Overview
You may be surprised to learn that your diet, lifestyle, and environment all have a profound bearing on your individual reproductive health. There are a number of things that you can do to maximize your chances of conception and encourage a healthy pregnancy.
Common causes of Infertility in females
For pregnancy to occur, every part of the complex human reproduction process has to take place just right. The steps in this process are as follows:
- One of the two ovaries releases a mature egg.
- The egg is picked up by the fallopian tube.
- Sperm swims up to the cervix, through the uterus, and into the fallopian tube to reach the egg for fertilization.
- The fertilized egg travels down the fallopian tube to the uterus.
- The fertilized egg implants and grows in the uterus.
- In women, a number of factors can disrupt this process at any step. Female infertility is caused by one or more of these factors.
Ovulation disorders
Ovulation disorders, meaning you ovulate infrequently or not at all, account for infertility in about 25 percent of infertile couples. These can be caused by flaws in the regulation of reproductive hormones by the hypothalamus or the pituitary gland, or by problems in the ovary itself.
Polycystic ovary syndrome (PCOS): In PCOS, complex changes occur in the hypothalamus, pituitary gland, and ovaries, resulting in a hormone imbalance, which affects ovulation. PCOS is associated with insulin resistance and obesity, abnormal hair growth on the face or body, and acne. It’s the most common cause of female infertility.
Hypothalamic dysfunction: The two hormones responsible for stimulating ovulation each month — follicle-stimulating hormone (FSH) and luteinizing hormone (LH) — are produced by the pituitary gland in a specific pattern during the menstrual cycle. Excess physical or emotional stress, a very high or very low body weight, or a recent substantial weight gain or loss can disrupt this pattern and affect ovulation. The main sign of this problem is irregular or absent periods.
Premature ovarian insufficiency: This disorder is usually caused by an autoimmune response where your body mistakenly attacks ovarian tissues or by premature loss of eggs from your ovary due to genetic problems or environmental insults such as chemotherapy. It results in the loss of the ability to produce eggs by the ovary, as well as a decreased estrogen production under the age of 40.
Too much prolactin: Less commonly, the pituitary gland can cause excess production of prolactin (hyperprolactinemia), which reduces estrogen production and may cause infertility. Most commonly this is due to a problem in the pituitary gland, but it can also be related to medications you’re taking for another disease.
Damage to fallopian tubes (tubal infertility)
When fallopian tubes become damaged or blocked, they keep sperm from getting to the egg or block the passage of the fertilized egg into the uterus. Causes of fallopian tube damage or blockage can include:
- Pelvic inflammatory disease, an infection of the uterus and fallopian tubes due to chlamydia, gonorrhea or other sexually transmitted infections.
- Previous surgery in the abdomen or pelvis, including surgery for ectopic pregnancy, in which a fertilized egg becomes implanted and starts to develop in a fallopian tube instead of the uterus.
- Pelvic tuberculosis, a major cause of tubal infertility worldwide, although uncommon in the United States.
Endometriosis
Endometriosis occurs when tissue that normally grows in the uterus implants and grows in other locations. This extra tissue growth — and the surgical removal of it — can cause scarring, which may obstruct the tube and keep the egg and sperm from uniting. It can also affect the lining of the uterus, disrupting implantation of the fertilized egg. The condition also seems to affect fertility in less-direct ways, such as damage to the sperm or egg.
Uterine or cervical causes
- Several uterine or cervical causes can impact fertility by interfering with implantation or increasing the likelihood of a miscarriage
- Benign polyps or tumors (fibroids or myomas) are common in the uterus, and some types can impair fertility by blocking the fallopian tubes or by disrupting implantation. However, many women who have fibroids or polyps can become pregnant
- Endometriosis scarring or inflammation within the uterus can disrupt implantation
- Uterine abnormalities present from birth, such as an abnormally shaped uterus, can cause problems becoming or remaining pregnant
- Cervical stenosis, a cervical narrowing, can be caused by an inherited malformation or damage to the cervix
- Sometimes the cervix can’t produce the best type of mucus to allow the sperm to travel through the cervix into the uterus
Unexplained infertility In some instances, a cause for infertility is never found. It’s possible that a combination of several minor factors in both partners underlie these unexplained fertility problems. Although it’s frustrating to not get a specific answer, this problem may correct itself with time.
Common causes of infertility in males
Male fertility is a complex process. To get your partner pregnant, the following must occur:
You must produce healthy sperm. Initially, this involves the growth and formation of the male reproductive organs during puberty. At least one of your testicles must be functioning correctly, and your body must produce testosterone and other hormones to trigger and maintain sperm production.
Sperm has to be carried into the semen. Once the sperm is produced in the testicles, delicate tubes transport them until they mix with semen and are ejaculated out of the penis.
There needs to be enough sperm in the semen. If the number of sperm in your semen (sperm count) is low, it decreases the odds that one of your sperm will fertilize your partner’s egg. A low sperm count is fewer than 15 million sperm per milliliter of semen or fewer than 39 million per ejaculate.
Sperm must be functional and able to move. If the movement (motility) or function of your sperm is abnormal, the sperm may not be able to reach or penetrate your partner’s egg.
Medical Causes
Problems with male fertility can be caused by a number of health issues and medical treatments. Some of these include:
Varicocele: A varicocele is a swelling of the veins that drain the testicle. It’s the most common reversible cause of male infertility. This may prevent normal cooling of the testicle, leading to reduced sperm count and fewer moving sperm. Treating the varicocele can improve sperm numbers and function, and may potentially improve outcomes when using assisted reproductive techniques such as in vitro fertilization.
Infection: Some infections can interfere with sperm production or sperm health, or can cause scarring that blocks the passage of sperm. These include some sexually transmitted infections, including chlamydia and gonorrhea; inflammation of the prostate (prostatitis); and inflamed testicles due to mumps (mumps orchitis). Although some infections can result in permanent testicular damage, most often sperm can still be retrieved.
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. Some men with spinal cord injuries or certain diseases can’t ejaculate semen, even though they still produce sperm. Often in these cases, sperm can still be retrieved for use in assisted reproductive techniques. 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 or can affect the glands that release hormones related to reproduction, such as the pituitary gland. 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.
Sperm duct defects: The tubes that carry sperm (sperm ducts) can be damaged by illness or injury. Some men experience blockage in the part of the testicle that stores sperm (epididymis) or a blockage of one or both of the tubes that carry sperm out of the testicles. Men with cystic fibrosis and some other inherited conditions may be born without sperm ducts altogether.
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 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.
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 this blockage or to retrieve sperm directly from the epididymis and testicles.
Environmental Causes
Overexposure to certain environmental elements such as heat, toxins, and chemicals can reduce sperm production or sperm function. Specific causes include:
Industrial chemicals: Extended exposure to benzenes, toluene, xylene, pesticides, herbicides, organic solvents, painting materials, and lead may contribute to low sperm counts.
Heavy metal exposure: Exposure to lead or other heavy metals also may cause infertility.
Radiation or X-rays: Exposure to radiation can reduce sperm production, though it will often eventually return to normal. With high doses of radiation, sperm production can be permanently reduced.
Overheating the testicles: Frequent use of saunas or hot tubs may temporarily lower your sperm count. Sitting for long periods, wearing tight clothing or working on a laptop computer for long stretches of time also may increase the temperature in your scrotum and slightly reduce sperm production. The type of underwear you wear is unlikely to make a significant difference in male fertility.
Health, lifestyle and other causes
Illegal drug use: Anabolic steroids taken to stimulate muscle strength and growth can cause the testicles to shrink and sperm production to decrease. Use of cocaine or marijuana may temporarily reduce the number and quality of your sperm as well.
Alcohol use: Drinking alcohol can lower testosterone levels, cause erectile dysfunction and decrease sperm production. Liver disease caused by excessive drinking also may lead to fertility problems.
Occupation: Certain occupations can increase your risk of infertility, including those associated with extended use of computers or video display monitors, shift work, and work-related stress.
Tobacco smoking: Men who smoke may have a lower sperm count than do those who don’t smoke. Secondhand smoke also may affect male fertility.
Emotional stress: Stress can interfere with certain hormones needed to produce sperm. Severe or prolonged emotional stress, including problems with fertility, can affect your sperm count.
Weight: Obesity can cause hormone changes that reduce male fertility.
Prolonged bicycling: Prolonged bicycling is another possible cause of reduced fertility due to overheating the testicles. In some cases, bicycle seat pressure on the area behind the testicles (perineum) can cause numbness in the penis and erectile dysfunction.
It can be heartbreaking to miscarry one baby after another. Each new pregnancy brings both hope and anxiety. And each new loss may be harder to bear, especially if you feel that time is running out. The experience can place great strain on even the strongest relationships. You and your partner might react differently from each other and that can cause great tension. Family and friends may find it harder to support you with each miscarriage; they may even think you’re getting used to losing and able to cope. And all the time there may be a sense that your life is on hold while you try – and try again – for a baby.