[Ultrasonic studies of the human embryo sac]

The growth of the embryo sac and of the uterus was determined between the 5th and 12th weeks of amenorrhoea in 91 normal pregnancies. 24 measurements of the ovaries and the uterus were made for each case by means of two-dimensional echograms. The averages, the standard deviations, the deviations of the mean, the correlation coefficients and the regression polynomials are reported for each of the dimensions measured. The results are compared with those obtained by other authors. The dimensions that gave the best indication of the evolution of gestation were the area and perimeter of the ultrasonic scans of the embryo sac and of the uterus as well as the cephalo-caudal diameter of the embryo sac.