The development of high venous velocity at the fetal umbilical ring during gestational weeks 11-19

The Fetal Liver Afferent Venous Flow Volumes in Fetuses With Appropriate for Gestational Age Birth Weight

OBJECTIVES

The present study aimed: 1) to simultaneously investigate the relationship between blood flow volumes of the two fetal liver afferent venous systems of normally appropriate for gestational age newborns. 2) to establish the normal reference range centiles values that will serve as a basis for future investigations.

METHODS

A cross-sectional, prospective study of singleton low obstetric risk pregnancies. Doppler examination included the measurement of the umbilical and the main portal vein vessels' diameters and time-averaged maximum velocity. The absolute and per kilogram of estimated fetal weight flow volumes and the ratio between the placental and portal blood volume flow were calculated from these data.

RESULTS

Three hundred and sixty-three pregnant women were included in the study. The umbilical and portal flow volumes' capacity to provide blood flow per kilogram of fetal weight, in the period of maximum fetal growth, was diverse. The placental flow decreased continuously from a mean of 121.2 mL/min/kg at the 20th week of gestation to 64.1 mL/min/kg at the 38th week of gestation. Meanwhile, the portal flow volume per kilogram of fetal weight increased from 9.6 mL/min/kg at 32 weeks of gestation to 10.3 at the 38th week of gestation. This resulted in a decrease in the umbilical to portal flow volume ratio from 13.3 to 9.6 during this period.

CONCLUSION

Our results indicate that in the period of maximum fetal growth, the placental/portal ratio diminishes emphasizing the portal flow's predominance with low oxygen and nutrient supply to the liver.

Amnioinfusion and Bed Rest May Effectively Improve the Insufficient Circulation of the Umbilical Cord in Pregnant Women With Hyper-Coiled Cord and Oligohydramnios

We experienced two cases with hyper-coiled cord in which fetal-umbilical-placental circulation was improved after amnioinfusion or bed rest. Therefore, amnioinfusion and bed rest to reduce the compression of the vulnerable umbilical cord in cases of hyper-coiled cord might improve the pathologic fetal-umbilical-placental circulation.

A case report of umbilical ring constriction with application of amnioinfusion

This is a case report of a pregnant 38-year-old primigravida woman. Due to severe fetal growth restriction and oligohydramnios, she was referred to our tertiary perinatal center at 24 weeks' gestation. To rule out chromosomal abnormalities and facilitate ultrasound evaluation of fetal morphology, we performed amniocentesis and subsequent amnioinfusion. Thereafter, a precise ultrasound examination revealed no obvious fetal morphological abnormalities except for a hyper-coiled cord and marginal placenta previa. During expectant management, the amount of amniotic fluid was maintained at 20-26 mm for a few days; however, the pregnancy resulted in intrauterine fetal death after 26 weeks + 5 days of gestation. The stillborn infant weighed 530 g (-3.3 SD) and had no obvious external abnormalities apart from umbilical ring constriction. Although a postmortem autopsy was not performed, it is suspected that the fetal growth restriction and the intrauterine fetal death were associated with the hyper-coiled cord and the umbilical ring constriction. It is thought that umbilical ring constriction might therefore be an irreversible fatal condition in cases with a hyper-coiled cord.

Sonographic Assessment of the Umbilical Cord

The umbilical cord is not an inert structure, suspended between the fetus and placenta, but it plays an active role and it is involved in several processes afflicting the feto-placental unit.

Its study has to be regarding not only its morphology and morphometry, and the impendance of blood flow by Doppler waveform analysis, but it includes also an analysis of the coiling type and the amount of the Wharton Jelly. The umbilical cord has been considered like an important and huge source of informations, useful to assess the well-being of the fetus and the outcome of pregnancy.

The standardization of ultrasound techniques is the first step to speak the same language and make the study of this structure a fundamental part of well-being fetus assessment.

This article is carefully focused on morphologic, morphometric and functional ultrasound examination of umbilical cord and suggests that any anomaly detected should provide an indication for an intense fetal follow-up, useful for early helpful therapy, preventing serious complication for the pregnancy.

How to cite this article

Di Naro E, Raio L, Cromi A Giocolano A. Sonographic Assessment of the Umbilical Cord. Donald School J Ultrasound Obstet Gynecol 2012;6(1):66-75.