HSG Test (Hysterosalpingogram): What to Expect and What Your Results Mean

An HSG is one of the most common tests in a fertility work-up. This guide explains what it checks, how it is done, whether it hurts, and, most importantly, how to read your result calmly and know the right next step.

What is an HSG test?

A hysterosalpingogram (HSG) is a short X-ray test that checks two things at once: the shape of the inside of your uterus, the cavity where a pregnancy implants, and whether your fallopian tubes are open. A fine tube is passed gently through the cervix, and a small amount of contrast dye is instilled. Under live X-ray, called fluoroscopy, the dye outlines the cavity and, if the tubes are open, spills freely from their ends into the abdomen. The whole picture is captured in a few images. The name itself is descriptive: hystero refers to the uterus and salpingo to the fallopian tubes, so an HSG is simply an X-ray map of the uterus and tubes. It is usually one part of a wider fertility evaluation, not a stand-alone answer.

Why is an HSG done?

Most HSGs are requested because blocked or damaged fallopian tubes are a common, and often treatable, reason for difficulty conceiving. The test answers practical questions that genuinely change management: are both tubes open, is the uterine cavity normal, and is there anything such as a polyp, a fibroid pressing into the cavity, adhesions, or a uterine septum that should be addressed before trying further. It is also used at times to check tubal status after tubal surgery or a sterilisation reversal, and occasionally in the work-up for recurrent pregnancy loss when a cavity problem is suspected. Importantly, an HSG is not a test everyone needs. Your gynaecologist decides based on your history, examination, and ultrasound, a considered, individualised approach rather than a routine box to tick.

When in your cycle is an HSG performed?

Timing matters. An HSG is done in the first half of the menstrual cycle, usually between about days 6 and 12 — after your period has finished but before ovulation. This window serves two purposes: it makes sure you are not in the early days of a pregnancy, and the lining is thin enough for clear images. Because the test uses X-rays, you should avoid unprotected intercourse from the start of that cycle until the HSG is done, so there is no possibility of exposing an early pregnancy. If there is any chance you could already be pregnant, tell the team and the test will be postponed. This simple scheduling is one reason it helps to plan the HSG a cycle in advance.

How to prepare for your HSG

Preparation is straightforward. Taking a simple pain reliever, such as an anti-inflammatory tablet, about an hour before the appointment reduces cramping for most women, check first if you have any reason to avoid these medicines. You do not usually need to fast. Wear comfortable clothing, bring a sanitary pad for the light spotting that can follow, and plan a relaxed rest of the day, although most women return to normal activity the same afternoon. Tell the team in advance if you have a known allergy to iodine-based contrast, or a history of pelvic infection, so they can plan appropriately. Coming in calm and informed, rather than anxious and rushed, genuinely makes the experience easier.

What happens during the test, step by step

The test itself is quick, the imaging usually takes only about five to ten minutes. You lie on the X-ray table as you would for a routine pelvic examination. A speculum is placed, the cervix is cleaned, and a fine catheter is passed just inside the cervical opening. The speculum is often removed, and the contrast is instilled slowly while a few X-ray pictures are taken. You may feel period-like cramping as the dye fills the uterus and moves through the tubes. The clinician watches the dye in real time: a normal study shows a smooth, triangular cavity with dye spilling out of both tube ends into the abdomen. Once the images are captured, the catheter is removed and you can get up. There is no anaesthesia and no recovery room, you simply rest for a few minutes and go home.

Does an HSG hurt?

This is the question most women ask, and an honest answer helps more than reassurance alone. Most women feel cramping similar to strong period pain during and just after the dye is instilled; it is short-lived. A smaller number find it more uncomfortable, and some barely notice it. Discomfort tends to be greater when a tube is narrowed or blocked, because the dye meets resistance. An anti-inflammatory tablet taken beforehand, slow instillation of the dye, and a calm, unhurried setting all make a real, measurable difference. The cramping settles quickly once the test is over. What is not expected is severe or persistent pain in the hours afterwards, that should always be reported rather than endured.

Understanding your HSG results

A normal HSG shows a regularly shaped uterine cavity with dye spilling freely from both tubes, reassuring evidence that the cavity and tubes are open. Several other patterns call for interpretation rather than alarm. When one or both tubes do not fill, the point of blockage may be where the tube joins the uterus (proximal) or at the far end (distal); a proximal “blockage” is not always real, because the tube can go into temporary spasm or a mucus plug can hold the dye back, giving a false result. A dilated, club-shaped tube that does not spill may indicate a hydrosalpinx — a fluid-filled, damaged tube, which matters because it can lower IVF success and is usually treated before starting IVF. A rounded gap within the cavity, called a filling defect, can suggest a polyp, a fibroid pressing inwards, or adhesions, and may lead to a hysteroscopy. Your result is always read alongside your history and ultrasound, never in isolation.

HSG, SIS/HyCoSy, or laparoscopy, which tubal test?

HSG is one of several ways to assess the tubes and cavity, and they are complementary rather than competing. A saline or foam ultrasound test — SIS or HyCoSy — checks the same structures without X-rays or iodinated dye, and is often preferred when ultrasound is already the main modality. Laparoscopy with dye, called chromopertubation, is the most definitive test of tubal patency and lets the surgeon see and, where appropriate, treat disease such as endometriosis or adhesions at the same sitting, but it is a keyhole operation under anaesthesia, so it is reserved for when it is genuinely needed. Which test suits you depends on your history: a straightforward screen might begin with HSG or HyCoSy, whereas a woman with pelvic pain or suspected endometriosis may be better served by laparoscopy from the outset. The principle is to choose the least invasive test that will actually answer the question.

Accuracy, benefits, and a possible fertility bonus

HSG is a good screening test, but not a perfect one, and it is fairer to say so. Compared with laparoscopy, it reliably confirms open tubes but is less certain when it suggests a blockage, because tubal spasm can imitate a true occlusion, which is exactly why a “blocked” proximal tube is sometimes rechecked or confirmed at laparoscopy rather than acted on immediately. Its strengths are real: it is quick, widely available, needs no anaesthesia, and images the cavity as well as the tubes. There is also a genuine, evidence-based bonus. Flushing the tubes with contrast appears to modestly improve the chance of natural conception in the months that follow, and a randomised trial found this effect was greater with oil-based contrast. This is not a reason to have the test purely as a treatment, but it is a welcome possibility for couples who already need their tubes assessed.

Risks and side effects

An HSG is a low-risk test. Light spotting and mild cramping for a day are common and settle on their own. The main uncommon risk is a pelvic infection, which is why the test is avoided during an active infection, and why a short course of antibiotics is given beforehand if you have a history of pelvic inflammatory disease or a dilated tube. Allergic reactions to the contrast are rare. The radiation dose is small and well within safe limits for a diagnostic test. Serious complications are unusual. Knowing the few genuine warning signs, covered below, means you can have the test with confidence rather than worry.

What happens after your HSG

The result guides the next step, and there is a clear path forward whatever it shows. If everything is normal, attention turns to the rest of the picture, ovulation, egg reserve, the sperm, and how long you have been trying, and to timed natural attempts or treatment such as IUI or IVF where appropriate. If a tube is blocked or a hydrosalpinx is found, the options are discussed individually: some tubal problems can be treated, a hydrosalpinx is often dealt with before IVF, and in many situations IVF sensibly bypasses the tubes altogether. A cavity finding may lead to a hysteroscopy to correct it. Throughout, the aim is the most direct, least invasive route to a healthy pregnancy, not more procedures than you actually need.

When to call us after an HSG

Most women feel back to normal within a day. Contact the clinic promptly if, in the days after the test, you develop a fever, a foul-smelling discharge, heavy bleeding that is more than light spotting, or worsening lower abdominal pain. These can be early signs of infection and are easily treated when caught early. Reassuringly, such problems are uncommon, but knowing what to watch for lets you act quickly on the rare occasion it matters.

Medically reviewed by Dr. Priyadatt Patel, MBBS, MS (Obstetrics & Gynaecology) — Senior Gynecologist · Advanced Laparoscopic Surgeon · IVF and Endometriosis Programme Lead, IVF and Endometriosis Programme Lead and Advanced Laparoscopic Surgeon, Balaji Horizon Women’s Hospital, Ahmedabad. Last reviewed: 7 July 2026.

This article is for education and does not replace an individual consultation. Whether you need an HSG, and how your result is interpreted, depends on your own history and examination. Please discuss your situation with a qualified gynaecologist.

Sources and further reading

• National Institute for Health and Care Excellence (NICE). Fertility problems: assessment and treatment (CG156) — hysterosalpingography for tubal-patency screening.
• Practice Committee of the American Society for Reproductive Medicine (ASRM). Diagnostic evaluation of the infertile female: a committee opinion.
• Dreyer K, et al. Oil-Based or Water-Based Contrast for Hysterosalpingography in Infertile Women (H2Oil trial). New England Journal of Medicine, 2017.
• Royal College of Obstetricians and Gynaecologists (RCOG) and ESHRE — tubal-patency assessment within the infertility work-up.