Infertility
In biology, infertility is the inability of a male and female organism to reproduce. It is usually not the natural state of a healthy organism that has reached sexual maturity, so children who have not undergone puberty, which is the body's start of reproductive capacity, are excluded. It is also a normal state in women after menopause.
In humans, infertility is defined as the inability to become pregnant after at least one year of unprotected and regular sexual intercourse involving a male and female partner. There are many causes of infertility, including some that medical intervention can treat. Estimates from 1997, suggest that worldwide about five percent of all heterosexual couples have an unresolved problem with infertility. That figure has been on the rise, with the World Health Organization reporting in 2023 that about 17.5% of people experience infertility during their lifetime, while prevalence at a given time point is 12.6%. Many more couples, however, experience involuntary childlessness for at least one year, with estimates ranging from 12% to 28%.
Male infertility is responsible for 20–30% of infertility cases, while 20–35% are due to female infertility, and 25–40% are due to combined problems in both partners. In 10–20% of cases, no cause is found.
The most common causes of female infertility are hormonal in nature, including low estrogen, imbalanced GnRH secretion, PCOS, and aging, which generally manifests in sparse or absent menstrual periods leading up to menopause. As women age, the number of ovarian follicles and oocytes decline, leading to a reduced ovarian reserve. Some women undergo primary ovarian insufficiency or the loss of ovarian function before age 40, leading to infertility. 85% of infertile couples have an identifiable cause and 15% is designated unexplained infertility. Of the 85% of identified infertility, 25% is due to disordered ovulation. Tubal infertility is responsible for 11–67% of infertility in women of childbearing age, with the large range in prevalence due to different populations studied. Endometriosis, the presence of endometrial tissue outside of the uterus, accounts for 25–40% of female infertility.
Women who are fertile experience a period of fertility before and during ovulation, and are infertile for the rest of the menstrual cycle. Fertility awareness methods are used to discern when these changes occur by tracking changes in cervical mucus or basal body temperature.
Male infertility is most commonly due to deficiencies in the semen, and semen quality is used as a surrogate measure of male fecundity. Male infertility may also be due to retrograde ejaculation, low testosterone, functional azoospermia and obstructive azoospermia in which the pathway for the sperm is obstructed.
Definition
"Demographers tend to define infertility as childlessness in a population of women of reproductive age," whereas the epidemiological definition refers to "trying for" or "time to" a pregnancy, generally in a population of women exposed to a probability of conception. Currently, female fertility normally peaks in young adulthood and diminishes after 35 with pregnancy occurring rarely after age 50. A female is most fertile within 24 hours of ovulation. Male fertility peaks usually in young adulthood and declines after age 40.The time needed to pass for that couple to be diagnosed with infertility differs between different organizations. Existing definitions of infertility lack uniformity, rendering comparisons in prevalence between countries or over time problematic. Therefore, data estimating the prevalence of infertility cited by various sources differ significantly. A couple that tries unsuccessfully to have a child after a certain period is sometimes said to be subfertile, meaning less fertile than a typical couple. Both infertility and subfertility are defined similarly and often used interchangeably, but subfertility is the delay in conceiving within six to twelve months, whereas infertility is the inability to conceive naturally within a full year.
World Health Organization
The World Health Organization defines infertility as follows:United States
One definition of infertility that is frequently used in the United States by reproductive endocrinologists, doctors who specialize in infertility, to consider a couple eligible for treatment is:- a woman under 35 has not conceived after 12 months of contraceptive-free intercourse.
- a woman over 35 has not conceived after six months of contraceptive-free sexual intercourse.
United Kingdom
Other definitions
Researchers commonly base demographic studies on infertility prevalence over five years.Primary vs. secondary infertility
Primary infertility is defined as the absence of a live birth for women who desire a child and have been in a union for at least 12 months, during which they have not used any contraceptives. The World Health Organization also adds that 'women whose pregnancy spontaneously miscarries, or whose pregnancy results in a stillborn child, without ever having had a live birth, would present with primarily infertility'.Secondary infertility is defined as the difficulty in conceiving a live birth in couples who previously had a child.
Effects
Psychological
The consequences of infertility are manifold and can include societal repercussions and personal suffering. Advances in assisted reproductive technologies, such as IVF, can offer hope to many couples where treatment is available, although barriers exist in terms of medical coverage and affordability. The medicalization of infertility has unwittingly led to a disregard for the emotional responses that couples experience, which include distress, loss of control, stigmatization, and a disruption in the developmental trajectory of adulthood. One of the main challenges in assessing the distress levels in women with infertility is the accuracy of self-report measures. It is possible that women "fake good" to appear mentally healthier than they are. It is also possible that women feel a sense of hopefulness/increased optimism before initiating infertility treatment, which is when most assessments of distress are collected. Some early studies concluded that infertile women did not report any significant differences in symptoms of anxiety and depression than fertile women. The further into treatment a patient goes, the more often they display symptoms of depression and anxiety. Patients with one treatment failure had significantly higher levels of anxiety, and patients with two failures experienced more depression when compared with those without a history of treatment. However, it has also been shown that the more depressed the infertile woman, the less likely she is to start infertility treatment and the more likely she is to drop out after only one cycle. Researchers have also shown that despite a good prognosis and having the finances available to pay for treatment, discontinuation is most often due to psychological reasons. Fertility does not seem to increase when the women takes antioxidants to reduce the oxidative stress brought by the situation.Infertility may have psychological effects. Parenthood is one of the major transitions in adult life for both men and women. The stress of the non-fulfilment of a wish for a child has been associated with emotional consequences such as anger, depression, anxiety, marital problems, and feelings of worthlessness.
Partners may become more anxious to conceive, increasing sexual dysfunction. Marital discord often develops, especially when they are under pressure to make medical decisions. Women trying to conceive often have depression rates similar to women who have heart disease or cancer. Emotional stress and marital difficulties are greater in couples where the infertility lies with the man.
Male and female partners respond differently to infertility problems. In general, women show higher depression levels than their male partners when dealing with infertility. A possible explanation may be that women feel more responsible and guilty than men during the process of trying to conceive. On the other hand, infertile men experience psychosomatic distress.
Social
Having a child is considered to be important in most societies. Infertile couples may experience social and family pressure, leading to a feeling of social isolation. Factors of gender, age, religion, and socioeconomic status are important influences. Societal pressures may affect a couple's decision to approach, avoid, or experience an infertility treatment.Moreover, the socioeconomic status influences the psychology of infertile couples: low socioeconomic status is associated with increased chances of developing depression.
In many cultures, the inability to conceive bears a stigma. In closed social groups, a degree of rejection may cause considerable anxiety and disappointment. Some respond by actively avoiding the issue altogether.
In the United States, some treatments for infertility, including diagnostic tests, surgery, and therapy for depression, can qualify one for Family and Medical Leave Act leave. It has been suggested that infertility be classified as a form of disability.