Reproductive Endocrinology and Infertility
What this domain tests
Reproductive endocrinology questions test the workup of anovulation, PCOS diagnosis, ovulation induction, endometriosis, male factor, and ovarian reserve - plus safe practice in assisted reproduction.
Core rules
- PCOS. Rotterdam: two of three - oligo/anovulation, clinical or biochemical hyperandrogenism, polycystic ovaries (≥12 follicles 2–9 mm or ovarian volume >10 mL). Exclude thyroid disease, hyperprolactinemia, and non-classic congenital adrenal hyperplasia.
- Ovulation induction. Lifestyle and weight loss first. Letrozole 2.5–5 mg on cycle days 3–7 is first-line and gives higher live-birth rates than clomiphene. Clomiphene 50–150 mg is an alternative but has antiestrogenic effects on endometrium and mucus. Metformin helps in insulin resistance.
- OHSS. Risk rises with high antral follicle count, high gonadotropin dose, and hCG trigger. Prevent with an antagonist protocol, low-dose gonadotropins, cabergoline, and freeze-all.
- Semen analysis (WHO 2021). Volume ≥1.4 mL, concentration ≥16 million/mL, total motility ≥42%, normal morphology ≥4%.
- Endometriosis. Laparoscopy is diagnostic; ASRM stage correlates poorly with pain. Ovarian reserve markers: AMH and antral follicle count; day-3 FSH is less sensitive.
- Hyperprolactinemia. Exclude pregnancy and hypothyroidism; image the pituitary if prolactin is >100 ng/mL or neurologic signs are present.
Worked example
A 30-year-old with PCOS, BMI 33, anovulation, normal semen analysis, and patent tubes. Start lifestyle change and letrozole 2.5 mg on days 3–7, with mid-luteal progesterone to confirm ovulation. If she does not ovulate, increase to 5 mg before adding metformin or gonadotropins.
Traps
Diagnosing PCOS on ultrasound alone; giving clomiphene without confirming tubal patency; treating hyperprolactinemia before excluding pregnancy; ignoring the male partner.