Infertility: Causes, Risk Factors & Treatments

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Infertility refers to an inability to conceive after having regular unprotected sex. Infertility can also refer to the biological inability of an individual to contribute to conception, or to a female who cannot carry a pregnancy to full term. In many countries infertility refers to a couple that has failed to conceive after 12 months of regular sexual intercourse without the use of contraception.

Infertility may be due to a single cause in either you or your partner, or a combination of factors that may prevent a pregnancy from occurring or continuing. Fortunately, there are many safe and effective therapies for overcoming infertility. These treatments significantly improve the chances of becoming pregnant.

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Infertility facts

Infertility facts medically edited by: Charles Patrick Davis, MD, PhD

  • Infertility means not being able to become pregnant, within certain parameters.
  • Infertility is a common problem of about 10% of women aged 15 to 44.
  • Infertility can be due to the woman (33%), the man (33%) and by both sexes or due to unknown problems (33%), approximately.
  • Infertility in men can be due to varicocele, low or absent sperm count, sperm damage or certain diseases.
  • Risk factors for men’s infertility include alcohol and drug use, toxins, smoking, age, health problems, medicines, radiation, and chemotherapy.
  • Risk factors for women’s infertility include ovulation problems, blocked Fallopian tubes, uterine problems, uterine fibroids, age, stress, poor diet, athletic training, and those risk factors listed for men.
  • Aging decreases a woman’s fertility; after age 35 about 33% of couples have fertility problems; older women’s eggs are reduced in number, not as healthy and less likely to be released by the ovary – the woman is also more likely to have a miscarriage and other health problems.
  • Women under 35 should try for a year or 6 months if 35 or older to become pregnant before contacting their doctor if they have no health problems.
  • Doctors use the histories of both partners and may run tests such as sperm studies, ovulation tests, ultrasound, hysterosalpingography, or laparoscopy.
  • Infertility may be treated with medicine, surgery, artificial insemination, or assisted reproductive technology, based on the couples test results and other factors.
  • There are multiple medicines that may be used to treat infertility in women.
  • Intrauterine insemination is artificial insemination where a woman is injected with sperm into the uterus.
  • ART (assisted reproductive technology) is when a woman’s eggs are removed, mixed with sperm to make embryos that are placed back in the woman’s body; it’s successful about 11% to 39%, depending on the woman’s age.
  • There are several types of ART; in vitro fertilization, Zygote transfer, Gamete transfer and intracytoplasmic sperm injection.
  • Surrogacy (the woman’s male partner sperm is used to fertilize another woman egg and that other woman carries the fetus to term and the infant is then adopted ) is a way for some couples to obtain a baby.
  • A gestational carrier is a woman who has an embryo placed in her uterus, carries the fetus to term and gives the baby to the couple (or responsible persons) that produced the embryo.

Is infertility a common problem?

Yes. About 6% of married women 15–44 years of age in the United States are unable to get pregnant after one year of unprotected sex (infertility).

Also, about 12% of women 15–44 years of age in the United States have difficulty getting pregnant or carrying a pregnancy to term, regardless of marital status (impaired fecundity)

Causes of infertility

Many physical and emotional factors can cause infertility. It may be due to problems in the woman, man, or both.

FEMALE INFERTILITY

Female infertility may occur when:

  • A fertilized egg or embryo does not survive once it attaches to the lining of the womb (uterus).
  • The fertilized egg does not attach to the lining of the uterus.
  • The eggs cannot move from the ovaries to the womb.
  • The ovaries have problems producing eggs.

Female infertility may be caused by:

  • Autoimmune disorders, such as antiphospholipid syndrome (APS)
  • Birth defects that affect the reproductive tract
  • Cancer or tumor
  • Clotting disorders
  • Diabetes
  • Drinking too much alcohol
  • Exercising too much
  • Eating disorders or poor nutrition
  • Growths (such as fibroids or polyps) in the uterus and cervix
  • Medicines such as chemotherapy drugs
  • Hormone imbalances
  • Obesity
  • Older age
  • Ovarian cysts and polycystic ovary syndrome (PCOS)
  • Pelvic infection or pelvic inflammatory disease (PID)
  • Scarring from sexually transmitted infection, abdominal surgery or endometriosis
  • Smoking
  • Surgery to prevent pregnancy (tubal ligation) or failure of tubal ligation reversal (reanastomosis)
  • Thyroid disease

MALE INFERTILITY

Male infertility may be due to:

  • Decreased number of sperm
  • Blockage that prevents the sperm from being released
  • Defects in the sperm

Male infertility can be caused by:

  • Birth defects
  • Cancer treatments, including chemotherapy and radiation
  • Exposure to high heat for prolonged periods
  • Heavy use of alcohol, marijuana, or cocaine
  • Hormone imbalance
  • Impotence
  • Infection
  • Medicines such as cimetidine, spironolactone, and nitrofurantoin
  • Obesity
  • Older age
  • Retrograde ejaculation
  • Scarring from sexually transmitted infections, injury, or surgery
  • Smoking
  • Toxins in the environment
  • Vasectomy or failure of vasectomy reversal

Healthy couples under age 30 who have sex regularly will have a 25 to 30% per month chance of getting pregnant each month.

A woman is most fertile in her early 20s. The chance a woman can get pregnant drops greatly after age 35 (and especially after age 40). The age when fertility starts to decline varies from woman to woman.

Infertility problems and miscarriage rates increase significantly after 35 year of age. There are now options for early egg retrieval and storage for women in their 20’s. This will help ensure a successful pregnancy if childbearing is delayed until after age 35. This is an expensive option, but for women who know they will need to delay childbearing, it may be worth considering.

Risk factors of infertility

In medicine, a risk factor is something that raises the risk of developing a condition, disease or symptom. For example, obese people are more likely to develop diabetes type 2 compared to people of normal weight; therefore, obesity is a risk factor for diabetes type 2.

Age – a woman’s fertility starts to drop after she is about 32 years old, and continues doing so. A 50-year-old man is usually less fertile than a man in his 20s (male fertility progressively drops after the age of 40).

Smoking – smoking significantly increases the risk of infertility in both men and women. Smoking may also undermine the effects of fertility treatment. Even when a woman gets pregnant, if she smokes she has a greater risk of miscarriage.

Alcohol consumption – a woman’s pregnancy can be seriously affected by any amount of alcohol consumption. Alcohol abuse may lower male fertility. Moderate alcohol consumption has not been shown to lower fertility in most men, but is thought to lower fertility in men who already have a low sperm count.

Being obese or overweight – in industrialized countries overweight/obesity and a sedentary lifestyle are often found to be the principal causes of female infertility. An overweight man has a higher risk of having abnormal sperm.

Eating disorders – women who become seriously underweight as a result of an eating disorder may have fertility problems.

Being vegan – if you are a strict vegan you must make sure your intake of iron, folic acid, zinc and vitamin B-12 are adequate, otherwise your fertility may become affected.

Over-exercising – a woman who exercises for more than seven hours each week may have ovulation problems.

Not exercising – leading a sedentary lifestyle is sometimes linked to lower fertility in both men and women.

Sexually transmitted infections (STIs) – chlamydia can damage the fallopian tubes, as well as making the man’s scrotum become inflamed. Some other STIs may also cause infertility.

Exposure to some chemicals – some pesticides, herbicides, metals (lead) and solvents have been linked to fertility problems in both men and women.

Mental stress – studies indicate that female ovulation and sperm production may be affected by mental stress. If at least one partner is stressed it is possible that the frequency of sexual intercourse is less, resulting in a lower chance of conception.

Medicines used to treat infertility in women

Some common medicines used to treat infertility in women include:

  • Clomiphene citrate (Clomid): This medicine causes ovulation by acting on the pituitary gland. It is often used in women who have polycystic ovarian syndrome (PCOS) or other problems with ovulation. This medicine is taken by mouth.
  • Human menopausal gonadotropin or hMG (Repronex, Pergonal):This medicine is often used for women who don’t ovulate due to problems with their pituitary gland. hMG acts directly on the ovaries to stimulate ovulation. It is an injected medicine.
  • Follicle-stimulating hormone or FSH (Gonal-F, Follistim): FSH works much like hMG. It causes the ovaries to begin the process of ovulation. These medicines are usually injected.
  • Gonadotropin-releasing hormone (Gn-RH) analog: These medicines are often used for women who don’t ovulate regularly each month. Women who ovulate before the egg is ready can also use these medicines. Gn-RH analogs act on the pituitary gland to change when the body ovulates. These medicines are usually injected or given with a nasal spray.
  • Metformin (Glucophage): Doctors use this medicine for women who have insulin resistance and/or PCOS. This drug helps lower the high levels of male hormones in women with these conditions. This helps the body to ovulate. Sometimes clomiphene citrate or FSH is combined with metformin. This medicine is usually taken by mouth.
  • Bromocriptine (Parlodel): This medicine is used for women with ovulation problems due to high levels of prolactin. Prolactin is a hormone that causes milk production.

Many fertility drugs increase a woman’s chance of having twins, triplets, or other multiples. Women who are pregnant with multiple fetuses have more problems during pregnancy. Multiple fetuses have a high risk of being born too early (prematurely). Premature babies are at a higher risk of health and developmental problems.

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