Jörg Kessler

Fetal cardiac output, distribution to the placenta and impact of placental compromise.

Intrauterine growth restriction is a common clinical problem, but the underlying hemodynamic changes are not well known. Our aim was to determine the normal distribution of fetal cardiac output to the placenta during the second half of pregnancy, and to assess the changes imposed by growth restriction with various degrees of placental compromise.

Ductus venosus shunting in growth-restricted fetuses and the effect of umbilical circulatory compromise

To determine the degree of ductus venosus (DV) shunting in fetuses with intrauterine growth restriction (IUGR) and the effect of various degrees of umbilical circulatory compromise.

Longitudinal reference ranges for ductus venosus flow velocities and waveform indices

Serial Doppler measurements of the ductus venosus are used increasingly for monitoring fetuses at risk of hemodynamic compromise, but existing reference ranges are based on cross‐sectional studies and thus are less suitable for comparison with serial measurements. We aimed to establish longitudinal reference ranges for ductus venosus flow velocities and waveform indices and to provide the necessary terms for calculating conditional reference ranges for serial measurements.

Longitudinal study of umbilical and portal venous blood flow to the fetal liver: low pregnancy weight gain is associated with preferential supply to the fetal left liver lobe.

Recent data suggest that umbilical venous perfusion of the fetal liver has an important influence on fetal growth and postnatal liver function, and that maternal factors in late pregnancy modify this circulation. In a longitudinal study of 160 low-risk pregnancies, we determined how umbilical and portal venous blood flows to the fetal liver changed during gestation, and examined the hypothesis that maternal body mass index and pregnancy weight gain influenced fetal liver blood flows. We measured blood flows in the umbilical and portal veins, left portal branch, and ductus venosus using ultrasound. Normalizing for estimated fetal weight, fetal liver total venous blood flow fell from 84 to 57 mL · min−1 · kg−1 during 21–39 wk of gestation; toward term the portal contribution increased (from 14 to 20%) and the umbilical contribution fell, whereas distribution between the left and right liver lobes was stable, 60%/40%. Greater flow of nutrient-rich umbilical venous blood to the liver was associated with higher birth weight and neonatal ponderal index. Maternal body mass index was not related to fetal liver blood flows, but low pregnancy weight gain strongly influenced flow distribution between the right and left liver lobes, sparing the left lobe and increasing the difference between lobes by 16%.

The fetal portal vein: normal blood flow development during the second half of human pregnancy

The umbilical vein is the major source of blood for the fetal liver, but portal blood, which has not been measured directly in human fetuses, probably constitutes a physiologically important contribution. We aimed to establish a method for measuring blood flow in the fetal portal vein and to produce longitudinal reference ranges for diameter, blood flow velocities and volume blood flow during the second half of pregnancy.

Fetal Growth Restriction Is Associated With Prioritization of Umbilical Blood Flow to the Left Hepatic Lobe at the Expense of the Right Lobe

Eighty to 85% of the venous perfusion to the fetal liver is from the umbilical vein, the rest from the portal vein. Umbilical venous flow to the liver is essential for intrauterine growth, and is impaired in placental insufficiency. We hypothesized that in growth-restricted fetuses portal blood flow compensates for insufficient umbilical blood flow to the liver. In 29 fetuses with fetal growth restriction (estimated fetal weight ≤5th percentile), we used ultrasound to measure blood flows in the umbilical vein, ductus venosus, left portal vein, and main portal stem. Compared with normal fetuses, both absolute and normalized total venous liver blood flows were reduced in growth-restricted fetuses, related to the degree of placental compromise and equally affecting both liver lobes. However, portal replaced umbilical flow to the right lobe, in a manner graded according to placental vascular resistance; in extreme cases, the right lobe received no umbilical perfusion. In fetal growth restriction, the liver suffers from venous hypoperfusion, and portal blood partially replaces umbilical flow to the right lobe; this will result in right liver lobe hypoxemia. This striking prioritization in nutrient delivery of left over right lobes suggests an adaptive response to poor placental perfusion that may have functional consequences.

The left portal vein as an indicator of watershed in the fetal circulation: development during the second half of pregnancy and a suggested method of evaluation

The left portal vein represents a watershed area in the fetal circulation and the change of flow direction is a suggested marker of circulatory compromise. Our aim was to study the left portal vein of uncompromised human pregnancies and establish reference ranges.

Intrapartum monitoring of high‐risk deliveries with ST analysis of the fetal electrocardiogram: an observational study of 6010 deliveries

To evaluate the clinical use of ST analysis (STAN) for intrapartum monitoring of high‐risk pregnancies.

Venous liver blood flow and regulation of human fetal growth: evidence from macrosomic fetuses.

OBJECTIVE Experimental studies show that fetal liver venous perfusion is a determinant for growth in utero. Here we explore the relationship between fetal venous blood flow to the liver and macrosomia. STUDY DESIGN From diameter and blood flow velocity measurements, we derived liver venous blood flow in a longitudinal ultrasound study of 25 macrosomic fetuses of nondiabetic mothers during the second half of pregnancy. RESULTS Compared with appropriately growing fetuses, macrosomic fetuses directed more umbilical blood to the liver tissue, with correspondingly less contribution from the portal circulation when normalized for fetal weight. Whereas total venous liver blood flow showed no late gestation rise in the reference population, it continued to increase in macrosomic fetuses and was accompanied by greater fetal weight. CONCLUSION The direct relationship between venous liver blood flow and macrosomia in the fetus supports the concept that intrauterine growth is linked to the amount and distributional pattern of venous liver perfusion.

A critical appraisal of the evidence for using cardiotocography plus ECG ST interval analysis for fetal surveillance in labor. Part II: the meta-analyses.

We appraised the methodology, execution and quality of the five published meta‐analyses that are based on the five randomized controlled trials which compared cardiotocography (CTG)+ST analysis to cardiotocography. The meta‐analyses contained errors, either created de novo in handling of original data or from a failure to recognize essential differences among the randomized controlled trials, particularly in their inclusion criteria and outcome parameters. No meta‐analysis contained complete and relevant data from all five randomized controlled trials. We believe that one randomized controlled trial excluded in two of the meta‐analyses should have been included, whereas one randomized controlled trial that was included in all meta‐analyses, should have been excluded. After correction of the uncovered errors and exclusion of the randomized controlled trial that we deemed inappropriate, our new meta‐analysis showed that CTG+ST monitoring significantly reduces the fetal scalp blood sampling usage (risk ratio 0.64; 95% confidence interval 0.47–0.88), total operative delivery rate (0.93; 0.88–0.99) and metabolic acidosis rate (0.61; 0.41–0.91).