What factor can lead to low urine output in a fetus under stress?

Low urine output in a fetus under stress can be attributed to diverted blood flow. Under stress conditions, such as hypoxia or uteroplacental insufficiency, the body prioritizes essential organs, leading to a redistribution of blood flow. This can result in reduced perfusion to the kidneys, thus decreasing urine output. The kidneys, being less vital compared to the heart and brain during times of fetal distress, may not function optimally, leading to oligohydramnios (low amniotic fluid) due to decreased fetal urination.

Increased amniotic fluid, normal fetal heart pulsations, and active fetal behavior do not contribute to low urine output in the same way. Increased amniotic fluid typically suggests greater fetal urine production, while normal heart pulsations indicate stable fetal conditions rather than stress. Active fetal behavior may actually reflect well-being and not stress, thus not being linked to decreased urine output.