9 Things That Can Cause a Low Sperm Count

Oligospermia (low sperm count) is a common reason for a couple’s infertility. In fact, male infertility is an issue in about 50% of couples who can’t get pregnant. If you and your partner are having trouble getting pregnant, it’s important that you both get checked. Low sperm count could be a factor.

A healthcare provider can help you figure out if you have a low sperm count, and why. Simple tests can help make the diagnosis and tell if the cause is reversible. Let’s review some of the most common reasons for a low sperm count and when you should talk with your healthcare provider.

What does low sperm count mean?

Oligospermia, or a low sperm count, means that you have less than 15 million sperm per mL of ejaculate. If you have a low sperm count, it may affect your fertility and decrease your chances of getting your partner pregnant. 

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One study found that a sperm count of about 50 million/mL or more was a reliably fertile sperm count. However, it’s still possible for you to get your partner pregnant with a low sperm count. 

Sometimes, even though the sperm count is more than 50 million, there’s still a chance the sperm won’t cause a pregnancy. That’s because there are other factors as well. In addition to the number of sperm, it’s important to make sure that the sperm is shaped correctly and moving well.

What causes a low sperm count?

In general, you need the right balance of hormones, proper anatomy, and overall good health to ejaculate with a sperm count in the normal range. Here are some of the most common causes of low sperm count.

1. Injury

Injury to the reproductive organs can decrease the sperm count. This may be in the form of: 

• Surgeries (like hernia repair, surgery on an undescended testicle)

• Infections (like sexually transmitted infections, and mumps virus)

• Trauma (an injury by force)

These types of injuries can cause damage or inflammation that decrease the number of sperm made or block their path to the penis.

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2. Genetic conditions

Certain genetic conditions can also lower your sperm count. People with Klinefelter syndrome have an extra X chromosome and often have a low or absent sperm count. Abnormalities of the Y chromosome can also affect sperm count.

3. Chronic disease

Low sperm count has also been linked to chronic diseases. Conditions that can decrease sperm count include:

• Insulin resistance

• Metabolic syndrome

• Diabetes

• High cholesterol

• Hypertension

Those who have high stress and anxiety or are being treated for hypertension may also have a lower sperm count.

4. Cancer treatment

If you have a history of cancer of any type with chemotherapy treatment, you may be at risk for a low sperm count. Certain chemotherapy medications can permanently decrease your sperm count. Or they can stop you from making sperm altogether. But in some cases, your sperm production can improve over time. 

Common chemotherapy medications that may affect sperm count include:

• Carboplatin

• Chlorambucil

• Cisplatin

• Cyclophosphamide

• Doxorubicin

• Procarbazine

• Vincristine

The risk of damage increases with high doses or combination treatments. Adding radiation treatment to the chemotherapy may also increase the risk of decreased sperm count.

5. Structural issues

Any structural or functional problem of the testicles or pathway the sperms have to travel could lead to a low sperm count. This could include issues with the epididymis, vas deferens, or ejaculatory ducts.

Common conditions involving the testicle that can decrease sperm count include: 

• Varicocele (enlargement of the veins around the testicle)

• Testicular torsion (twisting of the testicles)

• Undescended testicle (testicle that hasn’t moved down into the scrotum before birth)

6. Hormonal imbalances

Many hormones must work together to produce a typical number of healthy sperm. Any change in their balance can reduce sperm production. Most of the hormones that affect sperm count are made in the hypothalamus or pituitary gland. Conditions affecting these hormones include: 

• Pituitary gland tumors

• Congenital adrenal hyperplasia

• Cushing’s syndrome

• Excess testosterone exposure

• Excess estrogen exposure

• Chronic steroid use (like prednisone)

7. Medications for low testosterone

Using testosterone replacement for low testosterone levels can also lower the sperm count. Testosterone can prevent the release of hormones from the hypothalamus and pituitary gland that you need to make sperm.  

Although it works to improve sexual function, testosterone can have a negative impact on your fertility. If you and your partner want to become pregnant in the next 6 to 12 months, you shouldn’t use testosterone replacement therapy. 

8. Vasectomy

A vasectomy interrupts the pathway for sperm to make it into the ejaculate. It‘s an effective form of permanent birth control because it works to reduce the sperm count. Keep in mind, the body will still make a regular amount of sperm after a vasectomy. But it just gets reabsorbed in the body rather than making its exit during ejaculation.  

9. Lifestyle choices

Certain habits and lifestyle choices can affect your sperm count. Things that can disrupt regular sperm production include:

• Alcohol overuse

• Smoking tobacco

• Anabolic steroid use (to build muscle)

• Substance abuse 

What are the signs of a low sperm count?

Low sperm count doesn’t really have any symptoms that you would notice. Most people who have low sperm count find out when their partner doesn’t get pregnant after both decide to try. 

If the low sperm count is caused by another medical condition, medication, or trauma, you might have symptoms related to those conditions. 

How do doctors diagnose low sperm count?

A semen analysis will allow your healthcare provider to diagnose low sperm count. You’ll have to provide a semen sample by masturbating and ejaculating into a container. The volume of ejaculate is measured in the lab and the semen is examined under a microscope. The sperm will be checked for overall number, shape, and how well they move.

How can you increase your sperm count?

One of the first steps to improve your sperm count is to address any lifestyle factors that may be affecting how much sperm you’re making. Some of the changes you might want to try are:

• Quit smoking.

• Avoid substance abuse.

• Eat more antioxidant-rich foods and avoid trans-fats.

• Increase physical activity.

In addition to lifestyle changes, medical treatments may be used to improve sperm count, including:

• Fertility medications like Gonal-F, HCG

• Antibiotics to treat any infections that are present

• Surgery to remove any abnormal growths or blockages

Why trust our experts?

Written by:

Frank Schwalbe, MD

Frank Schwalbe, MD, is an assistant professor of anesthesiology at the Yale School of Medicine. He has practiced anesthesiology for 30 years.

Edited by:

Karla Robinson, MD

Karla Robinson, MD, is a medical editor for GoodRx. She is a licensed, board-certified family physician with almost 20 years of experience in health through varied clinical, administrative, and educational roles.

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