Male Factor Infertility

How male fertility is assessed

Both partners should be evaluated at the same time. For the male partner, this includes:

1. History: childhood conditions (undescended testes), puberty, past surgery, infections, cancer treatment, medicines, testosterone or anabolic steroid use, heat exposure, smoking, alcohol, cannabis, and sexual function.
2. Physical examination: testicle size and consistency, whether the vas deferens can be felt on both sides, and a check for a varicocele (enlarged veins in the scrotum).
3. Semen analysis: at least one, usually two, collected after 2 to 7 days without ejaculation.

Semen analysis results explained

The World Health Organization (2021) lower reference limits are the values below which only about 5% of fertile men fall:

Important caveats:

• Results vary a lot from sample to sample. One abnormal result needs repeating.
• Values above the limits do not guarantee fertility, and values below them do not mean pregnancy is impossible.
• Fever or illness in the previous 3 months can lower sperm counts, because sperm take about 74 days to develop.
• Low counts with low motility and abnormal shape together are called OAT (oligoasthenoteratozoospermia).

Further tests after an abnormal result

• Hormone tests: testosterone (morning), FSH and LH. High FSH suggests the testes are not making sperm well. Low FSH and LH point to a pituitary problem.
• Genetic tests: a karyotype (for Klinefelter syndrome) and Y chromosome microdeletion testing for men with very low counts or azoospermia. CFTR (cystic fibrosis gene) testing if the vas deferens is absent.
• Post-ejaculation urine test: for low volume, to check for retrograde ejaculation into the bladder.
• Scrotal or transrectal ultrasound: when examination is difficult or a blockage is suspected.
• Sperm DNA fragmentation and antisperm antibody tests in selected cases.

Causes

Problems making sperm (testicular)

• Varicocele: present in about 15% of all men and about 35% to 40% of men with infertility
• Undescended testes (cryptorchidism), even if corrected in childhood
• Genetic: Klinefelter syndrome, Y chromosome microdeletions
• Testicular damage from mumps after puberty, injury, torsion, chemotherapy or radiation
• Unknown cause in many men (idiopathic)

Hormone problems

• Testosterone or anabolic steroid use: shuts down the brain's signals to the testes and can stop sperm production completely. A very common, reversible cause.
• Pituitary or hypothalamic disease, high prolactin, severe obesity
• Hypogonadism from other causes

Blockage or delivery problems

• Vasectomy
• Congenital absence of the vas deferens (linked to cystic fibrosis genes)
• Blockage after infection or surgery
• Retrograde ejaculation (often after prostate surgery, or with diabetes)
• Erectile dysfunction or ejaculation problems

Lifestyle and environment

Smoking, heavy alcohol, cannabis, obesity, heat exposure (hot tubs, laptops on the lap), some medicines (sulfasalazine, some chemotherapy, opioids) and occupational chemicals can lower sperm quality.

Azoospermia: obstructive vs non-obstructive

About 1% of all men and 10% to 15% of infertile men have no sperm in the ejaculate.

• Obstructive: sperm are made normally but cannot get out. Usually normal FSH and testicle size. Often fixable with surgery (vasectomy reversal) or sperm retrieval.
• Non-obstructive: the testes make very few or no sperm. Often high FSH and small testes. Micro-TESE (microsurgical sperm extraction) finds sperm in about half of men.

Treatment

Treating the cause

• Stop testosterone and anabolic steroids. Sperm production often recovers within 6 to 12 months, sometimes longer.
• Varicocele repair (microsurgery or embolization) for men with a palpable varicocele and abnormal semen. It improves semen quality in many men.
• Hormonal treatment: hCG and FSH injections for pituitary causes, which can restore sperm production. Clomiphene or anastrozole are sometimes used off-label.
• Vasectomy reversal or reconstruction of blockages.
• Medicines for retrograde ejaculation, and treatment of erectile dysfunction.

Lifestyle measures

Stop smoking, limit alcohol, avoid cannabis, reach a healthy weight, avoid hot tubs and saunas, and keep laptops off the lap. Changes take about 3 months to show in a semen sample.

Assisted reproduction

• Intrauterine insemination (IUI): washed sperm placed in the uterus. Works best with mild abnormalities.
• IVF with ICSI (intracytoplasmic sperm injection): a single sperm is injected into each egg. It allows pregnancy with very low counts or sperm surgically retrieved from the testis.
• Donor sperm when no sperm can be found.

Male infertility and health

An abnormal semen analysis can be a sign of other health problems. Studies link male infertility with higher rates of testicular cancer, metabolic disease and earlier death. The AUA recommends that men with infertility have a general health evaluation. For signs to look for before testing, see male infertility.

Frequently asked questions

What is a normal sperm count?

According to WHO 2021 values, a concentration of at least 16 million sperm per ml, or at least 39 million per ejaculate, is within the reference range. Lower counts reduce the chance of natural conception per month but do not rule it out.

Can male factor infertility be fixed?

Often, yes. Stopping testosterone or steroids, repairing a varicocele, treating hormone problems or reversing a vasectomy can restore fertility. When the cause cannot be corrected, IVF with ICSI can achieve pregnancy with very few sperm, including sperm retrieved from the testicle.

How long does it take to improve sperm count?

Sperm take about 74 days to develop and another couple of weeks to travel, so changes from treatment or lifestyle take around 3 months to appear in a semen analysis. Recovery after stopping testosterone can take 6 to 12 months or more.

Does testosterone therapy cause infertility?

Yes, it can. Taking testosterone suppresses the hormones that drive sperm production, often lowering the count to zero. Men who want children should not use testosterone. Alternatives exist for low testosterone that preserve fertility.

What causes low sperm motility?

Low motility can be caused by varicocele, infections, smoking, heat exposure, antisperm antibodies, long abstinence periods, and genetic defects in the sperm tail. Often no single cause is found. Repeat testing confirms the result before treatment decisions.