Rosalinde Snijders

The hidden mortality of monochorionic twin pregnancies

In an ultrasound screening study at 10 to 14 weeks of gestation for measurement of fetal nuchal translucency thickness there were 102 monochorionic and 365 dichorionic twin pregnancies. In the monochorionic compared with the dichorionic pregnancies there was a higher rate of fetal loss before 24 weeks of gestation (12.2%versus 1.8%), perinatal mortality (2.8%versus 1.6%), prevalence of delivery before 32 weeks (9.2%versus 5.5%), and prevalence of birthweight below the 5th centile in both twins (7.5%versus 1.7%). However, the proportion of pregnancies with a birthweight discordancy of more than 25% was similar in the two groups (11.3%versus 12.1%).

Fetal nuchal translucency: ultrasound screening for fetal trisomy in the first trimester of pregnancy

Objective To investigate a new method of screening for fetal trisomies on the basis of maternal age and fetal nuchal translucency thickness at 10 to 13 weeks of gestation.

New charts for ultrasound dating of pregnancy and assessment of fetal growth: longitudinal data from a population-based cohort study.

Correct assessment of gestational age and fetal growth is essential for optimal obstetric management. The objectives of this study were, first, to develop charts for ultrasound dating of pregnancy based on crown–rump length and biparietal diameter and, second, to derive reference curves for normal fetal growth based on biparietal diameter, head circumference, transverse cerebellar diameter, abdominal circumference and femur length from 10 weeks of gestational age onwards.

Fetal venous, intracardiac, and arterial blood flow measurements in intrauterine growth retardation: Relationship with fetal blood gases☆

OBJECTIVE Our purpose was to investigate arterial, venous, and intracardiac blood flow in growth-retarded fetuses and to relate the Doppler results to blood gases in umbilical venous blood obtained by cordocentesis. STUDY DESIGN A cross-sectional, pulsed-wave color Doppler ultrasonographic study of 23 severely growth-retarded fetuses undergoing cordocentesis and measurement of blood gases was performed. Blood velocity waveforms were recorded from the descending thoracic aorta, middle cerebral artery, inferior vena cava, ductus venosus, and atrioventricular valves. RESULTS The Doppler studies demonstrated evidence of redistribution in the arterial system with increased impedance to flow in the aorta and decreased impedance in the cerebral circulation. The velocity of flow in the venous system and across the atrioventricular valves was decreased, whereas pulsatility of waveforms in the inferior vena cava and ductus venosus was increased. The mean umbilical venous blood PO2 and pH were decreased, and there were significant associations between blood gases and Doppler parameters in the thoracic aorta, middle cerebral artery, and ductus venosus. CONCLUSION In severe intrauterine growth retardation the degree of fetal acidemia can be estimated from Doppler measurements of pulsatility in both the arterial system and the ductus venosus.

Screening for trisomy 21 in twin pregnancies by maternal age and fetal nuchal translucency thickness at 10–14 weeks of gestation

Objective To determine the prevalence of increased fetal nuchal translucency thickness in twin pregnancies and to evaluate screening for trisomy 21 by a combination of translucency thickness and maternal age.

RELATION OF FETAL BLOOD-GASES AND DATA FROM COMPUTER-ASSISTED ANALYSIS OF FETAL HEART-RATE PATTERNS IN SMALL FOR GESTATION FETUSES

Summary. Fetal heart rate (FHR) monitoring and computer‐assisted analysis were performed immediately before cordocentesis in 25 severely small‐for‐gestational age fetuses. There were significant associations between FHR variation and both umbilical vein blood Po2 (r= 0–66) and pH (r=0.69). However, the wide scatter of values around the regression lines prevented accurate prediction of fetal blood gases from FHR patterns. Nevertheless, FHR variation <20 ms was always associated with severe fetal hypoxaemia and acidaemia.

Fetal plasma erythropoietin in pregnancies complicated by maternal diabetes mellitus

OBJECTIVE Our purpose was to investigate the relationship between fetal plasma erythropoietin concentration and measures of short-term and long-term glycemic control and fetal oxygenation in pregnancies complicated by maternal diabetes mellitus. STUDY DESIGN A cross-sectional study was performed at The Harris Birthright Research Centre for Fetal Medicine, London. Cordocentesis was performed in 31 diabetic pregnancies for the measurement of umbilical venous blood pH, PO2, PCO2, lactate and glucose concentration, erythroblast count, hemoglobin, and plasma erythropoietin concentrations. RESULTS The mean pH was significantly lower and the PCO2, lactate, erythropoietin, hemoglobin, and erythroblast counts were significantly higher than the appropriate normal mean for gestation. There were significant associations between (1) fetal erythropoietin and erythroblast count, (2) fetal erythroblast count and hemoglobin, (3) fetal hemoglobin and maternal glycosylated hemoglobin, and (4) maternal glucose and fetal glucose, pH, and lactate. CONCLUSIONS We postulate that maternal hyperglycemia causes fetal hyperglycemia and acidemia. Increased erythropoietin may be caused by tissue hypoxia or hyperinsulinemia. The increase in fetal hemoglobin may be the consequence of increased erythropoiesis, mediated by either erythropoietin or hyperinsulinemia.

Ethnic differences in prenatal growth and the association with maternal and fetal characteristics

The objectives of this study were to determine ethnic differences in prenatal growth and to examine their association with differences in maternal and fetal characteristics such as maternal height, weight, age, parity and fetal gender.

Increased nuchal translucency in trisomy 13 fetuses at 10–14 weeks of gestation

In a multicenter screening study for trisomy 21 involving ultrasonographic measurement of fetal nuchal translucency thickness (NT) at 10-14 weeks of gestation, 100,311 singleton pregnancies with a live fetus were examined. There were 46 cases of trisomy 13, and in 33 (72%) of these, the NT was above the 95th centile. The estimated risk for trisomy 21, based on maternal age-related risk for this chromosomal abnormality and fetal NT, was above 1 in 300 in 37 (80.1%) of the trisomy 13 fetuses. The fetal crown-rump length was significantly reduced, but the fetal heart rate was increased, being above the 95th centile in 64% of cases. Additionally, 24% of trisomy 13 fetuses had holoprosencephaly and 10% had exomphalos. This study has demonstrated that at 10-14 weeks of gestation, about 80% of fetuses with trisomy 13 can be identified in a screening program for trisomy 21, based on a combination of maternal age and fetal NT.

First trimester maternal serum pregnancy‐associated plasma protein A and pregnancy‐specific βl‐glycoprotein in fetal trisomies

Objective To examine the potential value of maternal serum levels of pregnancy‐associated plasma protein A (PAPP‐A) and pregnancy‐specific βl‐glycoprotein (SP1) in the detection of fetal trisomy.