The Facts About Fertility

Fertility refers to the ability to naturally conceive and produce children. To be fertile, a number of processes and structures have to be functioning correctly. Healthy eggs and sperm, unobstructed fallopian tubes, healthy embryos and a nourishing hormonal environment in a woman's body are typical prerequisites for fertility.

Infertility is usually diagnosed in a couple who have attempted natural conception for at least a year without success. Infertility can be caused by a variety of elements, including low sperm count or motility, ovulation disorders and inhospitable environmental factors. Infertility affects about 10 percent to 15 percent of couples in the United States, according to the American Pregnancy Association.

Fertility is a broad subject and can be discussed at both micro and macro levels. At the macro level or the level of the nation, fertility is highly influenced by economic factors.

In a 2020 study published in BMC Public Health, researchers Frank Götmark and Malte Andersson demonstrated that a nation's total fertility rate, or TFR, goes down under a set of circumstances. When women are more educated and pervasive contraceptive use is encouraged and family planning programs are well established, the number of pregnant women is fewer.

As with most aspects of human health, nutrition and exercise play a role in fertility. The National Institutes of Health (NIH) noted that infertility can be linked to these physical factors:

• Obesity
• Undernourishment
• Overexercising
• Substance abuse
• High blood pressure
• Radiation and chemotherapy
• Pesticides

Physical factors also play a role at the level of the organ. In men, infertility can be the consequence of low sperm motility or production, abnormal sperm production or genetic disorders. In women, infertility can be caused by blocked fallopian tubes, ovulation disorders, endometriosis, uterine fibroids and aging.

A man's fertility is affected by a host of factors, including his environment, lifestyle choices, physical health and organ functionality. Male infertility is typically catalyzed by sperm-related issues: Sperm is not produced, or is produced abnormally, or cannot reach the egg to fertilize it.

Some of the underlying causes for sperm dysfunction, according to Mayo Clinic, include:

• Physical or structural issues such as undescended testicles, infections like chlamydia and enlarged veins in the testes can all detract from sperm quality.
• Premature ejaculation, blockages in the testicle or injuries can prevent the sperm from being delivered.
• Excess exposure to certain chemicals or environments, such as pesticides, radiation and cigarette smoking, can impede the production of sperm.
• Cancer, or the treatments for cancer, can also interfere with sperm production.
• Aging can also reduce the motility (movement) of sperm.

A big factor in fertility is the quality of the sperm. When sperm is of high quality, a viable pregnancy is more likely. Sperm quality is determined by its quantity and motility. An ejaculate that has 15 million sperm per milliliter is considered an ideal quantity for likely fertilization.

The sperm within an ejaculate must also have motility, which is the ability to move through the female reproductive organs to reach the egg. Pregnancy can be attained with fewer than 40 percent of the sperm moving, but it is progressively more difficult for fertilization to occur below this baseline. The quality of sperm can also be measured by shape: those with long tails and ovular heads tend to do well on their journey to the egg.

A woman's fertility is influenced by a variety of physical, environmental and structural factors. Female infertility is correspondingly various and can be the consequence.

• Disorders of ovulation can inhibit the normal functioning of the ovaries and the release of the egg, which in turn prohibits fertilization. Ovulation disorders can be caused by too much prolactin, too much or too little thyroid hormone, too much exercise, eating disorders and tumors.
• Cervical or uterine structural issues can cause fertility problems. Uterine fibroids can block the path of sperm or prevent a fertilized egg from reaching the uterus.
• Damage to the fallopian tubes can reduce or prohibit sperm motility. This damage can come from STI-related inflammation, endometriosis or growths.
• Endometriosis, which is the growth of tissue outside the uterus, can block the normal functioning of the female reproductive system.
• Early menopause can be a contributor to infertility. It is defined as the end of menstruation before age 40 in women.
• Adhesions in the pelvis can also cause infertility by binding organs together and causing blockages.
• Cancer and treatments for cancer can negatively impact fertility.

A menstrual cycle is the monthly preparation of a woman's body for a possible pregnancy. Typical menstruation cycles last 28 days, but they can range anywhere from 25 to 35 days, according to Cleveland Clinic. The cycle can be broken down into four distinct phases:

1. In the menses phase, which is typically day one to day five, the body sheds the lining of the uterus in the form of blood.
2. In the follicular phase, which is subdivided but as a whole encompasses day one to day 14, the lining of the uterus grows and thickens. In the latter portion of this phase, an egg fully matures.
3. During ovulation, which is about day 14, the egg is released from the ovary. Ovulation comes with changes in vaginal secretions and rising body temperature.
4. Finally, during the luteal phase—day 15 to day 28—the egg makes its way through the fallopian tubes. If fertilized, it sticks to the uterine wall and begins developing into an embryo. If not, it is released in the menses phase.

The most fertile time in a menstrual cycle is about five days before and during ovulation. Partners who have sex during this phase in the cycle increase their chances of conceiving.

Infertility can be incredibly painful for couples who planned for a life with children. A diagnosis of infertility can cause significant emotional distress, anxiety and even depression. Couples who undergo fertility treatments without success can feel a strong sense of grief, according to Cedars-Sinai healthcare in Los Angeles. If you or a loved one is experiencing the pain of infertility, talk to your doctor about support groups and mental health resources.

To increase the chances of conception, partners should have sex regularly as well as strategically. Sperm can live for as long as five days in a woman's reproductive system, so having sex five days before and during ovulation increases the chances that an egg will encounter live sperm in the fallopian tubes and become fertilized.

Most couples who are healthy and have regular unprotected sex conceive within a year. To increase fertility in general, maintain healthy habits: avoid smoking and alcohol, minimize caffeine and keep strenuous exercise to a minimum. Talk to your doctor about your medications as well.

For couples who have had regular unprotected sex for one year without getting pregnant, fertility specialists may recommend trying assisted reproductive technology (ART). According to the Centers for Disease Control and Prevention (CDC), assisted reproductive tech refers to any fertility treatment that involves the handling of eggs or embryos.

In practice, this means removing eggs or embryos from a woman's body, combining them with sperm in a laboratory setting, and then replacing them in either the body of the woman or a surrogate. The most common type of ART is in vitro fertilization (IVF). For couples who cannot conceive naturally for whatever reason, IVF can be an option. Approximately 2 percent of babies born in the U.S. each year are the result of in vitro fertilization.

Though there are more options than ever before for couples who wish to conceive, science has not yet totally outrun the natural aging process. Though healthy men have a fairly large window of fertility and can conceive children into their later decades, healthy women are constrained by a more limited range of fertile years.

Women in their late teens and early 20s have the best chance of conceiving healthy children easily. As women enter their late 20s and early 30s, their chances remain good but decline slightly. In their late 30s, women can still conceive but may experience infertility issues and riskier pregnancies. And women in their early 40s have the slimmest chance of all to conceive—but before menopause, it is still possible.

Despite the biological limitations, assisted reproductive technologies improve with each passing year. So couples who are planning to get a later start on their families will have more and better chances in the coming years.

Menopause typically occurs between the ages of 45 and 55 for healthy women. It is made up of three distinct phases: perimenopause, menopause and postmenopause.

In perimenopause, which can last anywhere from four to 10 years, a woman typically experiences symptoms such as hot flashes, night sweats and vaginal dryness. Once she has not had a period in 12 months, she is "officially" in menopause and can no longer become pregnant. In postmenopause, her perimenopausal symptoms ease and eventually disappear.

Fertility is complicated and fraught with pitfalls. For many people, it is a source of joy: With pregnancy comes new life and new chapters. Its flip side, infertility, can be incredibly painful and cruel. Arming yourself with the facts can give you the knowledge you need to make choices that are best for you.

How common is infertility?

Infertility affects about 10 percent to 15 percent of couples in the United States, according to the American Pregnancy Association. The causes of infertility can be attributed to male factors, female factors or a combination of both; in some cases, the cause is unknown.

While men can often conceive children into their later decades, women are constrained by a more limited range of fertile years. By their late 30s, they can still conceive but may experience infertility issues and riskier pregnancies.

What are some options for infertile couples?

Assisted reproductive technology (ART) is any fertility treatment that involves the handling of eggs or embryos. The most common procedure is in vitro fertilization, or IVF. Approximately 2 percent of babies born in the U.S. each year are the result of in vitro fertilization.

To increase fertility in general, maintain healthy habits: avoid smoking and alcohol, minimize caffeine and keep strenuous exercise to a minimum.