Final answer:
Renal function during pregnancy involves increased urine production due to the handling of both maternal and fetal waste, and it is impacted by significant changes in blood volume, circulatory and respiratory systems. Despite these changes, autoregulatory mechanisms maintain a stable filtration rate in the kidneys.
Step-by-step explanation:
During pregnancy, renal function undergoes several significant changes. The maternal urinary system processes waste products from both the mother and the fetus, increasing the total volume of urine produced. The increase in urine production is exacerbated by the 30 percent growth in maternal blood volume that occurs to nourish the fetus and manage waste removal.
This expanded blood volume combined with a moderate rise in pulse and blood pressure facilitates the increased demands on the kidneys. Moreover, as the uterus expands, it compresses pelvic blood vessels, contributing to changes in the circulatory system and sometimes causing varicose veins or hemorrhoids. Physiological alterations including a substantial increase in respiratory minute volume, by approximately 50 percent, can also affect renal function indirectly. Therefore, while the kidneys work hard to manage the additional load, autoregulatory mechanisms such as the myogenic mechanism and the tubuloglomerular feedback help maintain a relatively stable filtration rate despite these changes.