Asthenozoospermia & Teratozoospermia: Sperm Motility and Shape

Understanding Two Common Semen Analysis Findings

A semen analysis is one of the first tests in a fertility work-up, and two of the most common abnormal findings are asthenozoospermia (sperm that do not move well) and teratozoospermia (sperm with an abnormal shape). They often occur together with a low count, and they can feel worrying when you first see them on a report. In my experience they are also among the more approachable causes of male infertility, because the cause can often be identified and there are several routes to a pregnancy.

This article is for education only and does not replace a consultation with a qualified fertility specialist or urologist.

What Do These Terms Mean?

Asthenozoospermia: reduced motility

Sperm must swim through the cervix, uterus and fallopian tube to reach an egg. Motility is graded as:

• Progressive: moving forward in a straight line or large circles
• Non-progressive: moving, but not getting anywhere
• Immotile: not moving at all

Reference limits come from the World Health Organization and are updated periodically. Under the fifth edition (2010), the lower limits were 40% total motility and 32% progressive motility. The sixth edition (2021) uses slightly different values (about 42% total and 30% progressive). Laboratories differ in which edition they follow, so read your result against your own report's reference range. Asthenozoospermia means motility below the lower limit.

Teratozoospermia: abnormal shape

A normal sperm has an oval head, a midpiece packed with energy-producing mitochondria and a long tail. In teratozoospermia a high proportion have defects in the head (round, small or double), midpiece or tail (short, bent or coiled). Strict-criteria morphology values are low even in fertile men. The WHO lower reference limit is 4% normal forms, so a report showing 96% "abnormal" is often not as alarming as it sounds.

When they occur together

Low count, poor motility and abnormal shape together is called OAT (oligoasthenoteratozoospermia). To understand the count side, see low sperm count causes and treatment, and to read the whole report see understanding a semen analysis report.

What Causes Poor Motility or Shape?

• Varicocele. Enlarged scrotal veins cause blood to pool and raise temperature, which harms sperm production and movement. See varicocele and male fertility.
• Infections and inflammation of the prostate, epididymis or urethra
• Hormonal problems, such as low testosterone or abnormal FSH and LH signalling
• Oxidative stress, when harmful reactive oxygen molecules overwhelm the semen's natural antioxidants and damage the sperm membrane and its energy-producing mitochondria
• Heat exposure from frequent hot baths, saunas, tight clothing or a laptop kept on the lap
• Smoking, heavy alcohol use, drugs and environmental toxins. See smoking, alcohol and caffeine and fertility
• Genetic causes, including inherited defects in the sperm tail structure, in a small number of men
• Long illness, fever, obesity and certain medicines

How It Is Diagnosed

Semen analysis

• Abstain from ejaculation for two to seven days before the test.
• The sample should be analysed promptly and kept at body temperature if collected at home.
• Because semen quality naturally varies, a single abnormal result is usually repeated after a few weeks.

Examination and blood tests

A doctor may examine the testicles for a varicocele and check for infection. Hormone tests such as testosterone, FSH, LH and prolactin are added when the picture suggests it.

Sperm DNA fragmentation

A standard analysis shows count, movement and shape, but not the quality of the DNA inside the sperm. A DNA fragmentation test may be considered after recurrent miscarriage, repeated failed IUI or IVF, unexplained infertility with a normal semen analysis, or when a varicocele or heavy exposure to toxins is present.

How Poor Motility and Shape Affect Conception

Only sperm with strong forward movement get through cervical mucus and reach the fallopian tubes. Abnormally shaped sperm may also be less able to attach to and penetrate the egg. A diagnosis therefore lowers the chance of conceiving per cycle; it does not mean pregnancy is impossible.

See a specialist after one year of trying (or six months when the woman is over 35). If there is a history of undescended testicles, testicular injury, hernia repair or infection, or if the semen result is very abnormal, get evaluated earlier.

Treatment

Treatment is chosen according to the cause and the couple's overall picture, including the female partner's age and tests.

Treat the cause

• Varicocele repair (varicocelectomy) may improve semen parameters in some men when a clinically significant varicocele is the likely cause. Improvement is not guaranteed, and I weigh it against the female partner's age.
• Infections are treated with appropriate antibiotics.
• Hormonal problems may be treated with medicines chosen after specialist assessment.

Lifestyle changes

• Wear loose, breathable underwear and avoid prolonged heat on the groin.
• Stop smoking, cut back on alcohol and avoid recreational drugs.
• Keep a healthy weight and exercise moderately without overdoing endurance training.
• Eat a varied diet. See foods and habits that improve sperm health and lifestyle factors in male fertility.

Antioxidants

Nutrients such as CoQ10, vitamins C and E, zinc, selenium and L-carnitine are often used because oxidative stress is a common finding. Evidence for benefit is mixed, so they are best used under medical guidance rather than in a random combination of supplements.

Fertility Treatments

IUI for mild problems

In intrauterine insemination, the semen is washed in the laboratory to separate the best-moving sperm, which are placed directly into the uterus around ovulation. This bypasses the cervix. It is mostly suitable when the abnormality is mild and the woman's tubes are open. See the IUI treatment process.

IVF with ICSI for moderate to severe problems

In ICSI, an embryologist selects a single sperm and injects it directly into a mature egg, so the sperm's ability to swim or penetrate the egg is no longer a limiting factor. It is typically advised when motility is severely reduced, when sperm shape is very abnormal, or after failed IUI or fertilisation in earlier cycles. Learn when ICSI is recommended, read about the ICSI cost in Chennai and see my ICSI treatment service.

Sperm selection under magnification matters for ICSI. I work with the embryologists on sperm and embryo selection, because the quality of the laboratory step affects your outcome.

If no sperm is seen in the ejaculate

If motile sperm are absent or none are found, see azoospermia treatment options and TESA and micro-TESE explained.

Working Out the Best Route

The right treatment depends on the semen parameters, DNA fragmentation, the woman's age and ovarian reserve, and how long you have been trying. If you have an abnormal semen report and want a clear plan, learn more about my male fertility care or book a consultation with Dr. Rukkayal Fathima.

Medical disclaimer: this article is general information. Diagnosis and treatment depend on individual test results. Please consult a qualified fertility specialist or urologist.