An HSG (hysterosalpingogram) is an X-ray based test that checks whether your fallopian tubes are open and your uterine cavity is normal. It takes about 5–10 minutes. Pain ranges from mild cramping to significantly uncomfortable (take 800 mg ibuprofen an hour before). Most women describe it as a brief intense cramp followed by relief. Some women experience a temporary “fertility boost” in the 1–3 months after the test.
What Happens During an HSG
You lie on an X-ray table in a position similar to a pelvic exam. A thin catheter is inserted through your cervix (this is the part most women feel). Through the catheter, a contrast dye is slowly injected into your uterus. The dye fills the uterine cavity and, if the tubes are open, flows through the fallopian tubes and spills into the pelvic cavity. X-ray images are taken throughout to visualize the path of the dye.
The entire procedure takes 5–10 minutes. Most of the discomfort lasts only 30–60 seconds while the dye is being injected. After the catheter is removed, cramping usually resolves quickly.
Does It Hurt?
Pain is the most common concern, and honesty helps more than reassurance here. Experiences vary widely:
- Mild: About 30–40% of women describe it as similar to a Pap smear with some cramping.
- Moderate: About 40–50% experience noticeable cramping that's uncomfortable but manageable.
- Significant: About 10–20% find it quite painful, particularly if one or both tubes are blocked (the dye creates pressure against the blockage).
Pain management tips
- Take 600–800 mg ibuprofen one hour before the procedure
- Ask about a numbing spray or gel for the cervix (not all clinics offer this, but some do)
- Breathe slowly and deeply during the dye injection — tensing up makes cramping worse
- Bring a pad for light spotting and dye leakage afterward
- Plan a quiet afternoon — most women feel fine within hours, but taking it easy is reasonable
What Results Mean
| Finding | What It Means | Next Steps |
|---|---|---|
| Both tubes open (bilateral spill) | Normal — dye flows freely through both tubes | Tubal factor is ruled out; continue with other aspects of the workup |
| One tube blocked | One tube is open, one is not | Conception is still possible through the open tube; IVF bypasses tubes entirely |
| Both tubes blocked | Dye cannot pass through either tube | Natural conception is very unlikely; IVF is the standard treatment path |
| Uterine filling defect | Something is distorting the uterine cavity (fibroid, polyp, septum) | Follow-up with SHG or hysteroscopy for detailed evaluation |
| Proximal tubal obstruction | Blockage at the junction of tube and uterus | May be spasm (false positive) rather than true blockage; retest or evaluate with hysteroscopy |
The Post-HSG Fertility Boost
There's a well-documented phenomenon where pregnancy rates appear to increase in the 1–3 months after an HSG, particularly when oil-based contrast dye is used. A 2017 RCT in the New England Journal of Medicine (the H2Oil study) found that oil-based contrast resulted in significantly higher pregnancy rates (39.7%) compared to water-based (29.1%) over 6 months after HSG.
The mechanism isn't fully understood. Hypotheses include the flushing of minor debris from the tubes, disruption of small adhesions, and an anti-inflammatory or immunomodulatory effect of the oil-based dye. Not all clinics use oil-based contrast, so you can ask which type they use.
What Comes After Testing?
Understanding your results is the first step toward the right treatment plan.
When to See a Fertility Specialist