Evaluation of Abnormal Uterine Bleeding Before Initiating Oral Contraceptives

Diagnostic Approach

The American College of Radiology recommends transvaginal ultrasound with Doppler as the first-line imaging study for all patients with abnormal uterine bleeding, allowing identification of structural causes including polyps, adenomyosis, leiomyomas, and endometrial hyperplasia/malignancy 1, 2
A combined transabdominal and transvaginal approach provides comprehensive evaluation of the uterus and adnexa, critical before masking symptoms with hormonal therapy 2
Starting oral contraceptives without imaging risks missing serious pathology that would be temporarily suppressed by hormonal contraception, delaying diagnosis of conditions like endometrial cancer or significant structural lesions 3, 2

The Centers for Disease Control and Prevention recommends that hormonal testing, such as FSH and LH, does not contribute substantially to safe oral contraceptive initiation according to contraceptive guidelines 5, 6, 7
These tests are classified as "Class C" (not contributing substantially to safe contraceptive use) in the U.S. Selected Practice Recommendations 5, 6
Among healthy women, no examinations or tests are needed before oral contraceptive initiation, though women with known medical problems may need additional evaluation 5, 6

The initial step in evaluating abnormal uterine bleeding is to obtain transvaginal and transabdominal ultrasound with Doppler to assess endometrial thickness and architecture, identify structural lesions, and evaluate for masses or other pathology 2, 4
Endometrial biopsy is indicated for women ≥35 years or younger women with risk factors for endometrial cancer, and its need is guided by ultrasound findings 4
Additional testing, such as pregnancy test, TSH, and prolactin, should be performed as indicated by the clinical presentation 2