Previous changes

August 2018 — minor update. Citation amended.

April 2018 — reviewed. A literature search was conducted in February 2018 to identify evidence-based guidelines, UK policy, systematic reviews, and key randomized controlled trials (RCTs) published since the last revision of this topic. No changes to clinical recommendations have been made, but the topic has been restructured.

April 2013 — reviewed. A literature search was conducted in February 2013 to identify evidence-based guidelines, UK policy, systematic reviews, and key RCTs published since the last revision of this topic. Information from the National Institute for Health and Care Excellence (NICE) guideline Fertility: assessment and treatment for people with fertility problems (National Collaborating Centre for Women's and Children's Health, 2013) has been added. Minor changes have been made to the recommendations.

March 2012 — minor update. A broken table link was fixed in the section on When to refer. 

March 2011 — the topic structure was revised to ensure consistency across CKS topics. No changes to clinical recommendations have been made.

June 2009 — minor typographical error corrected. The Human Fertilisation and Embryology Association is now correctly referred to as the Human Fertilisation and Embryology Authority. 

June to October 2007 — converted from CKS guidance to CKS topic structure. The evidence base has been reviewed in detail, and recommendations are more clearly justified and transparently linked to the supporting evidence. There are no major changes to the recommendations.

November 2005 — minor technical update. Issued in November 2005.

March 2004 — reviewed. Validated in May 2004 and issued in July 2004.

October 2003 — updated to incorporate Department of Health advice that seronegative women should be vaccinated using the MMR (measles, mumps, and rubella) vaccine.

November 2001 — reviewed. Validated in March 2002 and issued in April 2002.

January 1999 — written and replaces the previous guidance on female infertility. Validated in March 1999 and issued in May 1999.

New evidence

Evidence-based guidelines

No new evidence-based guidelines since 1 July 2023.

HTAs (Health Technology Assessments)

No new HTAs since 1 July 2023.

Economic appraisals

No new economic appraisals relevant to England since 1 July 2023.

Systematic reviews and meta-analyses

No new systematic reviews published since 1 July 2023.

Primary evidence

• Jones, C. A., Kulshreshtha, A., Born, K., & Katiyar, P. (2025). Initial assessment of infertility in primary care. bmj, 390. [Abstract]

New policies

No new national policies or guidelines since 1 July 2023.

New safety alerts

No new safety alerts since 1 July 2023.

Changes in product availability

No changes in product availability since 1 July 2023.

Causes of infertility in women

• Ovulatory disorders 
  • Anovulation and oligo-ovulation are ovulatory disorders estimated to cause 21% of infertility in women [NICE, 2017a].
  • The World Health Organization (WHO) categorizes ovulation disorders into three groups [NICE, 2017a]: 
    
    • Group I ovulation disorders are caused by hypothalamic-pituitary failure. They are present in about 10% of women with infertility and include conditions such as hypothalamic amenorrhea (which commonly develops as a result of low body weight or excessive exercise) and hypogonadotropic hypogonadism (cause is unknown in most cases but may be congenital, for example, when associated with anosmia [Kallmann syndrome]). Women typically present with amenorrhoea (primary or secondary), characterized by low gonadotrophins and oestrogen deficiency.
    • Group II ovulation disorders are defined as dysfunctions of the hypothalamic-pituitary-ovarian axis. They are present in about 85% of women with infertility and include conditions such as hyperprolactinaemic amenorrhoea and polycystic ovary syndrome (PCOS). PCOS is the most commonly encountered type of  Group II ovulation disorder and is responsible for most ovulation disorders. See the CKS topic on Polycystic ovary syndrome for more information.
    • Group III ovulation disorders are caused by ovarian failure and are characterized by high gonadotrophins, hypogonadism, and a low oestrogen level. They are present in about 4–5% of women with infertility.
  • Other conditions that can cause ovulatory disorders include [BMJ, 2023]:
    • Hyperthyroidism and hypothyroidism — may lead to menstrual disorders and ovulatory dysfunction. See the CKS topics on Hyperthyroidism and Hypothyroidism for more information.
    • Cushing's syndrome and congenital adrenal hyperplasia — may cause anovulation.
    • Chronic debilitating diseases (such as uncontrolled diabetes, cancer, AIDS, end-stage kidney disease, and malabsorption) — may lead to anovulation and amenorrhoea [American Society for Reproductive Medicine, 2004].
• Tubal damage 
  • Tubal factors account for 14% of the causes of subfertility in women [NICE, 2017a].
  • The most common cause of tubal factor infertility is pelvic inflammatory disease (PID) and acute salpingitis [Dun, 2012]. However, all pelvic infections, including appendicitis and diverticulitis, can damage the fallopian tubes [BMJ, 2023].
    
    • Chlamydia trachomatis, Neisseria gonorrhoea, and anaerobic organisms are the most common organisms that infect the lower genital tract and cause PID [Dun, 2012]. 
    • The incidence of tubal damage is about 10–12% after one episode of pelvic infection, 23–35% after two episodes, and 54–75% after three episodes [Dun, 2012]. 
    • The risk of ectopic pregnancy can increase sixfold to sevenfold after an episode of PID [Dun, 2012]. 
  • Endometriosis is commonly associated with infertility, with a 25–40% prevalence in infertile women compared with 0.5–5% in fertile women [NICE, 2017b]. The growth of hormonally responsive endometrial tissue outside the uterus may cause anatomical obstruction of the fallopian tubes. It may also lead to infertility by producing cytokines that may be toxic to sperm or embryos. See the CKS topic on Endometriosis for more information.
  • Other factors affecting tubal patency include injury to the fallopian tube due to previous tubal surgeries or sterilization, ischemic nodules, polyps or mucus, tubal spasm, and congenitally abnormal tubes [Ambildhuke, 2022].
• Uterine or peritoneal disorders 
  • Uterine abnormalities (such as adhesions, polyps, submucous leiomyomas, and septae) have been found in 10–15% of women seeking treatment for fertility problems [NICE, 2017a]. 
  • Uterine fibroids may be the sole cause of infertility in 2–3% of women. Depending on their location in the uterus, fibroids have been implicated in recurrent pregnancy loss and infertility [Freytag, 2021,]. 
  • Peritoneal factors, such as peritubular adhesions, endometriosis, altered tubal motility, and fimbrial end blockage, can also affect tubal patency [Ambildhuke, 2022].
• Unexplained cause
  • Unexplained infertility is a diagnosis made by exclusion in couples who have not conceived and in whom standard investigations have not detected any abnormality. It accounts for about 40% of infertility in women and 8–28% of infertility in couples [NICE, 2017a].

Causes of infertility in men

• Testicular failure
  • Primary testicular failure is the most common cause of infertility in men due to oligozoospermia and is the cause of non-obstructive azoospermia [NICE, 2017a].
  • Testicular failure may be due to factors such as cryptorchidism (undescended testicles), testicular torsion or trauma, orchitis, chromosome disorders (such as Y chromosome deletions and Klinefelter syndrome [XXY]), systemic disease, radiotherapy, or chemotherapy. However, in most cases (66%) the cause is unknown [BMJ, 2022].
  • Varicocele is present in almost 15% of the normal population of men, in 25% of men with abnormal semen analysis, and in 35–40% of men presenting with infertility. Clinically detectable varicoceles can be associated with abnormal gonadotrophin levels, impaired spermatogenesis, and histological changes to sperm [EAU, 2023]. See the CKS topic on Varicocele for more information.
  • Several endocrinopathies are associated with low testosterone levels, including hyperprolactinaemia and genetic conditions (such as Kallmann syndrome). Clinically significant endocrinopathies are found in only 2% of infertile men [BMJ, 2022].
  • Risk factors that alter spermatogenesis through low testosterone levels include obesity and exposure to certain drugs or environmental toxins.
• Obstructive azoospermia 
  • Obstructive azoospermia is the absence of spermatozoa in the sediment of a centrifuged sample of ejaculate due to obstruction [BMJ, 2022].
  • Obstruction may be [BMJ, 2022]:
    • Congenital, such as congenital bilateral absence of vas deferens, prostatic cysts (Mullerian cysts), or idiopathic epididymal obstruction.
    • Acquired secondary to epididymal or prostatic infections, vasectomy, or complications of surgical procedures (such as inguinal hernia repair or orchiopexy for undescended testicles).
    • Related frequently to a mutation in the cystic fibrosis transmembrane regulator gene.
  • Obstructive azoospermia is less common than non-obstructive azoospermia and occurs in 20–40% of men with azoospermia [EAU, 2023].
• Ejaculatory and erectile dysfunction
  • Ejaculatory disorders result from conditions that interfere with the ejaculation process, a complex physiological process comprising two phases (emission and expulsion) and is mediated by complex neurological and hormonal pathways. Ejaculatory disorders include [EAU, 2023]:
    • Premature ejaculation.
    • Delayed ejaculation.
    • Retrograde ejaculation (semen passing backwards into the bladder).
    • Anejaculation (no ejaculation).
    • Painful ejaculation.
    • Anorgasmia (perceived absence of orgasm, which can give rise to anejaculation).
    • Haematospermia (blood in the ejaculate, which may indicate underlying pathology).
  • Erectile dysfunction is defined as the persistent inability to attain and maintain an erection sufficient to permit satisfactory sexual performance [Hackett, 2018; EAU, 2023]. See the CKS topic on Erectile dysfunction for more information.
  • Erectile and ejaculatory dysfunction may be associated with psychological factors, hypogonadism, spinal cord disease, metabolic and vascular conditions (such as diabetes mellitus), lifestyle factors (such as smoking, excessive alcohol intake, and obesity), and the use of certain drugs [BMJ, 2022].
• Abnormal sperm function and quality
  • Conditions or situations that cause abnormal shape (morphology) and movement (motility) of the sperm negatively affect fertility [WHO, 2023]. 
  • Sperm motility can be reduced in men with Kartagener syndrome (immotile cilia syndrome) and those with antisperm antibodies [BMJ, 2022].
  • Urogenital tract infections (such as prostatitis, orchitis, and epididymitis) may result in an inflammatory response leading to obstruction or immunogenic spermatogenic dysfunction [BMJ, 2022].
  • Anabolic steroids can cause abnormal semen parameters (such as sperm count and shape) [WHO, 2023].
• Unexplained cause
  
  • Unexplained infertility in men is defined as infertility of unknown origin with normal sperm parameters and partner evaluation. It is now believed that idiopathic infertility may be associated with several previously unidentified pathological factors, including endocrine disruption due to environmental pollution, generation of reactive oxygen species (ROS)/sperm DNA damage, or genetic and epigenetic abnormalities [EAU, 2023].

Risk factors for infertility in women

• Age
  • Natural fertility in women declines with age due to dwindling oocyte numbers and poorer oocyte quality [BMJ, 2023]. 
  • The fecundity of women decreases gradually, but significantly, beginning approximately at 32 years and decreasing rapidly after 37 years of age [ACOG/ASRM, 2014].
• Sexually transmitted infections (STIs) 
  • Chlamydia and gonorrhoea particularly affect fertility by causing damage to the genital anatomy [BMJ, 2023].
• Obesity 
  • High body fat produces a range of factors, including adipokines and oestrone, that can significantly influence reproductive function [BMJ, 2023].
  • Women with a body mass index (BMI) of 30 or over are likely to take longer to conceive compared with women with a normal BMI [NICE, 2017a]. 
  • Women with obesity are at increased risk of infertility and of developing maternal and fetal complications during pregnancy [ASRM, 2021].
  • Obesity in women is associated with ovulatory dysfunction, reduced ovarian responsiveness to treatments that induce ovulation, altered oocyte and endometrial function, and lower birth rates after in vitro fertilization [ASRM, 2021].
• Low body weight
  • A weight of 10% below normal body weight in most women will cause menstrual irregularities [BMJ, 2023].
  • In women with a BMI of less than 19 who have irregular menstruation or are not menstruating, increasing body weight is likely to improve their chances of conception [NICE, 2017a].
• Lifestyle factors
  • Smoking is likely to reduce fertility in women [NICE, 2017a].
  • Stress (in either the man or the woman) may affect the couple's relationship and is likely to reduce libido and the frequency of intercourse, which may contribute to infertility [NICE, 2017a].
• Occupational and environmental factors
  • Exposure to pesticides, nitrous oxide, metals (lead, cadmium, manganese), solvents, formaldehyde and other occupational and environmental hazards can reduce fertility [NICE, 2017a].
• Drugs
  • Some prescription, over-the-counter, and recreational drugs can interfere with fertility. For example: 
    • Nonsteroidal anti-inflammatory drugs (NSAIDs) may inhibit ovulation [NICE, 2017a]. 
    • Chemotherapy can induce ovarian failure, which may be permanent [Janssen, 2000].
    • Metoclopramide, methyldopa, sertraline, fluoxetine, and antipsychotics (such as chlorpromazine, prochlorperazine, haloperidol, and risperidone) can suppress hypothalamic-pituitary function and increase prolactin levels [BMJ, 2023; BNF, 2023]. 
    • Recreational drugs (such as marijuana and cocaine) can adversely affect ovulatory and tubal function [NICE, 2017a].

Risk factors for infertility in men

• Age
  • Advanced paternal age has emerged as one of the main risk factors associated with the progressive increase in the prevalence of infertility in men [EAU, 2023].
  • Increasing age (over 55 years) may affect sperm motility [BMJ, 2022]. 
• Sexually transmitted infections (STIs) 
  • STIs can produce scarring and obstruction of the reproductive tract [BMJ, 2022]. 
• Obesity 
  • Obesity contributes to infertility in men. This can be attributed to multiple factors, including reduced testosterone levels and increased aromatisation of testosterone to oestrogen (which has a negative feedback effect on follicle-stimulating hormone production) [BMJ, 2022]. 
  • Men with obesity may exhibit impaired reproductive function. However, additional research is needed to understand further the relationship between obesity in men and reproductive function [ASRM, 2021].
  • Obesity is also associated with erectile dysfunction [BMJ, 2022]. See the CKS topic on Erectile dysfunction for more information.
• Lifestyle factors
  • There is an association between smoking and reduced semen quality, although this impact on fertility is uncertain [NICE, 2017a]. 
  • Excessive alcohol intake harms semen quality [NICE, 2017a; Ricci, 2017].
  • Stress (in either the man or the woman) may affect the couple's relationship and is likely to reduce libido and the frequency of intercourse, which may contribute to infertility [NICE, 2017a].
• Occupational and environmental factors
  • Exposure to pesticides, nitrous oxide, metals (lead, cadmium, manganese), solvents, formaldehyde and other occupational and environmental hazards can reduce fertility [NICE, 2017a].
• Tight underwear
  • There is an association between elevated scrotal temperature and reduced semen quality, but it is uncertain whether wearing loose-fitting underwear improves fertility [NICE, 2017a].
• Drugs
  • Some prescription, over-the-counter, and recreational drugs can interfere with fertility. For example [BMJ, 2022]:
    • Sulfasalazine and some antifungal treatments can adversely affect spermatogenesis.
    • Certain antipsychotics, antidepressants, and antihypertensives can cause retrograde ejaculation and orgasmic dysfunction.
    • Long-term opiate use can cause hormonal dysregulation and impair bulk semen parameters.
    • 5-alpha reductase inhibitors can cause sexual dysfunction.
    • Finasteride may impair semen parameters.
    • Hormone treatment, particularly testosterone supplementation or anabolic steroid treatment, can inhibit spermatogenesis and impair fertility.
    • Recreational drugs (such as anabolic steroids and cocaine) can adversely affect semen quality [NICE, 2017a].

Basis for recommendation

These recommendations are based largely on the National Institute for Health and Care Excellence (NICE) guideline Fertility problems: assessment and treatment [NICE, 2017a], the British Medical Journal Best Practice guide Infertility in women [BMJ, 2023], and on what CKS considers to be good clinical practice.

Basis for recommendation

These recommendations are based largely on the National Institute for Health and Care Excellence (NICE) guideline Fertility problems: assessment and treatment [NICE, 2017a], the European Association of Urology (EAU) guideline Sexual and Reproductive Health: Male Infertility [EAU, 2023], the British Medical Journal Best Practice guide Male factor infertility [BMJ, 2022], and on what CKS considers to be good clinical practice.

How should I advise a couple seeking information on infertility?

• Involve both partners in all aspects of management. 
  • Provide evidence-based information (verbal and written) to enable them to make an informed decision regarding their care and treatment.
  • Ensure the information provided is in a form that is accessible to people who have additional needs, such as people with physical, cognitive, or sensory disabilities, and people who do not speak or read English.
• Give women and men general advice on the following:
  • Chance of conception
    • Advise that over 80% of couples in the general population will conceive within 1 year if the woman is aged under 40 years and they have regular (every 2–3 days) unprotected sexual intercourse. About half of those who do not conceive in the first year will do so in the second year (cumulative pregnancy rate over 90%). 
    • Inform people who are using artificial insemination to conceive and are concerned about their fertility that over 50% of women under 40 years old will conceive within 6 cycles of intrauterine insemination (IUI). About half of those who do not conceive within 6 cycles of IUI will do so with a further 6 cycles (cumulative pregnancy rate over 75%). 
    • Advise that fertility in women (and, to a lesser extent) fertility in men declines with age. 
  • Smoking
    • Advise women that smoking (including passive smoking) will likely reduce their fertility and that maternal smoking can harm a developing baby.
    • Advise men that smoking affects semen quality (although it is unknown if this adversely affects fertility).
    • Discuss the benefits of quitting smoking to general health.
    • Offer those who smoke support to help them quit. See the CKS topic on Smoking cessation for more information.
  • Alcohol intake
    • Advise women that alcohol consumption during pregnancy is not advised as it can adversely affect the foetus. 
    • Advise men that excessive alcohol consumption may affect semen quality. However, there is no evidence that drinking within recommended safe limits (no more than 14 units per week) has an adverse effect. 
    • Offer those who drink excessively support to help them quit. See the CKS topic on Alcohol - problem drinking for more information.
  • Obesity
    
    • Advise women that a body mass index (BMI) of 30 kg/m² or over may increase their time to conceive.
    • Advise men that a BMI greater than 29 kg/m² is likely to have reduced fertility.
    • Advise women with a BMI of 30 kg/m² or over who are not ovulating that losing weight is likely to increase their chance of conception.
    • Explain that women with obesity are at increased risk of infertility and developing maternal and fetal complications during pregnancy.
    • Offer those who are overweight or obese support to help them lose weight. See the CKS topic on Obesity for more information.
  • Low body weight
    • Advise women with a BMI less than 19 kg/m² plus either amenorrhoea or irregular menstruation that gaining weight is likely to increase their chance of conception.
  • Drugs
    • Advise that some prescription, over-the-counter, and recreational drugs can interfere with fertility in women and men.
    • Offer users of illicit drugs referral to a specialist drugs and alcohol service.
  • Stress management
    • Advise that stress in either partner can affect their relationship and is likely to reduce libido and frequency of intercourse, which can contribute to fertility problems.
    • Explain that psychological stress (for both the woman and the man) may be caused by infertility as well as the investigation and treatment.
    • Offer counselling before, during, and after investigation and treatment, irrespective of the outcome of these procedures. 
  • Occupational risks
    • Advise anyone concerned about occupational risks to their health, including their fertility, to seek specialist advice from occupational health at their place of work or from the Health and Safety Executive website, which provides detailed information on occupational risks. 
  • Caffeinated beverages
    • Advise that no consistent evidence exists of an association between consumption of caffeinated beverages (tea, coffee, and colas) and fertility problems. 
  • Complementary therapies
    • Advise that the effectiveness of complementary therapies for fertility problems has not been adequately evaluated, so further research is needed before such interventions can be recommended.
  • Tight underwear
    • Advise men that although an elevated scrotal temperature is associated with reduced semen quality, it is uncertain whether wearing loose-fitting underwear improves semen quality.
• Give women additional relevant pre-conception advice.
  • Folic acid
    • Dietary supplementation with folic acid before conception and up to 12 weeks of gestation reduces the risk of having a baby with neural tube defects.
    • The recommended dose is 0.4 mg per day. For women who have previously had an infant with a neural tube defect or who are receiving anti-epileptic medication, or who have diabetes, a higher dose of 5 mg per day is recommended.
  • Susceptibility to rubella
    
    • Offer testing for rubella status.
    • Women who are susceptible to rubella should be offered vaccination and advised not to become pregnant for at least 1 month following vaccination.
  • Cervical cancer screening
    • Ask about the timing and result of their most recent cervical smear test to avoid delay in fertility treatment.
    • Where applicable, offer cervical screening in accordance with the national cervical screening programme guidance.
  • See the section on Advice for all women in the CKS topic on Pre-conception - advice and management for more information on these and other pre-conception care that is applicable to all women who are planning a pregnancy.
• Provide sources of additional information and support.
  • Patient information on infertility is available on:
    • The NHS website (www.nhs.uk).
    • The National Institute for Health and Care Excellence website (www.nice.org.uk). 
    • The British Fertility Society website (britishfertilitysociety.org.uk).
  • Patient support is available from the following charities:
    • The British Infertility Counselling Association (www.bica.net).
    • Fertility Network UK (fertilitynetworkuk.org).
  • The Human Fertilisation and Embryology Authority (www.hfea.gov.uk) provides information on In vitro fertilisation (IVF), clinics, and other fertility treatments from the UK government fertility regulator.
  • The NHS website provides an information guide, trying for a baby, to explain how a woman can prepare for a pregnancy, how conception occurs, and how she and her partner can improve her chances of getting pregnant.

What initial investigations should I arrange in a woman?

Investigate both partners simultaneously to categorize the cause of infertility. Start investigations in couples who have not conceived after 1 year of regular (every 2–3 days) unprotected sexual intercourse. Offer investigations earlier than 1 year to couples identified as less likely to conceive. Early investigations may be prompted by the same factors that prompt early referral.

• Measure mid-luteal phase progesterone in all women to confirm ovulation.
  • Offer a blood test to measure serum progesterone in the mid-luteal phase of the cycle (day 21 of a 28-day cycle) even if the woman has regular menstrual cycles.
• Screen for chlamydia. 
  • Before undergoing uterine instrumentation, women should be offered screening for Chlamydia trachomatis using an appropriately sensitive technique. 
  • If the result is positive, the woman and her sexual partner(s) should be referred for appropriate management with treatment and contact tracing.
  • Prophylactic antibiotics should be considered before uterine instrumentation if screening has not been done.
  • See the section on Testing to confirm the diagnosis in the CKS topic on Chlamydia - uncomplicated genital for more information.
• The following additional tests may be needed:
  • Serum progesterone (in women with prolonged irregular menstrual cycles) — depending on the timing of menstrual periods, serum progesterone may need to be measured later (for example, on day 28 of a 35-day cycle) to confirm ovulation and repeated weekly after that until the next menstrual cycle starts.
  • Gonadotrophin measurement (in women with irregular menstrual cycles) — gonadotrophin (follicle-stimulating hormone and luteinizing hormone) measurements are of value in women with anovulation or oligo-ovulation. They can be used to identify ovulation disorders.
  • Thyroid function tests (in women with symptoms of thyroid disease).
  • Prolactin measurement (in women with symptoms of an ovulatory disorder [for example, polycystic ovary syndrome], galactorrhoea, or a suspected pituitary tumour).
• The following investigations are not recommended:
  • Endometrial biopsy — there is no evidence that medical treatment of luteal phase defects improves pregnancy rates.
  • Basal body temperature charts — they do not reliably predict ovulation.
  • Use of ovulation predictor kits — there is no evidence that attempts to time sexual intercourse to the menstrual cycle result in improved conception rates. Furthermore, there is evidence that the use of these kits causes stress.
  • Postcoital testing of cervical mucus — has no predictive value for pregnancy rates.

What initial investigations should I arrange in a man?

Investigate both partners simultaneously to categorize the cause of infertility. Start investigations in couples who have not conceived after 1 year of regular (every 2–3 days) unprotected sexual intercourse. Offer investigations earlier than 1 year to couples identified as less likely to conceive. Early investigations may be prompted by the same factors that prompt early referral.

• Arrange for semen analysis. 
  • Give clear written and verbal instructions concerning the collection of the semen sample:
    • The specimen should be collected by masturbation; ejaculated into a clean, wide-mouthed container made of plastic from a batch that has been confirmed to be non-toxic for spermatozoa; and protected from extremes of temperature (below 20°C or above 37°C).
    • The specimen should be collected after a minimum of 2 days and a maximum of 7 days of sexual abstinence.
    • Ideally, the sample should be collected in a private room near the laboratory to avoid exposure of the semen sample to fluctuations in temperature and to control the time between collection and analysis. 
    • If the man, for any reason, must collect the sample at another place, the specimen container should be kept close to the body under the clothes (for example, in the armpit) during transport and should be delivered to the laboratory, preferably within 30 minutes after collection and at least no longer than 50 minutes after collection.
  • Emphasize that the semen sample needs to be complete and that the man should report any loss of any fraction of the sample.
  • The results should be interpreted using the most recent World Health Organization (WHO) reference values for human semen characteristics.
    • If the result of the first semen sample is normal, there is no need to do a repeat confirmatory test.
    • If the result of the first semen sample is abnormal, order a repeat test.
    • Testing should ideally be repeated 3 months after the initial test to allow time for the cycle of spermatozoa to be completed.
    • It may be appropriate to test earlier, for example, if the man is very anxious about the test result and prefers to have the test done earlier. In these circumstances, or if there is a gross spermatozoa deficiency (azoospermia or severe oligospermia), repeat the test within 2–4 weeks.
    • If the repeat test result is normal, regard the semen as normal; no further testing is required.
    • Refer men with two abnormal semen examination results to secondary care for further assessment.
• Screen for chlamydia. 
  • See the section on Testing to confirm the diagnosis in the CKS topic on Chlamydia - uncomplicated genital for more information.
• The following tests are not recommended:
  
  • Screening for antisperm antibodies — there is no evidence of effective treatment to improve fertility.

When should I refer a couple presenting with infertility?

Referral criteria for people presenting with infertility may vary between health authorities. Refer to local guidelines.

• In women younger than 36 years of age:
  • In general, consider referring the couple for additional investigations and management if history, examination, and investigations are normal in both partners and the couple has not conceived after 1 year.
• Consider earlier referral if the following factors are present:
  • In women:
    • Age 36 years and older (refer after 6 months).
    • Amenorrhoea or oligomenorrhoea.
    • Previous abdominal or pelvic surgery.
    • Previous pelvic inflammatory disease.
    • Previous sexually transmitted infection (STI).
    • Abnormal pelvic examination.
    • Known reason for infertility (for example, prior treatment for cancer).
  • In men:
    • Previous genital pathology.
    • Previous urogenital surgery.
    • Previous STI.
    • Varicocele.
    • Significant systemic illness.
    • Abnormal genital examination.
    • Two abnormal semen examination results.
    • Known reason for infertility (for example, prior treatment for cancer).
• Ensure that the couple is offered counselling before, during, and after investigation and treatment regardless of the outcome of these procedures.
  
  • Psychological stress (for both the woman and the man) may be caused by infertility as well as the investigation and treatment.
  • Usually, counselling will be arranged by the specialist infertility team.
  • Infertility counsellors are provided by all licensed clinics in the UK, and the British Infertility Counselling Association (www.bica.net).

How should I manage complications that may occur after assisted conception?

• Ovarian hyperstimulation syndrome (OHSS) is a potentially life-threatening complication of superovulation. 
  • Symptoms and signs include:
    • Mild — abdominal bloating and mild abdominal pain.
    • Moderate — nausea and vomiting and increased abdominal discomfort.
    • Severe — oliguria, generalized oedema, abdominal pain and/or distension (caused by enlarged ovaries and acute ascites), and hydrothorax (occasionally).
    • Critical — oligo/anuria, tense ascites or large hydrothorax, thromboembolism, and acute respiratory distress syndrome.
  • If a woman presents with these symptoms and signs:
    • Consider alternative diagnoses, such as complications of an ovarian cyst (torsion, haemorrhage), pelvic infection or abscess, intra-abdominal haemorrhage, ectopic pregnancy, bowel perforation, or appendicitis.
    • If OHSS is suspected, seek urgent advice from the specialist unit. The severity of OHSS can worsen over time, and even initially mild presentations should be kept under review.
• Other possible complications that may occur after assisted conception include:
  • Ectopic pregnancy — see the CKS topic on Ectopic pregnancy for more information on when to suspect an ectopic pregnancy and how to manage the woman. 
  • Pelvic infection — see the CKS topic on Pelvic inflammatory disease for management information.
  • Multiple pregnancy — the National Institute for Health and Care Excellence (NICE) guideline on Twin and triplet pregnancy covers the care that should be offered to women with a twin or triplet pregnancy in addition to the routine care that is offered to all women during pregnancy.