THE SIZE OF THE SPLEEN AND THE ADRENALS DURING PREGNANCY AND THE PUERPERIUM

Abstract

The spleen wt.-body wt. (SW/BW) and the adrenal wt.-body wt. (AW/BW) ratios were detd in 52 normal [female] guinea pigs. These ratios were also detd. in 33 guinea pigs during the 7th wk. of gestation and in 29 guinea pigs approximately 72 hrs. after parturition. With the exception of the exptl. conditions, all 3 groups of animals belonged to the same statistical population. In the pregnant animals, the spleen was found to be about 15% smaller than in the control group. There was, however, no significant difference in the wt. of the spleens of the post-partum group and the control animals. The adrenals in the pregnant animals were of normal size. This finding does not substantiate the prevailing opinion that the adrenals hypertrophy during pregnancy. In the post-partum group, however, the adrenals were found to be increased in size about 34%; the possibility of this occurring by chance was less than 1 in a 100. The rapid increase in wt. of the adrenals in the post-partum period can best be explained as being due to a redistr. of fluid following the hypervolemia of pregnancy.