|Percent of women in 2010, who have never had a child, who are unable to get pregnant|
|Causes||Women: Polycystic ovarian syndrome (PCOS), primary ovarian insufficiency, pelvic inflammatory disease, endometriosis, uterus fibroids|
Men: Varicocele, insufficient sperm, poorly mobile sperm
|Risk factors||Alcohol, smoking, older age, kidney disease, certain medications, sexually transmitted infections, being over or underweight, toxins such as lead|
|Treatment||Medications, surgery, assisted conception|
|Frequency||30 million (2017 males), 61 million (2017 females)|
Infertility is the inability of a couple to sexually reproduce by natural means. In humans it is defined as the inability to become pregnant after one year of trying (six months if a women is over 35 years). In this definition trying to get pregnant involves having unprotected sex every 2 to 3 days. The term is also used for those who are unable to stay pregnant.
Male infertility may occur due to a varicocele, insufficient sperm, or poorly mobile sperm. Female infertility may occur due to polycystic ovarian syndrome (PCOS), primary ovarian insufficiency, pelvic inflammatory disease, endometriosis, and uterus fibroids. Risk factors for infertility include alcohol, smoking, older age, kidney disease, certain medications, sexually transmitted infections, being over or underweight, and toxins such as lead. Diagnosis may include an examination of semen, ovarian ultrasound, and hysterosalpingography. In 25% of cases, no cause is found.
Treatment depends on the underlying cause and may include medications, surgery, or assisted conception. Medications may include clomifene to increase ovulation], metformin in those with PCOS, or gonadotrophins. surgical procedures may include repairing blocked fallopian tubes or removal of fibroids. Assisted conception may include intrauterine insemination, in vitro fertilization, or egg or sperm donation. Alternative medicine is not supported by evidence.
Difficulty getting pregnant affects about 10% to 14% of couples. About a third of cases are due to male infertility, a third female infertility, and a third a mixture of both. In 2017 about 30 million males were infertile and 61 million females were infertile globally.
"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 at age 24 and diminishes after 30, with pregnancy occurring rarely after age 50. A female is most fertile within 24 hours of ovulation. Male fertility peaks usually at age 25 and declines after age 40. The time needed to pass (during which the couple tries to conceive) for that couple to be diagnosed with infertility differs between different jurisdictions. 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 differs significantly. A couple that tries unsuccessfully to have a child after a certain period of time (often a short period, but definitions vary) is sometimes said to be "subfertile", meaning less fertile than a typical couple. Both infertility and subfertility are defined as the inability to conceive after a certain period of time (the length of which vary), so often the two terms overlap.
World Health Organization
Infertility is “a disease of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse (and there is no other reason, such as breastfeeding or postpartum amenorrhoea). Primary infertility is infertility in a couple who have never had a child. Secondary infertility is failure to conceive following a previous pregnancy. Infertility may be caused by infection in the man or woman, but often there is no obvious underlying cause.
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. Twelve months is the lower reference limit for Time to Pregnancy (TTP) by the World Health Organization.
- a woman over 35 has not conceived after six months of contraceptive-free sexual intercourse.
These time intervals would seem to be reversed; this is an area where public policy trumps science. The idea is that for women beyond age 35, every month counts and if made to wait another six months to prove the necessity of medical intervention, the problem could become worse. The corollary to this is that, by definition, failure to conceive in women under 35 isn't regarded with the same urgency as it is in those over 35.
In the UK, previous NICE guidelines defined infertility as failure to conceive after regular unprotected sexual intercourse for two years in the absence of known reproductive pathology. Updated NICE guidelines do not include a specific definition, but recommend that "A woman of reproductive age who has not conceived after 1 year of unprotected vaginal sexual intercourse, in the absence of any known cause of infertility, should be offered further clinical assessment and investigation along with her partner, with earlier referral to a specialist if the woman is over 36 years of age."
Researchers commonly base demographic studies on infertility prevalence on a five-year period. Practical measurement problems, however, exist for any definition, because it is difficult to measure continuous exposure to the risk of pregnancy over a period of 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 Organisation also adds that 'women whose pregnancy spontaneously miscarries, or whose pregnancy results in a still born child, without ever having had a live birth would present with primarily infertility'.
Secondary 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 since their last live birth, during which they did not use any contraceptives.
Thus the distinguishing feature is whether or not the couple have ever had a pregnancy which led to a live birth.
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” in order to appear mentally healthier than they are. It is also possible that women feel a sense of hopefulness/increased optimism prior to 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.
Infertility may have psychological effects. 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.
Older people with adult children appear to live longer. Why this is the case is unclear and may dependent in part on those who have children adopting a healthier lifestyle, support from children, or the circumstances that led to not having children.
In many cultures, inability to conceive bears a stigma. In closed social groups, a degree of rejection (or a sense of being rejected by the couple) may cause considerable anxiety and disappointment. Some respond by actively avoiding the issue altogether; middle-class men are the most likely to respond in this way.
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.
Antisperm antibodies (ASA) have been considered as infertility cause in around 10–30% of infertile couples. In both men and women, ASA production are directed against surface antigens on sperm, which can interfere with sperm motility and transport through the female reproductive tract, inhibiting capacitation and acrosome reaction, impaired fertilization, influence on the implantation process, and impaired growth and development of the embryo. The antibodies are classified into different groups: There are IgA, IgG and IgM antibodies. They also differ in the location of the spermatozoon they bind on (head, mid piece, tail). Factors contributing to the formation of antisperm antibodies in women are disturbance of normal immunoregulatory mechanisms, infection, violation of the integrity of the mucous membranes, rape and unprotected oral or anal sex. Risk factors for the formation of antisperm antibodies in men include the breakdown of the blood‑testis barrier, trauma and surgery, orchitis, varicocele, infections, prostatitis, testicular cancer, failure of immunosuppression and unprotected receptive anal or oral sex with men.
Sexually transmitted infections
Infections with the following sexually transmitted pathogens have a negative effect on fertility: Chlamydia trachomatis and Neisseria gonorrhoeae. There is a consistent association of Mycoplasma genitalium infection and female reproductive tract syndromes. M. genitalium infection is associated with increased risk of infertility.
Mutations to NR5A1 gene encoding Steroidogenic Factor-1 (SF-1) have been found in a small subset of men with non-obstructive male factor infertility where the cause is unknown. Results of one study investigating a cohort of 315 men revealed changes within the hinge region of SF-1 and no rare allelic variants in fertile control men. Affected individuals displayed more severe forms of infertility such as azoospermia and severe oligozoospermia.
Factors that can cause male as well as female infertility are:
- DNA damage
- DNA damage reduces fertility in female ovocytes, as caused by smoking, other xenobiotic DNA damaging agents (such as radiation or chemotherapy) or accumulation of the oxidative DNA damage 8-hydroxy-deoxyguanosine
- DNA damage reduces fertility in male sperm, as caused by oxidative DNA damage, smoking, other xenobiotic DNA damaging agents (such as drugs or chemotherapy) or other DNA damaging agents including reactive oxygen species, fever or high testicular temperature. The damaged DNA related to infertility manifests itself by the increased susceptibility to denaturation inducible by heat or acid  or by the presence of double-strand breaks that can be detected by the TUNEL assay.
- General factors
- Hypothalamic-pituitary factors
- Environmental factors
German scientists have reported that a virus called adeno-associated virus might have a role in male infertility, though it is otherwise not harmful. Other diseases such as chlamydia, and gonorrhea can also cause infertility, due to internal scarring (fallopian tube obstruction).
- Alimentary habits
- Obesity: The obesity epidemic has recently become is a serious issue, particularly in industrialized nations. The rising number of obese individuals may be due in part to an energy-rich diet as well as insufficient physical exercise. In addition to other potential health risks, obesity can have a significant impact on male and female fertility. BMI (body mass index) may be a significant factor in fertility, as an increase in BMI in the male by as little as three units can be associated with infertility. Several studies have demonstrated that an increase in BMI is correlated with a decrease in sperm concentration, a decrease in motility and an increase DNA damage in sperm. A relationship also exists between obesity and erectile dysfunction (ED). ED may be the consequence of the conversion of androgens to estradiol. The enzyme aromatase is responsible for this conversion, and is found primarily in adipose tissue. As the amount of adipose tissue increases, there is more aromatase available to convert androgens, and serum estradiol levels increase. Other hormones including inhibin B and leptin, may also be affected by obesity. Inhibin B levels have been reported to decrease with increasing weight, which results in decreased Sertoli cells and sperm production. Leptin is a hormone associated with numerous effects including appetite control, inflammation, and decreased insulin secretion, according to many studies. Obese women have a higher rate of recurrent, early miscarriage compared to non-obese women.
- Low weight: Obesity is not the only way in which weight can impact fertility. Men who are underweight tend to have lower sperm concentrations than those who are at a normal BMI. For women, being underweight and having extremely low amounts of body fat are associated with ovarian dysfunction and infertility and they have a higher risk for preterm birth. Eating disorders such as anorexia nervosa are also associated with extremely low BMI. Although relatively uncommon, eating disorders can negatively affect menstruation, fertility, and maternal and fetal well-being.
The following causes of infertility may only be found in females. For a woman to conceive, certain things have to happen: vaginal intercourse must take place around the time when an egg is released from her ovary; the system that produces eggs has to be working at optimum levels; and her hormones must be balanced.
For women, problems with fertilisation arise mainly from either structural problems in the Fallopian tube or uterus or problems releasing eggs. Infertility may be caused by blockage of the Fallopian tube due to malformations, infections such as chlamydia or scar tissue. For example, endometriosis can cause infertility with the growth of endometrial tissue in the Fallopian tubes or around the ovaries. Endometriosis is usually more common in women in their mid-twenties and older, especially when postponed childbirth has taken place.
Another major cause of infertility in women may be the inability to ovulate. Malformation of the eggs themselves may complicate conception. For example, polycystic ovarian syndrome is when the eggs only partially develop within the ovary and there is an excess of male hormones. Some women are infertile because their ovaries do not mature and release eggs. In this case synthetic FSH by injection or Clomid (Clomiphene citrate) via a pill can be given to stimulate follicles to mature in the ovaries.
Other factors that can affect a woman's chances of conceiving include being overweight or underweight, or her age as female fertility declines after the age of 30.
Sometimes it can be a combination of factors, and sometimes a clear cause is never established.
Common causes of infertility of females include:
- ovulation problems (e.g. polycystic ovarian syndrome, PCOS, the leading reason why women present to fertility clinics due to anovulatory infertility.)
- tubal blockage
- pelvic inflammatory disease caused by infections like tuberculosis
- age-related factors
- uterine problems
- previous tubal ligation
- advanced maternal age
- immune infertility
The main cause of male infertility is low semen quality. In men who have the necessary reproductive organs to procreate, infertility can be caused by low sperm count due to endocrine problems, drugs, radiation, or infection. There may be testicular malformations, hormone imbalance, or blockage of the man's duct system. Although many of these can be treated through surgery or hormonal substitutions, some may be indefinite. Infertility associated with viable, but immotile sperm may be caused by primary ciliary dyskinesia. The sperm must provide the zygote with DNA, centrioles, and activation factor for the embryo to develop. A defect in any of these sperm structures may result in infertility that will not be detected by semen analysis. Antisperm antibodies cause immune infertility. Cystic fibrosis can lead to infertility in men.
In some cases, both the man and woman may be infertile or sub-fertile, and the couple's infertility arises from the combination of these conditions. In other cases, the cause is suspected to be immunological or genetic; it may be that each partner is independently fertile but the couple cannot conceive together without assistance.
In the US, up to 20% of infertile couples have unexplained infertility. In these cases abnormalities are likely to be present but not detected by current methods. Possible problems could be that the egg is not released at the optimum time for fertilization, that it may not enter the fallopian tube, sperm may not be able to reach the egg, fertilization may fail to occur, transport of the zygote may be disturbed, or implantation fails. It is increasingly recognized that egg quality is of critical importance and women of advanced maternal age have eggs of reduced capacity for normal and successful fertilization. Also, polymorphisms in folate pathway genes could be one reason for fertility complications in some women with unexplained infertility. However, a growing body of evidence suggests that epigenetic modifications in sperm may be partially responsible.
If both partners are young and healthy and have been trying to conceive for one year without success, a visit to a physician or women's health nurse practitioner (WHNP) could help to highlight potential medical problems earlier rather than later. The doctor or WHNP may also be able to suggest lifestyle changes to increase the chances of conceiving.
Women over the age of 35 should see their physician or WHNP after six months as fertility tests can take some time to complete, and age may affect the treatment options that are open in that case.
A doctor or WHNP takes a medical history and gives a physical examination. They can also carry out some basic tests on both partners to see if there is an identifiable reason for not having achieved a pregnancy. If necessary, they refer patients to a fertility clinic or local hospital for more specialized tests. The results of these tests help determine the best fertility treatment.
Treatment depends on the cause of infertility, but may include counselling, fertility treatments, which include in vitro fertilization. According to ESHRE recommendations, couples with an estimated live birth rate of 40% or higher per year are encouraged to continue aiming for a spontaneous pregnancy. Treatment methods for infertility may be grouped as medical or complementary and alternative treatments. Some methods may be used in concert with other methods. Drugs used for both women and men include clomiphene citrate, human menopausal gonadotropin (hMG), follicle-stimulating hormone (FSH), human chorionic gonadotropin (hCG), gonadotropin-releasing hormone (GnRH) analogues, aromatase inhibitors, and metformin.
Medical treatment of infertility generally involves the use of fertility medication, medical device, surgery, or a combination of the following. If the sperm are of good quality and the mechanics of the woman's reproductive structures are good (patent fallopian tubes, no adhesions or scarring), a course of ovulation induction maybe used. The physician or WHNP may also suggest using a conception cap cervical cap, which the patient uses at home by placing the sperm inside the cap and putting the conception device on the cervix, or intrauterine insemination (IUI), in which the doctor or WHNP introduces sperm into the uterus during ovulation, via a catheter. In these methods, fertilization occurs inside the body.
If conservative medical treatments fail to achieve a full term pregnancy, the physician or WHNP may suggest the patient undergo in vitro fertilization (IVF). IVF and related techniques (ICSI, ZIFT, GIFT) are called assisted reproductive technology (ART) techniques.
ART techniques generally start with stimulating the ovaries to increase egg production. After stimulation, the physician surgically extracts one or more eggs from the ovary, and unites them with sperm in a laboratory setting, with the intent of producing one or more embryos. Fertilization takes place outside the body, and the fertilized egg is reinserted into the woman's reproductive tract, in a procedure called embryo transfer.
In vitro fertilization
IVF is the most commonly used ART. It has been proven useful in overcoming infertility conditions, such as blocked or damaged tubes, endometriosis, repeated IUI failure, unexplained infertility, poor ovarian reserve, poor or even nil sperm count.
Intracytoplasmic sperm injection
ICSI technique is used in case of poor semen quality, low sperm count or failed fertilization attempts during prior IVF cycles. This technique involves an injection of a single healthy sperm directly injected into mature egg. The fertilized embryo is then transferred to womb.
Fertility tourism is the practice of traveling to another country for fertility treatments. It may be regarded as a form of medical tourism. The main reasons for fertility tourism are legal regulation of the sought procedure in the home country, or lower price. In-vitro fertilization and donor insemination are major procedures involved.
Stem cell therapy
Nowadays, there are several treatments (still in experimentation) related to stem cell therapy. It is a new opportunity, not only for partners with lack of gametes, but also for homosexuals and single people who want to have offspring. Theoretically, with this therapy, we can get artificial gametes in vitro. There are different studies for both women and men.
- Spermatogonial stem cells transplant: it takes places in the seminiferous tubule. With this treatment, the patient experience spermatogenesis, and therefore, it has the chance to have offspring if he wants to. It is specially oriented for cancer patients, whose sperm is destroyed due to the gonadotoxic treatment they are submitted to.
- Ovarian stem cells: it is thought that women have a finite number of follicles from the very beginning. Nevertheless, scientists have found these stem cells, which may generate new oocytes in postnatal conditions. Apparently there are only 0.014% of them (this could be an explanation of why they were not discovered until now). There is still some controversy about their existence, but if the discoveries are true, this could be a new treatment for infertility.
Stem cell therapy is really new, and everything is still under investigation. Additionally, it could be the future for the treatment of multiple diseases, including infertility. It will take time before these studies can be available for clinics and patients.
Prevalence of infertility varies depending on the definition, i.e. on the time span involved in the failure to conceive.
- Infertility rates have increased by 4% since the 1980s, mostly from problems with fecundity due to an increase in age.
- Fertility problems affect one in seven couples in the UK. Most couples (about 84%) who have regular sexual intercourse (that is, every two to three days) and who do not use contraception get pregnant within a year. About 92 out of 100 couples who are trying to get pregnant do so within two years.
- Women become less fertile as they get older. For women aged 35, about 94% who have regular unprotected sexual intercourse get pregnant after three years of trying. For women aged 38, however, only about 77%. The effect of age upon men's fertility is less clear.
- In people going forward for IVF in the UK, roughly half of fertility problems with a diagnosed cause are due to problems with the man, and about half due to problems with the woman. However, about one in five cases of infertility has no clear diagnosed cause.
- In Britain, male factor infertility accounts for 25% of infertile couples, while 25% remain unexplained. 50% are female causes with 25% being due to anovulation and 25% tubal problems/other.
- In Sweden, approximately 10% of couples wanting children are infertile. In approximately one third of these cases the man is the factor, in one third the woman is the factor, and in the remaining third the infertility is a product of factors on both parts.
Society and culture
Perhaps except for infertility in science fiction, films and other fiction depicting emotional struggles of assisted reproductive technology have had an upswing first in the later part of the 2000s decade, although the techniques have been available for decades. Yet, the number of people that can relate to it by personal experience in one way or another is ever growing, and the variety of trials and struggles is huge.
Other individual examples are referred to individual subarticles of assisted reproductive technology
There are several ethical issues associated with infertility and its treatment.
- High-cost treatments are out of financial reach for some couples.
- Debate over whether health insurance companies (e.g. in the US) should be required to cover infertility treatment.
- Allocation of medical resources that could be used elsewhere
- The legal status of embryos fertilized in vitro and not transferred in vivo. (See also beginning of pregnancy controversy).
- Pro-life opposition to the destruction of embryos not transferred in vivo.
- IVF and other fertility treatments have resulted in an increase in multiple births, provoking ethical analysis because of the link between multiple pregnancies, premature birth, and a host of health problems.
- Religious leaders' opinions on fertility treatments; for example, the Roman Catholic Church views infertility as a calling to adopt or to use natural treatments (medication, surgery, or cycle charting) and members must reject assisted reproductive technologies.
- Infertility caused by DNA defects on the Y chromosome is passed on from father to son. If natural selection is the primary error correction mechanism that prevents random mutations on the Y chromosome, then fertility treatments for men with abnormal sperm (in particular ICSI) only defer the underlying problem to the next male generation.
Many countries have special frameworks for dealing with the ethical and social issues around fertility treatment.
- One of the best known is the HFEA – The UK's regulator for fertility treatment and embryo research. This was set up on 1 August 1991 following a detailed commission of enquiry led by Mary Warnock in the 1980s
- A similar model to the HFEA has been adopted by the rest of the countries in the European Union. Each country has its own body or bodies responsible for the inspection and licensing of fertility treatment under the EU Tissues and Cells directive 
- Regulatory bodies are also found in Canada  and in the state of Victoria in Australia 
- Advanced maternal age
- Voluntary childlessness
- Human overpopulation
- Population control
- Conception device
- Birth control
- Inherited sterility in insects
- Medical ethics
- Mossman-Pacey paradox
- Oncofertility, fertility in cancer patients
- Surrogate marriage
- Mascarenhas, MN; Flaxman, SR; Boerma, T; Vanderpoel, S; Stevens, GA (2012). "National, regional, and global trends in infertility prevalence since 1990: a systematic analysis of 277 health surveys". PLoS medicine. 9 (12): e1001356. doi:10.1371/journal.pmed.1001356. PMID 23271957.
- "Infertility - NHS". nhs.uk. 23 October 2017. Retrieved 24 October 2020.
- "Infertility". womenshealth.gov. 8 March 2017. Retrieved 24 October 2020.
- "treatment for infertility - NHS". nhs.uk. 23 October 2017. Retrieved 24 October 2020.
- GBD 2017 Disease and Injury Incidence and Prevalence, Collaborators. (10 November 2018). "Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017". Lancet (London, England). 392 (10159): 1789–1858. doi:10.1016/S0140-6736(18)32279-7. PMID 30496104.
- "Causes of infertility". National Health Service. 18 February 2020.
- Gurunath S, Pandian Z, Anderson RA, Bhattacharya S (2011). "Defining infertility--a systematic review of prevalence studies". Human Reproduction Update. 17 (5): 575–88. doi:10.1093/humupd/dmr015. PMID 21493634.
- Tamparo, Carol; Lewis, Marcia (2011). Diseases of the Human Body. Philadelphia, PA: F.A. Davis Company. pp. 459. ISBN 9780803625051.
- "WHO | Infertility". Who.int. 19 March 2013. Retrieved 17 June 2013.
- Cooper TG, Noonan E, von Eckardstein S, Auger J, Baker HW, Behre HM, Haugen TB, Kruger T, Wang C, Mbizvo MT, Vogelsong KM (2010). "World Health Organization reference values for human semen characteristics". Hum. Reprod. Update. 16 (3): 231–45. doi:10.1093/humupd/dmp048. PMID 19934213.
- Fertility: Assessment and Treatment for People with Fertility Problems (PDF). London: RCOG Press. 2004. ISBN 978-1-900364-97-3. Archived from the original (PDF) on 15 November 2010.
- "Fertility: assessment and treatment for people with fertility problems, section: Defining infertility". NICE Clinical guidelines, CG156. February 2013.
- "WHO | Infertility definitions and terminology".
- Cousineau TM, Domar AD (2007). "Psychological impact of infertility". Best Pract Res Clin Obstet Gynaecol. 21 (2): 293–308. doi:10.1016/j.bpobgyn.2006.12.003. PMID 17241818.
- Rooney, Kristin L.; Domar, Alice D. (March 2018). "Dialogues in Clinical Neuroscience". The Relationship Between Stress and Infertility. 20 (1294–8322): 41–47. PMC 6016043. PMID 29946210.
- Donor insemination Edited by C.L.R. Barratt and I.D. Cooke. Cambridge (England): Cambridge University Press, 1993. 231 pages., page 13, citing Berger (1980)
- Domar AD, Zuttermeister PC, Friedman R (1993). "The psychological impact of infertility: a comparison with patients with other medical conditions". J Psychosom Obstet Gynecol. 14 (Suppl): 45–52. PMID 8142988.
- Donor insemination Edited by C.L.R. Barratt and I.D. Cooke. Cambridge (England): Cambridge University Press, 1993. 231 pages., page 13, in turn citing Connolly, Edelmann & Cooke 1987
- Childlessness in Europe: Contexts, Causes, and Consequences. Springer. 2017. p. 352. ISBN 978-3-319-44667-7.
- Schmidt L, Christensen U, Holstein BE (April 2005). "The social epidemiology of coping with infertility". Hum. Reprod. 20 (4): 1044–52. doi:10.1093/humrep/deh687. PMID 15608029.
- Khetarpal A, Singh S (2012). "Infertility: Why can't we classify this inability as disability?". The Australasian Medical Journal. 5 (6): 334–9. doi:10.4066/AMJ.2012.1290. PMC 3395292. PMID 22848333.
- Restrepo, B.; Cardona-Maya, W. (October 2013). "Antisperm antibodies and fertility association". Actas Urologicas Espanolas. 37 (9): 571–578. doi:10.1016/j.acuro.2012.11.003. ISSN 1699-7980. PMID 23428233.
- Rao, Kamini (30 September 2013). Principles & Practice of Assisted Reproductive Technology (3 Vols). JP Medical Ltd. ISBN 9789350907368.
- Lis, R.; Rowhani-Rahbar, A.; Manhart, L. E. (2015). "Mycoplasma genitalium Infection and Female Reproductive Tract Disease: A Meta-Analysis". Clinical Infectious Diseases. 61 (3): 418–26. doi:10.1093/cid/civ312. ISSN 1058-4838. PMID 25900174.
- Ljubin-Sternak, Suncanica; Mestrovic, Tomislav (2014). "Review: Chlamydia trachonmatis and Genital Mycoplasmias: Pathogens with an Impact on Human Reproductive Health". Journal of Pathogens. 2014 (183167): 183167. doi:10.1155/2014/183167. PMC 4295611. PMID 25614838.
- Ferraz-de-Souza, Bruno; Lin, Lin; Achermann, John C. (10 April 2011). "Steroidogenic factor-1 (SF-1, NR5A1) and human disease". Molecular and Cellular Endocrinology. 336 (1–2): 198–205. doi:10.1016/j.mce.2010.11.006. ISSN 0303-7207. PMC 3057017. PMID 21078366.
- Zenzes MT (2000). "Smoking and reproduction: gene damage to human gametes and embryos". Hum. Reprod. Update. 6 (2): 122–31. doi:10.1093/humupd/6.2.122. PMID 10782570.
- Mark-Kappeler CJ, Hoyer PB, Devine PJ (November 2011). "Xenobiotic effects on ovarian preantral follicles". Biol. Reprod. 85 (5): 871–83. doi:10.1095/biolreprod.111.091173. PMC 3197911. PMID 21697514.
- Seino T, Saito H, Kaneko T, Takahashi T, Kawachiya S, Kurachi H (June 2002). "Eight-hydroxy-2'-deoxyguanosine in granulosa cells is correlated with the quality of oocytes and embryos in an in vitro fertilization-embryo transfer program". Fertil. Steril. 77 (6): 1184–90. doi:10.1016/s0015-0282(02)03103-5. PMID 12057726.
- Gharagozloo P, Aitken RJ (July 2011). "The role of sperm oxidative stress in male infertility and the significance of oral antioxidant therapy". Hum. Reprod. 26 (7): 1628–40. doi:10.1093/humrep/der132. PMID 21546386.
- Nili HA, Mozdarani H, Pellestor F (2011). "Impact of DNA damage on the frequency of sperm chromosomal aneuploidy in normal and subfertile men". Iran. Biomed. J. 15 (4): 122–9. doi:10.6091/ibj.990.2012. PMC 3614247. PMID 22395136.
- Shamsi MB, Imam SN, Dada R (November 2011). "Sperm DNA integrity assays: diagnostic and prognostic challenges and implications in management of infertility". J. Assist. Reprod. Genet. 28 (11): 1073–85. doi:10.1007/s10815-011-9631-8. PMC 3224170. PMID 21904910.
- Evenson DP, Darzynkiewicz Z, Melamed MR (1980). "Relation of mammalian sperm chromatin heterogeneity to fertility". Science. 210 (4474): 1131–1133. Bibcode:1980Sci...210.1131E. doi:10.1126/science.7444440. PMID 7444440.CS1 maint: multiple names: authors list (link)
- Gorczyca W, Traganos F, Jesionowska H, Darzynkiewicz Z (1993). "Presence of DNA strand breaks and increased sensitivity of DNA in situ to denaturation in abnormal human sperm cells. Analogy to apoptosis of somatic cells". Exp Cell Res. 207 (1): 202–205. doi:10.1006/excr.1993.1182. PMID 8391465.CS1 maint: multiple names: authors list (link)
- Jangir RN, Jain GC (May 2014). "Diabetes mellitus induced impairment of male reproductive functions: a review". Curr Diabetes Rev. 10 (3): 147–57. doi:10.2174/1573399810666140606111745. PMID 24919656.
- Livshits A, Seidman DS (November 2009). "Fertility issues in women with diabetes". Womens Health (Lond Engl). 5 (6): 701–7. doi:10.2217/whe.09.47. PMID 19863473.
- Andreeva P (2014). "[Thyroid gland and fertility] [Article in Bulgarian]". Akush Ginekol (Sofiia). 53 (7): 18–23. PMID 25675618.
- Tersigni C, Castellani R, de Waure C, Fattorossi A, De Spirito M, Gasbarrini A, Scambia G, Di Simone N (2014). "Celiac disease and reproductive disorders: meta-analysis of epidemiologic associations and potential pathogenic mechanisms". Hum. Reprod. Update. 20 (4): 582–93. doi:10.1093/humupd/dmu007. PMID 24619876.
Physicians should investigate women with unexplained infertility, recurrent miscarriage or IUGR for undiagnosed CD. (...) CD can present with several non-gastrointestinal symptoms and it may escape timely recognition. Thus, given the heterogeneity of clinical presentation, many atypical cases of CD go undiagnosed, leading to a risk of long-term complications. Among atypical symptoms of CD, disorders of fertility, such as delayed menarche, early menopause, amenorrhea or infertility, and pregnancy complications, such as recurrent abortions, intrauterine growth restriction (IUGR), small for gestational age (SGA) babies, low birthweight (LBW) babies or preterm deliveries, must be factored. (...) However, the risk is significantly reduced by a gluten-free diet. These patients should therefore be made aware of the potential negative effects of active CD also in terms of reproductive performances, and of the importance of a strict diet to ameliorate their health condition and reproductive health.
- Lasa, JS; Zubiaurre, I; Soifer, LO (2014). "Risk of infertility in patients with celiac disease: a meta-analysis of observational studies". Arq Gastroenterol. 51 (2): 144–50. doi:10.1590/S0004-28032014000200014. PMID 25003268.
Undiagnosed celiac disease is a risk factor for infertility. Women seeking medical advice for this particular condition should be screened for celiac disease. Adoption of a gluten-free diet could have a positive impact on fertility in this group of patients.(...)According to our results, non-diagnosed untreated CD constitutes a risk factor significantly associated with infertility in women. When comparing studies that enrolled patients previously diagnosed with CD, this association is not as evident as in the former context. This could be related to the effect that adoption of a gluten-free diet (GFD) may have on this particular health issue.
- Hozyasz, K (March 2001). "Coeliac disease and problems associated with reproduction". Ginekol Pol. 72 (3): 173–9. PMID 11398587.
Coeliac men may have reversible infertility, and as in women, if gastrointestinal symptoms are mild or absent the diagnosis may be missed. It is important to make diagnosis because the giving of gluten free diet may result in conception and favourable outcome of pregnancy.
- Sher, KS; Jayanthi, V; Probert, CS; Stewart, CR; Mayberry, JF (1994). "Infertility, obstetric and gynaecological problems in coeliac sprue". Dig Dis. 12 (3): 186–90. doi:10.1159/000171452. PMID 7988065.
There is now substantial evidence that coeliac sprue is associated with infertility both in men and women. (...) In men it can cause hypogonadism, immature secondary sex characteristics and reduce semen quality. (...) Hyperprolactinaemia is seen in 25% of coeliac patients, which causes impotence and loss of libido. Gluten withdrawal and correction of deficient dietary elements can lead to a return of fertility both in men and women.
- Reichman DE, White PC, New MI, Rosenwaks Z (February 2014). "Fertility in patients with congenital adrenal hyperplasia". Fertil Steril. 101 (2): 301–9. doi:10.1016/j.fertnstert.2013.11.002. PMID 24355046.
- van den Boogaard E, Vissenberg R, Land JA, van Wely M, van der Post JA, Goddijn M, Bisschop PH (2011). "Significance of (sub)clinical thyroid dysfunction and thyroid autoimmunity before conception and in early pregnancy: A systematic review" (PDF). Human Reproduction Update. 17 (5): 605–619. doi:10.1093/humupd/dmr024. PMID 21622978.
- Mendiola J, Torres-Cantero AM, Moreno-Grau JM, Ten J, Roca M, Moreno-Grau S, Bernabeu R (June 2008). "Exposure to environmental toxins in males seeking infertility treatment: a case-controlled study". Reprod Biomed Online. 16 (6): 842–50. doi:10.1016/S1472-6483(10)60151-4. PMID 18549695.[permanent dead link]
- Smith EM, Hammonds-Ehlers M, Clark MK, Kirchner HL, Fuortes L (February 1997). "Occupational exposures and risk of female infertility". J Occup Environ Med. 39 (2): 138–47. doi:10.1097/00043764-199702000-00011. PMID 9048320.
- Regulated fertility services: a commissioning aid – June 2009, from the Department of Health UK
- "Common virus linked to male infertility - 26 October 2001". New Scientist. 26 October 2001. Retrieved 17 June 2013.
- "Virus linked to infertility". BBC News. 27 October 2001. Retrieved 2 April 2010.
- "Infertility & STDs - STD Information from CDC". cdc.gov. 11 January 2019.
- Martha E. Wittenberg. "STDs That Can Cause Infertility". LIVESTRONG.COM.
- "5 Most Common Causes of Infertility". HowStuffWorks. 17 February 2011.
- Sharma R, Biedenharn KR, Fedor JM, Agarwal A (2013). "Lifestyle factors and reproductive health: taking control of your fertility". Reprod Biol Endocrinol. 11: 66. doi:10.1186/1477-7827-11-66. PMC 3717046. PMID 23870423.CS1 maint: multiple names: authors list (link)
- About infertility & fertility problems Archived 29 August 2008 at the Wayback Machine from the Human Fertilisation and Embryology Authority.
- Lessy, B.A. (2000) Medical management of endometriosis and infertility: 1089-1096.
- "Female Infertility". Mayo Clinic. Retrieved 21 September 2020.
- Balen AH, Dresner M, Scott EM, Drife JO (2006). "Should obese women with polycystic ovary syndrome receive treatment for infertility?". BMJ. 332 (7539): 434–5. doi:10.1136/bmj.332.7539.434. PMC 1382524. PMID 16497735.
- Mishail, A., et al. (2009) Impact of a second semen analysis on a treatment decision making in the infertile man with varicocele: 1809-1811
- Avidor-Reiss T, Khire A, Fishman EL, Jo KH (April 2015). "Atypical centrioles during sexual reproduction". Front Cell Dev Biol. 3: 21. doi:10.3389/fcell.2015.00021. PMC 4381714. PMID 25883936.
- Altmäe S, Stavreus-Evers A, Ruiz JR, Laanpere M, Syvänen T, Yngve A, Salumets A, Nilsson TK (2010). "Variations in folate pathway genes are associated with unexplained female infertility". Fertility and Sterility. 94 (1): 130–137. doi:10.1016/j.fertnstert.2009.02.025. PMID 19324355.
- Kenneth I. Aston; Philip J. Uren; Timothy G. Jenkins; Alan Horsager; Bradley R. Cairns; Andrew D. Smith; Douglas T. Carrell (December 2015). "Aberrant sperm DNA methylation predicts male fertility status and embryo quality". Fertility and Sterility. 104 (6): 1388–1397. doi:10.1016/j.fertnstert.2015.08.019. PMID 26361204.
- Dada R, Kumar M, Jesudasan R, Fernández JL, Gosálvez J, Agarwal A (2012). "Epigenetics and its role in male infertility". J. Assist. Reprod. Genet. 29 (3): 213–23. doi:10.1007/s10815-012-9715-0. PMC 3288140. PMID 22290605.
- Infertility Help: When & where to get help for fertility treatment Archived 25 December 2008 at the Wayback Machine
- ESHRE Capri Workshop Group (2013). "Failures (with some successes) of assisted reproduction and gamete donation programs". Human Reproduction Update. 19 (4): 354–365. doi:10.1093/humupd/dmt007. PMID 23459992.
- Edmund S. Sabanegh, Jr. (20 October 2010). Male Infertility: Problems and Solutions. Springer Science & Business Media. pp. 82–83. ISBN 978-1-60761-193-6.
- Vassena, R; Eguizabal, C; Heindryckx, B; Sermon, K (2015). "Stem cells in reproductive medicine: Ready for the patient?". Hum. Reprod. 30 (9): 2014–2021. doi:10.1093/humrep/dev181. PMID 26202914.
- Hermann, BP; Sukhwani, M; Winkler, F; Pascarella, JN (2012). "Spermatogonial stem cell transplantation into rhesus testes regenerates spermatogenesis producing functional sperm". Cell Stem Cell. 11 (5): 715–26. doi:10.1016/j.stem.2012.07.017. PMC 3580057. PMID 23122294.
- Johnson, J; Canning, J; Kaneko, T; Pru, JK (2004). "Germline stem cells and follicular renewal in the postnatal mammalian ovary". Nature. 428 (March(6979)): 145–50. Bibcode:2004Natur.428..145J. doi:10.1038/nature02316. PMID 15014492. S2CID 1124530.
- Maheshwari, A. (2008). Human Reproduction. pp. 538–542.
- "HFEA Chart on reasons for infertility". Archived from the original on 30 May 2008. Retrieved 2 June 2008.
- Khan, Khalid; Janesh K. Gupta; Gary Mires (2005). Core clinical cases in obstetrics and gynaecology: a problem-solving approach. London: Hodder Arnold. p. 152. ISBN 978-0-340-81672-1.
- Sahlgrenska University Hospital. (translated from the Swedish sentence: "Cirka 10% av alla par har problem med ofrivillig barnlöshet." Archived 26 June 2008 at the Wayback Machine)
- chicagotribune.com Heartache of infertility shared on stage, screen By Colleen Mastony, Tribune reporter. 21 June 2009
- O'Neill Desmond (2009). "Up with ageing". BMJ. 339: b4215. doi:10.1136/bmj.b4215. S2CID 73118359.
- "EUROPA". europa.eu. Archived from the original on 21 May 2008.
- Assisted Human Reproduction Canada Archived 23 May 2008 at the Wayback Machine
- "Independent Theatre Association".
- Inhorn MC (2003). "Global infertility and the globalization of new reproductive technologies: illustrations from Egypt". Social Science & Medicine. 56 (9): 1837–1851. doi:10.1016/s0277-9536(02)00208-3. PMID 12650724.
- Lock, Margaret and Vinh-Kim Nguyen. 2011. An anthropology of biomedicine: Wiley-Blackwell.
- Gerrits T, Shaw M (2010). "Biomedical infertility care in sub-Saharan Africa: a social science review of current practices, experiences and view points". Facts, Views & Vision in ObGyn. 2 (3): 194–207. PMID 25013712.
- Fertility: Assessment and Treatment for People with Fertility Problems. London: RCOG Press. 2004. ISBN 978-1-900364-97-3.
- Anjani Chandra et al. (2013). Infertility and Impaired Fecundity in the United States, 1982-2010: Data from the National Survey of Family Growth. Hyattsville, Md.: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics.
- Pamela Mahoney Tsigdinos (2009). Silent Sorority: A Barren Woman Gets Busy, Angry, Lost and Found. BookSurge Publishing. p. 218. ISBN 978-1-4392-3156-2.
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- RCOG clinical guidelines for infertility (concise guidelines)
- Fertility: Assessment and Treatment for People with Fertility Problems, 2004 (extensive guidelines)
- GeneReviews/NCBI/NIH/UW entry on CATSPER-Related Male Infertility
- Infertility not just a Female Problem
- Assisted Reproduction in Judaism
- Facing Life Without Children When It Isn’t by Choice
- Patient Voices – Infertility