Question

Give an account of infertility in human beings.

Answer 1

In humans, infertility is the inability to become pregnant/impregnate or carry a pregnancy to full term.

The following are common causes of infertility in men:

1. Low sperm count: The man ejaculates a low number of sperm. A sperm count of under 15 million is considered low. Around one-third of couples have difficulty conceiving due to a low sperm count.
   
2. Low sperm mobility (motility): The sperm cannot "swim" as well as they should to reach the egg.
   
3. Abnormal sperm: The sperm may have an unusual shape, making it harder to move and fertilize an egg.
   
4. Abnormal semen may not be able to carry the sperm effectively. This can result from testicular infection, cancer, undescended testicle, a varicocele, or varicose vein in the scrotum etc.
   

Infertility in women can also have a range of causes. Some medical conditions can affect fertility.

• Ovulation disorders:
  

1. Premature ovarian failure: The ovaries stop working before the age of 40 years.
   
2. Polycystic ovary syndrome (PCOS): The ovaries function abnormally and ovulation may not occur.
   
3. Hyperprolactinemia: If prolactin levels are high, and the woman is not pregnant or breastfeeding, it may affect ovulation and fertility.
   
4. Poor egg quality: Eggs that are damaged or develop genetic abnormalities cannot sustain a pregnancy. The older a woman is, the higher the risk.
   
5. Thyroid problems: An overactive or underactive thyroid gland can lead to a hormonal imbalance.
   
6. Chronic conditions: These include AIDS or cancer.
   

• Other factors:
  

1. Age: The ability to conceive starts to fall around the age of 32 years.
   
2. Smoking: Smoking significantly increases the risk of infertility in both men and women.
   
3. Diet: A lack of folic acid, iron, zinc, and vitamin B-12 can affect fertility.
   
4. Sexually transmitted infections (STIs): Chlamydia can damage the fallopian tubes in a woman and cause inflammation in a man's scrotum. Some other STIs may also cause infertility.
   
5. Exposure to some chemicals, alcohol, even obesity, and overeating.