244 Obstetrics and Gynecology Board Review •••
❍ What is the normal endometrial thickness in women of reproductive age?
Proliferative phase 4 and 8 mm and secretory phase 8 and 14 mm.
❍ Broadly characterize the major categories of DUB?
Estrogen breakthrough bleeding, estrogen withdrawal bleeding, and progesterone breakthrough bleeding.
❍ What are the causes of estrogen withdrawal bleeding?
Bilateral oophorectomy, radiation of mature follicles, and administration of estrogen to a previously
oophorectomized woman followed by its withdrawal
❍ What is the cause of midcycle spotting or light bleeding?
The decline in estrogen that occurs immediately prior to the LH surge.
❍ How does estrogen affect breakthrough vaginal bleeding?
Low doses of estrogen cause intermittent spotting that may be prolonged. High levels of estrogen lead to
amenorrhea followed by acute, often profuse bleeding.
❍ What are the causes of progesterone withdrawal bleeding?
Removal of the corpus luteum, medically or surgically. Pharmacologically a similar event can be achieved by
administration and discontinuation of progesterone or a synthetic progestin, provided the endometrium is estrogen
primed.
❍ How can you narrow the differential diagnosis of uterine bleeding in patients of reproductive age?
By establishing ovulatory status.
❍ How can you determine ovulatory status?
Menstrual cycle charting, day 3 FSH, anti-Mullerian hormone levels, basal temperature monitoring, measurement
of the serum progesterone concentration, monitoring of urinary LH excretion, and sonographic demonstration of
periovulatory follicle.
❍ How can you determine ovulatory status based on menstrual history?
If there are predictable cyclic menses, with duration of cycle 24 and 35 days, then most likely they are ovulatory.
If the cycles vary in length by >10 days from one cycle to the next, then they are most likely anovulatory.
❍ If a single value of serum progesterone is low for the luteal phase, does it mean that the patient is not in the
luteal phase?
Not necessarily because it may be obtained between LH pulses, though a single level above 6 ng/mL is usually
indicative of normal luteal phase.
❍ What are the systemic illnesses that may cause anovulatory bleeding?
Hypo- and hyperthyroidism, chronic liver disease, chronic renal failure, Cushing disease, PCOS, prolactinoma,
empty sella syndrome, Sheehan syndrome, adrenal and ovarian tumors, and tumors infiltrating the hypothalamus.