Are Follicle Sizes Related to the Chance of Conceiving?

Follicles play a critical role in conception, and the size of the follicle does matter. Carry on reading to learn more

By Nancy Amon
Edited by Taj Schlebusch

Published October 30, 2021.

Follicles are an essential aspect of having a baby, and the size and maturity of the follicle also account for fertility. The follicle houses the ovum (egg), and when it's matured, the egg is released. Thus, having the right follicle size for conceiving matters. Let's learn more about follicle size and why this is so important.

Does Follicle Size Affect The Chance Of Pregnancy?

Yes, the follicle size affects pregnancy. Follicles can differ in size, but the simple answer is the bigger the follicle, the better the egg quality. However, this may not apply to polycystic ovary syndrome (POCS), ovarian tumors, and cysts.

Smaller follicles mean fewer eggs in reserve and also lower egg quality. Egg size also differs, but the minimum egg size to get pregnant is about 2.5-5cm long, 1.5-3cm wide, 0.6-1.5cm thick.

The follicle sizes on the left ovary may differ from the right ovary. Still, either way, one cannot control whether it's the right or left follicle that produces the queen egg for conceiving, as there is a natural rotation that takes place.

Chance Of Conception For Different Follicle Sizes

Follicle sizes differ, and in this list below, you'll see the optimum follicle size for conceiving and other sizes with less chance of conception.

  • 16mm diameter follicle has a 31% chance of implantation success (58 follicles)
  • 15mm diameter follicle stands an 8% chance of implantation (74 follicles)
  • 14mm diameter follicle is only 1 mm less but has 4% fewer chances of successful implantation. (97 follicles)
  • 13 mm diameter follicle has 0% implantation chance (123 follicles)

In the case of 16mm and up, there are also higher chances of multiple pregnancies (multiple fetal hearts). It is also the size follicle that is big enough and has a good chance for conceiving ( an estimated 74% chance).

More follicles may not necessarily mean successful fertilization. For fertilization to be successful, the quality of the egg is essential to sustain the process.

Can You Increase Follicle Size?

If the egg quality is good and the follicle count is low, then IVF (in-vitro fertilization) treatment can help increase follicle count and increase the follicle size to get pregnant.

There are many ways to increase the chances of getting pregnant; these include IVF, as mentioned, and Intrauterine Insemination (IUI). These infertility treatments have been shown to help many couples successfully conceive.