Hystero = uterus,  salpinx = fallopian tubes, graphy = study

Introduction: 

HSG is an outpatient procedure, performed to outline the uterine cavity and the two fallopian tubes as an X-ray picture. The fallopian tubes or oviducts, one on either side of the uterus serves as a conduit or passage between the uterine cavity and the ovaries. Each tube measures 10 cms in length, with an internal diameter of 1 mm. Their inner end is in direct communication with the uterine cavity, whilst their outer end opens out like a trumpet with finger-like projections called fimbriae. The fimbriae capture the oocyte after its release from the ovary at the time of ovulation.

(Diagram – female reproductive system)

The fallopian tube has many functions:

Hence it is important that the fallopian tubes are patent. The patency of the fallopian tube is evaluated by 2 methods - HSG and/or laparoscopy (see booklet). HSG will be outlined in brief.

What is HSG?

It is a radiological examination performed by injecting a radio-opaque, non-toxic dye into the uterine cavity and  taking X-Ray pictures to outline the uterus and fallopian tubes. 

It will diagnose the following:

Timing of HSG

The test is usually performed between the 5^th and the 9^th  (D5-D9) day of the menstrual cycle. This period is chosen to avoid a pregnancy, to avoid radiation to the oocyte or egg during its later development, and to ensure that the woman is bleeding-free. The normal menstrual bleeding may last from 2 – 8 days. HSG should be performed after the bleeding stops.

Procedure 

• It is an outpatient procedure, taking approximately 15-30 minutes. The woman is asked to report at the clinic/hospital in the morning hours, after a light breakfast. There is no need for her to fast overnight.
• An analgesic or painkiller is given by mouth 1- 2 hours before the procedure.
• The woman is usually given a gown to wear during the test, to avoid soiling of her own clothes. She is asked to pass urine in order to keep the bladder empty.
• She lies on a special table in a specific, yet comfortable position.
• All instruments to be used are sterile i.e. free from harmful organisms.   
• After adequately covering the genital area, an instrument called the speculum is gently inserted into the vagina to allow the mouth of the uterus (cervix) to be seen easily.
• The cervix is gently cleansed of any secretions and its anterior lip is held by a special forceps.
• A cannula or hollow tube is inserted into the cervix for the purpose of injecting the dye into the uterine cavity. Cannulas vary, but they serve the same purpose. 
• Once the cannula is in place other instruments are removed. 
• The dye is slowly injected into the uterine cavity via the cannula. Mild to moderate cramping usually occurs at this point.
• The progress of the dye may be viewed on a TV screen (fluoroscopy).
• Photographs are taken at short intervals to cover the passage of the dye into the uterine cavity, through the fallopian tubes and out into the pelvic cavity (if the tubes are open).  The amount of dye required is around 5-10 ml, and 2-3 films are usually taken.
• The medical attendant first ensures the quality of the films taken and then removes the cannula from the cervix. If required the procedure may be repeated at the same sitting.
• The woman is observed for half an hour and then allowed to leave.
• Antibiotics and anti-inflammatroy analgesics though not absolutely necessary, are given as a preventive measure against infection and inflammation.
• The woman is permitted to resume work the next day. The results of the test will be available to her a couple of hours later or the next day. 
• The dye inside the body is usually absorbed within 24 hours with no harmful effects.

Diagnosis - normal

• The contours of the uterine cavity are outlined, showing no deformity.
• The fallopian tubes are outlined in their entire length with no filling defect.
• The dye is seen as a spill outside the fallopian tubes.

If one or both tubes are blocked the dye will not move beyond the point of obstruction.Sometimes the findings may be false positive (15%) i.e. the tubes may seem to be blocked due to tubal spasm and not due to any obstruction. AdvantagesThe HSG may serve as a therapeutic procedure as well in some cases. Although controversial, studies have reported an increase in the pregnancy rate after the procedure. This can be explained by the dye acting as a lavage inside the tube. When mucus plugs/debris are flushed out, or flimsy adhesions within the tubal lumen are broken down as are result of the passage of the dye, the tubes ultimately become patent.

Side effects

• Pain/discomfort: The symptom varies with each woman. Some experience only an “uncomfortable feeling” whilst some others feel cramping pain similar to a period. The latter may be relieved by analgesics. 
• Rarely a woman may have a syncopal or fainting spell, with sweating and breatlessness. This is caused by passage of the cannula through the cervix. Hence all steps are gently performed.
• If the test is not performed under sterile conditions a pelvic infection can occur – hence prophylactic antibiotics are given.
• If the woman has had a pelvic infection in the past , she can opt for a laparoscopy and dye test, or HSG is performed under antibiotic cover i.e. antibiotics are started 48 hours before the procedure and continued for a total period of  7 days.
• There may be an allergic reaction to the dye.

Contraindications  

• Pregnancy – known or suspected.
• Previous history of severe pelvic infection.
•  Known allergy to the dye

HSG is a relatively inexpensive and convenient screening test. It has a role in infertility investigations as it detects a large proportion of women with tubal blockage. However a laparoscopy or dye test may be required in some cases to confirm the findings. It is heartening to note that even if a blockage or a uterine problem is diagnosed there are measures to correct the same.