CHANGES IN RENAL FUNCTION IN LATE PREGNANCY

Renal haemodynamics and tubular function in human pregnancy

In human pregnancy, effective renal plasma flow and glomerular filtration rate increase to levels 50-80% above non-pregnant values. The increments occur shortly after conception, persist throughout the second trimester and reduce slightly in late pregnancy. The hyperfiltration of pregnancy does not seem to be a potentially damaging process. The increased excretion of glucose and other nutrients, as well as uric acid and protein, is related in part to altered tubular function. Renal physiology is altered so much in pregnancy that non-pregnant norms cannot be used in antenatal care.

Investigations into the influence of posture on renal plasma flow and glomerular filtration rate during late pregnancy

Renal plasma flow and glomerular filtration rate were investigated in three positions (supine, left lateral and sitting) in a group of eighteen healthy women during late pregnancy and again after the puerperium. No difference in renal function could be attributed to the position adopted. However, an unexplained decrease in both of the indices occurred during the course of prolonged infusion in any position.