A hysterosalpingogram, commonly abbreviated as an HSG, is a specialized X-ray procedure used to visualize the internal structure of the uterus and the fallopian tubes. This outpatient diagnostic test involves the injection of a contrast dye into the reproductive tract while a continuous X-ray, known as fluoroscopy, captures the movement of the dye. The procedure allows healthcare providers to assess the shape and contour of the uterine cavity and determine whether the fallopian tubes are open or blocked.
Why a Hysterosalpingogram is Needed
The primary reason a healthcare provider requests an HSG is during the evaluation of female infertility. Tubal factors, such as blocked or damaged fallopian tubes, are significant contributors to a person’s difficulty in conceiving, since the egg and sperm must meet there. The procedure provides direct evidence of tubal patency, showing if the contrast material flows freely through the tubes and spills out into the pelvic cavity.
The test also helps identify abnormalities within the uterine cavity that could impede implantation or lead to recurrent pregnancy loss. These irregularities can include submucosal fibroids, polyps, or intrauterine adhesions. HSG can also be used to evaluate the success of certain surgical procedures, such as confirming the closure or reversal of a tubal ligation. The information gained from the HSG directs the subsequent treatment plan, whether it involves surgery or assisted reproductive technologies like in vitro fertilization.
The Professionals Who Perform the Test
The Hysterosalpingogram is typically performed in a specialized setting, such as a hospital’s radiology department or an outpatient imaging center. The physician who oversees and performs the core steps of the procedure is most often a board-certified Radiologist. The Radiologist is responsible for inserting the cannula, injecting the contrast dye, and personally interpreting the real-time X-ray images captured by the fluoroscope.
A specialized healthcare provider, such as an obstetrician-gynecologist or a reproductive endocrinologist, may also perform the HSG, particularly in fertility clinics. Working alongside the physician is a Radiologic Technologist, a professional who operates the fluoroscopy machine and manages the imaging equipment. Nursing staff also play a supportive role, preparing the patient, administering any necessary medications, and providing post-procedure care.
Preparing for the Test
The timing of the HSG is carefully controlled to ensure patient safety and maximize the quality of the images. The procedure must be scheduled in the first half of the menstrual cycle, specifically after the menstrual flow has ended but before ovulation, typically between cycle days 6 and 12. This timing avoids the risk of performing the test during an early, undetected pregnancy.
Patients are often instructed to take an over-the-counter pain reliever, such as ibuprofen or acetaminophen, about an hour before the scheduled appointment time. This premedication helps to mitigate the cramping sensation that can occur when the contrast dye is injected into the uterus. In some cases, a physician may prescribe a course of antibiotics to be taken before the procedure, especially if the patient has a history of pelvic infection. A negative pregnancy test result is also confirmed on the day of the exam before the procedure can begin.
What Happens During the Procedure
The procedure begins with the patient lying on an examination table in a position similar to a standard pelvic exam. A speculum is gently inserted into the vagina to visualize the cervix, which is then cleaned with an antiseptic solution. The physician then carefully inserts a thin, flexible tube or cannula through the cervical opening and into the lower part of the uterus.
The speculum is removed once the catheter is securely in place, and the patient is positioned beneath the fluoroscopy unit, which is the specialized X-ray machine. The contrast dye is slowly injected through the catheter into the uterine cavity, which is the point where many patients experience a feeling of cramping, similar to moderate menstrual pain. If the fallopian tubes are blocked, this cramping may feel more intense due to the pressure buildup.
As the dye fills the uterus, the fluoroscope captures images of the uterine shape and tracks the material as it moves into the fallopian tubes. If the tubes are open, the dye will be seen flowing through their entire length and spilling out of the ends into the surrounding pelvic area. Multiple X-ray images are taken from different angles to document the passage of the dye and any structural findings. The entire injection and imaging process usually takes only a few minutes, after which the catheter is removed.