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)

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