4 Finally, the status of maternal hydration and the amount of decidual prolactin may alter the transfer of amniotic fluid through fetal and maternal tissues. 3 Amniotic fluid volume is also influenced by intramembranous (between amniotic fluid and fetal blood within the placenta) and transmembranous (between amniotic fluid and maternal blood within the uterus) pathways in both physiologic and pathophysiologic states. After this period, the volume of amniotic fluid is a function of production, from fetal urine (600 to 1200 mL/day near term) and respiratory tract secretions (60 to 100 mL/kg fetal body weight/day), and removal through fetal swallowing (200 to 250 mL/kg fetal body weight/day). During this period, the composition of amniotic fluid is similar to fetal extracellular fluid, owing to the absence of keratin in the fetal skin.
![real amniotic fluid real amniotic fluid](https://i.ytimg.com/vi/v8-HdDZNquQ/maxresdefault.jpg)
2 Between 10 and 20 weeks’ gestation, the volume of amniotic fluid increases in a predictable and linear manner from approximately 25 mL to 400 mL. The expression of aquaporins changes as gestation advances and with certain pathologic states, such as polyhydramnios. 1 The formation and maintenance of amniotic fluid is an intricate process that depends on fetal maturation and maternal hydration, hormonal status, and uteroplacental perfusion.Īmniotic fluid during early embryogenesis is principally derived from maternal plasma by the passage of water and solutes through aquaporin water channels expressed in the fetal maternal membranes (amnion and chorion). Amniotic fluid serves a number of vital roles, including the facilitation of fetal growth, the provision of a microgravity environment that cushions the fetus, and the generation of a defense mechanism against invading microbes. The fetus is surrounded by amniotic fluid, a complex fluid that changes as the pregnancy progresses.
![real amniotic fluid real amniotic fluid](https://healthjade.com/wp-content/uploads/2018/07/Amniotic-fluid-index.jpeg)
![real amniotic fluid real amniotic fluid](https://1.bp.blogspot.com/-J_P4_S-fRcI/VO0S8iDfFTI/AAAAAAAAdXc/6Kat3c-weyg/s1600/baby%2Bborn%2Binside%2Bamniotic%2Bsac.jpg)
Chestnut MD, in Chestnut's Obstetric Anesthesia, 2020 Amniotic Fluid