Infertility has a wide range of causes stemming from three general sources: physiological dysfunctions, preventable causes, and unexplained issues. Anatomical, genetic, endocrinological and immunological problems can cause or contribute to infertility. Physiological causes of female infertility include: tubal blockage, abnormal ovulation, congenital malformation, and endometriosis. Male factors include issues with sperm counts, motility, and quality; and ejaculatory dysfunctions. Unexplained factors can emanate from the male or
female. In addition to the core prevalence of infertility due to physiological conditions, additional cases are caused by the incidence of preventable conditions such as infection, “lifestyle factors”, advancing maternal age, and environmental and occupational hazards.
Most primary and secondary infertility in developing countries is attributable to infectious disease and subsequent damage or blockage of the fallopian tubes. Tubal blockage is responsible for up to two-thirds of infertility in nulliparous women in sub-Saharan Africa, up to one-third of the infertility in other parts of the developing world and up to one-quarter in the developed world. Infection-related infertility can be caused by undiagnosed or poorly treated genital tract infections, sexually transmitted infections (STIs), or postpartum or postabortion infection. Infection and parasitic diseases such pelvic tuberculosis, schistosomiasis or malaria can also cause infertility. Finally, infection resulting from genital scarification or cutting can also cause infertility.
The most common preventable causes of infertility are sexually transmitted infection, especially Chlamydia and gonorrhea. Undiagnosed or inadequately treated Chlamydia and gonorrhea in women can lead to pelvic inflammatory disease (PID) which can lead to infertility. In men, chronic Chlamydia genital infection can also possibly lead to infertility. It is estimated that 40% of women in developed countries with inadequately treated Chlamydia develop PID with 20% of those becoming infertile due to tubal scarring. These rates could be higher in developing countries.
The potential for Chlamydia and gonorrhea to contribute to infertility rates is startling when the incidence and prevalence of these STIs is considered. Worldwide there are an estimated 62 million cases of gonorrhea and 92 million cases of genital Chlamydia every year. There are among the most easily transmitted STIs with one in every two acts of unprotected intercourse with an infected partner resulting in gonorrhea transmission and one in five acts of unprotected intercourse with an infected partner resulting in transmission of Chlamydia. While prevalence of Chlamydia infection is estimated between 2% and 27% of sexually active females, the true prevalence of Chlamydia is unknown and almost surely underreported because the infection is asymptomatic in half of infected men and three-quarters of women. On a population scale these STIs could have a large impact on fertility. 20% incidence of untreated gonorrhea in sexually active adults may reduce population growth as much as 50% due to infection-caused infertility. Fortunately, screening can identify these two diseases and both can successfully be treated.
Other preventable causes of infertility include “lifestyle factor”, a diverse group of issues such as obesity, weight gain and loss, eating disorders, malnutrition, excessive exercise, and use of nicotine, alcohol or caffeine. While these factors are important, their effects on infertility are considerably less than those of infection.
An increasing common cause of infertility in the developed world is advancing maternal age. As maternal age increases egg quality and ovulatory function diminish while risk of reproduction disorders such as endometriosis increases. As women delay childbearing in favour of pursuing education and vocation opportunities they face potentially increased difficulty in becoming pregnant.
Environmental and occupational hazards constitute another cause of infertility. The link between these hazards and decreased fertility is not always clearly established and is difficult to measure. However, there are more than 50 chemical found in the workplace and environment which are known to be associated with adverse reproductive outcomes in men and women. Additionally, there is a significant possibility for additional negative chemical-related harms; only a small number of the 60,000 chemical and 4 million chemical mixture in commercial use today have been tested for reproductive effects. Several occupations are associated with significantly higher rates of infertility and exposure to chemicals such as nitrous oxide, glycol ethers, organic solvents, soil fumigants, 1,2-dibromo-3-chloropropane (DBCP), pesticides, arsenic, aflatoxins and endocrine disruptors such as dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs), and dioxins are all associated with higher than average rates of infertility. Environmental exposure to reproductive toxicants may affect significantly greater numbers of people than toxicants encountered in specific occupational settings as individuals may come into contact with chemicals in a variety of ways including: direct exposure, industrial emission, pesticides and their residues, ingested foods, or contaminated water.
The causes of infertility discussed above are rooted in the Western, bio-medical paradigm and it is important to understand that infertility is understood differently in each sociocultural context in which it is experienced. Traditional knowledge in Anglophone Africa acknowledges both male and female causes of infertility, however in patriarchal societies men are protected and women are almost always blamed for involuntary childlessness. In Tanzania, for example, medical treatment for infertility is often delayed or precluded in favour of traditional and religious treatments because evil forces are often thought to be the cause of infertility. In Latin America, strong social stigma is attached to infertility and machismo attitudes create a dynamics where women blame themselves for infertility. In the Far East, Confucian texts recognize three elements that control reproduction, a male component, a female and an element with comes from both male and female. Infertility however is usually blamed on women and often seen as retribution for past wrong doing either on the part of the man, woman or one’s ancestors. When attempting to explore infertility from a social science perspective it is vital to investigate local perceptions in order to capture a culturally relevant understanding of infertility. While there are some global similarities in perceptions regarding infertility, such as the pervasive notion that women are usually to blame for unwanted childlessness, there is also variation in perceived causation and significance.
