BGDA Practical Placenta - Cord Development

From Embryology
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.

Kyoto16834 stage17-umbilicus.jpg

Umbilicus containing initial 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

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Placental Cord Histology

Moodle icon2.jpg Slide - Human Placental Cord

Placental Cord Ultrasound

Placental cord ultrasound 03.jpg Ultrasound of transverse scan through the cord

There are a number of analyses that can be made by ultrasound scanning of the fetal placental cord. Some detected abnormalities (blood vessel number, blood flow[1]) have been associated with adverse developmental outcomes.

  • Quantification of cord length, diameter, structural abnormalities.
  • Quantification of placental blood vessel number and size.
  • Quantification of uterine artery blood flow (doppler analysis).

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.
Placental cord cross-section.jpg

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

Fetal circulation 01 icon.jpg
 ‎‎Fetal Circulation
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Fetal circulation 01 icon.jpg
 ‎‎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.

Placental Cord Interactive Component

Attempt the Quiz - Placental Cord  

Here are a few simple Quiz questions that relate to Placental Cord from the practical.

1 The placental cord developmentally originates from the:

  yolk sac
  yolk stalk
  connecting stalk
  chorionic plate
  all of the above are correct

2 At birth, the placental cord blood vessel circulation is decreased by:

  Wharton jelly expansion
  vessel smooth muscle contraction
  placental artery spiral contraction
  all of the above

3 In the human placental cord development which blood vessel is typically lost?

  right umbilical artery
  left umbilical artery
  right umbilical vein
  left umbilical vein
  none of the vessels are lost

4 The human placental artery carries oxygenated blood to the fetus.


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

Additional Information: placental cord

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.

Placenta Links: placenta | Lecture - Placenta | Lecture Movie | Practical - Placenta | implantation | placental villi | trophoblast | maternal decidua | uterus | endocrine placenta | placental cord | placental membranes | placenta abnormalities | ectopic pregnancy | Stage 13 | Stage 22 | placenta histology | placenta vascular | blood vessel | cord stem cells | 2013 Meeting Presentation | Placenta Terms | Category:Placenta
Historic Embryology - Placenta 
1883 Embryonic Membranes | 1907 Development Atlas | 1909 | 1910 Textbook | 1917 Textbook | 1921 Textbook | 1921 Foetal Membranes |1921 human | 1921 Pig implantation | 1922 Single placental artery | 1923 Placenta Review | 1939 umbilical cord | 1943 human and monkey | 1944 chorionic villus and decidua parietalis | 1946 placenta ageing | 1960 first trimester placenta | 1960 monkey | 1972 Placental circulation | Historic Disclaimer

Persistent Right Umbilical Vein

Persistent Right Umbilical Vein (PRUV)

Adiego-Calvo I, Saviron-Cornudella R, Martinez-Payo C, Rubio-Aranda E, Sancho-Sauco J, Cisneros-Gimeno AI, Perez-Perez P, Lerma-Puertas D & Whyte-Orozco J. (2016). Are congenital malformations more frequent in fetuses with intrahepatic persistent right umbilical vein? A comparative study. Taiwan J Obstet Gynecol , 55, 782-785. PMID: 28040119 DOI.

Kumar SV, Chandra V, Balakrishnan B, Batra M, Kuriakose R & Kannoly G. (2016). A retrospective single centre review of the incidence and prognostic significance of persistent foetal right umbilical vein. J Obstet Gynaecol , 36, 1050-1055. PMID: 27599270 DOI.

Canavan TP & Hill LM. (2016). Neonatal Outcomes in Fetuses With a Persistent Intrahepatic Right Umbilical Vein. J Ultrasound Med , 35, 2237-41. PMID: 27582531 DOI.

Hill LM, Mills A, Peterson C & Boyles D. (1994). Persistent right umbilical vein: sonographic detection and subsequent neonatal outcome. Obstet Gynecol , 84, 923-5. PMID: 7970470

  • A study of 15,237 obstetric ultrasound examinations performed after 15 weeks' gestation identified only 33 cases of persistent right umbilical vein.
  • Note that there can be also an intrahepatic portion of PRUV (I-PRUV)

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.[2]

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.


  1. Shwarzman P, Waintraub AY, Frieger M, Bashiri A, Mazor M & Hershkovitz R. (2013). Third-trimester abnormal uterine artery Doppler findings are associated with adverse pregnancy outcomes. J Ultrasound Med , 32, 2107-13. PMID: 24277892 DOI.
  2. Henry E, Andres RL & Christensen RD. (2013). Neonatal outcomes following a tight nuchal cord. J Perinatol , 33, 231-4. PMID: 22699359 DOI.

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