Ovulation, Menstrual Disorders, and Anovulation
Classification
Use WHO categories: Group I hypothalamic–pituitary failure (low FSH, low estradiol); Group II eugonadotrophic normoestrogenic anovulation (PCOS is the prototype); Group III hypergonadotrophic hypogonadism (ovarian failure). This framework drives treatment choice.
PCOS is diagnosed by Rotterdam criteria (two of three: oligo/anovulation, clinical or biochemical hyperandrogenism, polycystic ovaries), after excluding other causes. Remember that polycystic ovarian morphology on ultrasound alone is not PCOS.
Menstrual disorders
Abnormal uterine bleeding is classified by PALM-COEIN: structural (Polyp, Adenomyosis, Leiomyoma, Malignancy) versus non-structural (Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not otherwise classified). Heavy menstrual bleeding in an adolescent should prompt von Willebrand screening.
Traps
- Treating anovulation without excluding pregnancy, thyroid disease, and hyperprolactinaemia.
- Overlooking endometrial protection in a woman with chronic anovulation-unopposed estrogen raises endometrial cancer risk.
- Confusing primary amenorrhoea workup (karyotype, anatomy) with secondary amenorrhoea workup (pregnancy test, TSH, prolactin, FSH).
Worked example
A 28-year-old with 4-month cycles, hirsutism, and BMI 34: check pregnancy test, TSH, prolactin, and testosterone; if Rotterdam criteria met, first-line is lifestyle plus letrozole for ovulation induction (superior to clomiphene in PCOS), with metformin as adjunct.