Infertility and Bartholin gland disease

• Infertility is the inability of a couple to achieve a successful pregnancy after a period of regular, unprotected intercourse. The ASRM 2023 definition treats it as a disease, condition or status, and recognises that needing medical help (including donor gametes or embryos) to conceive can itself qualify.^[2]
• Most couples under 40 conceive within the first year of trying by natural means, and about half of the remainder in the second year; this is why evaluation begins after 12 months at most.^[3]
• It is always a couple's problem: female factors, male factors and combined or unexplained factors each explain roughly a third of cases in many series, and unexplained infertility is defined as infertility with otherwise normal basic findings.^[1]
• Evaluation runs in parallel for both partners from the outset: history and examination, semen analysis, confirmation of ovulation, then targeted tests for tubal and uterine factors.^[3][4][5]
• Treatment follows the cause: ovulation induction for ovulatory disorders, IUI with ovarian stimulation then IVF for unexplained infertility, and correction of identifiable male and female factors first.^[1][3]
• A Bartholin gland cyst is a painless swelling at the 4 or 8 o'clock position of the vulvar vestibule; when infected it becomes an abscess. Both occur in about 2% of women, usually in the reproductive years.^[6]

By the end of this page you should be able to:

1. Define infertility in modern terms and give the age-based timing for starting an evaluation.
2. Classify causes of infertility in the female and in the male partner, and recognise when it is unexplained.
3. Take a focused couple's history and examination and choose investigations in a sensible order.
4. State the WHO semen reference values and the normal ovulation, tubal and uterine cut-offs or standards used.
5. Outline medical, surgical and assisted reproduction management, and long-term criteria for IVF.
6. Manage a Bartholin cyst or abscess, including Word catheter and marsupialisation, and quote recurrence figures.
7. Counsel on prognosis and preconception prevention.

Infertility is among the most common problems in gynaecology and andrology. It is best managed as a couple's condition rather than as one person's disease. In most couples the difficulty is with conception, not with a single organ, and the effective approach is to search for all relevant factors at once, starting with the least invasive tests, rather than investigating one partner to completion before looking at the other.^[1][4] This page explains the reasoning in that order, then covers the Bartholin gland separately, since a Bartholin cyst or abscess is a common minor gynaecological problem that is often confused with other vulval swellings.

The older definition was simply failure to conceive after 12 months of regular, unprotected intercourse in women under 35, or after 6 months in women over 35. The international societies now frame it more broadly. The American Society for Reproductive Medicine (ASRM), in a 2023 committee opinion, calls infertility:

"Infertility" is a disease, condition, or status characterised by any of the following: the inability to achieve a successful pregnancy based on a patient's medical, sexual and reproductive history, age, physical findings, diagnostic testing, or any combination of those factors; the need for medical intervention, including donor gametes or donor embryos, to achieve a successful pregnancy either alone or with a partner; and, in patients having regular unprotected intercourse with no known cause of impaired reproductive ability, evaluation should begin at 12 months for a female partner under 35 years and at 6 months for one 35 years or older.^[2]

Two phrases in that definition matter for practice. First, "status" and "need for medical intervention" extend the concept to people who cannot conceive without donor gametes, including single people and same-sex couples, and the document states that nothing in the definition may be used to deny or delay treatment on the basis of relationship status or sexual orientation.^[2] Second, the age-based evaluation times are a floor, not a ceiling: an earlier assessment is appropriate whenever there is a known cause or a predisposing history.^[3]

The European Society of Human Reproduction and Embryology (ESHRE) adds the ICMART standard for a woman with regular cycles: 12 months of regular, unprotected intercourse before investigations are started. ESHRE defines unexplained infertility specifically as infertility in a couple with apparently normal ovarian function, fallopian tubes, uterus, cervix and pelvis, age 40 or under, adequate coital frequency, and apparently normal testicular function, genito-urinary anatomy and a normal ejaculate.^[1]

• Primary infertility: never a prior pregnancy.
• Secondary infertility: at least one previous pregnancy, even if it did not result in a live birth.
• Female factor, male factor, combined: the same couple may have more than one contributor.
• Unexplained: all basic investigations normal, diagnosed by exclusion.

Female causes are best grouped by where they act:

1. Ovulatory dysfunction. Failure to ovulate or erratic ovulation; often irregular or very frequent cycles. Polycystic ovary syndrome is the commonest single cause of anovulation.
2. Tubal and peritoneal factors. Damage or obstruction of the fallopian tubes, or adhesions that impair pickup of the oocyte: previous pelvic inflammatory disease, chlamydial infection, surgery, endometriosis.
3. Uterine factors. Fibroids distorting the cavity, congenital anomalies, intrauterine adhesions, adenomyosis, and endometrial pathology.
4. Cervical factors. Rarely isolated; mucus hostility and cervical stenosis.
5. Fertility-limiting female factors at the extremes of age or ovarian reserve. Age-related decline and premature ovarian insufficiency.

Male causes group by level:

1. Pre-testicular. Hypothalamic-pituitary disorders (hypogonadotrophic hypogonadism, hyperprolactinaemia) and endocrine disease.
2. Testicular. Varicocele, undescended testis, orchitis, drugs and toxins, systemic illness, genetic (Klinefelter syndrome, Y-chromosome microdeletions).
3. Post-testicular. Obstruction (vas deferens, epididymis, ejaculatory ducts), infection, retrograde ejaculation, erectile dysfunction, hypospadias.
4. Unexplained (idiopathic) male infertility. Abnormal semen without an identified cause.

Age matters on both sides: sperm count and motility fall with age, and male and female age together shift the chance of spontaneous pregnancy.

Each Bartholin gland lies at about the 4 and 8 o'clock positions of the vulvar vestibule. They produce mucus for vulval lubrication. A Bartholin cyst forms when the duct is obstructed and the glandular secretion accumulates; it is a smooth, painless or mildly uncomfortable swelling of variable size. When the cyst or gland becomes infected it becomes an abscess, with pain, redness, swelling, heat and tenderness. There is no clear line between them: an abscess is often an infected cyst.^[6]

For a healthy couple with the woman under 40, the cumulative chance of a clinical pregnancy is high: over 80% by 12 cycles and about 90% by 24 cycles of unprotected intercourse. Of those who do not conceive in the first year, about half do so in the second. The probability is strongly age dependent, falling most sharply for women from the mid-30s onward.^[3] Sexual intercourse every 2 to 3 days optimises the chance, and a woman with regular cycles is likely to be ovulating.^[3]

Across clinical practice, unexplained infertility accounts for roughly 30% of couples, using the definition above.^[1] Among infertile women the commonest overall cause is ovulatory dysfunction, of which polycystic ovary syndrome is the leading example, but reliable figures for each category vary by population and definition, so no single prevalence can be quoted.

About 2% of women develop Bartholin cyst or abscess at some point, usually during the reproductive years.^[6]

• Female age. The sharpest non-modifiable predictor. The NICE model shows cumulative pregnancy rates falling from the early 90% range for younger women to roughly 82% after 12 cycles for women 35 to 39.^[3]
• Body mass index. Women with a BMI of 30 or higher take longer to conceive, and weight loss improves the chance if they are not ovulating; men with a BMI of 30 or higher also have reduced fertility.^[3]
• Alcohol, smoking, and recreational drugs. Smoking and passive smoking reduce the chance of conception, and excessive alcohol intake is detrimental to semen quality. The NICE advice limits alcohol to no more than 1 or 2 units once or twice a week and avoidance of intoxication when trying to conceive.^[3]
• Folic acid. Women planning pregnancy should take folic acid before conception.^[3]
• Previous infection or surgery. Pelvic inflammatory disease, especially chlamydial, is the main cause of tubal factor infertility; pelvic surgery may produce adhesions.
• Endometriosis. Present in a proportion of infertile women and reduces fecundability by several mechanisms.
• Environmental and occupational exposure. Heat, certain solvents and pesticides, and exposure to cytotoxic or gonadotoxic drugs reduce male fertility; this is reviewed in the male infertility guideline.^[5]
• Male age and lifestyle. Less decisive than female age, but advanced age and obesity matter.^[3]

A cyst follows duct obstruction; the contents are mucus or, when infected, pus. Infection is polymicrobial and may be introduced from the skin or vaginal flora. The cyst is not sexually transmissible in itself; an abscess may form during or after an infection, but a specific organism cannot be assumed. Larger cysts and abscesses are more likely to need intervention, and recurrence after simple drainage is common because the duct mouth may close again.^[6]

Conception requires five steps, and infertility is the failure of one or more of them.^[4][1]

1. Ovulation. A mature follicle must release an egg each cycle. Failure is usually hypothalamic (stress, extremes of weight, exercise), pituitary (prolactin, thyrotrophin) or ovarian (polycystic ovary syndrome, primary ovarian insufficiency).
2. Sperm production and delivery. Men must make at least a few million motile, morphologically normal sperm, transport them through the epididymis and vasa, and deposit them in the vagina or (in assisted reproduction) use them in the laboratory.
3. Tubal capture and transport. The fimbrial end must capture the oocyte and move it, and later the embryo, toward the uterus.
4. Fertilisation. In the tube, a single sperm must penetrate the oocyte; defects of sperm number, motility and morphology, and zona pellucida defects, block this step.
5. Implantation. The uterus must be receptive and the endometrium must be adequate.

Age impairs steps 1 and 5 because ovarian reserve and egg quality fall progressively. Tubal disease blocks steps 2 and 3. Male factor disease blocks steps 1 to 3 of that sequence.

Bartholin pathophysiology is simpler. Obstruction of the 1 to 2 cm duct traps glandular secretion; the retained mucus produces a cyst. If bacteria colonise the trapped mucus, pressure rises and the lesion becomes an abscess, with all the local signs of an acute inflammatory collection. Incision and drainage (or catheter insertion) re-creates a tract, allows re-epithelialisation, and lowers the chance that the duct closes again before it has healed wide open.^[6]

The single most useful organisational point is to see the couple together, because each partner is a stakeholder in both diagnosis and treatment.^[5] The following are worth asking, with the reason.

• Duration of trying and frequency of intercourse. 12 versus 24 months separates expectant management from investigation; intercourse every 2 to 3 days is optimal.^[3]
• Menstrual pattern. Cycle length and variation (regular means 24 to 38 days with variation under 7 to 9 days), amount of bleeding, dysmenorrhoea and intermenstrual bleeding point toward anovulation, fibroids, adenomyosis or endometriosis.^[1][3]
• Pain. Dyspareunia, deep pelvic pain and painful periods suggest endometriosis or adhesive disease.
• Infertility history. Previous pregnancies and pregnancy losses, sexually transmitted infection, pelvic inflammatory disease, ectopic pregnancy, surgery, contraception.
• Male partners. Libido, erections, ejaculation (including retrograde or dry), libido changes, scrotal pain or heaviness, pubertal development, medications, testicular cancer history, smoking, alcohol, heat exposure.
• Systemic and lifestyle factors. Weight change, exercise, diet, thyroid symptoms, headaches or visual fields (pituitary disease), galactorrhoea.
• Co-morbidity. Thyroid disease, diabetes, eating disorders, chemotherapy or radiotherapy, pelvic tuberculosis where relevant.

A routine complete physical examination is not needed for the standard evaluation unless the history asks for it; the examination should be targeted.^[4]

Female. Assess BMI, blood pressure, signs of endocrine or androgen excess, goitre, galactorrhoea, features of the polycystic ovary syndrome and acanthosis nigricans. Abdominal and pelvic examination may reveal a mass, an enlarged or irregular uterus, an adnexal swelling, or signs of cervical or vaginal pathology. If infection is not suspected and the woman is not sexually active or responds well to treatment, examination may be deferred.^[4]

Male. General appearance, body habitus, secondary sexual characteristics and virilisation. Genital examination assesses testicular size and consistency, the epididymis, vas deferens and spermatic cord (varicocele worsens with Valsalva), the foreskin and urethral meatus. Scrotal or inguinal masses and hernias are sought. A large varicocele or small testes are significant findings.^[5]

Bartholin examination. The woman complains of a one-sided vulval lump. Inspection and palpation localise it to the vestibule, posterior to the fourchette, at 4 or 8 o'clock. A cyst is smooth, fluctuant and usually non-tender. An abscess is tense, erythematous, very tender and often makes walking or sitting painful. Always record size and laterality; bilateral cases are uncommon. Examine for satellite lesions or a firm fixed mass in an older woman.^[6]

The evaluation is parallel. Neither partner is investigated to completion first.^[3][4][5]

1. Pregnancy test if there is any possibility of pregnancy.
2. Female hormonal and ovarian reserve assessment. Confirm ovulation (mid-luteal progesterone) and check total antral follicle count, anti-Mullerian hormone or FSH, plus thyroid function and prolactin only where indicated. Regular cycles are strong evidence of ovulation, so ovulation testing is not routinely required when cycles are regular.^[1][3]
3. Semen analysis. At least one, using an external-quality-assured laboratory; repeat at 3 months if abnormal, since spermatogenesis takes 74 days. If gross azoospermia or severe oligozoospermia is found, repeat sooner.^[3][5]
4. Tubal and uterine assessment. Hysterosalpingography or hysterosalpingo-contrast-sonography for tubal patency, and 3D ultrasound for the uterine cavity; chlamydia antibody testing can stratify risk but does not replace direct visual demonstration when risk is high. Routine diagnostic laparoscopy is not recommended without another indication.^[1]
5. Secondary tests only where indicated. Genetic testing, karyotype and Y-chromosome microdeletions in severe male factor or azoospermia; post-coital testing is not recommended; endometrial biopsy not routinely.^[1][5]

Note two important exclusions from the NICE work-up: basal body temperature charting is not a reliable predictor of ovulation, and routine prolactin or thyroid tests are not needed in a standard infertility assessment, though rubella status and cervical screening should be brought up to date.^[3] ASRM likewise cautions that ovarian volume, ovarian blood flow, inhibin B and oestradiol are not useful as standalone tests.^[3][4]

This is the diagnosis of exclusion above, applicable when the woman is 40 or younger, both partners show apparently normal function and the couple have adequate coital frequency.^[1] A regular, 24 to 38 day, low-variation cycle and a single normal WHO semen analysis are part of the diagnosis. If the first semen analysis is abnormal it should be repeated; if ovulation confirmation is really needed, urinary LH kits, cycle monitoring ultrasound or mid-luteal progesterone are all acceptable, but not routine. Routine measurement of mid-luteal progesterone is not recommended for women with regular cycles.^[1]

The diagnosis is clinical. A simple cyst at the vestibule is distinguished from abscess by tenderness, erythema and systemic symptoms. Investigations are rarely needed: a large or atypical, recurrent or persistent lesion in an older woman warrants biopsy, because gland carcinoma, although rare, mimics benign disease. The distinction to keep in mind is that a fixed, firm, irregular or non-fluctuant mass is not a simple abscess and needs histology.^[6]

• Couple first. Both partners are assessed and treated together.^[5]
• Least invasive first. Lifestyle, weight and timed intercourse before drugs; drugs before procedures; clear criteria before IVF.^[3][4]
• Correct reversible causes first. Endocrine disorders, thyroid disease, hyperprolactinaemia and varicocele are treatable causes, not footnotes.
• Honest prognosis. About 50% of the couples who fail to conceive in the first year succeed in the second without treatment, so expectant management is rational for younger couples without a clear cause.^[3]
• Folic acid and preconception care for all couples trying.

Ovulatory dysfunction. Restore ovulation. For anovulatory women who wish to conceive, clomiphene citrate is a labelled first-line oral agent: start 50 mg daily for 5 days, typically beginning on cycle day 5, and if ovulation does not occur increase to 100 mg daily for 5 days; cycles beyond about 6 are not recommended. Pregnancy rates of around 30% are reported across the clinical trial experience with this drug.^[7] Letrozole, an aromatase inhibitor, is commonly used off-label as an alternative first-line agent, often at 2.5 mg daily for 5 days, particularly in polycystic ovary syndrome. Exogenous gonadotrophins are used when oral agents fail, by clinicians trained in monitored protocols, with serial ultrasound to avoid multiple pregnancy and ovarian hyperstimulation; combination therapy with clomiphene or letrozole and gonadotrophins is discouraged where stimulation is unmonitored.^[1][7]

Tubal factors. Proximal occlusion may be amenable to selective tubal cannulation; distal tubal disease is treated with laparoscopic salpingostomy or neosalpingostomy, with realistic counselling (ectopic pregnancy risk rises after tubal surgery). In practice, for significant tubal disease, in vitro fertilisation is often the most effective route.^[1][3]

Uterine factors. Submucosal fibroids and polyps are resected hysteroscopically; septa are divided. Intrauterine adhesions are lysed. Expectations are set: removing a fibroid that does not distort the cavity does not clearly improve fertility.^[1]

Male factors. Lifestyle (weight loss, stopping smoking, avoiding heat and recreational drugs), correcting endocrinopathies, treating genital tract infection and, for obstructive azoospermia, surgical sperm retrieval with ICSI. Varicocele repair is offered when a clinically significant varicocele coexists with abnormal semen. Sperm retrieval in obstructive azoospermia and hormonal treatment of hypogonadotrophic hypogonadism carry good prognoses.^[5] Comparisons should be made with an andrology or reproductive urology specialist.

Endometriosis. Laparoscopic excision or ablation of lesions improves fertility in mild to moderate disease; ovarian endometriomata and severe disease are managed case by case. For endometriosis-associated infertility, assisted reproduction is often the next step.

The ESHRE 2023 guideline is explicit and should be quoted in practice.^[1]

• First-line: intrauterine insemination with ovarian stimulation (low-dose, with monitoring to prevent multiple pregnancy and ovarian hyperstimulation).
• Not recommended: conventional-dose gonadotrophins without adequate monitoring, ICSI without male factor, routine hysteroscopy, endometrial scratching, routine laparoscopy, post-coital test and almost all "add-ons" (anti-sperm antibodies, sperm DNA fragmentation, chromatin tests, aneuploidy screening, microbiology or oxidative stress tests when semen is normal). ^[1]
• IVF is probably not superior to IUI with stimulation overall, but decisions are individualised on age, duration of infertility and previous treatment.
• Hysterosalpingography (or equivalent) with an oil-soluble contrast medium is preferable to a water-soluble one, with risks and benefits explained. ^[1]
• Couples should not be offered oral ovulation drugs (clomiphene, anastrozole, letrozole) for unexplained infertility, since these have not been shown to help.^[3]

NICE CG156 sets clear, auditable thresholds, updated in detail by later reviews.^[3]

• Women under 40 with 2 years of regular unprotected intercourse, or 12 cycles of artificial insemination of which 6 or more were by intrauterine insemination, are offered 3 full cycles of IVF. ^[3]
• Women aged 40 to 42 who have never had IVF, with no evidence of low ovarian reserve and after a full discussion of its implications, are offered one full cycle.
• Any previous full IVF cycle, self-funded or NHS, counts toward the total of 3.

Management depends on symptoms, size and recurrence.

• Asymptomatic small cysts need no treatment, only reassurance. Large but symptomless cysts can be observed.
• Acute large or symptomatic cyst or abscess needs a procedure that establishes drainage. The simplest option is incision and drainage with a scalpel (local anaesthetic), which gives immediate relief, but the duct edge frequently closes again and recurrence is common.^[6] It is best regarded as a temporising measure.
• Word catheter. A 5.5 cm, 15-French silicone device with a 3 cm inflatable balloon is inserted into the cavity through a 5 mm incision, inflated with saline, and left for about 4 to 6 weeks while the tract epithelialises. It can be carried out as a day case with local anaesthetic, needs no sutures, and leaves the gland functional. The pitfalls are the discomfort of the catheter for several weeks and expulsion or displacement if it is disturbed; instruct the woman not to squeeze it and to check its presence weekly. Repeat small discharges are usual. Removal completes the process.^[6]
• Marsupialisation. The classic definitive office procedure: the cervix of the cyst is opened with a 1.5 to 3 cm vertical incision lateral to the hymen, the cavity drained and washed, and the everted wall sutured to the skin edge so that a patent tract forms. It requires local, regional or general anaesthesia, takes around 20 to 22 minutes on average, but gives better satisfaction and a lower recurrence rate in the available cohort data.^[6]
• Silver nitrate, alcohol sclerotherapy, CO2 laser and gland excision are alternatives for recurrent disease, but each has limitations (silver nitrate can burn surrounding skin, excision carries more bleeding and scarring). Gland excision is reserved for recurrent abscess, carcinoma suspicion and persistent disease that fails office procedures.
• Antibiotics are used for cellulitis, spreading infection or systemic illness, and postoperative infection; they are not a substitute for drainage. The Karabuk cohort recorded postoperative infection rates of 5.3% after marsupialisation and 3.1% after Word catheter.^[6]

A single comparative cohort of 196 patients (132 marsupialisation, 64 Word catheter) found recurrence in 8.3% of the marsupialisation group and 18.8% of the Word catheter group, with median satisfaction 4 out of 5 for marsupialisation versus 3 out of 5 for catheter, and 4-6 week catheter dwell time. Operation time was shorter with the catheter (about 16 versus 22 minutes). Median recurrence times were roughly 7 and 6 months respectively.^[6] A randomised trial (WoMan) referenced in that paper compared the two methods with similar endpoints and did not show a clear difference in recurrence. The literature as a whole quotes recurrence after marsupialisation at 3 to 25% and after Word catheter at 2 to 17%.^[6]

Infertility. The most serious complication is the psychological burden of prolonged treatment and the risk of multiple pregnancy and ovarian hyperstimulation with ovarian stimulation and IVF. Ectopic pregnancy risk rises after tubal surgery. Miscarriage, pre-eclampsia and gestational diabetes are slightly more common in assisted reproduction pregnancies and should be discussed.

Bartholin disease. Recurrence, local infection, abscess rupture, persistent pain, scarring and dyspareunia after repeated surgery. Incomplete drainage and a prematurely removed catheter are the usual reasons for recurrence. Recurrent or atypical lesions justify histology, because gland carcinoma (rare) mimics benign cysts.

• Spontaneous prognosis is good for younger couples without an identified cause: over 80% conceive by 12 cycles and about 90% by 24 cycles under age 40.^[3]
• With treatment, unexplained infertility: IUI with stimulation about doubles or trebles monthly fecundability over no treatment in trial meta-analyses, and IVF live birth rates per cycle depend on age, from roughly 30% in women under 35 to much lower after 40. These figures vary by clinic and protocol and should be quoted from the centre's own data rather than from a headline.
• Bartholin disease carries a good prognosis with proper drainage; most women are cured, and recurrence is reduced by marsupialisation (about 8% in the cohort cited) compared with simple drainage.

Infertility. There is no screening programme for infertility. Prevention is preconception care, which also serves as risk identification:

• Folic acid before conception; ensure rubella immunity; keep cervical screening up to date.^[3]
• Avoid smoking and passive smoking; limit alcohol; maintain a healthy BMI.^[3]
• Treat sexually transmitted infection promptly and trace contacts; use barrier contraception to reduce pelvic infection and protect tubal patency.
• Avoid gonadotoxic drugs and heat exposure where possible.
• Assess couples who have not conceived after 12 months routinely (earlier if aged 36 or older, known cause or predisposing history).^[3]
• Cancer treatment recipients should be offered fertility preservation counselling before therapy.^[5]

Bartholin disease. No proven prevention exists. General vulval hygiene, prompt treatment of vulval infection and avoiding repeated attempts at palpation or early catheter removal reduce recurrence. Regular sexual activity does not influence it. Where abscess is recurrent, marsupialisation or excision is preventive.

• Women under and over 35. The evaluation clock starts at 12 months for a woman under 35 and at 6 months for a woman 35 or older, but starts immediately with a known cause or history.^[2][3]
• Women aged 40 to 42. One full IVF cycle is offered only if there has been no previous IVF, no evidence of low ovarian reserve, and a full discussion of implications; women over 42 are not routinely offered IVF on the NHS criteria.^[3]
• Women with low ovarian reserve or premature ovarian insufficiency. IVF uses donor oocytes in many cases; specialist counselling is needed.
• Men. Severe oligozoospermia and azoospermia require karyotype and Y-chromosome microdeletion testing; testicular sperm retrieval with ICSI offers paternity in many cases of obstructive azoospermia.^[5]
• Pregnancy. Infertility treatment is suspended once pregnancy is confirmed. Clomiphene is contraindicated in pregnancy.^[7] Any Bartholin abscess in pregnancy should be drained by a clinician experienced in pregnancy and with antibiotic choice compatible with gestation.
• Children and adolescents. Infertility is not a paediatric concept; Bartholin disease is uncommon before puberty and in an adolescent should prompt assessment for sexual health, infection and safeguarding concerns.
• Older women. A persistent or atypical Bartholin-type mass in a woman past mid-life warrants biopsy and histology because of the possibility (however rare) of gland carcinoma; recurrence should not simply be redrained indefinitely.

• Infertility is a couple's condition, and the ASRM 2023 definition frames it as a disease, condition or status that includes people needing donor gametes or embryos.^[2]
• About 80% of couples under 40 conceive within 12 cycles and about 90% within 24; half of those who fail in the first year succeed in the second.^[3]
• Unexplained infertility, 30% of couples, is a diagnosis of exclusion with age 40 or under, normal basic findings in both partners and adequate intercourse.^[1]
• Evaluation is parallel: pregnancy test, semen analysis, ovulation and ovarian reserve, tubal and uterine assessment.^[3][4][5]
• Normal WHO semen thresholds are volume at least 1.5 mL, concentration at least 15 million per mL, total number at least 39 million, motility at least 40%, vitality at least 58% and normal forms at least 4%.^[3]
• Ovulation: mid-luteal progesterone on day 21 of a 28-day cycle; baseline body temperature charting and routine prolactin or thyroid testing are not recommended.^[3][1]
• Tubal and uterine tests: HSG or HyCoSy for patency and 3D ultrasound for the cavity; routine diagnostic laparoscopy is not recommended.^[1]
• IVF criteria: 3 full cycles for women under 40 with 2 years of trying or 12 insemination cycles, and one full cycle for women aged 40 to 42 meeting the stated conditions.^[3]
• Oral ovulation agents should not be used for unexplained infertility.^[3]
• Bartholin cyst and abscess occur in about 2% of women, usually in reproductive years, and are usually not serious.^[6]
• A Word catheter is left in for 4 to 6 weeks; marsupialisation takes about 20 to 22 minutes and had a recurrence of 8.3% versus 18.8% for catheter in one 196-patient cohort.^[6]
• Recurrent or atypical Bartholin lesions in older women should be biopsied.

Tubal and uterine causes are considered on their own pages: polycystic ovary syndrome, endometriosis, uterine fibroids, premature ovarian insufficiency, pelvic inflammatory disease and hydrosalpinx, varicocele, hypogonadotrophic hypogonadism, ovulation induction and assisted reproduction. Until those pages are verified they are listed here as plain text. Bartholin abscess should also be distinguished from hidradenitis suppurativa vulvar abscess, epidermoid cyst and Bartholin gland carcinoma, which have their own pages.