Until recently there has been uncertainty as to whether kidney function in normal pregnancy differs significantly from that in the nonpregnant state. The earlier studies reviewed by Smith (1), Chesley (2) and Bucht (3) were for the most part limited to the immediate pre-and postpartum period when deviations from the nonpregnant state are less marked. On the other hand, the studies of Nice (4) demonstrated a marked increase of urea clearance in mid-pregnancy while those of Bonsnes and Lange (5) and Bucht (3) showed significant increases in both renal plasma flow and in glomerular filtration rate during mid-pregnancy which persisted to approximately the thirtyeighth week.At the time the present study was begun, no serial studies of renal function during normal pregnancy and in the postpartum period had been reported and it was the purpose of this study to make such observations. Serial studies eliminate the element of apprehension encountered in single studies which, as emphasized by Miles and DeWardener (6), may distort the results. Our findings confirm the increased renal function in pregnancy, and define the resultant lowering of the normal range of values for plasma urea averaging 27 years. One subject (K) was studied during a second pregnancy. Their parity was from one to five children, with an average of two children. No patient exhibited any suggestion of toxemia during the study or during any previous pregnancy, nor was there any evidence of hypertension or urologic disease. One patient (E) was delivered by cesarean section at 38 weeks because of a placenta previa, and another (H) spontaneously delivered twins at 34 weeks. A group of nine nonpregnant women were control subjects. One of the control subjects (N) subsequently became pregnant. The average age was 25.7 years, with a range of 21 through 33 years and an average parity of 1.1. Procedure. Renal clearances of para-aminohippurate (PAH) and of inulin were determined by the constant infusion technique of Goldring and Chasis (7). When creatinine clearances were measured, meat was eliminated from the diet, as recommended by Camara, Arn, Keimer and Newburgh (8). During the period of study, the patients were in a semi-supine position. For comparison, studies were also made on seven subj ects in both supine and left lateral positions. A minimum of three collection periods of 15 to 30 minutes in length, depending on the urine flow, were employed. Each period was terminated by irrigation of the bladder with 100 to 200 ml. of physiological saline solution and 50 to 100 ml. of air, both of which were totally recovered before the next period was begun. In a subsequent series of clearance studies during pregnancy (9), the patients were asked to stand at the end of the collection period. In only one instance was more than a few additional ml. of urine obtained. These observations in conjunction with those of Chesley and co-workers (10), who found that during pregnancy no better results could be obtained by direct irrigation of the renal pelves, suggest that re...

No abstract

No abstract

No abstract

No abstract