Folliculometry is the monitoring of the growth and development of follicles in the ovaries using vaginal ultrasound. This is an important part of fertility treatments and helps determine ovulation and the most fertile time for pregnancy. By monitoring follicle development, it is possible to understand how the ovaries respond to the natural cycle or to medications given.

 

In a natural menstrual cycle or during ovulation stimulation, follicles (fluid-filled sacs containing eggs) grow as ovulation approaches. Folliculometry can monitor this growth process and predict when a maturing follicle will be ready to ovulate. This increases the chance of pregnancy.

Folliculometry usually begins on day 9 or 10 of the menstrual cycle and is followed by ultrasounds every few days until ovulation is expected. The number of scans may vary depending on whether a person is having a natural cycle or is undergoing assisted reproductive treatment (such as IUI, IVF).

 

Why Is Folliculometry Important?

• Timing of Ovulation: Helps to accurately predict when ovulation will occur, which allows for the most appropriate time for intercourse, insemination (IUI) or egg retrieval (IVF).

• Assessing Response to Treatment: In women undergoing ovulation induction or controlled ovarian stimulation (COS), folliculometry is used to monitor how the ovaries are responding to medications.

• Reducing Risks: By monitoring the number and size of developing follicles, possible complications such as hyperstimulation syndrome (OHSS) or multiple pregnancy can be prevented.

• Preventing Treatment Cancellation: When follicles do not grow as expected, this can be detected early so that medication doses can be adjusted or the treatment plan can be changed.

 

How is Folliculometry Performed?

Folliculometry is performed via vaginal ultrasound. This is a safe, painless imaging method that only takes a few minutes. During the ultrasound, important data such as the size and number of developing follicles and the thickness of the endometrium are obtained.

 

Generally, when a follicle reaches 18–20 mm in diameter, it is considered mature and ready to ovulate. At this stage, depending on the treatment plan, an injection such as hCG may be administered to trigger ovulation.

 

Folliculometry may be used in the following situations:

• In natural cycles (tracking of spontaneous ovulation)

• In cycles where ovulation is stimulated (with oral or injectable medications)

• In insemination (IUI) treatments

• In in vitro fertilization (IVF) treatments