Early second‐trimester low umbilical coiling index predicts small‐for‐gestational‐age fetuses.

Abstract

Objective. To evaluate the role of the early second-trimester Doppler velocimetric studies of the umbilical coiling index and umbilical cord cross-sectional area as tests for the prediction of small-for-gestationalage infants. Methods. Doppler blood flow studies in 147 singleton pregnancies at risk for delivery of a small-for-gestational-age neonate were performed at 15 ± 1 (SD) weeks' gestation from the uterine artery, umbilical artery, middle cerebral artery, inferior vena cava, and ductus venosus. Pulsatility index values were calculated for the arteries, and preload index values and systolic-atrial contraction ratios were calculated for the veins. The sonographic cross-sectional area of the umbilical cord was measured in a plane adjacent to the insertion into the fetal abdomen. The umbilical coiling index was calculated by using sonographic longitudinal views of cord vessels from several segments antenatally and by dividing the total number of helices by cord length (centimeters) postnatally. Small-for-gestational-age neonates were identified when the birth weight was below the 10th percentile for gestational age. Results. Among 147 pregnancies studied, 124 fulfilled the study criteria. Thirty-nine of the neonates were small for gestational age at birth (31.5%). The mean ± SD gestational age at delivery of the appropriate-for-gestational-age neonates was 39.7 ± 1.28 weeks, and that of the small-forgestational-age neonates was 36.4 ± 2.9 weeks (range, 28-40 weeks). The best single predictor of a small-for-gestational-age infant was the coiling index, with sensitivity of 79%, specificity of 86%, a positive predictive value of 72%, and a negative predictive value of 90%. Conclusion. The umbilical coiling index measured in the second trimester is useful in predicting the birth of a small-forgestational-age infant and may serve as a marker for subsequent growth restriction.

Growth Restriction: Etiology, Maternal and Neonatal Outcome. A Review

“…Velamentous umbilical cord insertion occurs in 0.24 -1.8% of all singleton pregnancies and is associated with circulating disturbances and IUGR [192,194]. Both hypo-and hypercoiled cords may cause reduced umbilical blood flow, decreased placental blood flow and concequently IUGR [195][196][197]. Reduced Wharton's jelly in a single umbilical artery and cord aneurisms are associated with polyhydramnios and chromosome anomalies and may be a cause of IUGR [193,198].…”

Absence of a Relationship Between Umbilical Cord Thickness and Coiling Patterns

“…10,11 In a prospective study, Degani et al 12 evaluated 147 fetuses at risk for delivery of an SGA neonate. They performed Doppler studies of the maternal, placental, and fetal vessels, as well as the coiling index and cross-sectional areas of umbilical cords in square millimeters and found 39 SGA neonates.…”

Antenatal umbilical cord parameters and perinatal outcome

“…9,10 Statistical correlation of hypocoiled umbilical cord noted very early in second trimester with small for gestational age babies is documented. 11 But the results from different authors are not uniform. Some have shown an association between UCI and SGA, but did not find any correlation between UCI and a low 5-min Apgar score, not even with SGA by some.…”

“…9,12 The inconsistency in the results obtained could be because, the measurement of coiling across the various studies by the researchers is not uniform, varying from single to several segments, and being made at different periods of gestation, May be because of this reason UCI may be a poor marker when taken as a single parameter to presuppose perinatal outcome. 8,11 For this reason, we combined both the antenatal umbilical cord parameters to find out association if any with some of the pregnancy or perinatal outcome measures studied. They were measured after 34 weeks of pregnancy.…”