European Journal of Cardiovascular Medicine

Umbilical cord connects the fetus to the placenta. It is a vital structure and plays crucial role for foetal development. Aristotle originally identified the umbilical cord as the connection between mother and unborn child¹. The umbilical cord begins to form at five weeks after conception. It becomes progressively longer until 28 weeks of pregnancy, reaching an average length of 55-65 cm long with outer amniotic epithelium; bulk is composed of a special type of mucoid connective tissue known as Wharton’s jelly.  Umbilical cord diameter depends on lumen of vessels and Wharton’s jelly^2,3The umbilical cord contains three blood vessals i.e. two umbilical arteries and one vein. These vessels exchange the blood between placenta and fetus and help in growth of fetus⁴. The Umbilical cord diameter affects the overall outcome of fetus⁵. Wharton’s jelly is an extracellular matrix, gelatinous material it protects the umbilical cord vessels from compression or bending⁶. An increase in umbilical cord diameter as a gestational age progresses up to 34-36 week of gestation followed by reduction of umbilical cord size.⁷ Intrauterine growth retardation (IUGR) predisposes by Reduction in wall thickness of the umbilical cord arteries and vein⁸.The human umbilical cord average diameter is 1.5 up to 2 cm and average circumference of 3.6 cm at birth. The umbilical cord diameter was found to correlate with fetal biometry So, it can be concluded that reduction in umbilical cord diameter can compromises the fetal growth.Thick umbilical cord observed in foetus of diabetic mother could be associated with excessive fetal weight gain, macrosomia and also carry risk for fetal aneuploidy.⁹

This cross sectional study was conducted in Anatomy department in collaboration with gynecology department of our hospital.100 freshly delivered samples of placenta with cord obtained from labour room of our Government Hospital. Healthy women with term gestation with normal singleton pregnancy, irrespective of their parity, who were in active labour  were admitted to the labour room, were taken for the study. Patients were asked relevant antenatal obstetric history and maternal risk factors were assessed (eg.preeclampsia, diabetes) as these cases were not included in the study. Each patient was observed in 2nd and 3rd stage of labour. Intrapartum fetal monitoring was done. History of IUGR was noted.

After birth the umbilical cord was clamped and cut on fetal side by keeping 5 cm cord on fetal side.The tag details of name of mother, age, gestational week was attached to the cord with thread. After delivery fetal parameter was noted on data sheet as birth weight, liquor. Umbilical cord diameter was measured with divider and measuring tape

Mean cord diameter IUGR babies is 1.68 and mean cord diameter is normal babies is 1.86. And SD of IUGR is 0.14 and normal babies is 0.17. This difference is considered to be statistically significant (P< 0.0001) This study shown that the umbilical cords of IUGR foetuses are smaller than those of normal gestational age foetuses

Cord diameter:

Table No 1: Comparison cord diameter and IUGR

Figure 1:Measurement of umbilical cord diameter

Figure 2: Umbilical cord diameter

A: Thick diameter

B: medium size diameter

C & D: small cord diameter

The presence of a thin cord during pregnancy places the fetus at risk of restricted growth and birth weight, classified as small for gestational age. The cord diameter is depending on the amount of Wharton’s jelly, reduction in the amount of Wharton’s jelly decrease diameter.

Silver et al. (1987)¹⁰reported that in post term pregnancies, the umbilical cord diameter is smaller in patients with oligo hydramnios compared with normal amniotic fluid. In addition they found a higher incidence of ante partum variable deceleration in patients with small cord diameter as compared to those with normal cord diameter.

Bruch et al. (1997)¹¹ reported that umbilical cords of IUGR foetuses with normal umbilical artery. Doppler parameters were characterized by a reduction of both the total vessel area and the Wharton jelly area in comparison with foetuses with normal umbilical artery. Doppler parameters were compared with those with abnormal Doppler parameters, a further decrease of the total vessel area was observed, which was mainly due to a reduction of the vessel wall thickness. A number of anatomic studies investigated the umbilical cord of small for gestational age (SGA infants). Foetus with lean cord had a risk of 4.4 fold higher of being SGA at birth than those normal cord.

Raio L (2003)¹² compared prenatal morphological changes of umbilical cord components in intrauterine growth-restricted foetuses with and without abnormal umbilical artery Doppler parameters.

 A total of 84 intrauterine growth-restricted foetuses and 168 appropriate-for-gestational-age foetuses were included in the study. All umbilical cord components (umbilical cord cross-sectional area, vein area, artery area, and Wharton jelly area) were smaller in the intrauterine growth-restricted foetuses. The prevalence of lean umbilical cords (cross-sectional area <10th percentile for gestational age) was significantly higher in intrauterine growth-restricted foetuses compared with appropriate-for-gestational-age foetuses (73.8% versus 11.3%; P < .0001). A significant and progressive reduction of the umbilical vein area corresponding to the degree of umbilical artery Doppler parameter abnormality was found. The proportion of lean umbilical cords was higher in intrauterine growth restricted foetuses than in appropriate-for-gestational-age foetuses. Umbilical vein caliber decreases significantly with worsening of umbilical artery Doppler parameters.

Baergen R (2007) ¹³ described four cases of still birth and umbilical cord constriction. In all four cases there was absence of Wharton’s jelly around the umbilical cord arteries and it was associated with acute fetal distress and perinatal death. This may had been due to compression of unprotected vessels. According to Baergen, chronic partial obstruction can also lead to fetal growth restriction.

Togni FA et al. (2007)¹⁴found statistically significant correlation between cross sectional area of cord component and fetal anthropometric parameter (p<0.001) as well as gestational age (p< 0.001); and it is important component in fetal growth.

Goynumer G et al. (2008)¹⁵ studied association between diameter of cord and perinatal outcome on 216 pregnant women and concluded that the relative risk of the adverse perinatal outcome in lean umbilical cord was 6.92 (2.71-17.67, 95% CI).The umbilical cord diameter correlated with birth weight.

Morteza et al. (2011)¹⁶ had done study sonographically for evaluation of umbilical cord thickness, cross sectional area predictor of pregnancy outcome. A statistically significant correlation was observed between umbilical cord thickness & cross sectional area and low birth weight with sensitivity 52.9%,57.9%, specificity 95.0% ,95%, positive predictive value of 52.6%,52%, negative predictive value 95.0%,95%. They also noted that there was significant correlation found between small umbilical cord thickness and cross sectional area with meconium staining (p= 0.001).

The Umbilical cord diameter (UCD)could serve as an important indicator of fetal growth, well-being, and perinatal outcome. Abnormal umbilical cord size might be an important marker for the identification of patients at risk of Intrauterine foetal death, fetal distress and poor fetal outcomes. Umbilical cord small in diameter associated with IUGR Babies with large diameter are associated with macrosomic baby or large for gestational age.

Abbreviations:

UCD: Umbilical cord diameter

IUGR: intrauterine growth retardation

SGA; Small for gestational age

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