TUBAL BLOCK AND IVF

What are Fallopian Tubes and how do they function?

Fallopian tubes are around 10 cm long tubular structures, less than the thickness of your little finger, that connect the uterus and the ovary. They perform the crucial function of transporting  the egg from the ovary to the uterus.

An egg is normally produced by the ovary on the 14th day of the menstrual cycle. The tube with its finger like end catches the egg and takes it in.

The life of this egg lying in the Fallopian tube is less than 24 hours. During this time, if a good sperm manages to reach the egg, then fertilization occurs and the journey to parenthood begins.

There are very thin hair like structures called cilia inside the fallopian tubes which help in the movement of egg, sperms and embryo from and towards the uterus as per the physiological period of menstrual cycle. Normal function of the tube depends on normal functioning of these cilia.

There is a wider portion of tube called ampulla where the fertilization i.e. union of egg with sperms takes place. If the tubes are blocked or diseased then this union of egg and sperm can not take place. This eliminates any chance of natural pregnancy resulting in Infertility.

It is often seen that the tubes are open but the inner lining and cilia are destroyed or diseased and therefore, function of the tube is not proper. In these situations though the tube is open but still natural pregnancy can not take place.

Causes of Tubal Block

Most common pathology for Tubal Block is formation of scar tissue due to infection and pelvic adhesions. In India, common causes of tubal block are:-

1. Infections  like tuberculosis, still very common in Asian countries, and sexually transmitted diseases, which lead to pelvic inflammatory disease (PID) causing adhesion formation.

2. Previous tubal ectopic pregnancy wherein fertilised egg got implanted somewhere in the fallopian tubes and the problem was treated surgically.

3. Fibroids are benign outgrowths of uterus which can cause infertility in many ways. They can be the reason of tubal block if they are present where tubes attach to the uterus or if they are very large so that tubes are stretched causing mechanical blockage. Presence of fibroids also predisposes a woman to acquire pelvic infections.

4. Hydrosalpinges is a condition where the tubes are blocked due to some infection and the fluid gets collected inside the tube .These hydrosalpinges can be very distressing as they are not only the reason for infertility but even if the couple opts for IVF as treatment, they compromise the success rate of IVF. If such a couple wants to go for IVF it is advisable to disconnect the attachment of fluid filled tubes from uterus or remove these diseased tubes.

5. Tubectomy or previous tubal reconstructive surgery. 

Some women might have undergone tubal ligation as a permanent method of contraception. But if they change their mind or due to some mishap with the kids the couple wants to go for another pregnancy then the reversal operation is not very successful. Then the only way out for pregnancy is IVF.

How to Diagnose Tubal Block?

1. Laparoscopy (gold standard).

Doctors can check the patency of tubes by directly visualising the passage of a fluid dye down the fallopian tube. Main disadvantage of laparoscopy is that it is an invasive procedure requiring anesthesia. 

2. HSG (Hysterosalpingography) 

It is the x-ray of tubes and uterus performed by a radiologist. In this procedure a radio-opaque dye is pushed through the cervix, uterus and then, through fallopian tube, the dye spills into the abdominal cavity. X-ray taken at an appropriate time during the procedure will show the uterine cavity, fallopian tubes and the spill into the abdominal cavity, confirming tubal patency.

Advantage of HSG is that it is a simple and cheap procedure. However, there are some disadvantages as well. These are..

The procedure is slightly painful 

The dye used can cause allergy 

The procedure can cause pelvic infections 

It can aggravate pelvic tuberculosis 

Also, the test is not very sensitive so there are chances of false report of tubal block.

HSG has largely been replaced by an ultrasound test called contrast sonohysterography .

3. Contrast sonohysterography  involves sonographic visualisation of fluid / contrast passing down the tubes to see if they are open or not. It is a simple noninvasive and a very economical procedure .

HOW IVF SOLVES THE PROBLEM OF BLOCKED TUBES?

In IVF treatment the function of fallopian tubes is bypassed. Multiple eggs are grown by giving injections to the patient. These eggs are then taken out of the body directly from the ovary before they come out of the ovary naturally and go into the fallopian tubes. 

The sperms are also collected and they are used to fertilize the eggs outside the female body in the IVF laboratory either by conventional IVF or ICSI.

This means that any problems with the fallopian tube can be addressed by IVF as there is no need of fallopian tube at all.

Therefore, IVF is the best option for such patients to achieve their dreams of parenthood.