Frequency of X-chromatin in pregnant women during the second trimester of gestation.

The frequency of X-chromatin was determined in pregnant women during the second trimester of gestation in order to establish possible correlations with the changes in steroid hormone levels occurring during this period and compare the curve with that for normal nonpregnant women. The mean frequency of X-chromatin in oral mucosa cells from a salivary suspension was 19.97% for the 24 patients studied, a statistically higher value than that obtained for nonpregnant women.