How Follicular Monitoring can be done?
When you and your partner are trying to get pregnant, then the best chances of success are if you have relations during the time the egg is released from the ovary (ovulation).
To know that the egg is forming in the ovary and is being released, then one of the methods is Folliculometry / follicular monitoring.
What is a follicle?
A follicle is a sac containing the egg which is present in the ovary. At the beginning of the menstrual cycle i.e. the first or second day of periods, the follicles are small in size and the eggs inside them are immature.
Due to the effect of FSH hormone released from the pituitary gland in the brain, the follicles start growing. As the follicles grow, they become filled with fluid and so increase in size. At the same time, the egg inside also starts maturing.
When the follicle grows to the final mature stage, another hormone LH is released from the pituitary gland which causes rupture of the follicle with the egg getting released.
As the follicle grows and the egg matures, it releases a hormone called estrogen under whose effect the lining (endometrium) of the uterus/ womb starts getting thicker.
Follicular monitoring is a series of scans or ultrasounds done to track the growth of the follicles in the ovaries. Follicular Monitoring is generally done by transvaginal ultrasound because it is more accurate (pelvis can be seen more clearly), more convenient (you don’t have to hold urine) compared to a transabdominal ultrasound.
In transvaginal ultrasound, the ultrasound transducer or probe is covered with a sterile cover and a little jelly is applied. This probe is now introduced in to the vagina. The probe transmits sound waves which are converted in to images and displayed on the ultrasound monitor.
Follicular Monitoring starts with a Baseline scan.
Baseline scan- This is the first scan done on the second or third day of the periods. Here the doctor looks at the uterus- the lining is thin because it has been shed during periods. Both ovaries show the number of follicles which are available for growth in that cycle. The follicles should be less than 10mm in size. The doctor also rules out any problem like blood or fluid-filled follicles known as cysts in the ovaries.
Next Visit– If the follicular monitoring is being done in a natural cycle and you have 28-30 days cycle, the doctor will generally call you next on day 9 of your cycle.
The day may vary, either earlier or later depending on your cycle length or if you are being given medicines or injections to stimulate your ovaries to produce eggs.
In this visit, the doctor will see on the scan if any follicle has started growing in either of your ovaries. The lining of the uterus is also seen, whether it has started getting thicker as the estrogen hormone starts increasing. Depending on the size of the follicle, the doctor may next call you after 2-3 days.
After 2-3 such visits, when the follicle reaches a size of 18-20 mm, either we can wait for the follicle to rupture naturally on its own or injection may be given which mimics the effect of LH in our body causing the follicle to rupture and egg to release.
The follicle is visible on ultrasound scan as a round structure with white outline and black interior, inside the ovary. After the egg is released the follicle collapses and changes in to a crumpled structure known as corpus luteum. There may be small amount of fluid seen around the uterus. There are some changes visible in the lining of the uterus also.
At this point the follicular monitoring cycle is complete and you have to wait for two more weeks to know the result whether you have conceived or not.