CAUSES OF INFERTILITY IN MEN AND WOMEN
Causes of infertility in women include:
- Ovulation disorders: Regular ovulation is vital for women to conceive naturally. There are many disorders that may impact the ability for a woman to ovulate normally. The most common disorders impacting ovulation include polycystic ovary syndrome (PCOS), hypogonadotropic hypogonadism (from signaling problems in the brain), and ovarian insufficiency.
- Maternal age: Age-related infertility is one of the most common causes of female infertility. As women age, egg numbers decrease at a rapid rate, and the egg quality, or the likelihood of an egg being genetically normal, decreases as well.
- Tubal occlusion (blockage): In tubal occlusion, an ovulated egg is unable to be fertilized by sperm or to reach the endometrial cavity. If both tubes are blocked, then in vitro fertilization (IVF) is required. Some types of tubal blockage can affect implantation even after embryo transfer via IVF and may require surgery.
- Endometriosis: Endometriosis is caused by cells from the lining of the uterus found in various locations in the abdomen and pelvis, commonly on the ovaries.
- Uterine fibroids: Fibroids are benign growths in the uterus, which are very common (approximately 40% of women have them them). However, the presence of fibroids alone doesn’t necessarily cause infertility or predispose a woman to pregnancy loss. Fibroids that distort the uterine cavity have an impact on the ability of an embryo to implant and should be removed surgically. The impact of fibroids located elsewhere in the uterus are controversial and do not always require surgery.
- Endometrial polyps: Endometrial polyps are finger-like growths in the uterine cavity arising from the lining of the uterus, called the endometrium. Large polyps or multiple polyps can interfere with reproduction by interfering with the ability of embryo to implant and should be removed. The impact of small or single polyps is more controversial.
- Unexplained: Even after a full fertility work-up, for one in five couples an exact cause of infertility cannot be determined. Unexplained infertility is not the same thing as having no explanation, but rather reflects the fact that the tests performed have been normal. There is always an explanation! Often, in vitro fertilization (IVF) can reveal abnormalities in egg quality, sperm function, or embryo development that would not have been determined from standard testing. Thankfully, even when the cause of infertility is not known, various fertility treatments can eventually lead to delivery of a healthy baby.
Causes of infertility in men include:
- Varicocele: A varicocele is a swelling of the veins that drain the testicle. It’s the most common reversible cause of male infertility. Although the exact reason that varicoceles cause infertility is unknown, it may be related to abnormal testicular temperature regulation. Varicoceles result in reduced quality of the sperm.
- Infection: Some infections can interfere with sperm production or sperm health or can cause scarring that blocks the passage of sperm. These include inflammation of the epididymis (epididymitis) or testicles (orchitis) and some sexually transmitted infections, such as gonorrhea.
- Ejaculation issues. Retrograde ejaculation occurs when semen enters the bladder during orgasm instead of emerging out the tip of the penis. Various health conditions can cause retrograde ejaculation, including diabetes, spinal injuries, medications, and surgery of the bladder, prostate or urethra.
- Antibodies that attack sperm. Anti-sperm antibodies are immune system cells that mistakenly identify sperm as harmful invaders and attempt to eliminate them.
- Tumors. Cancers and nonmalignant tumors can affect the male reproductive organs directly, through the glands that release hormones related to reproduction, such as the pituitary gland, or through unknown causes. In some cases, surgery, radiation or chemotherapy to treat tumors can affect male fertility.
- Undescended testicles. In some males, during fetal development one or both testicles fail to descend from the abdomen into the sac that normally contains the testicles (scrotum). Decreased fertility is more likely in men who have had this condition.
- Hormone imbalances. Infertility can result from disorders of the testicles themselves or an abnormality affecting other hormonal systems including the hypothalamus, pituitary, thyroid and adrenal glands. Low testosterone (male hypogonadism) and other hormonal problems have a number of possible underlying causes.
- Defects of tubules that transport sperm. Many different tubes carry sperm. They can be blocked due to various causes, including inadvertent injury from surgery, prior infections, trauma or abnormal development, such as with cystic fibrosis or similar inherited conditions.
- Chromosome defects. Inherited disorders such as Klinefelter’s syndrome — in which a male is born with two X chromosomes and one Y chromosome (instead of one X and one Y) — cause abnormal development of the male reproductive organs. Other genetic syndromes associated with infertility include cystic fibrosis, Kallmann’s syndrome and Kartagener’s syndrome.
- Problems with sexual intercourse. These can include trouble keeping or maintaining an erection sufficient for sex (erectile dysfunction), premature ejaculation, painful intercourse, anatomical abnormalities such as having a urethral opening beneath the penis (hypospadias), or psychological or relationship problems that interfere with sex.
- Celiac disease. A digestive disorder caused by sensitivity to gluten, celiac disease can cause male infertility. Fertility may improve after adopting a gluten-free diet.
- Certain medications. Testosterone replacement therapy, long-term anabolic steroid use, cancer medications (chemotherapy), certain antifungal medications, some ulcer drugs and certain other medications can impair sperm production and decrease male fertility.
- Prior surgeries. Certain surgeries may prevent you from having sperm in your ejaculate, including vasectomy, inguinal hernia repairs, scrotal or testicular surgeries, prostate surgeries, and large abdominal surgeries performed for testicular and rectal cancers, among others. In most cases, surgery can be performed to either reverse these blockage or to retrieve sperm directly from the epididymis and testicles.