Female Testosterone Levels – Prof Kruger explains

The IAAF recently made new rules for female testosterone levels for certain track and field events, which has put the topic of female testosterone levels in the lime light. Marie Hudson, from ‘Gesondheid op RSG‘, interviewed Prof Kruger from Aevitas Fertility Clinic, on the topic. You can listen to the Potgooi Podcast in Afrikaans, or read the summary article below.

Men produce more testosterone than women, but where does testosterone come from?

  • In males the testis and adrenal glands produce testosterone. Most men have a testosterone level of 8.7nmol/liter – 29.5nmol/liter.
  • In females the ovaries and adrenal glands produce small amounts of testosterone. In females the testosterone levels might lift slightly (within normal female parameters) during ovulation, to increase sexual drive. 99% of all females’ testosterone levels are below 3.08nmol/liter. The limit set for IAAF for certain items are 5nmol/liter.

What conditions are related to increased female testosterone levels?

If females have increased testosterone levels, above female parameters for testosterone, there are reasons for concern. A sudden increase in testosterone levels could be a sign of a tumour of the adrenal glands or ovaries.

Whereas a longstanding increase in testosterone levels could be due to Polycystic Ovary Syndrome (PCOS) or Congenital Adrenal Hyperplasia:

  • PCOS
    With PCOS, enlarged ovaries occur and therefore increased levels of testosterone exist.
  • Congenital Adrenal Hyperplasia
    Congenital Adrenal Hyperplasia is caused by an enzyme shortage, causing an increase in testosterone and decrease in cortisone. Typically, these women can present with severe acne, no menstruation, male pattern of hair growth and may appear to look more like a man. The condition can be effectively treated with cortisone, which would lead to a drop in testosterone level, increasing chances of successful pregnancy. Congenital Adrenal Hyperplasia could also have an early onset, at birth, where genitalia may have a male like appearance. In this instance, the baby would require immediate assistance with treatment through cortisone. If a condition such as Congenital Adrenal Hyperplasia is left untreated, it could be detrimental, as someone with decreased cortisone does not have sufficient cortisone levels to respond adequately during stress/shock situations. Therefore, their chances of dying in a situation where their body goes into shock (e.g. motor vehicle accident), is increased.
Increased female testosterone levels - Conginetal Adrenal Hyperplasia

Via StarG

Can a baby be born with XY chromosomes, without external male genitalia?

Yes, this is possible. This is called Androgen Insensitivity Syndrome. Androgen Insensitivity Syndrome is caused by a gene mutation. The gene, which is mutated, is supposed to change testosterone into Dihydrotestosterone (DHT). As a result, the external genitalia of the fetus cannot develop into that of a male. The testis develops internally and requires removal, as it can become cancerous.

Although women with Androgen Insensitivity Syndrome have a feminine appearance with normal breast development, they have no pubic- or axillary hair development. Even though testosterone production takes place through the testis, the testosterone is unable to fulfill its purpose because of it’s inability to change to DHT and DHT is responsible for hair development during puberty.

Furthermore, women with Androgen Insensitivity Syndrome have no uterus. They therefore do not menstruate, which is one of the main reasons these women end up at the doctor’s office. This being said, the only way they could have a baby of their own, is through the selfless act of a surrogate mother.

*Androgen Insensitivity Syndrome can be picked up early (infancy), but if not, it’s normally picked up during puberty, when patients notice the complete absence of a menstruation cycle. 

Is there a way to know if someone (e.g. Olympic athlete) has high testosterone levels due to Congenital Adrenal Hyperplasia or due the use of testosterone as anabolic steroid?

Yes. A test can be performed for 17 hydroxyprogesterone, which would be increased in someone with Congenital Adrenal Hyperplasia, but not with someone who has increased levels of testosterone due to doping.

Final message

There are normal ranges for female testosterone levels and therefore it is not unethical to test a professional athlete, as increased levels could lead to a competitive advantage. Whether testosterone levels are increased above normal parameters for females, due to doping or congenital abnormalities, it can be detrimental to the athlete’s health.