Amniotic Fluid Dynamics

This newborn baby was delivered in it’s fully intact amniotic sac during this cesarian delivery! All babies are encased in this sac during gestation, it is however very rare to remain encased in the amniotic sac following delivery! Adequate amniotic fluid volume is essential in preserving fetal life and is maintained by a balance of fetal fluid production (lung liquid and urine) and resorption (swallowing and intramembranous flow).

When in the womb, the fetus maintains this balance by swallowing amniotic fluid, having it flow through it’s newly developing gastro-intestinal system and through the kidneys where it can then urinate into the amniotic sac! This cycle assures proper maturation of the fetal CNS and organ systems (including the lungs). If something alters this cycle, such as an obstruction or agenesis of the fetal kidneys (resulting in an inability to excrete urine), then the amniotic fluid volume dramatically decreases (oligohydramnios). In other cases, fetal malformations (e.g., esophageal/ duodenal atresia and anencephaly) can result in the inability to swallow amniotic fluid, causing an excess of fluid (polyhydramnios). This imbalance of fluid in either direction can result in many life threatening birth defects. Despite these conditions however, it is estimated that 95-97% of babies are born with no defects at all! It is incredible to ponder how life is in constant geometric balance even before we take our first breath on this planet.