Page 6 of 10
PY9.1-10 | Reproductive Physiology — Part 5
Infertility: When the Reproductive System Fails
Causes of Infertility in Couples
| Category | Proportion | Common Causes | Key Investigation |
|---|---|---|---|
| Male factor | 30-40% | Varicocele, azoospermia, oligospermia, hormonal | Semen analysis (count, motility, morphology) |
| Female — ovulatory | ~25% | PCOS, hypothalamic amenorrhoea, premature ovarian failure | Day 21 progesterone, FSH/LH, AMH, ultrasound |
| Female — tubal | ~20% | PID, endometriosis, previous ectopic | Hysterosalpingography (HSG), laparoscopy |
| Female — uterine | ~10% | Fibroids, Asherman's syndrome, congenital anomalies | Hysteroscopy, saline infusion sonography |
| Unexplained | 10-15% | No identifiable cause after standard workup | Empiric treatment: IUI → IVF |
Causes of Infertility in Couples
Figure: Infertility: When the Reproductive System Fails
| Category | Proportion | Common Causes | Key Investigation |
|---|---|---|---|
| Male factor | 30-40% | Varicocele, azoospermia, oligospermia, hormonal | Semen analysis (count, motility, morphology) |
| Female — ovulatory | ~25% | PCOS, hypothalamic amenorrhoea, premature ovarian failure | Day 21 progesterone, FSH/LH, AMH, ultrasound |
| Female — tubal | ~20% | PID, endometriosis, previous ectopic | Hysterosalpingography (HSG), laparoscopy |
| Female — uterine | ~10% | Fibroids, Asherman's syndrome, congenital anomalies | Hysteroscopy, saline infusion sonography |
| Unexplained | 10-15% | No identifiable cause after standard workup | Empiric treatment: IUI → IVF |
Causes of Infertility in Couples
| Category | Proportion | Common Causes | Key Investigation |
|---|---|---|---|
| Male factor | 30-40% | Varicocele, azoospermia, oligospermia, hormonal | Semen analysis (count, motility, morphology) |
| Female — ovulatory | ~25% | PCOS, hypothalamic amenorrhoea, premature ovarian failure | Day 21 progesterone, FSH/LH, AMH, ultrasound |
| Female — tubal | ~20% | PID, endometriosis, previous ectopic | Hysterosalpingography (HSG), laparoscopy |
| Female — uterine | ~10% | Fibroids, Asherman's syndrome, congenital anomalies | Hysteroscopy, saline infusion sonography |
| Unexplained | 10-15% | No identifiable cause after standard workup | Empiric treatment: IUI → IVF |
Infertility is defined as the failure to achieve a clinical pregnancy after 12 months of regular, unprotected sexual intercourse (or 6 months if the woman is >35 years old). It affects ≈10–15% of couples in India.
Figure: Infertility: When the Reproductive System Fails
Causes in couples (approximate distribution):
• Male factor alone: 30–40%
• Female factor alone: 30–40%
• Combined: 20–30%
• Unexplained: 10–15%
Male causes:
• Azoospermia (no sperm): obstructive (blocked vas deferens — post-vasectomy, post-infection) or non-obstructive (spermatogenic failure)
• Oligospermia (<15 million/mL): varicocele, hormonal causes, cryptorchidism (undescended testis → higher temperature → impaired spermatogenesis)
• Asthenospermia (poor motility): oxidative stress, infection
• Hypogonadism: low testosterone → low FSH/LH (hypothalamic/pituitary cause) or primary testicular failure
Female causes:
• Ovulatory dysfunction (25–30% of female infertility): PCOS (most common), hypothalamic amenorrhoea, premature ovarian insufficiency (POI), hyperprolactinaemia (prolactin inhibits GnRH)
• Tubal factor (20–30%): blocked fallopian tubes from PID (pelvic inflammatory disease), endometriosis, prior ectopic pregnancy, surgical adhesions
• Uterine/cervical: fibroids (submucosal), polyps, cervical stenosis, Asherman syndrome (intrauterine adhesions)
• Endometriosis: ectopic endometrial tissue → inflammation, adhesions, tubal occlusion
IVF — In Vitro Fertilisation:
• Indications: tubal factor, severe male factor (with ICSI), unexplained infertility, failed other treatments, same-sex couples
• Steps:
1. Ovarian stimulation: FSH injections (controlled ovarian hyperstimulation, COH) → multiple follicles develop
2. Oocyte retrieval: transvaginal ultrasound-guided aspiration of mature follicles (under sedation) → multiple eggs collected
3. Fertilisation: eggs incubated with prepared sperm in vitro; or ICSI (intracytoplasmic sperm injection — single sperm injected directly into egg)
4. Embryo culture: fertilised eggs cultured 2–5 days to blastocyst stage
5. Embryo transfer: 1–2 embryos transferred into uterine cavity; remaining embryos cryopreserved
6. Luteal support: progesterone supplementation until placenta takes over
• Success rate: ≈35–40% live birth per cycle in women <35 years; declines with age
• Complications: ovarian hyperstimulation syndrome (OHSS), multiple pregnancy
CLINICAL PEARL
Prolactin and Infertility:
Hyperprolactinaemia is a common, easily missed cause of infertility. Elevated prolactin (from a prolactinoma — a benign pituitary adenoma, or from hypothyroidism/drugs) suppresses GnRH → suppresses FSH + LH → anovulation + amenorrhoea.
Key point: always check serum prolactin in any woman with irregular periods or unexplained infertility, especially if she has galactorrhoea (milk secretion outside pregnancy/breastfeeding).
Treatment: cabergoline or bromocriptine (dopamine agonists — inhibit prolactin secretion). Most prolactinomas shrink without surgery.
SELF-CHECK — Part 5 Self-Check
A 50-year-old woman has FSH = 85 IU/L and her last period was 14 months ago. The most likely diagnosis is:
A. Premature ovarian insufficiency
B. PCOS
C. Menopause
D. Hypothalamic amenorrhoea
Reveal Answer
Answer: C. Menopause
Which investigation is MOST useful to diagnose ovulatory dysfunction as a cause of infertility?
A. Day 2–3 serum FSH and oestradiol
B. Mid-luteal phase (Day 21) serum progesterone
C. Transvaginal ultrasound on Day 1
D. Serum testosterone
Reveal Answer
Answer: B. Mid-luteal phase (Day 21) serum progesterone