How Does Testosterone Replacement Therapy (TRT) Affect Fertility?

Testosterone replacement therapy (TRT) can help men with low testosterone to have more energy, focus more easily, lose weight and build muscle, but what is the effect of TRT on fertility. There are some side effects that men considering this type of therapy need to take into account. In particular, men who want to have children in the future need to be aware of the possibility of TRT suppressing their fertility.

Naturally produced testosterone is important for male fertility, but other hormones also have essential roles to play. Although TRT can normalize testosterone levels, it does not improve fertility because it suppresses the pathway for managing the levels of the other hormones involved in testicular stimulation. In fact, TRT can even decrease sperm production and therefore negatively affect fertility.

TRT & Fertility

Male fertility is controlled by a part of the brain known as the hypothalamus and the pituitary gland. The hypothalamus produces a chemical called gonadotropin-releasing hormone (GnRH), which sends a message to the pituitary gland to tell it to produce two important fertility hormones, which are known as luteinizing hormone (LH) and follicular stimulating hormone (FSH).

FSH is responsible for triggering spermatogenesis – the process of creating sperm cells. FSH causes cells in the testes to divide via meiosis to create sex cells, each containing only one half of a normal set of chromosomes. These cells mature into sperm cells, which can combine with a female egg to create a new human being with a full set of DNA. Meanwhile, LH causes the testes to produce testosterone and this too has a hand in promoting sperm production.

While TRT increases testosterone levels, and reduces some of the symptoms associated with hypogonadism, it decreases the body’s production of LH and FSH. This is because when the brain detects that testosterone levels have increased, it will dial down the production of GnRH. The result is that the pituitary gland no longer produces FSH and LH at normal levels, so sperm production also declines. A lower sperm count means that a man’s chance of impregnating his partner will be lower.

This cannot be relied upon to render a man “infertile”, and should not be viewed as an alternative to contraception.

Preserving Fertility While Using Testosterone

For men who want to father children, the decision over whether or not to have testosterone replacement therapy is a difficult one. On the one hand, TRT can bring massive improvements to a man’s quality of life, by reducing fatigue, aiding concentration, and restoring his sex drive to its usual level. On the other hand, there is a risk that TRT will adversely affect fertility.

One solution is to bank some sperm before starting TRT. Sperm can be stored at a sperm bank for many years and used to impregnate the man’s partner when the right time comes. Couples have successfully conceived children using sperm that has been frozen for up to 12 years, so this can be a good option for men who do not want children right now but want to keep the option open for the future.

Studies have shown that sperm count often returns to normal several months after stopping testosterone replacement therapy. However, for men who do not want to risk not being able to father a child, banking sperm before starting TRT makes sense. Another option is to delay TRT until a child has been conceived. This is not an option for everyone, but it can be a possibility for couples who are ready to consider starting a family.

A short-term option for some men would be the use of hCG (human chorionic gonadotropin) for TRT. The hormone hCG mimics LH in the body without suppressing the levels of GnRH or FSH and therefore may actually have a positive effect on fertility. While this is not the best way to maintain normal testosterone levels, it is something that we would be happy to discuss with you if maintaining fertility is a concern for you or your family.

Making the right decision for you and your family is of utmost importance. There aren’t a lot of guarantees, but reasonable measures can be taken to lessen the negative impact that exogenous testosterone and TRT has on fertility.

Sources
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3635615/
http://www.spermbankdirectory.com/faqs/frozen-sperm-efficacy.htm