Amenorrhea is a lack of menstrual flow, while oligomenorrhea decribes cycles of over 35 days.
Pregnancy
Hypothalamic dysfunction and low FSH/LH
pituitary dysfunction
ovarian dysfunction
outflow defect
endocrine
drugs
Primary amenorrhea: no periods by age 14 in absence of secondary characteristics, or no menses by age 16 with secondary sexual characteristics
Secondary amenorrhea: no periods for over 6 months, or over 3 cycles, after menarche
Questions will depend on possible cause:
hypothalamic or pituitary: galactorrhea, headache, visual changes
ovarian: menopausal symptoms
endocrine: weight change, signs of virilization, hypothyroid/hyperthyroid symptoms
medical history
family history
social history
Past menstrual history
Age, sexual activity, medical history,
External genitalia and vagina: atrophy, clitoromegaly, imperforate hymen, vaginal septum, vaginal agenesis
beta-hCG
FSH, LH, androgens, estradiol
progesterone challenge to assess for withdrawal bleeding (normal)
karyotype if absent puberty
Ultrasound to assess anatomy and for PCOS
CT or MRI of head if FSH/LH are low