Causes of infertility are varied and can affect one or both partners. They may result from physical problems, hormone imbalances, lifestyle choices, environmental factors, genetics, or health conditions. Knowing the causes of infertility helps guide diagnosis, treatment, and emotional support. Since infertility can be stressful, identifying the root causes gives couples more clarity and control.
In women, causes of infertility fall into four main groups: ovulation problems, structural abnormalities, endometriosis, and age-related decline. Ovulation disorders are very common. They occur when eggs are not released properly. Conditions like polycystic ovary syndrome (PCOS), thyroid problems, and high prolactin levels disrupt normal ovulation. Women with these issues often have irregular or missing periods, lowering their chance to conceive.
Structural problems can block fertilisation or implantation. Blocked fallopian tubes, uterine fibroids, or congenital uterine defects may all cause infertility. Pelvic inflammatory disease (PID), often caused by untreated infections like chlamydia or gonorrhoea, can scar and block the tubes. Fibroids—non-cancerous uterine growths—can change the shape of the uterus and prevent an embryo from implanting or growing properly.
Endometriosis is another major cause in women. This condition makes uterine-like tissue grow outside the uterus. It causes inflammation, scarring, and adhesions that damage the ovaries, tubes, and uterus. Endometriosis also often causes chronic pelvic pain and contributes to unexplained infertility.
Causes of Infertility
Age plays a big role in female fertility. A woman’s supply of eggs, called ovarian reserve, drops as she gets older. After age 35, fertility declines faster and risks like miscarriage or genetic abnormalities rise. Delaying pregnancy for personal or career reasons means age-related infertility is increasingly common.
In men, infertility causes often relate to sperm problems. Low sperm count (oligospermia) or no sperm at all (azoospermia) greatly reduce the chance of fertilisation. Causes include genetic disorders like Klinefelter syndrome or infections such as mumps orchitis that harm the testes. Hormonal imbalances involving testosterone, LH, or FSH also lower sperm production.
Sperm quality matters too. Even with many sperm, poor movement or abnormal shape can stop sperm from reaching or fertilising the egg. Lifestyle habits like smoking, drinking, drug use, and chronic stress harm sperm quality. Exposure to heat from hot tubs or tight clothing may also reduce sperm production.
Obstructions in the male reproductive tract cause infertility as well. Varicoceles (swollen scrotal veins), blockages in sperm ducts, or previous vasectomy can stop sperm release. Surgery or sperm retrieval might be needed in these cases. Past infections and sexually transmitted diseases can also cause blockages.
Both partners’ lifestyle and environment play a role in infertility. Poor diet, obesity, too much caffeine, inactivity, and exposure to toxins like pesticides or heavy metals affect fertility. Smoking lowers ovarian function in women and sperm count in men. Excessive alcohol disrupts hormones and reproduction. Recreational drugs such as marijuana and cocaine also harm sperm and ovulation.
Causes of Infertility
Medical treatments and medications can impact fertility. Chemotherapy and radiation often damage reproductive organs and hormone glands. Some drugs for depression, high blood pressure, or epilepsy can reduce sperm or ovulation. Fertility preservation with egg or sperm freezing may be advised before such treatments.
Chronic illnesses and autoimmune diseases complicate fertility too. Lupus, diabetes, or celiac disease cause inflammation and hormone changes. The immune system may attack sperm or embryos, making fertilisation or implantation harder.
About 10–15% of infertility cases remain unexplained after tests. Couples with unexplained infertility can still benefit from treatments like intrauterine insemination or IVF, which may bypass hidden barriers.
Psychological stress is not a direct cause but can worsen infertility. Long-term stress changes hormones controlling ovulation and sperm production. It also lowers sex drive and leads to unhealthy habits. Stress both results from and contributes to fertility problems, creating a tough cycle.
In summary, causes of infertility are complex and involve biological, environmental, and lifestyle factors. Both men and women can be affected. Often, more than one cause exists. Early diagnosis and personalised treatment offer the best chance of success. As knowledge of these causes improves, so do options for prevention, care, and support.
