Effects of breast feeding practice on the post partum endometrium

Fundal endometrial samples from 91 white and 64 South African blacks were examined to assess postpartum endometrial patterns in the 2 racial groups and in relation to the lactation practice. The difference in the proportions of breast-feeding at 6 and 13 weeks postpartum was 26.5% and 16% for the white group and 68.75% and 47.9% for the black group. Endometria were separated into ''active'' groups which included proliferative, secretory, or hyperplastic specimens and ''inactive'' groups which showed atrophic or hypoplastic features. The chi-square for the association of an inactive endometrial pattern with lactation was significant for both white and black subjects, particularly at 13 weeks. Cystic hyperplasia was found to occur spontaneously, particularly in nonlactators, and with greater severity in patients who had received a long-acting estrogenic agent (quinestrol) for lactation suppression.