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Follicular phase is one of the four phases of the menstrual cycle, it starts with your period and ends when you ovulate.
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The follicular phase is the first phase of your menstrual cycle where the follicle (egg) matures. It starts with your period and ends when you ovulate.
There are four phases in your menstrual cycle: the Early Follicular Phase (aka Menstruation), the Late Follicular phase (just before Ovulation), the Mid-Luteal Phase (post ovulation), and the Late Luteal phase (just before your period).
Menstruation is when you shed the uterine lining for 3 to 7 days. The uterine lining starts to build up during the late follicular phase. During this phase, your hormone levels are low.
The late-follicular phase is where the follicle (egg) forms which causes estrogen to increase in your body which leads to ovulation. The higher levels of estrogen lead to the uterus producing a thick lining for the egg to implant there.
At this part of the cycle, the egg reaches full maturity. Your estrogen reach their peak.
Ovulation is the release of the egg to be fertilized. If this doesn’t happen, the egg is released in menstruation.
After ovulation, your Estrogen levels drop and your progesterone levels start to rise.
The Luteal phase is after Ovulation and before menstruation and can be divided into two - the Mid-Luteal phase and the Late Luteal phase. During this phase, the released egg from ovulation changes the structure that holds the egg into the corpus luteum.
The corpus luteum starts to produce progesterone which helps thicken the uterine lining. If the egg isn’t fertilized, the corpus luteum stops producing progesterone and releases the uterine lining which starts menstruation.
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In the follicular phase, Estrogen increases after menstruation. The higher Estrogen levels result in ovulation occurring.
The estrogen levels increase between the end of your period to ovulation. Estrogen levels drop immediately after ovulation (before a second lower peak in the luteal phase).
Your energy level during the follicular phase will rise from the previous phase (luteal phase). Your energy levels might be at their highest.
Physical strength is usually higher and you have more confidence. You’re also more likely to want to make plans and socialize more.
The follicular phase can last between 12 to 18 days which can change between cycles. Its length depends on how long it would take for the egg to mature based on your estrogen levels. The size of the phase changes for every woman. It can also change per cycle.
A study was done in 2010 which stated that a follicular phase can be considered short when it falls below 11 days. A shorter follicular phase could impact your likelihood of getting pregnant.
Depending on your age, it could be an indicator that you’re through menopause. In your late 30s, you will start to experience shorter follicular phases because your eggs are maturing faster from FSH not being able to reach the same levels as they used to.
Therefore, the eggs may not be able to be fertilized which is the start of menopause.
According to a study in 2010, a long follicular phase is 18 days or longer.
The length of the phase changes from woman to woman, therefore, it might be normal for you to have a long follicular phase but to someone else, it may not be.
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The main symptoms you can experience during your follicular phase are:
Physical symptoms
Mental symptoms
In the early follicular phase (menstruation) you bleed which is your uterine lining shedding. This lasts between 3 to 7 days depending on the cycle.
There could be heavy or light flow which depends on the person.
During the late follicular phase (ovulation) is the ideal time to become pregnant. In the late follicular phase, the follicle matures to be released for fertilization. Therefore, if intercourse happens during this phase, it is more likely for you to become pregnant.
The study “Temperature regulation in women: Effects of the menstrual cycle” showed women experience a change in core body temperature throughout their menstrual cycle, with body temperature rising during the luteal phase, post-ovulation.
As such, during the follicular phase, a woman’s body temperature is l0.3-0.7 degrees Celsius lower than during the Luteal phase.
This temperature change can be used to track ovulation and is influenced by hormones, but there is still much to learn about the mechanisms behind it.
Founder of Elara Care and O.A. Dip. Certified Women's Health Practitioner, Jas is working to create better solutions for women since 2018, sharing her struggles and experiences with female health
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Dr Natalie, PhD, MPhil - Sports Science Research Specialist investigating the menstrual cycle in sports, ranging from participation to elite sports performance. Swansea University Lecturer.
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