Many couples struggling with pregnancy worry that an underlying medical condition might prevent them from having children. While that can be true, follicle size is another important factor. The likelihood of becoming pregnant is largely dependent on follicle size. When a follicle size is inadequate or not yet developed, it might not be ready for fertilisation.
This article discusses the optimal follicle size required for pregnancy and how to boost your follicle size to maximise the chances of your pregnancy outcome.
What are Follicles?
The tiny sacs that are filled with fluids in ovaries are called follicles. Follicles are the home for mature and immature eggs. Women are born with millions of eggs. Most follicles stay inactive, but some begin to grow together in different stages lasting about a year. Immature follicles naturally fade away, leaving only the strongest ones.
Why Does Follicle Size Matter for Pregnancy?
Follicle size is crucial in determining the success of the IVF procedure. Your physician will track your follicle growth during the ovarian stimulation process to retrieve the right size of eggs for successful embryo transfer. The ideal follicle size for the retrieval process is 16 to 22 mm.
If the follicle size is small, then the chances of having immature eggs are high. However, if follicles are large, the eggs also get mature and ready for the retrieval process. In short, the right follicle size is vital for enhancing the success rate of IVF treatment and quality of embryos. Your physician will examine you using hormone testing and ultrasounds to find the right follicle size.
What Happens in the Follicular Phase of Your Cycle?
During the follicular phase of your menstrual cycle, nearly 11 to 20 eggs start growing, but only one egg will mature fully.
The hormones released from your brain and ovaries can control this process together. The pituitary gland, guided by the hypothalamus, releases follicle-stimulating hormone (FSH), which signals the ovaries to produce fluid-filled sacs called follicles, where eggs develop.
A dominant follicle is one that grows faster than the other. As it matures, it releases estrogen, which thickens the uterus lining for pregnancy. The rising estrogen levels reduce FSH, causing smaller follicles to fade.
At the end of this phase, high estrogen levels trigger the release of luteinizing hormone (LH), which signals the mature egg to be released (ovulation).
How Long Does the Follicular Phase Last?
A typical menstrual cycle for women lasts between 28 and 35 days. There are two primary stages to it:
- The first half, or follicular phase, can vary in duration and lasts from 14 to 21 days.
- The second half, or the luteal phase, lasts roughly 14 days and is constant.
Two different follicular phases:
The duration of a dominant follicle to fully mature and release an egg will determine how long your follicular period lasts.
Long Follicular Phase
A longer follicular phase does not imply that you can’t get pregnant. It simply means that your cycle is longer. The possible reasons include:
- Natural time is taken by your body and has no other issues.
- Use of birth control
- Vitamin D deficiency
Short Follicular Phase
A shorter follicular phase can impact pregnancy prospects. For example, it occurs from 14 days on average to 10 days. It often occurs with age, particularly around menopause.
- FSH can increase, but LH does not spike like it used to.
- Follicles might mature too quickly, releasing eggs that are not ready for pregnancy.
What Happens After Ovulation?
Each month, 6-20 follicles reach an ideal phase, where they can be seen on an ultrasound. Among those, one mature follicle will release an egg to support pregnancy. Now, the follicle remains empty without an egg and turns into the corpus luteum to secrete hormones that support pregnancy. If pregnancy fails, this corpus luteum will disintegrate and shed along with the uterine lining and begin the menstrual cycle.
In IVF, these follicles are stimulated by hormonal treatment to release more eggs for the egg retrieval procedure. These can influence the corpus luteum, and high progesterone will be given for successful implantation and pregnancy, particularly in the case of using fresh or frozen embryos in the IVF process.
Can You Get Pregnant During the Follicular Phase?
Yes. There is a higher chance of getting pregnant during your follicular phase. The days leading up to and on the day of ovulation are ideal phases for having the greatest opportunity of becoming pregnant.
If you have intercourse during this time, the sperm can still be around when your egg is released because it lasts up to five days in your body. You can figure out which days you are most fertile by monitoring your cycle.
The Best Follicle Size During Pregnancy
To determine if an egg is ready for fertilisation, physicians take the size of the follicles instead of the egg itself. The tiny fluid-filled sacs in the ovaries called follicles hold the eggs and release one egg during each ovulation. For fertilisation, follicles should ideally range between 18 to 20 mm (1.8 to 2 cm) in size. Egg quality is as important as quantity; size is not a guarantee of pregnancy.
To improve the chances of a successful pregnancy, physicians generally take out eggs in IVF procedures when the follicles measure between 16 and 22 mm. Scheduling the retrieval of eggs at the right time is facilitated through regular monitoring.
Follicle Growth Rate in IVF and Natural Conception
Because of hormonal changes and medical procedures, follicle growth rates vary between natural conception and IVF.
- Natural Conception
- Follicles grow between 1 – 2 mm every day during a typical menstrual cycle.
- Before ovulation, only one dominant follicle grows to 18 – 20 mm in natural conception.
- Generally in the natural menstrual cycle, ovulation happens around day 14 of a 28-day cycle and is triggered by a rise in LH hormone.
- IVF
- In IVF, pregnancy hormone injections help follicles to grow faster during ovarian stimulation.
- Under medical procedures, more follicles are stimulated to grow typically increasing 1.5 – 3 mm per day.
- A trigger shot (hCG or GnRH agonist) is administered after the follicles are 16–22 mm in length to cause final maturation before egg retrieval.
Is It Possible to Increase Follicle Size in 2 Days?
No, never. It is not possible to increase the size of follicles in 2 days. It is a process, in which the size of the follicle can be influenced by hormonal changes and medications. You won’t increase your follicle size within 2 days.
There is no method or medication invented yet. So don’t trust anything blindly without knowing the scientific cause. Trust the process and believe in slow and steady medical procedures that support your physical and mental health.
Conclusion
Every individual’s journey is different, and patience along with the correct medical guidance can enhance the number of follicles. Doubling the size of follicles considerably in only two days isn’t possible, but adhering to the above-mentioned suggestions might be of help.
Small follicles may influence your pregnancy process. But with the help of assisted reproductive methods like IVF and IUI, pregnancy is achieved.
