Female Infertility — Symptoms, Causes & Treatment | MyMedicPlus

Female infertility is defined clinically as the inability to achieve a clinical pregnancy after 12 months of regular unprotected sexual intercourse (or after 6 months in women aged 35 and over, given the steeper age-related decline in fertility). Female factors are identified in approximately 40% of infertility cases within couples; male factors account for another 40%; and combined or unexplained infertility accounts for the remaining 20%. An estimated 50 million women worldwide are affected, making female infertility one of the most prevalent and emotionally impactful reproductive health conditions globally. The principal causes are ovulatory disorders (25–30% of cases — most commonly polycystic ovary syndrome, PCOS), tubal factor infertility from pelvic inflammatory disease or endometriosis (25%), uterine or cervical abnormalities (10%), endometriosis (5–10% additional cases beyond tubal), and diminished ovarian reserve. Unexplained infertility — where all standard investigations are normal — accounts for 25–30% of couples. Modern reproductive medicine has transformed outcomes: in vitro fertilisation (IVF) with intracytoplasmic sperm injection (ICSI), egg donation, gestational surrogacy, and fertility-sparing surgical techniques have enabled many women with severe infertility to achieve parenthood, though success rates decline significantly with advancing female age.

Ovulatory disorders are the most common cause, accounting for 25–30% of female infertility, with polycystic ovary syndrome (PCOS) being the most prevalent (affecting 6–10% of reproductive-age women) — causing anovulation from disordered LH/FSH secretion, hyperandrogenism, and insulin resistance. Other causes include: tubal factor infertility from pelvic inflammatory disease (Chlamydia trachomatis — now the leading STI-related cause of tubal damage), previous ruptured appendix, or endometriosis (20–30% of endometriosis patients have significant tubal involvement); uterine abnormalities — submucosal fibroids (reducing implantation rates by 50–75%), endometrial polyps, Asherman's syndrome (intrauterine adhesions — from post-curettage scarring, causing hypomenorrhoea and amenorrhoea); diminished ovarian reserve (declining egg quantity and quality, accelerating after age 35; AMH below 0.5 ng/mL signals critically low reserve); cervical factor (hostile cervical mucus — uncommon with modern ART bypassing the cervix); premature ovarian insufficiency (POI — menopause before age 40, affecting 1% of women; causes include Turner syndrome, fragile X premutation, autoimmune oophoritis, prior chemotherapy or pelvic radiation). Risk factors include advanced age (the dominant factor — monthly fecundity falls from 20% at age 25 to 5% at age 40), smoking (accelerates ovarian ageing, reduces egg quality), obesity (impairs ovulation and implantation), low BMI (hypothalamic hypogonadism causing anovulation), prior STIs, endometriosis history, and previous pelvic or abdominal surgery (adhesion formation).

The defining symptom of female infertility is inability to conceive — the absence of pregnancy after 12 months of regular unprotected intercourse (or 6 months if the woman is over 35). Beyond this, symptoms reflect the underlying cause: menstrual irregularity — oligomenorrhoea (cycles greater than 35 days apart) or amenorrhoea (absent periods) strongly suggests anovulation from PCOS, hypothalamic dysfunction (excessive exercise, low body weight), hyperprolactinaemia, or premature ovarian insufficiency; regular 28–30-day cycles suggest ovulation is occurring. Dysmenorrhoea (painful periods) and deep dyspareunia (pain during sexual intercourse), particularly with bowel or bladder symptoms, are characteristic of endometriosis and warrant urgent gynaecological evaluation — diagnosis is often delayed by 7–10 years from symptom onset. Galactorrhoea (spontaneous nipple milk production outside pregnancy) indicates elevated prolactin (hyperprolactinaemia from prolactinoma or dopamine-blocking medications) — prolactin suppresses GnRH and prevents ovulation. Hirsutism (male-pattern hair growth on the face, chin, chest, abdomen), acne, and scalp hair thinning (alopecia) are features of androgen excess from PCOS. Hot flushes, vaginal dryness, and reduced libido in a woman under 40 suggest premature ovarian insufficiency. Many women with infertility — particularly from tubal damage or cervical factor — have no other symptoms, with the fertility investigation itself revealing the underlying cause.

The infertility workup is systematic and covers all major aetiological categories. Ovulatory function: mid-luteal (Day 21 in a 28-day cycle) serum progesterone — level above 30 nmol/L confirms ovulation; below 16 nmol/L suggests anovulation. LH surge detection using home urine ovulation predictor kits identifies the ovulatory window. Ovarian reserve assessment: anti-Müllerian hormone (AMH) — the best single marker of ovarian reserve (secreted by granulosa cells of preantral and antral follicles; normal above 1.0 ng/mL; below 0.5 ng/mL indicates diminished reserve); antral follicle count (AFC) on transvaginal ultrasound in the follicular phase (normal 5–10 follicles per ovary; below 3 per ovary indicates low reserve); FSH and oestradiol on day 2–3 of the cycle (elevated FSH above 10 IU/L or elevated oestradiol above 80 pg/mL indicates declining reserve). Tubal patency evaluation: hysterosalpingography (HSG — X-ray with contrast injected via the cervix; depicts the uterine cavity and tubal fill; sensitivity 78%, specificity 83% for tubal occlusion); HyCoSy (hysterosalpingo-contrast sonography — ultrasound alternative); laparoscopy with chromopertubation (the gold standard — directly visualises tubes and pelvis, simultaneously diagnosing and treating endometriosis, adhesions, and peritubal disease). Hormonal panel: prolactin (hyperprolactinaemia), TSH (thyroid dysfunction), androgens (testosterone, DHEAS — if PCOS features), and LH/FSH ratio (elevated LH:FSH above 2:1 in PCOS). Semen analysis of the male partner (normal morphology by Kruger strict criteria above 4%; motility above 40%; concentration above 15 million/mL) is essential — male factor is identified in 40% of infertile couples. Diagnostic hysteroscopy evaluates the uterine cavity for polyps, fibroids, septum, and adhesions.

Treatment is cause-specific. Ovulatory disorders: letrozole (aromatase inhibitor — 2.5–7.5 mg/day CD3–7; first-line for PCOS — superior to clomiphene in live birth rates in PCOS per the PPCOS-II trial; 15% live birth rate per cycle); clomiphene citrate (anti-oestrogen — 50–150 mg/day CD2–6; induces ovulation in 80% of PCOS patients, pregnancy in 40% over 6 cycles); metformin (500–2,500 mg/day) for insulin-resistant PCOS — improves menstrual regularity and ovulation; injectable gonadotropins (recombinant FSH — e.g., Gonal-F, Puregon — 50–150 IU/day starting dose) for clomiphene/letrozole-resistant anovulation, requiring intensive ultrasound monitoring to prevent ovarian hyperstimulation syndrome (OHSS) and multiple pregnancy. Tubal factor infertility: laparoscopic salpingolysis (division of peritubal adhesions) and fimbrioplasty (fimbriae repair) for distal tubal disease — success rates 20–35%; hydrosalpinx (fallopian tube filled with serous fluid from chronic infection) significantly reduces IVF implantation rates by 50% — salpingectomy or proximal occlusion before IVF is recommended. In vitro fertilisation (IVF) with intracytoplasmic sperm injection (ICSI — injection of a single sperm directly into the egg cytoplasm): the primary treatment for tubal factor, severe endometriosis, diminished ovarian reserve, or repeated IUI failure; live birth rates per embryo transfer: 40–50% under 35, 30–40% at 35–37, 20–30% at 38–40, 5–15% over 40 using own eggs; preimplantation genetic testing for aneuploidy (PGT-A) improves implantation rates per transfer by selecting euploid embryos, particularly in older patients. Uterine abnormalities: operative hysteroscopy for polyps, submucosal fibroids (Class 0 and 1 — those distorting the cavity), and intrauterine adhesions (Asherman's syndrome — hysteroscopic adhesiolysis with adjuvant oestrogen therapy post-operatively); myomectomy (laparoscopic or open) for larger intramural fibroids significantly displacing the cavity.

Infertility causes significant psychological distress — depression rates are 2–3 times higher in infertile women than fertile controls, and anxiety is nearly universal during active treatment cycles. Relationship strain from the medicalization of sexuality (timed intercourse, invasive investigations), financial pressure of treatments, and disagreement between partners on treatment intensity and limits is reported by 50–70% of couples. Ovarian hyperstimulation syndrome (OHSS): a potentially life-threatening complication of gonadotropin stimulation, caused by excessive ovarian response producing vascular endothelial growth factor (VEGF) — leading to increased capillary permeability, ascites, and in severe cases (1–2% of IVF cycles), haemoconcentration, thromboembolism, and renal or hepatic impairment requiring hospitalisation; the introduction of GnRH-agonist triggering and freeze-all embryo strategies has dramatically reduced severe OHSS incidence. Multiple pregnancy: the most common obstetric complication of fertility treatment — IVF twin pregnancy carries 50% risk of preterm birth before 37 weeks, 10% risk of very preterm birth before 32 weeks, 3-fold increased risk of maternal complications (gestational diabetes, preeclampsia, anaemia), and significantly elevated perinatal mortality; single embryo transfer (SET) policy has reduced twin rates in IVF from 28% to under 10% in centres following HFEA guidance. Financial toxicity: IVF costs £3,000–5,000 per cycle privately in the UK; many couples require 2–3 cycles to succeed; the psychological and financial burden of recurrent failed cycles is substantial and requires structured support.

Prevent STIs through consistent safe sex practices and regular screening to protect tubal function. Achieve and maintain a healthy body weight — both obesity and low weight impair ovulation. Quit smoking, which damages egg quality and reduces ovarian reserve. Seek prompt treatment for endometriosis and pelvic inflammatory disease before they cause irreversible tubal damage. Women over 35 should seek fertility evaluation after 6 months of trying. Consider egg freezing if anticipating delay in family building due to career or personal circumstances, as ovarian reserve declines significantly with age.

See a GP for a fertility review if you have been trying to conceive for 12 months (under 35) or 6 months (over 35) without success — earlier review is appropriate for women with known risk factors. Request early assessment (within 3-6 months of trying) if you have: irregular or absent periods (possible ovulatory disorder or PCOS), known or suspected endometriosis, previous pelvic infection or STI (tubal damage risk), prior pelvic or abdominal surgery, or a partner with known fertility issues. Your GP can initiate basic investigations — mid-luteal progesterone, FSH, AMH, and a semen analysis for your partner — before specialist referral. Seek gynaecology or reproductive medicine referral for investigation of the suspected cause and discussion of treatment options. Women with PCOS and infrequent periods should not wait the full 12 months — ovulation induction can be started early. Women over 40 pursuing pregnancy should seek specialist review promptly, as ovarian reserve declines sharply with each additional year.