Urinary system and pregnancy (original) (raw)

1 Renal haemodynamics and tubular function in human pregnancy

Baillière's Clinical Obstetrics and Gynaecology, 1987

Understanding of abnormality must be based upon a realistic appreciation of normality. Without this, the significance of changes observed in disease may be overlooked. This is especially true of the interpretation of early studies of renal function during human pregnancy. Inappropriate control data were obtained from women haphazardly selected during the last few weeks of pregnancy or the first few days of the puerperium or even from men; results were indiscriminately 'corrected' to a standard body surface area and the numbers investigated during any single study were small. As a result, it was incorrectly assumed that renal function changed little during pregnancy and the significance of the changes detected by some workers in women with renal complications was considerably underestimated. This chapter surveys current information about the substantial alterations that are now known to occur in renal haemodynamics and in renal tubular function during normal human pregnancy. Accurate information is difficult to acquire because of the limitations imposed upon research workers by the use of experimental subjects who are not only human but pregnant. Many of the techniques used have been indirect and experimental design has thus on occasions lacked the rigour that can be achieved using animal subjects. However there are important inter-species differences in the renal adaptation to pregnancy. Furthermore, there is no single acceptable animal model for many of the important renal complications of pregnancy, including preeclampsia. Such evidence as we have, despite its lack of precision, is therefore of considerable clinical importance.

The Effect of Pregnancy on Rat Urinary Tract Dynamics

The Journal of Urology, 1995

We investigated the urodynamics of the renal pelvis and bladder during spontaneous bladder filling and emptying in 13 pregnant and 19 nonpregnant Sprague-Dawley rats to examine the characteristics of the dilated urinary tract in pregnancy. For each group renal pelvic and bladder pressures were measured continuously and simultaneously during various urinary flows, while the bladder was filled and emptied. In pregnant rats the ureter was wider and the renal pelvis was longer and wider than in nonpregnant rats. At urinary flows of 10 to 30 ml./kg. per hour pregnant rats had significantly lower renal pelvic pressures than nonpregnant rats during bladder filling. In addition, pregnant rats had higher bladder compliance and capacity than nonpregnant rats (compliance 0.09 2 0.12 ml./cm. water versus 0.05 2 0.05 ml./cm. water, p cO.01 and bladder capacity 0.669 2 0.61 ml. versus 0.490 2 0.38 ml., p c0.05). These findings imply that much of the hydroureteronephrosis during pregnancy may relate to increased urinary tract compliance rather than obstruction.

Renal physiology in pregnancy

Postgraduate Medical Journal, 1979

The changes which occur in renal excretory function during pregnancy are discussed. The relationship between glomerular filtration rate and effective renal plasma flow is examined in the light of new serial data obtained under conditions of saline diuresis. Changes in the renal handling of nutrients and in the excretion of waste products during pregnancy are reviewed.

Urological problems in pregnancy

BJU International, 2002

During pregnancy the urinary tract undergoes extensive anatomical and physiological changes. These changes can result in many symptoms and pathological conditions that may affect the mother and fetus. It is well documented that childbirth may result in urinary tract damage which may predispose to postpartum symptoms. This review describes the physiological and pathological consequences of pregnancy and delivery on the urinary tract, and how these may be minimized.

HISTO-MORPHOMETRICAL STUDY ON KIDNEY GLOMERULI AND CORTICAL TUBULE IN LATE PREGNANCY

Background: Maternal accommodation to normal pregnancy begins shortly after conception,during pregnancy the anatomical and histological changes occur in the kidneyas a maternal adaptation for physiological changes. Aim: Evaluation morphological changes in the kidney glomeruli and tubules during pregnancy, Histomorphometrical assessment of glomeruli and tubular changes with pregnancy. Material and Method: This study carried on 40 mature mice divided into two groups, 20 pregnant mice served as experimental group and 20 non-pregnant mice as a control group, kidneys were removed; the weight is measured and then fixed, dehydrated in ascending grades of alcohol, cleared in xylene and infiltrated with paraffin. The paraffin blocks were made and 5?m thin sections were obtained using a rotary microtome. The sections were stained with H&E stain, PAS examined under light microscope. Result: Under the light microscope, the kidney in experimental group show the many anatomical changes as increase in Wight, elongated and increase in width, and showed many histological changes as a glomerular enlargement with decrease of urinary space and dilation in proximal and distal tubule. A statistically significant differences have been shown in the diameter of renal corpuscle, glomerular tuft and Bowman’s space, and also in the renal tubules proximal and distal convoluted tubules (p<0.001). And in Wight, elongation and width as (p<0.001). Conclusion: The results of the present study indicated during pregnancy kidney undergo to anatomic change as increase in size and Wight, and histologic change as elongation in glomeruli, and dilation in diameter of tubule.

Uroflowmetric observations in pregnancy

Neurourology and Urodynamics, 1988

Uroflowmetric studies were performed on 752 antepartum patients at various stages of pregnancy and 153 patients 6 weeks postpartum. The mean voided volume in the antepartum group (203.4 ml) was significantly lower (P < .001) than that of the postpartum group (261.1 ml). In the antepartum group, the data suggests a significant decrease in voided volume in the third trimester. The uroflowmetric parameters (FT, Q-max, T-Q-max) studied were observed to be directly related to voided volumes. This is an observation known in the nonpregnant female. Presenting stations of zero and above do not appear to influence the uroflowmetric parameters. Subjective increases in frequency of urination during pregnancy are correlated with objective decreases in the volumes voided, and the converse is also found to be true. The contributory roles of the mechanical and endocrinological factors on micturition in pregnancy are discussed. It appears that the predominant factor may be mechanical.