How does vaginal cytology diagnose functional uterine bleeding?

The maturity of vaginal epithelial cells is proportional to the level of estrogen in the body. The higher the estrogen level, the more mature the differentiation of vaginal epithelial cells. Observing the proportion of vaginal epithelial cells can reflect the level of estrogen in the body and understand the function of the ovaries or placenta. This test has a certain significance in diagnosing functional uterine bleeding. For anovulatory functional uterine bleeding, the exfoliative cytology shows that it is mainly affected by estrogen, lacks signs of progesterone action, and the cells are more dispersed and flat. They may fluctuate between low-medium or medium to high estrogen levels, and there is no cyclical change, especially no accumulation before menstruation; while for ovulatory functional uterine bleeding, some patients have a significant rightward shift in MI, cyclical changes, and a high degree of estrogen influence in the middle period. .

Vaginal exfoliative cytology is generally performed as follows: for married women, the secretions and cells on the upper 1/3 of the vaginal wall are gently scraped under the speculum; for unmarried women, a sterile female swab is soaked in physiological saline and then applied to the upper 1/3 of the vaginal wall. The swab is taken out, placed horizontally on a glass slide and rolled in one direction. After being evenly applied into a thin slice, it is placed in ethanol for fixation for 40 minutes, stained, and the cell morphology and staining are examined under a microscope.

The test results are usually expressed as a maturation index (MI). To calculate the percentage of the three layers of vaginal epithelial cells, observe 200 cells under a low-power microscope and write them in the order of bottom layer/middle layer/surface layer, such as bottom layer 0, middle layer 60, and surface layer 40, then write them as 0/60/40 (mid-follicular phase). The judgment criteria for this test are that smears affected by estrogen generally have basically no bottom layer cells; mildly affected patients have less than 20% of the surface layer; and highly affected patients have more than 60% of the surface layer cells. Bottom layer cells will appear when ovarian function is low: mildly low bottom layer cells <20%; moderately low bottom layer cells can account for 20%~40%; and highly low bottom layer cells >40%.