|Classification and external resources|
Infertility is the inability of a person, animal or plant to eusocial species (mostly haplodiploid insects).
In humans, infertility may describe a woman who is unable to conceive as well as being unable to carry a pregnancy to full term. There are many biological and other causes of infertility, including some that medical intervention can treat. Infertility rates have increased by 4% since the 1980s, mostly from problems with fecundity due to an increase in age. About 40% of the issues involved with infertility are due to the man, another 40% due to the woman, and 20% result from complications with both partners.
Women who are fertile experience a natural period of fertility before and during ovulation, and they are naturally infertile during 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.
- World Health Organization 1.1
- United States 1.2
- United Kingdom 1.3
- Other definitions 1.4
- Primary vs. secondary infertility 1.5
- Psychological impact 2.1
- Social impact 2.2
- Sexually transmitted disease 3.1
- Genetic 3.2
- Other causes 3.3
- Females 3.4
- Males 3.5
- Combined infertility 3.6
- Unexplained infertility 3.7
- Diagnosis 4
- Medical treatments 5.1
- Tourism 5.2
- Epidemiology 6
Society and culture 7
- Ethics 7.1
- Developing countries 7.2
- See also 8
- References 9
- Further reading 10
- External links 11
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. 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
- RCOG clinical guidelines for infertility (concise guidelines)
- Fertility: Assessment and Treatment for People with Fertility Problems, 2004 (extensive guidelines)
- Fertility treatment and clinics in the UK
- GeneReviews/NCBI/NIH/UW entry on CATSPER-Related Male Infertility
- CBC Digital Archives – Fighting Female Infertility
- InterNational Council on Infertility Information Dissemination
- Infertility not just a Female Problem
- Assisted Reproduction in Judaism
- Facing Life Without Children When It Isn’t by Choice
- Patient Voices – Infertility
- World Congress on Controversies in Obstetrics, Gynecology & Infertility (COGI)
- Penn Researcher Looks at Infertility’s Impact on Women
- Fertility: Assessment and Treatment for People with Fertility Problems. London: RCOG Press. 2004.
- 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.
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.
Inhorn, Marcia C. 2003. "Global infertility and the globalization of new reproductive technologies: illustrations from Egypt." Social Science & Medicine 56(9):1837-1851. Lock, Margaret and Vinh-Kim Nguyen. 2011. An anthropology of biomedicine: Wiley-Blackwell.
- Makar RS, Toth TL (2002). "The evaluation of infertility". Am J Clin Pathol. 117 (Suppl): S95–103.
- Maheshwari, A. (2008). Human Reproduction. pp. 538–542.
- Hudson, B. (1987). The infertile couple. Churchill-Livingstone, Edinburgh.
- Gurunath S, Pandian Z, Anderson RA, Bhattacharya S (2011). "Defining infertility--a systematic review of prevalence studies". Human Reproduction Update 17 (5): 575–88.
- "WHO | Infertility". Who.int. 2013-03-19. Retrieved 2013-06-17.
- 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.
- Fertility: Assessment and Treatment for People with Fertility Problems (PDF). London: RCOG Press. 2004.
- "Fertility: assessment and treatment for people with fertility problems, section: Defining infertility".
- Mascarenhas et al. 2012. National, Regional, and Global Trends in Infertility Prevalence Since 1990: A Systematic Analysis of 277 Health Surveys
- Cousineau TM, Domar AD (2007). "Psychological impact of infertility". Best Pract Res Clin Obstet Gynaecol. 21 (2): 293–308.
- 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 Gynaecol 14 (Suppl): 45–52.
- Beutel M, Kupfer J, Kirchmeyer P, Kehde S, Köhn FM, Schroeder-Printzen I, Gips H, Herrero HJ, Weidner W (Jan 1999). "Treatment-related stresses and depression in couples undergoing assisted reproductive treatment by IVF or ICSI". Andrologia 31 (1): 27–35.
- "Recovery From Traumatic Loss: A Study of Women Living Without Children After Infertility". Doctorate in Social Work (DSW) Dissertations. Paper 20. 2012
- 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
- Schmidt L, Christensen U, Holstein BE (Apr 2005). "The social epidemiology of coping with infertility". Hum Reprod. 20 (4): 1044–52.
- "The invisible pain of Infertility". Redbook. October 2011
- Khetarpal A, Singh S (2012). "Infertility: Why can't we classify this inability as disability?". The Australasian medical journal 5 (6): 334–9.
- Lis, R.; Rowhani-Rahbar, A.; Manhart, L. E. (2015). "Mycoplasma genitalium Infection and Female Reproductive Tract Disease: A Meta-Analysis". Clinical Infectious Diseases.
- Ljubin-Sternak, Suncanica; Mestrovic, Tomislav (2014). "Review: Clamydia trachonmatis and Genital Mycoplasmias: Pathogens with an Impact on Human Reproductive Health". Journal of Pathogens 2014 (183167).
- Zenzes MT (2000). "Smoking and reproduction: gene damage to human gametes and embryos". Hum. Reprod. Update 6 (2): 122–31.
- Mark-Kappeler CJ, Hoyer PB, Devine PJ (November 2011). "Xenobiotic effects on ovarian preantral follicles". Biol. Reprod. 85 (5): 871–83.
- 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.
- 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.
- 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.
- 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.
- Jangir RN, Jain GC (May 2014). "Diabetes mellitus induced impairment of male reproductive functions: a review". Curr Diabetes Rev 10 (3): 147–57.
- Livshits A, Seidman DS (Nov 2009). "Fertility issues in women with diabetes". Womens Health (Lond Engl) 5 (6): 701–7.
- Andreeva P (2014). "[Thyroid gland and fertility] [Article in Bulgarian]". Akush Ginekol (Sofiia) 53 (7): 18–23.
- 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.
- 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.
- Hozyasz, K (Mar 2001). "Coeliac disease and problems associated with reproduction". Ginekol Pol 72 (3): 173–9.
- 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.
- Reichman DE, White PC, New MI, Rosenwaks Z (Feb 2014). "Fertility in patients with congenital adrenal hyperplasia". Fertil Steril 101 (2): 301–9.
- 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". Human Reproduction Update 17 (5): 605–619.
- 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.
- 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.
- 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. 2001-10-26. Retrieved 2013-06-17.
- "Virus linked to infertility". BBC News. 2001-10-27. Retrieved 2010-04-02.
- "Infertility & STDs - STD Information from CDC". cdc.gov.
- Dr. Martha E. Wittenberg. "STDs That Can Cause Infertility". LIVESTRONG.COM.
- "5 Most Common Causes of Infertility". HowStuffWorks.
- About infertility & fertility problems from the Human Fertilisation and Embryology Authority.
- Lessy, B.A. (2000) Medical management of endometriosis and infertility: 1089-1096.
- "Are You At Your Optimal Weight?". Chelsea Fertility NYC. Retrieved 6 March 2015.
- "Should I Freeze My Eggs". Information on Egg Freezing. Retrieved 6 March 2015.
- 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.
- Mishail, A., et al. (2009) Impact of a second semen analysis on a treatment decision making in the infertile man with varicocele: 1809-1811
- Unexplained Infertility Background, Tests and Treatment Options Advanced Fertility Center of Chicago
- 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.
- Infertility Help: When & where to get help for fertility treatment
- "Failures (with some successes) of assisted reproduction and gamete donation programs". Human Reproduction Update 19 (4): 354–365. 2013.
- Edmund S. Sabanegh, Jr. (20 October 2010). Male Infertility: Problems and Solutions. Springer Science & Business Media. pp. 82–83.
- Paul McFedries. "fertility tourism - Word Spy". wordspy.com.
- Himmel W, Ittner E, Kochen MM, Michelmann HW, Hinney B, Reuter M, Kallerhoff M, Ringert RH; Ittner, E; Kochen, MM; Michelmann, HW; Hinney, B; Reuter, M; Kallerhoff, M; Ringert, RH (1997). "Voluntary Childlessness and being Childfree". British Journal of General Practice 47 (415): 111–8.
- "An error has occurred - NICE". nice.org.uk.
- HFEA Chart on reasons for infertility
- Khan, Khalid; Janesh K. Gupta; Gary Mires (2005). Core clinical cases in obstetrics and gynaecology: a problem-solving approach. London: Hodder Arnold. p. 152.
- Sahlgrenska University Hospital. (translated from the Swedish sentence: "Cirka 10% av alla par har problem med ofrivillig barnlöshet.")
- 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.
- "EUROPA". europa.eu.
- Assisted Human Reproduction Canada
- "Independent Theatre Association". Independent Theatre Association.
- (Inhorn 2003 p1841)
- (Lock and Nguyen 2011 p.269)
- (Gerrits and Shaw 2010)
- (Lock and Nguyen 2011 p.269-270)
- (Lock and Nguyen 2011 p.263)
- (Inhorn 2003 p.1842)
- "Infertility in Africa. [Popul Sci. 1992] - PubMed - NCBI". Ncbi.nlm.nih.gov. 2013-03-25. Retrieved 2013-06-17.
- (Inhorn 2003 p.1841)
- (2003 p.1839)
- (Inhorn 2003 p.1831)
- (Inhorn 2003 p.1842-3)
- (Gerrits and Shaw 2010)
- "IVF as cheap as £170, doctors claim". BBC News. 8 July 2013.
- (Gerrits and Shaw 2010)
- Advanced maternal age
- Conception device
- Inherited sterility in insects
- Medical ethics
- Oncofertility, fertility in cancer patients
- Surrogate marriage
High costs may also be a factor and research by the Genk Institute for Fertility Technology, in Belgium, claimed a much lower cost methodology (about 90% reduction) with similar efficacy, which may be suitable for some fertility treatment. At the 1994 United Nations International Conference on Population and Development (ICPD) in Cairo, the prevention and treatment of infertility was accepted into the program of action for reproductive healthcare. Infertility has shown to have a greater affect on developing nations than on birth rates or population control, but also on a social level as well. Reproduction is a large aspect of life for many cultures within developing nations, and infertility can lead to social and familial problems such as rejection or abandonment as well as personal psychological issues. Currently, fertility treatment options and programs are only available through private health sectors in developing nations and little-to-no treatment is available through public health sectors. The fertility treatment options offered through the private sectors are often costly or not easily accessible. Additionally, counseling is considered an essential aspect of fertility treatment, and due to lack of education and resources such forms of therapy remain scarce as well. While quality fertility care is not readily available in developing nations (such as sub-Saharan African countries), a standard procedure of care could be easily implemented for a low cost as a basic intervention. The lack of fertility treatment is problematic, and high birth and population rates are every reason to implement treatment options rather than reject them.
Due to the assumptions surrounding issues of hyper-fertility in developing countries, ethical controversy surrounds the idea of whether or not access to assisted reproductive technologies should comprise a critical aspect of reproductive health or at least, whether or not the distribution and access of such technologies should be subject to greater equity. However, as highlighted by Inhorn  the overarching conceptualisation of infertility, to a great extent, disguises important distinctions that can be made within a local context, both demographically and epidemiological and moreover, that these factors are highly significant in the ethics of reproduction. An important factor, argues Inhorn, is the positioning of men within the paradigm of reproductive health, whereby because rates of general infertility mask differences between male and female infertility, men remain a largely invisible facet within the theorisation and discourse surrounding infertility, as well as the related treatments and biotechnologies. This is particularly significant given that male infertility accounts for more than half of all cases of infertility  and moreover, it is evident that the attitudes and behaviours of men have profound implications for the reproductive health of both individuals and couples. For example, Inhorn  notes that when couples in Egypt are faced with seemingly intractable infertility problems - due to a range of family and societal pressures that centre around the place of children in constituting the gender identity of men and women - it is often the women who is forced to seek continued treatment; this continues to occur, even in known instances of male infertility and that the constant seeking of treatment frequently becomes iatrogenic for the women. Inhorn states that infertility often leads to “marital demise, physical violence, emotional abuse, social exclusion, community exile, ineffective and iatrogenic therapies, poverty, old age insecurity, increased risk of HIV/AIDS, and death” Significantly, Inhorn demonstrates that this phenomenon can not simply be explained by a lack of knowledge, rather it occurs in a complex interaction between the centrality of children in the male gender identity as a symbol of maturity and the relative lack of power of women in Egyptian society, whereby they effectively become scapegoats for a culturally accepted narrative as a site of blame for the lack of childlessness. It should be emphasised that this is not simply an issue of “women oppressed by men” but rather, that men and women both share the burden of this narrative, but in different, unequal and highly complex ways. Therefore, while the notion that reproductive health is a ‘women’s issue’, may have powerful social currency, especially within popular discourse and indigenous systems of meaning, the reality of infertility suggests that medical and health paradigms have a significant part to play in challenging the validity of this entrenched belief . Moreover, the effectiveness of any therapeutic intervention, medical or otherwise will be contingent on such outcomes and has an important part to play in the alleviation of gendered suffering, especially the burden imposed on women, who continue to suffer disproportionately from the effects of infertility.
Despite this, infertility has profound effects on individuals in developing countries, as the production of children is often highly socially valued and is vital for social security and health networks as well as for family income generation. Infertility in these societies often leads to social stigmatization and abandonment by spouses. Infertility is, in fact, common in sub-Saharan Africa. Unlike in the West, secondary infertility is more common than primary infertility, being most often the result of untreated STIs or complications from pregnancy/birth.
Infertility is often not seen (by the West) as being an issue outside industrialized countries. This is because of assumptions about overpopulation problems and hyper fertility in developing countries, and a perceived need for them to decrease their populations and birth rates. The lack of health care and high rates of life-threatening illness (such as HIV/AIDS) in developing countries, such as those in Africa, are supporting reasons for the inadequate supply of fertility treatment options. Fertility treatments, even simple ones such as treatment for STIs that cause infertility, are therefore not usually made available to individuals in these countries.
- Regulatory bodies are also found in Canada  and in the state of Victoria in Australia 
- 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 licencing of fertility treatment under the EU Tissues and Cells directive 
- 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
Many countries have special frameworks for dealing with the ethical and social issues around fertility 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, and/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.
There are several ethical issues associated with infertility and its treatment.
Other individual examples are referred to individual subarticles of assisted reproductive technology
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 latter 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.
Society and culture
- Some estimates suggest that worldwide "between three and seven per cent of all couples or women have an unresolved problem of infertility. Many more couples, however, experience involuntary childlessness for at least one year: estimates range from 12% to 28%." 
- 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.
Prevalence of infertility varies depending on the definition, i.e. on the time span involved in the failure to conceive.
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.
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.
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.
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 ovarian stimulating medication 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.
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.
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.
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.
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.
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.
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.
. primary ciliary dyskinesia Infertility associated with viable, but immotile sperm may be caused by  The main cause of male infertility is low
- 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
Common causes of infertility of females include:
Sometimes it can be a combination of factors, and sometimes a clear cause is never established.
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.
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 developed 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.
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 and/or scar tissue. For example, endometriosis can cause infertility with the growth of endometrial tissue in the Fallopian tubes and/or around the ovaries. Endometriosis is usually more common in women in their mid-twenties and older, especially when postponed childbirth has taken place.
The following causes of infertility may only be found in females. For a woman to conceive, certain things have to happen: 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.
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).
- 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
- General factors
- Hypothalamic-pituitary factors
- Environmental factors
Factors that can cause male as well as female infertility are:
A Robertsonian translocation in either partner may cause recurrent spontaneous abortions or complete infertility.
Infections with the following sexually transmitted pathogens have a negative effect on fertility: Chlamydia trachomatis, Neisseria gonorrhoeae, and Syphilis. There is a consistent association of Mycoplasma genitalium infection and female reproductive tract syndromes. M. genitalium infection is associated with increased risk of infertility.
Sexually transmitted disease
There are legal ramifications as well. Infertility has begun to gain more exposure to legal domains. An estimated 4 million workers in the U.S. used the Family and Medical Leave Act (FMLA) in 2004 to care for a child, parent or spouse, or because of their own personal illness. Many treatments for infertility, including diagnostic tests, surgery and therapy for depression, can qualify one for FMLA leave. It has been suggested that infertility be classified as a form of disability.
In an effort to end the shame and secrecy of infertility, Redbook in October 2011 launched a video campaign, The Truth About Trying, to start an open conversation about infertility, which strikes one in eight women in the United States. In a survey of couples having difficulty conceiving, conducted by the pharmaceutical company Merck, 61 percent of respondents hid their infertility from family and friends. Nearly half didn't even tell their mothers. The message of those speaking out: It's not always easy to get pregnant, and there's no shame in that.
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.
Emotional stress and marital difficulties are greater in couples where the infertility lies with the man.
The emotional losses created by infertility include the denial of motherhood as a rite of passage; the loss of one’s anticipated and imagined life; feeling a loss of control over one’s life; doubting one’s womanhood; changed and sometimes lost friendships; and, for many, the loss of one’s religious environment as a support system.
Infertility may have profound psychological effects. Partners may become more anxious to conceive, increasing sexual dysfunction. Marital discord often develops in infertile couples, especially when they are under pressure to make medical decisions. Women trying to conceive often have clinical depression rates similar to women who have heart disease or cancer. Even couples undertaking IVF face considerable stress.
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.
Thus the distinguishing feature is whether or not the couple have ever had a pregnancy which led to a live birth.
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 five years since their last live birth, during which they did not use any contraceptives.
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 five years, 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'.
Primary vs. secondary infertility
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.
In the UK, previous NICE guidelines defined infertility as failure to conceive after regular unprotected sexual intercourse for 2 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.
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 6 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.
- a woman under 35 has not conceived after 12 months of contraceptive-free intercourse. Twelve months is the lower 
- a woman over 35 has not conceived after 6 months of contraceptive-free sexual intercourse.
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:
|“||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.||”|