THE WEIGHT OF THE VENTRICLES IN THE LATER WEEKS OF INTRA-UTERINE LIFE

Abstract
At a stage of maturity that corresponds with 24-28 weeks gestation, a crown-rump length of 20-25 cm., and body weight of 500-1000 g, the 2 heart ventricles are of roughly equal weight. Prior to this time the left ventricle is usually heavier than the right. Thereafter, the more rapid right ventricular gain in weight that has already been described by a number of workers is confirmed. In children of over 39 weeks gestation and 3000 g a reversal of the right ventricular preponderance seems to commence. This may be a physiological anticipation of the post-natal reversion to left ventricular preponderance or an indication of post maturity.