Hysterosalpingography (HSG)

What Is Hysterosalpingography (HSG)?

Hysterosalpingography (HSG) is a specialized diagnostic method that images the uterine cavity and fallopian tubes under X-ray (fluoroscopy) with a radiopaque contrast agent. Commonly known as a “dye test of the uterus” or “uterine X-ray,” this procedure is one of the fundamental steps in the infertility work-up. Its ability to assess both tubal patency and the internal anatomy of the uterus in a single session is what makes HSG so valuable in the diagnosis of infertility. In Ankara, obstetrician-gynecologist Prof. Dr. Melahat Atasever performs HSG with an experienced approach as part of her infertility evaluation protocol. This article explains in detail what HSG is, how it is performed, what it shows, and what its results mean.

Hysterosalpingography derives from the Greek words “hystera” (uterus), “salpinx” (tube), and “graphein” (imaging). During the procedure, radiopaque contrast agent is introduced into the uterus through a thin catheter while continuous X-ray images are obtained with a fluoroscopy device. The contrast agent first fills the uterine cavity, then passes through both fallopian tubes and spreads into the abdominal cavity. This spillage confirms that the tubes are open.

HSG provides both anatomical and functional information. The shape, size, and possible deformities of the uterine cavity (septum, myoma, polyp, Asherman syndrome) are visualized, while whether the tubes are open or blocked is assessed in the same session. The ability to obtain both pieces of information at once makes HSG a single-visit, efficient test in the infertility work-up.

The contrast agent used may be water-based or oil-based. Today, water-based (iodinated) contrast is preferred in most cases; it is absorbed quickly and reduces the risk of infection. Oil-based contrast has been suggested in some studies to enhance tubal patency, but this effect remains debated.

Why Is HSG Performed? Indications

The primary indication for HSG is the infertility work-up. In couples unable to conceive, HSG assesses whether the fallopian tubes are open to sperm and whether tubal damage or hydrosalpinx (fluid accumulation in the tube) is present. Identifying a tubal blockage or damage directly shapes the treatment path and speeds the decision to direct the couple toward IVF.

Evaluation of uterine anatomy is also among the indications for HSG. Congenital anomalies such as a bicornuate uterus, a septate uterus, a T-shaped uterus, and a unicornuate uterus, as well as submucous myomas, polyps, and intrauterine adhesions (Asherman syndrome), can be visualized with HSG. It is also frequently used to investigate uterine shape anomalies in women with recurrent miscarriage.

Confirming successful tubal closure after sterilization (tubal ligation), or evaluating the tubes in the event of an unexpected pregnancy after sterilization, is likewise among the indications for HSG. It is also used to map the uterine anatomy before surgical procedures such as myomectomy or hysteroscopy.

When Is the Most Suitable Time for HSG?

HSG should be performed in the early follicular phase of the menstrual cycle. Scheduling the procedure between the seventh and tenth days after menstrual bleeding ends is recommended. This window offers several important advantages: image quality is at its highest because the endometrium is thin, the risk of radiation exposure to an existing pregnancy is eliminated because ovulation has not yet occurred, and catheter placement is easier because the cervical canal is relatively open.

HSG should not be performed during menstruation; bleeding makes it harder to evaluate the contrast agent and increases the risk of infection. The post-ovulation period is also avoided, as it raises concern about radiation exposure to a possible implanted pregnancy. Stating the date of your last menstrual period when booking the appointment allows the most suitable day to be planned.

Preparation Before HSG

Before HSG, the presence of active pelvic inflammatory disease (PID) or a vaginal infection is checked; if present, the procedure is postponed until treatment is complete. Any known iodine or contrast agent allergy must be reported to the physician; premedication is given if needed. Taking ibuprofen or paracetamol 30-60 minutes before the procedure significantly eases possible cramping.

Patients taking blood thinners or aspirin should mention this in advance. Because moderate discomfort may be experienced during the procedure, coming rested on the day of the procedure and, if possible, being accompanied is recommended. Some clinics administer antibiotic prophylaxis. Prof. Dr. Melahat Atasever provides comprehensive information to each patient before the procedure and answers any questions.

How Is HSG Performed?

The procedure takes place in a dedicated examination room equipped with a fluoroscopy device. The patient lies on the X-ray table in the gynecological position. A speculum is placed in the vagina to expose the cervix; after the cervix is cleansed, a thin HSG catheter is inserted through the cervical canal into the uterus.

Once the catheter is in place, the speculum is removed and the fluoroscopy device is activated. Radiopaque contrast agent is introduced slowly through the catheter while continuous X-ray imaging is performed. The contrast agent first fills the uterine cavity, then passes through both tubes and disperses into the abdominal cavity. X-ray films are taken in several positions during this process.

The imaging phase of the procedure takes only three to five minutes; including preparation and contrast administration, the total procedure time is 15-30 minutes. Anesthesia is not required; local anesthesia or sedation may be chosen. Discomfort resembling menstrual cramps may be felt as the contrast passes through. After the procedure, the patient is discharged following a short rest.

What Does HSG Show?

The images obtained from HSG reveal the shape and size of the uterine cavity, whether the tubes are open or blocked, the presence of tubal damage or hydrosalpinx (fluid accumulation within the tube), and intrauterine pathologies (submucous myoma, polyp, septum, adhesions).

Tubal patency is confirmed by the free spillage of contrast agent into the peritoneal cavity. Unilateral or bilateral tubal blockage is clearly seen when the contrast agent fails to advance beyond a certain point. Hydrosalpinx is recognized by a balloon-like appearance caused by fluid trapped in the tube. Even in the absence of blockage, asymmetry or delay in contrast passage through the tubes provides valuable information.

Treatment Path According to HSG Results

If the tubes are open and the uterine anatomy is normal, ovulation induction with IUI (intrauterine insemination) or attempting natural conception is planned. With unilateral tubal blockage, pregnancy may be possible through ovulation tracking on the open side; laparoscopic evaluation may be recommended depending on the situation. In cases of bilateral tubal blockage or severe tubal damage, IVF is the most effective treatment option.

When an intrauterine pathology is identified (such as a septum, Asherman syndrome, or a submucous myoma), hysteroscopic treatment of that condition is planned first. After treatment, the findings are reassessed and pregnancy attempts proceed accordingly. Prof. Dr. Melahat Atasever interprets the HSG findings comprehensively and determines the treatment path suited to your situation.

Possible Risks of HSG

HSG is generally a safe procedure. The most common issue is cramping and pain during the procedure, which resolves within a few hours. In rare cases infection can develop; to reduce this risk, the procedure is postponed if an active infection is present. Because patients allergic to iodinated contrast agents may react, allergies are checked in advance.

The radiation dose used by modern fluoroscopy devices is extremely low, corresponding to exposure equivalent to or less than a standard chest X-ray. Not performing the procedure during pregnancy eliminates this risk entirely.