What is Hysterosalpingogram?
💡 Hysterosalpingogram (HSG) = X-ray dye test of the uterus and fallopian tubes. Contrast injected through cervix; X-ray images show cavity shape and whether tubes are open (dye spills) or blocked. Standard first-line tubal patency test. Performed Day 5–10 of cycle. Bilateral blockage = IVF required. Unilateral block = IUI still possible.
Hysterosalpingogram is the full clinical name for HSG — the X-ray contrast investigation that assesses the uterine cavity and fallopian tube patency. "Hystero" = uterus, "salpingo" = fallopian tube, "gram" = X-ray image. It is the same procedure as HSG and the terms are used interchangeably in clinical practice.
🇮🇳 India Context: Hysterosalpingogram is widely assessed and treated across major Indian fertility centres including Chennai, Mumbai, Bangalore, Delhi, and Hyderabad.
What are the key characteristics of Hysterosalpingogram?
- Hysterosalpingogram and HSG are identical — "hysterosalpingogram" is the full anatomical term; "HSG" is the clinical abbreviation used universally
- Uterus imaging (hystero-): the triangular uterine cavity is outlined by contrast; filling defects indicate polyps, fibroids, synechiae; irregular shape indicates septum or congenital anomaly
- Tube imaging (salpingo-): contrast flows from cavity into both tubes; normal tubes appear smooth and thin; opacified tubes that taper to a blocked end = distal block; no opacification = proximal block
- Gram (X-ray image): fluoroscopy provides real-time imaging; spot films captured at key moments; low radiation dose (comparable to 2–3 chest X-rays)
- Sensitivity/specificity: HSG has ~85–90% sensitivity for tubal occlusion; specificity ~85%; false positives (tubal spasm) in 15–30% of proximal blocks
- Uterine cavity sensitivity: HSG has ~75–80% sensitivity for significant intracavitary lesions (polyps, fibroids); SIS (saline sonogram) is more sensitive (~95%) for soft tissue; HSG is superior for tubal patency
- HyCoSy/HyFoSy: ultrasound-based alternatives without radiation; increasingly replacing HSG as first-line in younger, lower-risk women with no strong indication for fluoroscopic imaging
- Post-HSG fertility boost: studies (including a large Cochrane review and the FOAM/H-TRUST RCTs) confirm higher conception rates in the 1–6 months after HSG — particularly with oil-based contrast; mechanism: flushing + anti-inflammatory effect
How does Hysterosalpingogram work?
Why does Hysterosalpingogram matter in fertility?
The hysterosalpingogram is the pivotal investigation separating women who can pursue natural conception/IUI from those who require IVF. Its result in under 30 minutes changes the entire treatment pathway. Beyond diagnosis, the procedure has a well-documented therapeutic benefit — the post-HSG "flush" effect increases pregnancy rates by 20–40% in the months following the procedure. This is why many guidelines recommend hysterosalpingogram before starting IUI, even in patients with a low pre-test probability of blockage, as the diagnostic and therapeutic value combined justify the procedure. The hysterosalpingogram is also the best investigation for detecting uterine congenital anomalies (septum, arcuate uterus, bicornuate uterus) that affect recurrent miscarriage.
What are related terms to Hysterosalpingogram?
HSG (Hysterosalpingogram)
HSG (hysterosalpingogram) is a radiological test using X-ray fluoroscopy and con…
HSG Test (Hysterosalpingography)
HSG (Hysterosalpingography) is a diagnostic X-ray procedure. A contrast dye is i…
Tubal Patency
Tubal patency refers to whether the fallopian tubes are open (patent) and functi…
Laparoscopy (Keyhole Surgery)
Laparoscopy is a minimally invasive surgery, also called keyhole surgery. A thin…
IUI (Intrauterine Insemination)
IUI (Intrauterine Insemination) is a fertility treatment where washed, concentra…
FAQs about Hysterosalpingogram
What is the difference between HSG and hysterosalpingogram?
There is no difference — hysterosalpingogram is the full clinical term; HSG is the abbreviation. Both refer to the identical procedure: contrast dye injected through the cervix, X-ray images taken to show the uterine cavity outline and whether contrast flows freely through the fallopian tubes (patent) or is blocked. The terms are used completely interchangeably in medical literature, fertility clinics, and radiology reports.
When should a hysterosalpingogram be done?
Timing: Day 5–10 of the menstrual cycle — the post-menstrual, pre-ovulatory window. This ensures: (1) endometrium is thin (better cavity visualisation); (2) no risk of disrupting an early pregnancy; (3) no dominant follicle that could be inadvertently traumatised. Indications: as part of female fertility workup (especially if >12 months TTC, or >6 months if over 35); before IUI cycles; investigation of recurrent miscarriage; prior pelvic infection or surgery history.
What does a normal hysterosalpingogram result look like?
Normal HSG report: "Uterine cavity is normal in shape and outline. Both fallopian tubes are opacified and free spillage of contrast is seen bilaterally into the peritoneum." This means: (1) uterine cavity is triangular with smooth walls — no polyps, fibroids, or adhesions; (2) both tubes fill with dye and dye spills freely into the abdomen (patent). Any deviation from this description — filling defects, irregular cavity, absent or partial tube fill, no spillage — requires follow-up investigation.
Can a hysterosalpingogram detect endometriosis?
No — HSG cannot directly detect endometriosis in the pelvis. Endometriosis implants are on peritoneal surfaces, not within the uterine cavity or tube lumen, so they are invisible to HSG. However, HSG can detect endometriosis-related complications: hydrosalpinx (distal tube blockage from endometriosis) and peritubal adhesions may cause distorted tube appearance or incomplete spillage. Definitive endometriosis diagnosis and staging requires diagnostic laparoscopy with biopsy.
What is oil-based contrast in hysterosalpingogram and is it better?
Oil-soluble contrast (lipiodol/Ethiodol) is a viscous contrast medium used as an alternative to water-soluble contrast (iohexol) for HSG. Multiple RCTs (FOAM trial: NEJM 2017; H-TRUST trial: NEJM 2020) demonstrated that oil-based HSG results in significantly higher spontaneous pregnancy and live birth rates in the 6 months post-procedure compared to water-based — proposed mechanism is oil's immunomodulatory effect on peritoneal macrophages. Oil HSG: slightly more cramping, slower excretion. Many fertility centres have switched to oil contrast as the preferred choice.
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