Everything You Need to Know About Follicles and Eggs

Understanding how your body works can help you make smart choices about your fertility. And when it comes to follicles and eggs, that understanding is crucial because it helps you make informed decisions about whether you should freeze your eggs and which fertility treatments are best for you. Plus, if you’re already undergoing fertility treatments, it helps you understand exactly what’s happening in your body and what the treatments are trying to achieve. Here’s everything you need to know about follicles and eggs.

Follicles and Eggs: The Basics

In your ovaries are very small fluid-filled sacs called follicles. Each follicle contains one immature egg cell, or oocyte. Most of your follicles are so small that they can’t be seen without a microscope, and the eggs inside aren’t yet capable of being fertilized. 

Once you reach puberty, some of your follicles begin to grow. Each month, only a few follicles grow large enough to potentially release an egg. These are antral follicles, and the ones your doctor can see on an ultrasound. 

During a typical menstrual cycle, your body selects one of the antral follicles to mature and release a single egg to be fertilized. All the other follicles, with their immature eggs, are broken down and absorbed by your body.

Follicles and Eggs by the Numbers

When you’re born, you have all the follicles and eggs you’ll ever have–approximately 1-2 million! However, your body regularly loses follicles through a process called follicular atresia. By the time you have your first menstrual cycle, you will have 400,000 to 500,000 follicles left. 

With every passing month, you continue to lose approximately 1,000 follicles, along with the immature eggs inside. In fact, 99% of your follicles and eggs are lost this way, making it easy to see why fertility declines with age.

How Follicles and Eggs Affect Fertility

Your ovarian reserve, the number of healthy follicles and eggs in your ovaries, corresponds to your fertility. When you’re younger, you have more follicles and eggs, so it’s easier to become pregnant. As you age, you have fewer and fewer follicles and eggs. The quality of your eggs also decreases over time, making it harder for you to conceive and carry to term and more likely that your baby will have a chromosomal abnormality. 

How do you know how many follicles and eggs you have? Because most of your follicles are too small to see, your doctor estimates your ovarian reserve through fertility testing. A blood test, called the anti-Mullerian hormone test (AMH), measures the amount of a specific hormone made by your follicles. A higher amount of anti-Mullerian hormone in your blood corresponds to a greater ovarian reserve.

Your doctor may also perform an antral follicle count. This test involves counting the mature follicles in your ovaries that are large enough to be seen during an ultrasound. The number of mature follicles visible in your ovaries helps your doctor estimate your ovarian reserve and determine whether you’d be a good candidate for certain fertility treatments.

Conditions that Impact Follicles and Eggs

Several conditions may impact your follicles and eggs. For example, if your follicle doesn’t release the egg and fluid inside, you can develop a functional cyst. These cysts typically go away on their own but may be quite painful. 

If you have polycystic ovarian syndrome PCOS, you have a lot of immature follicles and eggs that result in many cysts. With PCOS, your body also has high levels of male hormones, called androgens, that prevent your follicles from growing and releasing an egg (ovulating). 

Premature ovarian insufficiency happens when you have very few follicles and eggs before the age of 40. This can be caused by genetic conditions that may also impact the quality of your eggs. Certain medical treatments, like chemotherapy, may also damage your follicles and eggs or stop you from ovulating.

Follicles and Eggs During Fertility Treatments

If you have problems with ovulation, want to freeze your eggs, or need to try in vitro fertilization (IVF), your doctor will prescribe medication that helps your follicles and eggs function in a way that maximizes your fertility. 

If you have a hormonal imbalance, you may wish to try ovulation induction with timed intercourse. Medication will help your follicles mature and trigger ovulation, and this may be enough to help you conceive without further intervention.

Alternatively, if you wish to freeze your eggs or try IVF, your doctor will give you medicine to stimulate more follicles than usual to mature. Rather than triggering ovulation, your eggs will be retrieved and then frozen or combined with your partner’s sperm for IVF. 

Importantly, stimulating your follicles to produce more mature eggs does not diminish your ovarian reserve. Instead, these procedures trigger follicles that otherwise would have been broken down to mature

When to Use Donor Eggs

Sometimes your own eggs simply aren’t viable. This can happen when your follicles and eggs have been damaged, when your ovarian reserve is too low, or after you’ve reached menopause. In these cases, you may be able to have a baby with the use of donor eggs. Donor eggs are also necessary if your ovaries have been removed or if you are part of an LGBTQ+ partnership in which neither partner has ovaries. 

If you are able to support a pregnancy, donor eggs can be used to create an embryo with your partner’s sperm or donor sperm. If you’re unable to carry a pregnancy to term, you’ll need to work with a gestational carrier. Your doctor can explain your options and help you choose the best treatment for your family. 

If you suspect that you may have problems with your follicles and eggs, or if you want to freeze your eggs to preserve your fertility for the future, schedule a consultation to speak with a fertility specialist at our Fertility Clinic in Laguna Hills, CA. We’ll talk to you about which diagnostics are necessary to assess your fertility and work with you to come up with a treatment plan that meets your needs.