This paper is a description, with illustrations, of the technique used by the authors from 1938 to 1954 in searching for early human pregnancies prior to the first missed menstrual period. The myometrium was bivalved on the dissecting board down to the endometrium. The entire specimen was immersed in saline and the endometrial sac opened by dissection under the binocular microscope; contents were pipetted into embryologic dishes. The endometrial surface was inspected before and after partial fixation for implanted stages. In 211 uteri surgically removed, along with 102 Fallopian tubes, 34 specimens were found, 13 were abnormal – potential abortuses – and 21 were normal. There were eight segmenting ova – one tubal and seven intrauterine, of which four were normal and four were abnormal. There were 26 implanted specimens, nine abnormal and 17 normal. The specimens have all been described before, but the technique had never been illustrated nor described in detail.