The effect of umbilical venous constriction on placental development, cord length and perinatal outcome

• Published in: Early human development 2005-04, Vol.81 (4), p.325-331
• Main Authors: Skulstad, Svein Magne, Rasmussen, Svein, Seglem, Silje, Svanaes, Ragnhild H., Aareskjold, Hanne May, Kiserud, Torvid
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Apgar Score; Biological and medical sciences; Birth Weight; Blood Flow Velocity; Constriction; Cross-Sectional Studies; Doppler; Embryology: invertebrates and vertebrates. Teratology; Female; Fetus; Fundamental and applied biological sciences. Psychology; Gender; Gestational Age; Growth; Humans; Infant, Newborn; Male; Organ Size; Placenta; Placenta - anatomy & histology; Placentation - physiology; Pregnancy; Pregnancy Outcome; Regression Analysis; Sex Factors; Umbilical Cord - anatomy & histology; Umbilical vein; Umbilical Veins - physiology
• ISSN: 0378-3782; 1872-6232
• DOI: 10.1016/j.earlhumdev.2004.07.006

Umbilical vein constriction at the fetal abdominal inlet is a common finding after week 13, when the period of umbilical herniation is brought to an end. To test the hypothesis that a constricting umbilical ring within physiological ranges affects fetal hemodynamics by either pooling blood in the placenta or restricting nutrient transfer to the fetus and thus shift the birthweight/placental weight (BW/PW) ratio. A constriction could also cause pressure changes and elongation of the cord and possibly be a disadvantage during labour. Cross-sectional. 359 Low-risk singleton pregnancies at 13–40 weeks of gestation. Standard deviation score ( z-score) and regression analysis were used to determine the effect of umbilical vein constriction (expressed by increased blood velocity) on birthweight/placental weight ratio (BW/PW), cord length, Apgar score and emergency delivery due to fetal distress. Umbilical venous constriction had a mild but significant effect on BW/PW in male ( p=0.018) but not in female fetuses. Increased constriction was also associated with increased length of the cord but only in female fetuses ( p=0.019). Cord length was positively related to birthweight and placental weight, but an increased length of the cord was also associated with decreasing BW/PW ratio for the male fetuses only ( p=0.044). Increasing degree of venous constriction was associated with Apgar score ≤7 at 1 ( p=0.009) but not at 5 min after birth and was not associated with emergency delivery. Physiological umbilical venous constriction exerts a mild but significant gender-specific hemodynamic impact on intrauterine development.