Infertility

Overview – Infertility

Infertility refers to the inability to conceive after 12 months of regular, unprotected intercourse and is a common issue affecting around 20% of couples. It can be classified as primary (no previous pregnancies) or secondary (following one or more pregnancies). Causes are roughly split between male and female factors, with a further 20% attributed to combined or unexplained causes. Evaluation involves a systematic approach to identifying and managing the underlying cause, often leading to the consideration of Assisted Reproductive Technologies (ART). Understanding infertility is critical for clinicians working in reproductive medicine, general practice, and gynaecology.

Definition

• Generic: Failure to conceive after >12 months of unprotected intercourse during fertile periods
• Primary infertility: Above definition in a nulligravid woman
• Secondary infertility: Above definition in a previously pregnant woman

Epidemiology

• Affects ~20% of couples
• 40% due to male factors
• 40% due to female factors
• 20% due to combined or unexplained factors

Aetiology

Female Causes

• Ovulatory dysfunction:
  • Polycystic ovarian syndrome (PCOS)
  • Hypothalamic amenorrhoea (e.g. female athlete triad)
• Tubal factors:
  • Pelvic inflammatory disease (PID)
  • Endometriosis (40–60% conceive within 18 months post-surgery)
• Other causes:
  • Advanced maternal age (>35)
  • Menopause (~>45)
  • Smoking (↓ fertility by 60%)
  • Chemotherapy/radiotherapy
  • Turner’s syndrome
  • Ovarian cancer
  • Anti-sperm antibodies

Male Causes

• Pre-testicular:
  • Pituitary failure (hypogonadotropic hypogonadism)
  • Chemotherapy/radiotherapy
  • Anabolic steroid use
  • Strenuous cycling/horse riding
  • Impotence
• Testicular:
  • Klinefelter’s syndrome
  • Testicular cancer
  • Cryptorchidism
• Post-testicular:
  • Vas deferens fibrosis (STIs: chlamydia/gonorrhoea)
  • Vas deferens obstruction (e.g. cystic fibrosis)
  • Varicocoele compression
  • Retrograde ejaculation (e.g. BPH, spinal injury, diabetes)
• Sperm abnormalities:
  • Oligospermia (<20 million/mL)
  • Aspermia (no sperm)
  • Poor motility or morphology

Evaluation

1. Male Factor

• Semen analysis:
  • Sperm count: >20 million/mL normal
  • Motility: >50% forward progressive
  • Morphology: >30% normal forms

2. Ovulation

• Menstrual history (28 ± 7-day cycle)
• Ovulation tracking:
  • Cervical mucus (Day 12–14)
  • Follicle ultrasound (Day 10)
  • Hormone assays: oestrogen (D12), LH (D13), progesterone (D21)
  • Laparoscopy for corpus luteum (D21–23)

3. Cervical Function

• Post-coital test (PCT):
  • Intercourse D12–13, cervical mucus examined ~8hrs later
  • 10 motile sperm/high power field = satisfactory

4. Tubal Function

• Imaging options:
  • Hysterosalpingography (Day 7–10)
  • Laparoscopy + dye test
  • Falloscopy (proximal tube visualisation)
  • Salpingoscopy (distal tube visualisation)

5. Uterine Function

• Imaging:
  • Transvaginal ultrasound (Day 7–10)
  • Hysteroscopy for polyps, fibroids, congenital anomalies

Management

Assisted Reproductive Technologies (ART)

• Ovulation induction: Exogenous gonadotropins to stimulate follicle development
• Luteal phase support: Supplemental progesterone to maintain endometrium
• IUI (Intrauterine insemination): Bypasses cervical barriers
• IVF-ET: In vitro fertilisation with embryo transfer
• GIFT: Gametes placed directly in fallopian tube
• ZIFT: Zygote transferred into fallopian tube
• ICSI: Intracytoplasmic sperm injection into oocyte
• TESA: Testicular sperm aspiration (for ejaculatory dysfunction)
• Other: Surrogacy, adoption

Note: ART success rate is <30%

Summary – Infertility

Infertility is defined as the inability to conceive after one year of regular, unprotected sex, affecting 1 in 5 couples. It can be due to male, female, or combined causes. Evaluation requires a stepwise approach assessing sperm quality, ovulation, tubal patency, and uterine health. Assisted reproductive technologies provide therapeutic options but have modest success rates. For a broader context, see our Reproductive Health Overview page.