Causes of Infertility

worried couple with pregnancy test

Plus: Natural Ways to Boost Fertility

Increasing numbers of couples are experiencing infertility problems these days, finding that they are unable to conceive, or that the mother is unable to carry a pregnancy to full term. Though estimates vary, most fertility experts say that 10 percent or more of all couples in the United States experience infertility problems.

According to the Centers for Disease Control and Prevention and other sources, about one-third of all cases of infertility involve only the woman, one-third of cases involve only the man, and the remainder of cases involve both partners or are of unknown cause.

Infertility can be present at birth (congenital) or it can develop along the way when something goes wrong. To discuss this topic, let’s begin with the definition of infertility.

What Is Infertility?

There are two types:

Primary infertility is defined as the inability for a couple to conceive a baby after one year or longer of regular, unprotected sex.

Secondary infertility is when a couple has had previous children, but is unable to conceive again.

What Causes Infertility?

The possible causes of infertility are many. Below, we cover some of the more common ones.


One of the most frequent reasons for infertility problems is age: as a woman ages, her supply of healthy oocytes — eggs — that can be fertilized by sperm and produce a healthy embryo decreases.

Women’s fertility begins to drop starting at about age 35, and it continues decreasing until the woman reaches menopause, which is the cessation of all menstrual periods, at which point she is no longer able to conceive a child naturally. However, doctors caution that unhealthy lifestyle habits, or harmful, persistent environmental exposures (examples: eating lots of processed foods, smoking cigarettes or being exposed to toxic chemicals at home or at work) may cause a woman’s fertility to start diminishing earlier. Some women have trouble conceiving even in their late 20’s or early 30’s.

As for males, doctors used to believe that men’s fertility didn’t change much over time and remained fairly strong. But newer, large studies that controlled for the mother’s age, and studies of mothers receiving egg donations from young women, found that just like with women, as a man’s age increases, the chances of a successful pregnancy decrease.

Ovulation Disorders

A woman may have irregular ovulation cycles or no ovulation at all. There are a number of possible causes for this, including:

  • Hormonal imbalances — a doctor can perform a blood test to assess whether there is a problem with one or more of the endocrine glands, which release hormones into the blood
  • Poor nutrition
  • Being overweight or obese
  • Being underweight
  • Not getting enough physical activity
  • Exercising too much — for a woman, this means doing more than 7 hours of exercise per week
  • Emotional stress
  • Excessive exposure to natural or synthetic chemicals that act as hormones or interfere with the natural hormones in our bodies. Known as xenohormones or endocrine disruptors, examples of these chemicals are: bisphenyl A (BPA), a synthetic agent used as a softener in many plastics, and in the linings of soda cans and canned foods to prevent spoilage. Polychlorinated biphenyls (PCBs): these chemicals were used in industrial applications and in old fluorescent lights. They stopped being made in the United States in 1977, but they persist in the environment, so, they are widely distributed. In bodies of water, bigger predator fish and bottom-dwelling fish are found to have the highest concentrations of PCBs. Other hormone-disrupting chemicals are commonly found in grooming aids (body lotions, body washes, artificial fragrances, deodorants and some toothpastes; in the last two, the chemical may be called “Triclosan”), pesticides, herbicides and laundry detergents. Xenohormones are also used in medical applications, such as in birth control pills, corticosteroids (to treat asthma, cancer and other illnesses), psychiatric drugs and other pharmaceuticals. In addition to being suspected of contributing to infertility, xenohormones are thought to pose developmental risks to a growing fetus and to newborns, at a time when organs and neural cells are developing rapidly
  • Persistent exposure to other synthetic chemicals, including alkyl dimethyl benzalkonium chloride (ADBAC), or simply benzalkonium chloride. This compound is used as an active ingredient and preservative in many consumer products and pharmaceuticals, including eye, ear and nasal drops and sprays; hand sanitizers; wet wipes; throat lozenges; one-use over-the-counter medications for cold sores and herpes; floor and surface disinfectants like Lysol; laundry detergents and treatments; algaecides for clearing algae and moss from walkways and swimming pools, and many other products

Blocked Fallopian Tubes

The fallopian tubes are the tubes attached to the uterus, which take in the mature egg released by an ovary and transport it to the uterus for fertilization. It is common for women to have scar tissue blocking one or both fallopian tubes.

The most frequent cause for blocked fallopian tubes is pelvic inflammatory disease (PID), an infection of the reproductive organs that is most often caused by bacteria from two common sexually transmitted diseases: chlamydia and gonorrhea.

Sometimes, PID is caused by normal bacteria present in the vagina or cervix. PID can also result when bacteria travel up a contraceptive device such as an IUD, or when bacteria are introduced during certain gynecological procedures like insertion of an IUD or an abortion.

It can take from a few days to a few months for an infection to travel from the vagina to the pelvic organs. PID symptoms can include dull or sharp pain in lower or upper abdomen, yellow or green vaginal discharge or discharge with foul odor, painful intercourse, fever, infertility. PID can also have no symptoms.

Fallopian tubes may also be blocked by endometriosis, uterine fibroids or adhesions.

Endometriosis is when bits of endometrium, the blood-rich tissue that grows and lines the inside of the uterus in preparation for implantation of a fertilized egg, travel to other areas of the pelvic organs (uterus, ovaries, fallopian tubes) or even to other abdominal organs (bladder, intestines, etc.) and attach themselves to the outside or inside of these structures.

The condition may cause pelvic pain, heavy menstrual bleeding, bleeding between periods, painful intercourse, painful urination, fatigue and other symptoms. In addition, when a woman with endometriosis gets her period, the other bits of scattered endometrial tissue bleed also. A doctor can make a small incision on the abdomen and use a tiny camera mounted on a flexible tube, to find such growths and surgically remove them. This surgery, a laparoscopy, will eliminate symptoms and may improve fertility.

Uterine fibroids are non-cancerous tumors of varying sizes (they can be small or quite large) that develop inside the uterus, within the walls of the uterus, or on the outside of the uterus. They can lower chances of conception by distorting the shape of the uterus and making it harder for a fertilized egg to implant and grow inside the uterus.

Fibroids are relatively common in women of childbearing age, with most cases seen in women in their 40’s and early 50’s. Symptoms can be pelvic pain, irregular heavy bleeding and pressure on the bladder. Some women experience no symptoms. Fibroids can be surgically removed in a hospital.

Adhesions are bands of scar tissue that cause internal organs to get stuck together or bound. They most commonly result from abdominal or pelvic surgeries, but they can also be caused by pelvic infection or more pronounced cases of endometriosis.

Polycystic Ovary Syndrome

PCOS is believed to be caused by a hormonal imbalance in the woman’s body and it results in cysts growing inside her ovaries. It can also cause irregular menstrual cycles, weight gain, insulin resistance. Because the symptoms vary from one woman to another, PCOS may be difficult to diagnose. It is estimated that between 4 and 18 percent of women of reproductive age may develop this condition.

Poor Egg Health

In addition to age, other factors that may alone or in combination contribute to poor egg health include:

  • Hormonal imbalance
  • Poor diet
  • Smoking: cigarette-smoking also increases a pregnant woman’s risk of miscarriage, birth defects and serious pregnancy complications
  • Alcohol use or abuse: for a woman, no amount of alcohol is considered safe around conception or during pregnancy. If you are trying to get pregnant, your best bet is to greatly limit or avoid alcohol altogether
  • Use of recreational drugs like marijuana, cocaine and others. Both marijuana and cocaine decrease blood flow to bodily tissues, including reproductive organs
  • Lack of physical activity, which leads to poor blood circulation to the ovaries
  • Environmental toxins or pollution, including exposure to harsh chemicals, some solvents and dangerous metals like lead
  • Being a vegetarian: vegetarians need to insure that they get enough iron, zinc, vitamin B-12 and folate (a B vitamin that helps guard against birth defects). Supplements may be needed, but consult with your health care provider before starting on supplements, if you are taking any medications
  • Damage to the reproductive organs
  • Stress
  • Illness, such as cancer treated with chemotherapy or radiation
  • Autoimmune disorders
  • Long-term use of non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen and naproxen sodium; though it is believed that egg health returns after woman stops taking the medications

Baby girls are born with all the eggs they’re ever going to have; this fact makes it easy to see why it’s important for women to maintain healthy lifestyle habits throughout their reproductive years and before, so as to give themselves the best chances for fertility and healthy pregnancies.

Many of the above causes of infertility, such as age, poor diet, smoking, stress and so forth, may apply to either women or men who experience infertility. Next, let’s look at some of the more common factors for infertility that apply to men.

Causes of Male Infertility

Low Sperm Count

A healthy sperm count is 20 million sperm per mL (one-thirtieth of an ounce) of ejaculate. Anything below that is considered a low sperm count.

Low sperm count may be the result of one or more factors, including:

  • Smoking cigarettes or marijuana
  • Alcohol abuse; the sperm of men who abuse alcohol also display reduced movement
  • Poor diet
  • Being overweight: this not only reduces sperm count but also testosterone levels
  • Environmental toxins and exposure to dangerous metals like lead
  • Electromagnetic radiation from a nearby source, such as that emitted by a cell phone worn on a waistband or inside a pants’ pocket
  • Wearing tight underwear and / or pants: sperm need to live in an environment that is slightly cooler than body temperature — that is why the testicles, which produce the sperm, hang lower inside their pouch, the scrotum
  • Damage to reproductive organs, such as from sexually transmitted diseases
  • Excessive use of hot tubs or saunas, which subject sperm to higher temperatures
  • Stress. Stress can not only lower a man’s sperm production, but if either partner is suffering from chronic stress, it can result in less frequent sex, and therefore, decreased chance of conception
  • Certain illnesses such as diabetes, anemia and cancers treated with chemotherapy or radiation
  • Overexposure to steroids, including testosterone
  • Use of the anti-inflammatory drug sulfasalazine, used to treat arthritis
  • Previous non-STD illnesses such as mumps
  • Undescended testicles
  • Hypogonadism: the man’s body does not produce enough testosterone; testicular function is inhibited
  • Past surgeries

Poor Sperm Health

A man’s sperm may be defective in its motility (the way the heads or tails move) or it may have defects in its morphology (shape and proper formation of DNA). Causes of poor sperm health are often the same as those that produce low sperm count.

Not all men with low sperm count will have poor sperm quality, and not all men with poor sperm quality will have a low sperm count.

Blocked Vas Deferens

Also known as blockage of the epididymis; the vas deferens is the tube that transports sperm from the testicles to the penis. The most common reason for this blockage are varicoceles, or varicose veins, in the testicles and / or scrotum. These may cause pain and can result in shrinkage (atrophy) of the testicle. They are described as having the appearance of “worms” inside the scrotum.

Varicoceles are the result of blood vessel valves that don’t function properly and allow blood to pool inside, enlarging the vessel. Some experts believe that the additional blood in these vessels increases heat in the testicle, which may cause sperm quality and quantity to diminish. Varicoceles can be corrected with surgery.

As in the case of women’s fallopian tubes, a blocked vas deferens can also be caused by sexually transmitted diseases like chlamydia and gonorrhea. It is important to see a doctor if a person suspects that they have an STD, which can be treated with antibiotics. That will prevent damage to the reproductive organs.

Problems Delivering the Sperm

Sexual problems such as premature ejaculation, retrograde ejaculation (when semen enters the bladder instead of flowing through the penis during orgasm), genetic diseases such as cystic fibrosis, or injury to the reproductive organs can all prevent sperm from entering the woman’s vagina.

How to Boost Fertility Naturally

In the end, it’s quite clear that the way to attain fertility and optimize the chances of a healthy pregnancy and delivery … is the same way that you stay healthy overall: avoid things that you know are bad for you — all the more so when you’re trying to conceive and deliver a healthy baby — and maintain good habits.

Foods for Fertility

Your diet should include lots of raw fruits and vegetables, with special attention to potent antioxidants that help cells stay young and fight decay: berries and citrus fruits, to name but two excellent ones. Whole grains are also rich in antioxidants and fiber — but watch out for artificial preservatives and dough conditioners, which are found in most brands of store-bought breads.

The foods you eat should be minimally processed, when they’re processed at all. Eat lean meats and low-fat dairy foods (beware of any non-nutritious stabilizers or artificial preservatives that may be added to some low-fat dairy products like cheeses and nearly all ice creams).

Drink plenty of purified water every day, as well as other healthy beverages. This flushes out wastes from your body and helps the cells perform their round-the-clock daily processes.

Now may be a great time to take a daily multivitamin plus minerals, as insurance that you’re getting all the nutrients your body needs. Some health experts advise that you start taking folate supplements before you conceive. Folate is found naturally in dark-green, leafy vegetables, broccoli, beans, asparagus, avocado and citrus fruits.

Make Sure You Sleep Enough

Get plenty of sleep every night — this is one many Americans fall short on. If you want your body’s cells to work like they’re supposed to, and to have the strength to fight free radicals and decay, you must give them the nightly rest they require.

Avoid caffeine, as it is not advised for pregnant women.

Frequency of Intercourse

Doctors advise couples wanting to conceive to make sure they have sex often — but not too often. Frequent sex will improve your odds of conceiving and will help males fight off erectile dysfunction in the long-term. But if you have sex too often, as in daily, sperm counts and quality are likely to fall.

Aim to have sex 2 to 3 times a week, and more often (every 1 to 2 days) when you’re ovulating. Sperm can live inside the vagina for up to 3 days; an egg in the uterus can be fertilized for up to 24 hours.

Some couples have had success by placing a pillow under the woman’s buttocks as she lies on her back, to create a more steep downward slope toward the uterus. Also, doctors recommend that a woman remain lying down for 30 minutes after finishing intercourse, to let gravity help.

Fertility Massage

Some women feel that having massages or giving themselves massages to their abdominal area helps to increase blood flow to the reproductive organs, as well as possibly help to naturally remove blockages that may exist as a result of scarred tissue and so forth.

To do this massage, you put a little pressure with your fingertips, in a clock-wise direction, starting with a small circle around your navel and working your way out from there. But this massage must not be done while you’re having your period or if you think you may be pregnant.

By Cynthia Sanchez. A graduate of the University of Washington, Cynthia has extensive experience writing about health and wellness topics for different media.