What are ovarian follicles?

Ovarian follicles are small sacs filled with fluid that are found inside a woman’s ovaries and also known as an oocyte, They secrete hormones which influence stages of the menstrual cycle and women begin puberty with about 300,000 to 400,000 of them. Each has the potential to release an egg for fertilisation. Follicles and their size and status are a vital part of assessing fertility and fertility treatment. Each month during your menstrual cycle, a select group of follicles begin to grow and mature. While only one follicle is naturally selected most of the other follicles do not reach maturity and fade away on their own.

An evaluation of follicles involves a pelvic ultrasound scan of your womb and ovaries as well as an Anti-Mullerian Hormone blood test. Seeking fertility care can be confusing for some due to its heavy medical terminology. The pelvic ultrasound scan will assess the size and number of follicles present on your ovaries called an Antral Follicle Count. The results of this scan as well as your blood test will allow a fertility specialist to assess your fertility and therefore your ability to conceive.

How may eggs will there be in a follicle?

In a normal menstrual cycle one follicle will grow containing one egg. The follicle will get bigger until it ruptures at ovulation which then releases the egg. This is usually around 14 days after the beginning of your menstrual cycle.

Follicle size for Pregnancy

Follicles play an important role in determining your chances of getting pregnant as they ensure the ovulation process (the release of an egg from the ovaries).

Nearly on the 14th day of your cycle, your follicles complete their development and begin to rupture. This process supports the release of a healthy, mature egg. The egg released from the follicle travels down the fallopian tube to be fertilised with sperm.

The right egg size for pregnancy is dependent on the proper growth of follicles that results in a healthy pregnancy.

Ovarian follicles are also responsible for the secretion of the hormone – estrogen which thickens the wall of the uterus and prepares it for pregnancy. Follicles also receive their growth spurt with the release of estrogen in the bloodstream.

Will all follicles release an egg?

Usually, yes. In most cases follicles will release an egg. However, whether the egg is mature enough or is of good enough quality for fertilisation is another matter. If you have a good number of follicles, your potential of getting pregnant is higher as you have an abundance of immature eggs that can develop and burst leading to ovulation

How many follicles is normal?

This is relevant to the woman’s age, general health, and lifestyle. However, more follicles do not necessarily guarantee successful fertilisation. The quality of the eggs is key and many women with fewer follicles can still conceive successfully with IVF because of the quality of the eggs.It is thus recommended that women should try to conceive in their 20s. It is because, as mentioned earlier, the number of your follicles begins to decline as you age

How many follicles are left at 30?

The quality and quantity of a woman’s eggs is affected by her age as well as other health and lifestyle issues. The number of ovarian follicles a woman has does decline with age and so does the quality of her eggs. After the age of 35 however, a woman’s fertility starts to decline significantly, and by her early to mid-forties the chances of achieving a successful pregnancy are slim.

The main way to know if a patient is a low responder or not is by performing controlled ovarian stimulation and looking at the results of this first cycle.

However, there are some criteria that will allow us identify those patients with risk factors for a low response to stimulation prior starting of stimulation, which are as follows:

Age >40 years.
Previous cycle with a low response (three or fewer oocytes) after a conventional stimulation protocol.
Decreased ovarian reserve markers (AFR <5-7 or AMH < 0.5-1.1 ng/ml).

When there’s at least two of the aforementioned criteria present, we consider it to be a risk of low ovarian response to stimulation.

How do follicles relate to my chances of having a baby?

There are two main factors to consider when it comes to female virility:

Egg Quality
Follicle Count

The number of follicles present within your ovaries will tell a fertility specialist about the state of your fertility. This is because follicles contain immature eggs. These immature eggs develop and grow in size until the follicle they are held in is of optimum size, whereupon they are released (ovulation). If you have lots of follicles, then you have the potential to release more eggs increasing the chance that one of those eggs will be healthy enough to result in a successful pregnancy.

Egg quality is determined by your age and also your lifestyle. As a woman get older, the quality of eggs decreases, particularly after the age of 35, and normally from around her mid-40s most women will not be able to conceive naturally. Unfortunately, it is not possible to test the quality of your eggs.

If you are keen to understand your chances of having a baby, we would suggest a Mcurefertility.

Why happens to my follicles during IVF?

During IVF, you will be put on a course of drugs to stimulate your ovaries to produce more eggs. Monitoring the ovarian follicles is part of the fertility treatment process. You will have several pelvic ultrasound scans during the stimulation phase to assess that the dosage of medication is correct and when you are ready for or egg collection. This includes monitoring the number and size of the follicles on each ovary.

When your follicles have reached around 18-20mm in diameter they are deemed ready for egg collection. You’ll be given a hormone trigger injection to stimulate your follicles to release the mature eggs that have been prepared in your follicles. We will time your egg collection procedure around 36 hours after your trigger injection to allow us to collect your eggs at the best possible time. The mature eggs that are collected will then be transferred to the laboratory to be fertilised with sperm to create embryos.

Can my follicles be affected by IVF?

Ovarian Hyperstimulation Syndrome may occur if the ovaries are very sensitive to stimulation and produce an unusually large number of follicles and therefore eggs (usually more than 15) or high levels of oestradiol. This is a potentially dangerous situation, although OHSS, in its severe form, occurs in only 0.5% of patients. During the simulation phase of your treatment cycle, your follicles will be closely monitored by ultrasound scans. If we think you are at risk of developing severe OHSS, there are a number of options that you and your fertility specialist will need to consider including abandoning the cycle, delaying the egg collection, or freezing all the embryos for transfer in a later cycle.

What is Polycystic Ovarian Syndrome?

Polycystic ovarian syndrome (PCOS) is a condition which affects how the ovaries work. It usually means cysts can be seen on the ovaries or high levels of (male) hormones in the body can prevent the ovary from releasing an egg.

PCOS is very common and can affect up to one in every five women. Symptoms of PCOS can include irregular or no periods, difficulty getting pregnant, hair growth, weight gain and acne. Although PCOS cannot be cured it can be treated by losing weight or through medication. If you are trying for a baby, there are many options to help you to conceive including medication, Intrauterine Insemination (IUI) or IVF. In most cases women with PCOS can get pregnant.

Can you lose follicles during IVF?

Often it happens before egg retrieval, but sometimes it can happen afterward. For example, cancellation may occur when only a few follicles (fluid-filled sacs containing immature eggs) develop in the ovaries during the stimulation phase of IVF treatment.

What happens to follicles during IVF?

In IVF, your ovaries are stimulated to make the follicles grow and produce mature eggs. Ultrasound scans will tell us when your follicles have grown to the right size, and how many follicles have grown.

Can IVF damage your ovaries?

Ovarian hyperstimulation syndrome (OHSS), is a possible complication of in vitro fertilization (IVF). In this condition, the ovaries swell and fluid leaks into the body. This condition is more common in women with polycystic ovarian syndrome who are going through fertility treatments

Does IVF decrease egg quality?

So while IVF can help increase the chances of finding some healthy eggs, it can’t make more of your eggs healthy. If a woman in her 40s retrieves 10 eggs in an IVF cycle, it’s likely that only 10–20% of those eggs will be normal

Why are my follicles shrinking?

Now, scientists have uncovered a new mechanism behind hair loss: When stem cells in hair follicles are damaged by age, they turn themselves into skin. Over time, this happens to more and more stem cells, causing hair follicles to shrink and eventually disappear

Why are my follicles growing slowly IVF?

Stress (physical or mental) can impair the release of FSH (follicle stimulating hormone) from the pituitary gland. FSH stimulates the development of the egg and low FSH can result in a slow growing follicle that cannot produce sufficient progesterone to mature the uterine lining for implantation.

Why did my eggs not mature in IVF?

Sometimes, despite giving you hormone medication during the stimulation phase of IVF, your eggs remain immature. This occurs when maturation has started but hasn’t fully completed in time (Figure 2). These eggs may mature with time; however, when inseminated they may not fertilise at a high percentage