Technetium Tc 99m rapidly crosses the ovine placenta and intramembranous pathway

Treatment of PPROM with anhydramnion in humans: first experience with different amniotic fluid substitutes for continuous amnioinfusion through a subcutaneously implanted port system

“…According to Gilbert and Brace [7], the production of the amniotic fluid is predominantly accomplished by the excretion of fetal urine (∼300 mL/kg fetal weight/day or 600-1200 mL/day near term) and the secretion of oral, nasal, tracheal, and pulmonary fluids (∼60-100 mL/kg fetal weight/day). The fetus swallows ∼200-250 mL/kg fetal weight/day, and a significant intramembranous pathway transfers fluids and solutes from the amniotic cavity to the fetal circulation across the amniotic membranes [8]. In the second half of pregnancy, there is a decrease in sodium and chloride concentrations, an increase in urea and creatinine concentrations, and an overall decrease in amniotic fluid osmolality.…”

Amniotic Fluid: Not Just Fetal Urine Anymore

“…Additionally, a significant intramembranous pathway transfers fluid and solutes from the amniotic cavity to the fetal circulation across the amniotic membranes. 3 The human amnion is a single layer of epithelial cells separating the amniotic cavity from the vascularized chorion. Early in gestation these amniocytes are flattened, but as pregnancy progresses they become cuboidal and have increasing numbers of microvilli on their apical surface.…”

Amniotic Fluid as an Extended Milieu Intérieur

“…It is now broadly accepted that the fetus plays an important role in regulating its own fluid volume through the behaviors of swallowing and micturition (Ross & Brace, 2001;Ross & Nijland, 1997). Fetal swallowing is the major source of water loss and turnover in the fetus, although a significant volume of AF is removed by transfer from the amniotic cavity into the circulatory vessels within the fetal membranes (Gilbert, Newman, Eby-Wilkens & Brace, 1996). Fetal micturition is the major source of AF in late gestation, with additional contributions from excretion of oral, nasal, tracheal and pulmonary fluids (Gilbert & Brace, 1993).…”