Sheehan's syndrome (panhypopituitarism), caused by infarction of the anterior pituitary venous complex (usually after massive postpartum haemorrhage or trauma), and Kallman's syndrome (amenorrhoea with anosmia caused by congenital lack of hypothalamic [ncbi.nlm.nih.gov]

Women who are underweight for their height when they get pregnant are more likely to have “small for dates” babies; and children of women who have eating disorders are more likely to be admitted to hospital with failure to thrive. [ncbi.nlm.nih.gov]

Women with polycystic ovary syndrome commonly present in their late teens or early 20s with hirsutism, acne, or irregular periods (cycle length 35 days). [ncbi.nlm.nih.gov]

NCT00501787 Phase 4 Metformin 35 Clomiphene Citrate in Infertile PCOS Patients Withdrawn NCT00501839 Phase 4 clomiphene citrate 36 Therapy for Infertile PCOS Patients Ovulating Under Clomiphene Citrate or Metformin Withdrawn NCT00502229 Phase 4 Clomiphene [malacards.org]

[…] from the University of Heidelberg suggests that tests which use LH as a reference often lack sensitivity and specificity. [13] Classification [ edit ] The World Health Organization criteria for classification of anovulation include the determination of oligomenorrhea [en.wikipedia.org]

Anovulation can also cause cessation of periods ( secondary amenorrhea ) or excessive bleeding ( dysfunctional uterine bleeding ). Mittelschmerz and premenstrual symptoms tend to be absent or reduced when a woman is anovulatory. [en.wikipedia.org]

The side effects of bromocriptine (postural hypotension, nausea, vertigo, headache) can make it unacceptable to the patient. Cabergoline and quinagolide are newer long acting dopamine agonists with fewer side effects. [ncbi.nlm.nih.gov]