Fetal Circulation
Fetal Circulation
Umbilical cord-
- Contain one vein and 2 arteries.
- Made up of Wharton’s jelly
- Normal length=50cm
- Arteries carry Deoxygenated blood and waste products from the fetus.
- Vein carries Oxygenated blood and provide oxygen and nutrients to the fetus.
- Pressure in Umbilical vein>10mm Hg
- Pressure in Umbilical artery.>60mm Hg
- Right umbilical vein is disappearing by the 4 months.
Changes in Circulation after Birth-
- Closure of ductus venosum and becomes ligamentum Venosum. Umbilical Vein becomes ligamentum teres by one year time.
- Closure of ductus arteriosus occurs after establishment of Pulmonary Ventilation. Ductus arteriosus becomes ligamentum arteriosum
- Closure of foramen ovale occurs due to rise in pressure in left atrium and close foramen ovale gives fossa ovalis.
- Obliterated umbilical arteries form lateral umbilical ligaments. Functional closure occurs soon after birth but anatomical closure occurs in about one year time
Umbilical Cord (Funis)-
Umbilical cord of Funis is a long cord like structure that connects the foetal umbilicus with foetal surface of placenta. It is developed from body stalk of mesodormal cells stretching between embryonic disc and chorion.
Functions-
- It is the life line between placenta and foetus supplying oxygen and nutrients for foetus and disposing waste products.
- Exchange of fluid and electrolyte between umbilical vessels and amniotic fluid.
Cord Abnormality-
Battle dore Placenta-
- This cord is attached to the margin of placenta.
- Increase chances of cord compression.
Valamentous placenta-
The cord is attached to the membrane.
1. No cord (achordia)
2.Short cord-<20cm.
3.Long cord->100cm
- Increase chances of cord prolapsed.
- Cord entanglement round the neck or the body.
- True knot is rare, even with true knot the fetal vesse are protected from compression by Wharton’s Jelly.
- False knot are the result of accumulation of Wharton’s Jelly.
4.Single Umbilical Artery-
- Failure of development of one artery or Atrophy.
- More common is twin, baby born with Diabetic mother or is Polyhydramnios.
- Frequently associated with congenital malformation of the fetus, trisomy of 18(Edwards Syndrome)