Low sperm count or oligospermia, which is not to be confused with azoospermia (a sense of sperm in semen) is caused by numerous reasons, some of which are;
1. Variococele: This is characterized by the swelling of the veins which leads to the testicles getting drained. It leads to the production of low quality sperm. Good news is that it's reversible.
2. Ejaculation problems: This is also known as retrograde ejaculation and its characterised by some of the sperm flowing into the bladder during ejaculation instead of coming out of the tip of the penis. It can be cause by diabetes or surgery to the bladder, urethra or prostate.
3. Sperm attacking antibodies: Some antibodies might mistake sperm for harmful organisms and attack them, thus reducing the overall quality and number of sperm.
4. Hormonal imbalance: Yes, this also affects men too, not just women. Hormones produced by the hypothalamus, pituitary gland And the testicles produce hormones that are required in the production of sperm. If anything hinders the production of these hormones, sperm count may be reduced.
5. Certain medications: Certain medication like steroids, cancer medication and certain antibiotics can hinder or impair the production of sperm.
6 Alcoholism: Too much alcohol reduces testosterone levels
7. Tobacco use: Studies have shown that people who smoke almost always have lower sperm counts than those who don't.
8. Emotional stress: The body is one big organic machine and if it's CPU, the brain is under pressure (stressed) especially about infertility issues then it might end up interfering with the hormones required to produce sperm
Weight: Obesity can greatly affect sperm and hormone production in men.
There are numerous reasons why a man might have oligospermia but these ones are seemingly the most common reasons. As far as treatment goes, it depends on what's causing your oligospermia, but some treatments or remedies include
1. Surgery: This is mostly in the case of variococeles, a capable doctor can take on the procedure and close of the enlarged vein then redirect the blood through another vein.
2. Medication: There are medications that can be used to improve hormone levels and reduce inflammation.
3. Lifestyle changes: If you wanna have a baby then you're going to need to make some changes, lose some weight, drop the alcohol and quit smoking. It'll go a long way
I hope this helps.