Everything you need to know about the fetal membranes, amniotic fluid, and umbilical cord

Did you know that the fetus in the womb is surrounded by two layers of fetal membranes?

Jenny Jansson

Read time: 2 m

Verified by Jenny Jansson

Certified midwife

Everything you need to know about the fetal membranes, amniotic fluid, and umbilical cordPhoto: Preggers

The outer layer is called the Chorion (vascular membrane) and the inner layer closest to the baby is called the Amnion (amniotic membrane), which forms and encloses all of the amniotic fluid. The fetal membranes prevent bacteria from entering the uterus and also prevent the amniotic fluid from leaking out, but they also help to equalize the pressure of the amniotic fluid to protect both the baby and the umbilical cord during contractions.

Amniotic Fluid

During pregnancy, there is both production and drainage of amniotic fluid. The drainage occurs through the umbilical cord and placenta into the mother's circulation as the baby swallows the amniotic fluid. The highest level, around 1000 ml, is usually reached in weeks 38-39 of pregnancy, after which a normal decrease occurs. The amount of amniotic fluid can be checked by ultrasound. Initially, the amniotic fluid is clear but becomes increasingly cloudy during pregnancy due to sebum, skin particles, and hair that detach from the baby. Allowing the baby to move freely in the amniotic fluid, contributes to the development of muscles, skeleton, and lungs.

Umbilical Cord

The umbilical cord consists of two thin arteries and a vein that helps transport oxygenated blood from the placenta to the fetus and also removes carbon dioxide and waste products back to the placenta. The outside of the umbilical cord consists of a jelly-like connective tissue mass that helps to equalize pressure during contractions during delivery.

Jenny Jansson

Verified by Jenny Jansson

Certified midwife


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