Chemotherapy can significantly affect your fertility. But there are steps you can take to help preserve your sperm health in case you want to have a child later in life after chemotherapy.

Chemotherapy is often an effective treatment for many types of cancer.

But chemotherapy has side effects. Infertility is among the most common side effects in all people. Fewer than 30% of males who undergo chemotherapy return to their typical sperm health and testicular function.

Read on to learn more about how chemotherapy can cause male infertility and what you can do if you’re concerned about not being able to conceive after chemotherapy treatments.

Chemotherapy affects many types of fast-growing cells in your body, including cancer cells, which can sometimes grow at an extremely fast rate. This is why chemotherapy is such an effective treatment for some kinds of cancer.

But chemotherapy also affects fast-growing reproductive cells, including those that help your body produce sperm and reproductive hormones such as testosterone.

Chemotherapy can reduce the production of sperm

Chemotherapy medications are known to damage sperm as well as germ cells that eventually grow into sperm.

Chemotherapy treatments called alkylating drugs are especially likely to cause short-term and long-term decreases in sperm production. These drugs are gonadotoxic, which means they damage testicular cells and germ cells, lowering sperm production over time.

Chemotherapy reduces sperm motility

Chemotherapy treatments can also have gonadotoxic effects that reduce sperm motility, which is sperm’s ability to move through semen to fertilize an egg.

Vinca alkaloids such as vincristine and vinblastine are specifically linked to reduced sperm motility when they’re used to treat cancers like lymphoma and leukemia.

Chemotherapy changes sperm’s genetic makeup

Chemotherapy treatments can damage sperm DNA, changing the genes that sperm carry.

This can reduce your fertility and increase the risk that sperm will fertilize eggs with mutated DNA, introducing genetic conditions to any children born from those eggs.

Chemotherapy can reduce testosterone production

Chemotherapy is known to reduce testosterone production because of its gonadotoxic effects on the male reproductive system and disruptions to hormone balance.

You’re more likely to experience reduced testosterone production if you’re treated for testicular cancer with chemotherapy and orchidectomy (the removal of one or both testicles).

Chemotherapy may lead to erectile dysfunction

Some cancer treatments, such as chemotherapy (especially for prostate cancer), are known to result in erectile dysfunction (ED).

This is because cancer treatments can damage blood vessels and nerves in your penis that are involved in helping you become aroused and filling your penis with blood during an erection.

The type of drug, the dose you’re taking, and the type of cancer you have all factor into how chemotherapy affects your fertility.

Types of chemotherapy drugs

Chemotherapy drugs that have been linked to male infertility include:

  • alkylating agents that damage DNA inside cells, such as cisplatin (Platinol) and busulfan (Myleran, Busulfex)
  • plant alkaloids that stop cells from dividing, such as vincristine (Oncovin) and vinblastine (Velban)
  • antitumor antibiotics that unravel DNA inside cells, such as doxorubicin (Adriamycin, Doxil, Caelyx, Doxorubicin Hydrochloride, Doxorubicin HCL, Rubex, Myocet)

Dosage

Chemotherapy dosage can also make a difference in whether your fertility is affected in the short term or the long term.

Low doses of chemotherapy may not affect your fertility. But the higher the dose, the more likely it is that you may experience infertility.

High doses of chemotherapy are especially likely to reduce long-term male fertility in people who are treated for cancer before puberty.

Type of cancer

Cancers that affect your reproductive system, such as testicular cancer and prostate cancer, are more likely to result in infertility, especially when combined with chemotherapy treatments.

An older 2010 review also suggests that lymphoma and leukemia may have a greater chance of causing male infertility.

Consider talking with a fertility specialist about the following steps you can take if you’ve received a cancer diagnosis and want to preserve your sperm before chemotherapy. Your oncologist can make a referral.

Bank your sperm

Preserving your sperm at a sperm bank can help keep your sperm intact until you’re ready to conceive a child.

Cryopreservation is a common option for sperm banking. This process involves freezing sperm for a long period so that they stay alive and are viable for fertilizing an egg when they’re thawed.

Wait to try to have a baby

After chemotherapy, it can take some time for your sperm to regenerate or become healthy enough to fertilize an egg.

There’s little evidence on exactly how long you should wait. Some medical professionals recommend waiting 2–5 years after chemotherapy has ended and your cancer has been successfully treated before trying to conceive again.

Here are some of the most frequently asked questions about chemotherapy and fertility.

Does chemotherapy as a child cause male infertility?

Undergoing chemotherapy treatment as a child can cause male infertility.

An older 2013 study suggests that up to 43% of people who receive chemotherapy treatment for cancer as children may experience complications from disruptions to their endocrine systems, including those related to sexual function that can affect fertility.

What percentage of men are infertile after chemo?

Some research cited in a 2019 review suggests that about 24% of males who receive chemotherapy have low sperm count (oligospermia) or no sperm at all (azoospermia) for many years after treatment.

How can you increase sperm count after chemotherapy?

Waiting 2–5 years after chemotherapy can give your body the time it needs to produce new, healthy sperm. You can request a medical evaluation at any time.

Other possible ways to naturally increase your sperm count include:

Before you start chemotherapy treatments, you can talk with a doctor about your fertility. They can help you understand your options and outlook.