Causes of Infertility

Female

Women need properly functioning ovaries, fallopian tubes and uterus to get pregnant and carry a child. When one or more of these three are affected, their conditions may cause infertility. Infertility in women is harder to diagnose than in men due to the many possible factors.

Ovulation disorders hinder or prevent the ovaries from releasing eggs. Examples include polycystic ovary syndrome (PCOS), a condition that causes ovaries producing too much testosterone, and hyperprolactinemia, when the body has too much prolactin (the hormone that stimulates breast milk production). Other underlying causes may include excessive exercise, eating disorders, injury or tumors.

Uterine or cervical abnormalities, include problems with the opening of the cervix or cervical mucus, or abnormalities in the shape or cavity of the uterus. Benign tumors in the wall of the uterus that are common in women may rarely cause infertility by blocking the fallopian tubes. More often, these fibroids distort the uterine cavity interfering with implantation of the fertilized egg.

Fallopian tube damage or blockage usually results from inflammation of the fallopian tube, resulting from pelvic inflammatory disease, usually caused by sexually transmitted infection, endometriosis or adhesions.

Endometriosis occurs when endometrial tissue implants and grows outside of the uterus, often affecting the function of the ovaries, uterus and fallopian tubes.

Primary ovarian insufficiency, also called early menopause, occurs when the ovaries stop working and menstruation ends before age 40. 

Pelvic adhesions are bands of scar tissue that bind organs after pelvic infection, appendicitis, or abdominal or pelvic surgery.

Male

Abnormal sperm production or function can be caused by a variety of problems, including genetic defects, undescended testicles and diabetes. Enlarged veins in the testes can increase blood flow and heat, affecting the number and shape of sperm.

Problems with the delivery of sperm may include premature ejaculation, semen entering the bladder instead of emerging through the penis, genetic diseases (such as cystic fibrosis), structural issues like blockage of the part of the testicle that contains sperm, or damage or injury to the reproductive organs. For men who have had a vasectomy and want to the return of fertility will need to either have the vasectomy reversed or have sperm retrieved through a surgical procedure for use in assisted reproductive techniques.

Overexposure to certain chemicals and toxins, such as pesticides, radiation, tobacco smoke, alcohol, marijuana, and steroids (including testosterone). In addition, frequent exposure to heat, such as in saunas or hot tubs, can elevate the testicular temperature, impairing sperm production.

Damage related to cancer and its treatment, including radiation or chemotherapy. Treatment for cancer can impair sperm production, sometimes severely. Removal of one testicle due to cancer also may affect male fertility.