, and whether you need time away from work or driving afterwards.
Tell the team about previous difficult examinations, vaginismus, trauma, disability, language or sensory needs. Ask for a clear explanation of each stage, a chaperone and a plan to pause or stop if needed. You should be able to make an informed choice about the procedure.
What happens, and how painful is it?
Both tests generally involve a speculum examination, a small catheter through the cervix and the introduction of contrast. For HyCoSy, an internal ultrasound follows the fluid; for HSG, X-ray images are taken. Ask when you will receive the report and who will discuss the findings.
Period-like cramps or discomfort can occur, and experiences vary. It is unhelpful to promise that the test will be painless or assume that everyone finds it severe. Discuss options beforehand and tell the team if discomfort becomes difficult to tolerate. Mild spotting or cramping can occur afterwards. Follow your clinic’s aftercare instructions.
Seek prompt medical advice for fever, heavy bleeding, foul-smelling discharge, or severe or worsening abdominal pain after the procedure. Use your clinic’s urgent contact route or NHS 111; severe symptoms may require emergency assessment.
What do open, blocked or inconclusive results mean?
Open, or patent, usually means contrast appeared to pass through a tube and spill beyond it. This is useful evidence about passage at the examination. It does not directly measure every aspect of tubal function or predict whether conception will happen. Keep the result alongside the rest of your fertility picture.
A result suggesting blockage needs explanation: one tube or both, near the uterus or further along, and how certain the finding is. ASRM’s 2021 guidance specifically advises further evaluation when HSG suggests blockage in both tubes near the uterus, because transient contractions or catheter position can create an apparent obstruction.
An inconclusive examination is not the same as a confirmed blockage. Ask whether the images need review, whether a different test would help, and whether there is a specific reason to consider laparoscopy or another specialist procedure. Avoid making a major treatment decision from a report you have not had explained.
How do donor conception, IUI and IVF change the question?
For solo parents and same-sex couples using donor sperm, the investigation should follow the person who will carry the pregnancy and the chosen treatment route. ASRM recommends tailoring tubal and uterine assessment to history and risk. These questions are relevant without requiring a history of unsuccessful intercourse.
IUI still relies on sperm reaching an egg within the reproductive tract, so tubal information can matter to treatment planning. IVF moves fertilisation into the laboratory, but that does not make every tubal finding irrelevant. NICE recommends specialist management of hydrosalpinges—fluid-filled damaged tubes—before IVF. Your treating team should explain whether that issue applies to your findings; it is not a conclusion to draw from a generic “blocked tube” label.
Five questions to take to your appointment
Which part of my history makes tubal testing useful now? Would HyCoSy or HSG be preferable, and why? What preparation, pain-relief and infection precautions do I need? If a blockage is suspected, how will it be confirmed? How would an open, blocked or inconclusive result change the plan?
Bring the original reports and dates, your medicines, relevant surgery or infection history, and the decision you want help with. A connected review can identify what is already known and prioritise further questions without assuming that a previous clinician missed something. More tests do not automatically produce more useful answers.
Related guidance and support
Frequently asked questions
Is HyCoSy better than HSG?
Neither is always better. HyCoSy uses ultrasound and HSG uses X-rays. Your history, the question being investigated and local expertise help determine the appropriate test.
Does a normal ultrasound rule out blocked tubes?
No. A routine pelvic ultrasound and a dedicated tubal patency test answer different questions. Contrast passage is assessed during HyCoSy or HSG.
Does a blocked result always mean permanent obstruction?
No. Some apparent proximal blockages can reflect transient contractions or technical factors. Ask the specialist how certain the finding is and whether confirmation is appropriate.
Do open tubes guarantee pregnancy?
No. The result provides information about contrast passage. It cannot establish that every stage of conception will work or guarantee a treatment outcome.
Can I discuss tubal testing before trying for a year?
Yes. You can ask about your reproductive health and relevant history whenever you have a question. Whether testing is useful depends on the decision, risk factors and clinical context.
Clinical sources
- NICE NG257. Investigation of fertility problems and management strategies; published 31 March 2026, recommendations 1.18.13–1.18.15.
- NICE NG257. Management of female factor fertility problems; published 31 March 2026 (hydrosalpinges before IVF).
- ASRM. Fertility evaluation of infertile women: a committee opinion, 2021.
- Leeds Teaching Hospitals NHS Trust. HyCoSy patient information; reviewed 4 June 2025.
- Cambridge University Hospitals NHS. Hysterosalpingogram patient information; checked 10 October 2026.
Source check: 2026-10-10. This guide is educational and does not replace individual medical advice.