Reproductive Endocrinology and Infertility
Core concepts
Reproductive endocrinology questions test the hypothalamic-pituitary-ovarian axis, the diagnosis of anovulation, and the investigation of infertility. Know the causes of anovulation (hypothalamic, pituitary, ovarian, polycystic ovary syndrome, thyroid, hyperprolactinaemia) and the first-line investigations (cycle day 2–5 FSH/LH, oestradiol, prolactin, thyroid function, and for the partner a semen analysis).
Polycystic ovary syndrome is defined by the Rotterdam criteria: two of three of oligo/anovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology. Management depends on the goal: lifestyle and metformin for metabolic risk, clomiphene or letrozole for ovulation induction, and combined oral contraceptives for cycle regulation. Understand the principles of assisted reproduction, the risk of ovarian hyperstimulation syndrome, and the counselling around age-related fertility decline.
Traps
- Investigating infertility before confirming the partner's semen analysis.
- Diagnosing polycystic ovary syndrome on ultrasound alone.
- Forgetting that hyperprolactinaemia requires exclusion of pituitary adenoma.
- Missing that ovarian reserve testing does not predict spontaneous conception with certainty.
Worked rule of thumb
For a couple with infertility, follow the sequence: confirm ovulation, confirm tubal patency, confirm semen quality, then assess the uterine cavity. The first abnormal result directs the next step. In anovulation, the choice of ovulation induction depends on whether there is hypothalamic hypogonadism (gonadotrophins), polycystic ovary syndrome (letrozole or clomiphene), or hyperprolactinaemia (dopamine agonist).
Exam technique
State the diagnosis, the investigation that confirms it, and the treatment goal. Examiners reward a clear understanding of the couple as a unit.