Oligospermia: what a low sperm count means
Oligospermia — also written oligozoospermia — means your sperm concentration falls below the WHO reference threshold of 16 million per millilitre. It is the most common abnormal semen analysis finding, and in most men it is partially reversible.
The ranges, and why they matter
Mild oligospermia is 10–16 million/mL, moderate is 5–10 million/mL, and severe is under 5 million/mL. Below about 1 million/mL the term used is usually cryptozoospermia — extremely few sperm, but not zero.
These bands matter because they shape what comes next. Mild and moderate oligospermia often respond to treating an underlying cause and to lifestyle change, and natural conception remains realistic. Severe oligospermia more often points toward a treatable medical cause worth investigating, and toward IUI or IVF/ICSI if conception does not happen.
One point that surprises most men: the WHO thresholds are not a pass/fail line for fertility. They are the 5th percentile of men whose partners conceived within 12 months. Being below them means you are in the bottom 5% of that fertile group — not that conception is off the table.
What causes it
Varicocele — enlarged veins in the scrotum — is the most common correctable cause, present in roughly 40% of men with infertility. It raises testicular temperature and impairs production. Surgical repair improves semen parameters in a majority of appropriately selected men.
Hormonal causes include low testosterone, thyroid disease, and elevated prolactin. Medications are a frequent and reversible culprit: testosterone replacement, anabolic steroids, finasteride, some antidepressants, and chemotherapy agents all suppress production.
Lifestyle and environmental factors — smoking, heavy alcohol use, obesity, heat exposure from hot tubs or a laptop held against the lap, and certain pesticide and solvent exposures — each have a measurable effect. Infections, prior undescended testicles, and genetic causes account for most of the rest.
What actually raises the number
Sperm take about 74 days to develop, so nothing you change today shows up in a semen analysis for roughly three months. That lag is the single most useful thing to know: judge any intervention by a retest at 3 months, not by how you feel.
The changes with the strongest evidence are stopping smoking, reducing alcohol, losing weight if overweight, avoiding scrotal heat, and stopping any testosterone or steroid use. Treating a varicocele or a hormonal disorder, where present, tends to produce larger gains than lifestyle change alone.
Antioxidant supplements — CoQ10, zinc, selenium, vitamin C and E, folate — show modest benefit in trials, with the clearest effect in men who have documented oxidative stress. They are worth trying and unlikely to hurt, but they are not a substitute for finding the underlying cause.
FAQ
Can you get someone pregnant with a low sperm count?
Yes. Low sperm count reduces the chance of conception in any given month but rarely eliminates it. Many men with mild to moderate oligospermia conceive naturally, sometimes after longer than average. The lower the count, the longer the average time to conception and the more likely that IUI or IVF/ICSI shortens the path.
What is considered a severely low sperm count?
Below 5 million sperm per millilitre is generally classed as severe oligospermia. Below roughly 1 million/mL is often called cryptozoospermia. Severe counts warrant hormone testing and a reproductive urology referral, since they more frequently have an identifiable and sometimes treatable cause.
How long does it take to improve sperm count?
Plan on three months. A full cycle of sperm production takes about 74 days, plus a couple of weeks in transit, so a semen analysis reflects your health from roughly three months ago. Retesting sooner than that will not show the effect of any change you have made.
Does a single low result mean I have oligospermia?
No. Sperm count varies substantially between samples in the same man, and a fever, illness, stress, or an unusually short or long abstinence period can move a result considerably. A diagnosis should rest on at least two samples taken a few weeks apart.