What Is Follicular Study Scan?

A follicular study scan is a procedure that involves a series of ultrasound scans to monitor the size and quality of the follicles regularly during your menstrual cycle.

If you are not aware of what a follicle is and its impact on your reproductive health, let’s explain this to you.

Ovarian follicles are small fluid-filled sacs found inside a woman’s ovaries. These are produced by a follicle-stimulating hormone secreted by the pituitary gland.

Unfortunately, insufficient secretion of this hormone can also cause infertility in a woman.

Each follicle has the potential to release an egg for fertilization. Therefore, follicle count, size and quality play an essential role in a woman’s fertility cycle and fertility-related treatments.

This is why a follicular study scan precedes every fertility treatment.

Why Is Follicular Monitoring Necessary?

A follicular monitoring scan is done to study the follicular growth in a woman’s ovaries to find the ovulation window.

Each follicle contains an immature egg called an oocyte. A follicle needs to reach a particular size to release a mature egg. This scan helps the doctor detect the number of matured follicles and the ones capable of releasing a quality egg.

Several follicles begin to develop at the beginning of a woman’s menstrual cycle (between 6 to 9 days).

However, during the 14th and 20th days of your cycle, only one follicle will be capable of forming a fully mature egg Then, on about the 14th to 19th day of your cycle, a sudden surge in gives the follicle a sudden growth spurt that makes the egg detach from it and get released into the ovary and then into the uterus.

This process is called ovulation.

anatomy of ovary and follicle

anatomy of ovary and follicle Anatomy of Ovary And Follicle Your follicular study scan helps the doctor determine when your ovulation phase begins. This is when the couple would be advised to have intercourse to get conceived naturally.

Role of hCG injection in Follicular study Scan

Human chorionic gonadotropin (hCG) is a hormone that has a similar structure to the luteinizing hormone. When a dominant follicle (good quality and 20mm in size) is identified in your follicle study, an injection of hCG is given to the patient.

This makes the follicle rupture to release the egg. This is the ideal time for the couple to have intercourse to get pregnant.

Who should get a follicular study done?

When should a woman get her follicular study is depended upon the below criterion,


Who Should Get Follicular Study

Who Should Get Follicular Study

  • If you are a woman under 30 to 35years of age and have been trying to conceive naturally for a year without success.
  • If you are  for a year without success. Many people who fall under this age might have fertility issues, and follicular monitoring would help the doctor suggest the next step in their treatment.  
  • Suppose you have an irregular menstrual cycle with or without PCOD. With PCOD, you might also have an anovulatory cycle (no ovulation).
  • Suppose you can’t track your ovulation time. A woman’s menstrual cycle is 28days, but some can have a slightly lengthier cycle. Tracking the ovulation period might be challenging in such cases. 
  • If you are under some fertility drugs to trigger ovulation.

How Is a Follicular Study Scan Done?

A follicular study scan should be done by a trained fertility specialist or an Obstetrician. The best way to perform follicular monitoring is through a transvaginal scan.

You would be asked to empty your bladder before the scan commences since a full bladder might interfere with the results.

Transvaginal Ultrasound Scan                                     Transvaginal Ultrasound Scan 

                                 Image courtesy : Medical News Today

The procedure begins by inserting an ultrasound probe into your vagina to pick up images of your ovaries, follicles, and endometrium lining.

How Many Times Should a Follicular Scan Be Repeated?

This series of ultrasound scans are repeated 5 to 6 times during your menstrual cycle. So, for example, your first scan will commence on the 9th day of your period and be repeated till the 20th day.

Scans are repeated to ensure the exact moment when ovulation occurs. Follicular study is a painless procedure, and each takes 5 to 10minutes of your scan time. 

Your gynec will usually recommend repeating every scan the alternative day until ovulation. Ovulation generally occurs between the 14th day and 17th day, but it might be delayed in some women. 

All the readings taken during these days are logged in your follicular study report , which helps to track your changes periodically.

What Should Be The Size Of The Follicle To Get Pregnant?

Your doctor would be able to predict the ovulation time by studying the follicle’s size.

Your doctor would also see if the uterus lining (ET) is thick enough to support a fertilized egg (embryo).

Ideal Size Of Follicle

What is ET in Follicular Study?

The endometrium or endometrial lining is the inner wall of your uterus. Endometrium thickness varies with a woman’s age and menstrual cycle. A healthy and right-sized endometrium is required for a healthy pregnancy.


Endometrium in Uterus Endometrium – The inner lining of the uterus                   


There are two hormones involved in the formation of the endometrial lining – Estrogen, and Progesterone.

It is generally considered that an endometrium thickness of 11mm to 15mm is suitable for a healthy pregnancy. It is also very important for this inner cavity to have three layers (trilaminar) to accept the pregnancy.

During your follicular study, the doctor studies your endometrium thickness (ET)  along with the follicle size to check if your uterus is ready to implant the fertilized egg and support your baby’s placenta.

It is not a good sign if you have the right follicle size and a too thick or thin ET.

What Can a Follicular Study Detect?

Follicular Study Detects The size, shape, and condition of  the above are monitored in Follicular Study


Out of these, evaluating your follicles and endometrium lining is the most important.

Benefits Of a Follicular Study Scan

The main benefit of a follicular study scan  is to educate a couple on the right time to have intercourse to help conceive naturally. This also helps the gynec to assist the couple with fertility treatment if there is a low chance of getting pregnant naturally.  

Here are the benefits in detail, 

  • Helps to find your fertile window to conceive naturally
  • Identify your fertile window if age is limiting your eggs
  • Helps to find dominant follicle in a patient with PCOD (internal link)
  • Helps to assess your Fertility Drugs
  • Helps in your Advanced Fertility Drug Treatments

What Is The Next Step In Treatments After a Follicular Study Scan?

There might be cases where a couple might have a problem conceiving naturally. This can be due to any underlying fertility issues or a problem identified in a follicular scan.

These are some of the common and effective fertility treatments that most the couple are asked to undergo, 

  • IUI – Intrauterine-insemination
  • IVF (In vitro fertilization)
  • ICSI (Intracytoplasmic Sperm Injection)

Difference between IVF, IUI Difference between IVF, IUI and ICS

A follicular study is usually the first step of the procedure that precedes any fertility treatment. This is because this scan helps determine the presence of follicles and the best time to extract an egg for fertility treatments.

Does Follicular Monitoring  Need Any Preparation?

There are no significant preparations needed during your follicular monitoring. You just need to be careful about the days of your menstrual cycle. 

You would be advised to visit your gynec on the 2nd or 4th day of your period and make sure you don’t miss this. Please keep in mind that this is a series of scans, and you visit your doctor on all the prescribed days for the perfect result. 

Also, a full bladder is not recommended while doing this ultrasound. Emptying your bladder before the procedure would give you better results.

Are There Any Side Effects  Of A Follicular Study Scan?

There are no physical side effects in a follicle monitoring scan. However, some couples might be under stress since they have probably been trying for a baby for quite some time. 

Please remember that stress is the first enemy of your pregnancy or trying to get pregnant. So be relaxed, and rest will be taken care of by your obstetrician.

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