BGDA Practical Placenta - Cord Development

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Practical 14: Implantation and Early Placentation | Villi Development | Maternal Decidua | Cord Development | Placental Functions | Diagnostic Techniques | Abnormalities


Placental/Umbilical Cord

The placental cord (umbilical cord) is the connecting region between the functional placenta and the embryo/fetal umbilical region.


The human cord varies physically in overall length, increasing to about 60 to 70 cm at term, degree of coiling, number of vessels and insertion site on the placenta. This extraembryonic structure contains the placental blood vessels and allantois.


Normally a pair of placental arteries are wrapped around a single (left) placental vein. A persistent right umbilical vein is thought to be a rare anomaly.

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Placental cord (week 6)

Placental Arteries and Vein

Placental cord vessels 02.jpg Placental cord vessels 01.jpg Placental cord cross-section.jpg


Week 8

Stage 22 image 086.jpg Stage 22 image 090.jpg

Placental Cord Histology

Moodle icon2.jpg Slide - Human Placental Cord


Placental Cord Ultrasound

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Ultrasound image of transverse scan through the cord show the method of estimation of the cross-sectional area.


Placental cord ultrasound 04.jpg

Wharton's Jelly

First described and named after Thomas Wharton (1614–1673) an English physician and anatomist.
  • placental cord connective tissue (substantia gelatinea funiculi umbilicalis)
  • amorphous substance containing glycosaminoglycans, proteoglycans and hyaluronic acid.
  • cells similar to smooth muscle that allows a contractile function.
  • network of collagen that form canaliculi and perivascular spaces.
  • maintain blood flow to the fetus during placental cord compression during pregnancy or delivery.
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Placental cord cross-section

Hofbauer Cells

Named after Hofbauer (1903) who first described these cells.
  • located the core of placental villi
  • macrophages with micropinocytotic activity and phagocytosis ability
  • possible paracrine role for early stages of placental vasculogenesis
  • express angiogenic growth factors (VEGF)
Placenta Hofbauer cells 01.jpg

Fetal Circulation

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 ‎‎Fetal Circulation
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 ‎‎Neonatal Circulation
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Cord Features

Cord Length

The following are lengths and classifications at term.

  • Normal range - 50 to 60 cm.
  • Short cord - less than 35 cm.
  • Long cord - over 70 cm can be associated with wrapping around the fetus and other abnormalities.

Cord Coiling

  • Hypocoiling - associated with increased incidence of fetal demise, intrapartum fetal heart rate decelerations, operative delivery for fetal distress, anatomic-karyotypic abnormalities and chorio-amnionitis.
  • Hypercoiling - associated with increased incidence of fetal growth restriction, intrapartum fetal heart rate decelerations, vascular thrombosis and cord stenosis.


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Practical 14: Implantation and Early Placentation | Villi Development | Maternal Decidua | Cord Development | Placental Functions | Diagnostic Techniques | Abnormalities



Additional Information

Additional Information - Content shown under this heading is not part of the material covered in this class. It is provided for those students who would like to know about some concepts or current research in topics related to the current class page.

Persistent Right Umbilical Vein

A study of 15,237 obstetric ultrasound examinations performed after 15 weeks' gestation identified only 33 cases of persistent right umbilical vein.

<pubmed>7970470</pubmed>

Vessel Anomalies

  • Fetal intra-abdominal umbilical vein varix is a focal dilatation of the intra-abdominal portion of the umbilical vein.


Nuchal Cord

Recent large study of tight nuchal cord, where the placental cord is completely wrapped around the fetal neck.

The best practices for the care of a neonate born after a tight nuchal cord have not been defined. As a step toward this, we compared the outcomes of neonates born after a tight nuchal cord vs those born after a loose nuchal cord vs those born after no nuchal cord. This was a retrospective comparison using electronic data of all deliveries during a 6-year period (2005 to 2010) in a multihospital healthcare system in the western United States. At the time of delivery, each birth was recorded as having a tight nuchal cord, a loose nuchal cord or no nuchal cord. Nuchal cord was defined as a loop of umbilical cord ≥360° around the fetal neck. 'Tight' was defined as the inability to manually reduce the loop over the fetal head, and 'loose' as the ability to manually reduce the loop over the head.

Of 219,337 live births in this period, 6.6% had a tight nuchal cord and 21.6% had a loose nuchal cord. Owing to the very large number of subjects, several intergroup differences were statistically significant but all were judged as too small for clinical significance. For instance, those with a tight nuchal cord had a very slightly older gestational age, a very slightly lower birth weight, a preponderance of male fetuses, primagravid women, singleton pregnancies and shoulder dystocia (all P<0.001). Term neonates with a tight nuchal cord were slightly more likely to be admitted to a Neonatal Intensive Care Unit (6.6% vs 5.9% admission rate, P=0.000). Those with a tight nuchal cord were not more likely to have dopamine administered or blood hemoglobin measured on the first day, nor were they more likely to receive a transfusion or to die. The subset of very low birth weight neonates with a tight nuchal cord, compared with those with no nuchal cord, were of the same gestational age and birth weight, with the same Apgar scores, and were not more likely to have severe intraventrucular hemorrhage, retinopathy of prematurity or periventricular leukomalacia, or to die.


The presence of a tight nuchal cord is not uncommon, occurring in 6.6% of over 200,000 consecutive live births in a multihospital health system. No differences in demographics or outcomes, judged as clinically significant, were associated with a tight nuchal cord. Thus, we speculate that the best practices for neonatal care after a tight nuchal cord do not involve an obligation to conduct extra laboratory studies or extra monitoring solely on the basis of the report of a tight nuchal cord.


<pubmed>22699359</pubmed>| J Perinatol.


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Practical 14: Implantation and Early Placentation | Villi Development | Maternal Decidua | Cord Development | Placental Functions | Diagnostic Techniques | Abnormalities