Causes of abnormal vaginal bleeding Organic causes 1 Reproductive tract disease • Pregnancy-related conditions are the most common causes of abnormal vaginal bleeding in women of reproductive age (threatened,incomplete, and missed abortion; ectopic pregnancy; and gestational trophoblastic disease). Implantation bleeding is also quite common at about the time of the first missed menstrual period. • Uterine lesions commonly produce menorrhagia or metrorrhagia by increasing endometrial surface area, distorting the endometrial vasculature, or having a friable/inflamed surface. • Cervical lesions usually result in metrorrhagia (especially postcoitalbleeding) due to erosion or direct trauma. • Iatrogenic causes include the intrauterine device (IUD), oral/injectable steroids for contraception or hormone replacement, and tranquilizers or other psychotropic drugs. Oral contraceptives are often associated with irregular bleeding during the first 3 months of use, if doses are missed or the patient is a smoker. Long-acting progesteroneonly contraceptives (Depo-Provera, Nexplanon) frequently cause irregular bleeding. Some patients may be unknowingly taking herbal medications (St John’s wort, ginseng) that have an impact on the endometrium.
2 Systemic disease • Blood dyscrasias such as von Willebrand disease and prothrombin deficiency may present with profuse vaginal bleeding during adolescence. Other disorders that produce platelet deficiency (leukemia, severe sepsis) may also present as irregular bleeding. • Hypothyroidism is frequently associated with menorrhagia and/or metrorrhagia. Hyperthyroidism is usually not associated with menstrual abnormalities, but oligomenorrhea and amenorrhea are possible. • Cirrhosis is associated with excessive bleeding secondary to the reduced capacity of the liver to metabolize estrogens.
Dysfunctional (endocrinologic) causes The diagnosis of dysfunctional uterine bleeding (DUB) can be made after organic, systemic, and iatrogenic causes for abnormal vaginal bleeding have been ruled out (diagnosis of exclusion).
1 Anovulatory DUB • The predominant type in the postmenarchal and premenopausal years due to alterations in neuroendocrinologic function. • Characterized by continuous production of estradiol-17β without corpus luteum formation and progesterone release. • Unopposed estrogen leads to continuous proliferation of the endometrium which eventually outgrows its blood supply and is sloughed in an irregular, unpredictable pattern.
2 Ovulatory DUB • Incidence: up to 10% of ovulatory women. • Mid-cycle spotting following the LH surge is usually physiologic. Polymenorrhea is most often due to shortening of the follicular phase of menstruation. Alternatively, the luteal phase may be prolonged by a persistent corpus luteum.