Influence of the placental cord insertion site on the placental mass and the birth weight in dichorionic diamniotic twins

Abstract

The aim of the study was to determine the effect of the displacement of the umbilical cord insertion site from the centre of the placenta on the placental mass and the birth weight of dichorionic diamniotic twins and to consider the importance of the direction of the displacement, as well as to assess the influence of the umbilical cord displacement on the placental mass and the birth weight of dichorionic diamniotic twins taking into account the direction of displacement.
 Material and methods. The study was performed on 135 dichorionic diamniotic pairs: 68 opposite-sex, 35 same-sex males, and 32 same-sex females. The impact of an absolute cord displacement from the centroid of the placental disc and the direction of its shifting were compared with the birth weight and the placental mass.
 Results. In the investigated group, a central insertion was revealed in 6 (2.2 %), eccentric – in 224 (83.0 %), marginal – in 31 (11.5 %), and velamentous – in 9 (3.3 %) cases. The first two types of cord insertion are considered to be normal, the third and the fourth are seen as abnormal. The placental mass was in a strong positive correlation with the birth weight (r=0.71, p<0.0001). The placentas with an eccentric cord insertion had a smaller surface area. A negative correlation was established between the displacement of the cord insertion site and the placental mass (r=-0.4284, p<0.0001) as well as the birth weight (r=-0.6115, p<0.0001). The shift along the long axis was of greater importance than in relation to the shorter one. The placental mass and the birth weight were higher in the new-borns with a normal cord insertion site. In the abnormal cord insertion group, 32.5 % of the infants were under the 10th birth weight percentile, in the normal cord insertion group – only 8.3 %.
 Conclusions. The birth weight of dichorionic diamniotic twins and their placental mass are negatively correlated with the distance of the umbilical cord insertion site from the placental centre. The insertion site displacement along the long axis has a stronger negative effect on the birth weight and the placental mass in comparison with the shifting along the short axis. The placentas with an eccentric cord insertion have a smaller surface area.

The Relationship Between Placental Growth Rates and the Birth Weight in Dichorionic Diamniotic Twins

“…В площі верхньої поверхні плацентарного диска розташовували лінійку або сантиметрову стрічки для подальшого калібрування камери. Як і група американських дослідників [18], ми проводили вимірювання геометричних параметрів плацент на цифрових фотографіях [19]. На відміну від них користувалися програмою ImageJ/Fiji 1.46r, яка є у вільному доступі (http://imagej.nih.gov/ij/docs/guide).…”

“…В попередніх дослідженнях нами показано [19], що плаценти зі зміщеною від центру точкою фіксації пуповини мали дещо меншу поверхню. Виявлена слабка негативна кореляція між їх площею та ACD і XCD (r = -0,2068, p = 0,0006 та r = -0,2471, p = 0,00004 відповідно), більш сильна -між ACD та МП (r = -0,4284, p < 0,0001).…”