Follicular Phase

What Is the Follicular Phase?

The follicular phase is part of your menstrual cycle. It’s the time when hormones help an egg mature in one of your ovaries. This egg makes it possible for you to get pregnant. The follicular phase starts on the first day of your period and lasts until ovulation.

Your menstrual cycle consists of two phases: the follicular phase and the luteal phase. Menstruation (your period) and ovulation are important events that happen in each phase. It goes like this:

1. During your period, your body sheds the lining of your uterus through your vagina.
2. During the follicular phase, tiny fluid-filled sacs in your ovaries called follicles hold immature eggs. One follicle grows stronger than the others. This is the egg you’ll release at ovulation.
3. During ovulation, your ovary releases the egg. Ovulation is the end of the follicular phase and the beginning of the luteal phase.
4. During the luteal phase, the dominant follicle that released the mature egg changes into a structure called the corpus luteum. The corpus luteum produces important pregnancy hormones. If you don’t get pregnant, the corpus luteum will disappear. You’ll get your period again. Then, the cycle repeats.
5. The only time it doesn’t repeat is if you get pregnant.

What happens during the follicular phase of my menstrual cycle?

You’re born with about a million eggs. Once you start having your period, your body begins a process of maturing and releasing these eggs. Hormones in your brain and your ovaries control the changes in your body that make the follicular phase possible.

Stages

The stages of the follicular phase are:

1. The follicular phase begins on the first day of your period.
2. Your pituitary gland releases follicle-stimulating hormone (FSH). This hormone signals your ovaries to start growing follicles. These are tiny sacs that hold eggs.
3. One follicle starts growing faster and stronger than the others (the dominant follicle). The egg inside this follicle begins to mature and prepare for ovulation.
4. The dominant follicle releases more estrogen. Estrogen is a hormone that thickens the lining of your uterus to get it ready in case a fertilized egg needs to implant.
5. As estrogen rises, your body makes less FSH. This causes the smaller follicles to stop growing and disappear. The egg in the dominant follicle finishes maturing.
6. Rising estrogen levels cause your pituitary gland to release a burst of luteinizing hormone (LH). This hormone tells the mature egg to break out of its follicle and leave the ovary. This is ovulation.
7. The follicular phase ends when you ovulate.

This process takes about 10 to 14 days. It can be slightly shorter or longer depending on your cycle.

What are the symptoms of the follicular phase?

Common symptoms during the follicular phase can include:

• Bleeding (the start of your period)
• Cramping or bloating just before ovulation
• Increased sex drive just before ovulation
• “Egg white” cervical mucus (at ovulation)
• Clearer skin and a more positive, upbeat mood (due to estrogen increase)

How do you track it?

There are a few ways to track when you’re in the follicular phase:

• Basal body temperature: You take your temperature before you get out of bed each morning. Your temperature is generally lower during the follicular phase. It rises slightly once you ovulate.
• Cervical mucus: Just before you ovulate, your vaginal discharge becomes clear, slippery and stretchy, like egg whites. This signal can let you know you’re in the follicular phase.
• Ovulation prediction kits: These kits detect the surge in LH just before ovulation. You can use them to figure out when you’re about to ovulate.
• Period apps: There are several apps you can download that help you track where you are in your cycle. They usually have a digital calendar, symptom tracker and other tools to help you predict ovulation and menstruation.

What is the normal time range for the follicular phase?

It varies. On average, it lasts between 10 and 14 days. But yours can be shorter or longer. It can also change each cycle. But it always starts on the first day of your period and ends when you release an egg (ovulate).

Long follicular phase

Having a long follicular phase doesn’t mean you’re less likely to become pregnant. A long follicular phase most likely means that your menstrual cycle is longer, too. You can have a long follicular phase for many reasons. These include:

• Stress
• Obesity
• Thyroid issues

Short follicular phase

A short follicular phase could mean that you may have trouble becoming pregnant. It’s common for the follicular phase to shorten (for example, from 14 days on average to 10 days) as you approach menopause. Other causes could be:

• Stress
• Infection or illness
• Low body weight
• Hormone imbalances

Can you get pregnant during the follicular phase?

Yes. You have the greatest chance of becoming pregnant if you have sex during the five days leading up to ovulation and on the day you ovulate.

How does it affect fertility?

It’s very important for fertility. It’s the phase where your body prepares and releases an egg. This step is essential for getting pregnant.

What are the tips for a healthy follicular phase?

There are some things you can do to support a healthy follicular phase:

• Eat healthy foods, like fruits, vegetables and lean protein.
• Stay at a body weight that’s healthy for you.
• Avoid tobacco products and alcohol.
• Get enough sleep.
• Get at least 30 minutes of physical activity several times a week.
• Track your cycle and be aware of your body.