Prenatal detection of congenital renal malformations by fetal ultrasonographic examination: an analysis of 709,030 births in 12 European countries

The study was performed to evaluate the prevalence of prenatal ultrasound diagnoses for renal anomalies in 20 registries of 12 European countries, and to compare the different prenatal scanning policies. Standardized data were acquired from 709,030 livebirths, stillbirths, and induced abortions during the study period of 2.5 years and transmitted for central analysis. At least one renal malformation was diagnosed in 1130 infants and fetuses. Prenatal diagnosis (PD) was given in 81.8% of all cases, 29% of these pregnancies were terminated. The highest detection rate was reported for unilateral multicystic dysplastic kidneys with 97% (102/105). An early diagnosis was documented for exstrophy of bladder at a mean gestational age of 18.5 weeks. Dilatations of the upper urinary tract were seen late in pregnancy at 28.3 weeks. Terminations of pregnancies (TOP) were performed in 67% (58/86) of the detected bilateral renal agenesis/dysgenesis, but only 4% of the unilateral multicystic dysplastic renal malformations (4/102). In about 1/3 of the cases, renal malformations are within the category of associated malformations, which include multiple non-syndromal malformations, chromosomal aberrations, and non-chromosomal syndromes. Renal malformations were detected in 2/3 of the associated category by the first prenatal ultrasound scan. Detection rates vary in the different countries of the European community due to diverse policies, ethical, and religious background. Countries with no routine ultrasound show the lowest rates in detection, and termination of pregnancy. Prenatally detected renal malformations should result in a careful examination for further anomalies. Prenatal ultrasound fulfills the needs of screening examinations and is a good tool in detecting lethal and severe renal malformations.

Modelling gradient elution of bioactive multicomponent systems in non-linear ion-exchange chromatography

A theoretical framework for the ion-exchange behaviour of bioactive substances in non-linear ion-exchange chromatogaphy is described. The aim of the study was the creation of a model basis to support a process design for production-scale ion-exchange chromatography. The theory can be applied to a whole variety of biological substances, such as amino acids, polysaccharides, peptides and proteins and either isocratic or gradient elution can be carried out. The influence of the eluent concentration on the ion-exchange as well as on the characteristic charge was considered. Experimental measurements showed a strong non-linear ion-exchange equilibrium with a transition from a Langmuir-type to a sigmoidal isotherm at higher eluent concentrations. Hereby, the compound binds to the surface though it is not ionic. Therefore, the model considered the possibility of ion-exchange as well as adsorption. A simplified distribution of the counter-ions based on the Gouy-Chapman theory with a discrete distribution of the counter-ions was used. The theory was extended by a selectivity in the double layer to allow specific adsorption. Calculations of adsorption-elution cycles showed, in agreement with the experimental observations, the development of non-linear elution profiles with a desorption fronting. As a result, the column loading and the eluent concentration were varied. The effect of contaminants, in this case sodium ions, was investigated and included in the model. Finally, the model was extended to multicomponent systems to investigate the effect of side components on the retention behaviour. The development of the characteristic elution profiles and the effect of the column loading on the separation are discussed. Calculated concentration profiles along the column at discrete time steps were used to reveal the influence of side components and the underlying separation mechanism. The simulations provided a new insight into the phenomena involved in biochromatography and make convenient design concepts at least doubtful as the separation is in this case mainly determined by the loading step and not by the choice of the elution gradient.

[Pre- and postnatal kidney screening compared: an analysis of 34,450 newborn infants of the Mainz model birth register]

Malformations of the internal urogenital system are common. The birth registry "Mainz Model" reflects population-based prevalence of renal malformations, calculates sensitivity rates of the prenatal ultrasonographic findings and demonstrates rates of surgery needed.

METHOD AND MATERIAL

During the study period (1990-2001) all newborns of the area of Mainz were examined according to a standardized procedure including ultrasonography of the kidneys. Pathology reports were reviewed for stillbirth, abortions (> 15.SSW) and induced abortions. Beside these clinical findings, since 1996 (after implementation of a special ultrasonographic malformation screening according to the german maternity guidelines) the results of prenatal as well as postnatal ultrasonographic examinations of the kidney were recorded. All children with pathologic diagnoses of the kidneys were retrospectively analysed. Data about the follow up and surgery if needed, were collected.

RESULTS

During the study period from 1990-2001 34.450 newborns were examined. 407 of the neonates (1.2%) had a malformation of the kidney. During the study period from 1996-2001 13.162 neonates were examined. 194 neonates (1.5%) had pathologic and 225 neonates (2.07%) had controllable findings. The most common diagnoses were supernumerary kidney, hydronephroses und megaureter. 22 neonates (12.8%) underwent surgery. The sensitivity of the prenatal ultrasonography was 36% and the specificity was 99%.

CONCLUSION

Both, the prenatal as well as the postnatal ultrasonographic screening of the kidneys are ingenious examinations. The prenatal examination detects life threatening malformations of the kidneys. The postnatal examination completes early diagnosis of renal defects by uncovering the malformations, which have been missed prenatally. The prevalence of malformations of the kidney is comparable to the one of hip dislocation. We therefore conclude, that ultrasonographic screening of the kidneys is needed.

Malformations in newborn: results based on 30,940 infants and fetuses from the Mainz congenital birth defect monitoring system (1990-1998)

Prevalence rates of birth defects in the Federal Republic of Germany are informative to assess the general background risk of having a child with a birth defect. They provide basic figures to determine temporal and regional prevalence trends, to evaluate and initiate preventive measures and to initiate research projects. To avoid observer, definition and collection bias, active monitoring systems are required. Data collected in the active monitoring system of the Mainz Birth Defects Registry are presented. From 1990-1998, 30,940 live-births, stillbirths and abortions underwent standardized physical and sonographic examinations. Anamnestic data were collected from prenatal care records, maternity files and hospital records. Major malformations were diagnosed in 2144 (6.9%) and mild errors of morphogenesis in 11,104 (35.8%) of all infants. Risk factors associated with the occurrence of major malformations were identified by comparing anamnestic data from infants with and without major malformations. Using multivariate regression models, statistically significant associations were established for 9 risk factors. Causally related risk factors were parents or siblings with malformations, parental consanguinity, more than 3 minor errors of morphogenesis in the proband, maternal diabetes mellitus and ingestion of antiallergic drugs in the first trimester of pregnancy. Conjunctional risk factors were polyhydramnios, oligohydramnios and gestational age <32 weeks at birth. Using these risk factors, populations at risk for the occurrence of major malformation can be identified.

Evaluation of the prenatal diagnosis of limb reduction deficiencies. EUROSCAN Study Group

Ultrasound scans in the mid-trimester of pregnancy are now a routine part of antenatal care in most European countries. Using data from registries of congenital anomalies a study was undertaken in Europe. The objective of the study was to evaluate prenatal detection of limb reduction deficiencies (LRD) by routine ultrasonographic examination of the fetus. All LRDs suspected prenatally and all LRDs (including chromosome anomalies) confirmed at birth were identified from 20 Congenital Malformation Registers from the following 12 European countries: Austria, Croatia, Denmark, France, Germany, Italy, Lithuania, Spain, Switzerland, The Netherlands, UK and Ukrainia. These registries are following the same methodology. During the study period (1996-98) there were 709,030 births, and 7,758 cases with congenital malformations including LRDs. If more than one LRD was present the case was coded as complex LRD; 250 cases of LRDs with 63 (25.2%) termination of pregnancies were identified including 138 cases with isolated LRD, 112 with associated malformations, 16 with chromosomal anomalies and 38 non chromosomal recognized syndromes. The prenatal detection rate of isolated LRD was 24.6% (34 out of 138 cases) compared with 49.1% for associated malformations (55 out of 112; p<0.01). The prenatal detection of isolated terminal transverse LRD was 22.7% (22 out of 97), 50% (3 out of 6) for proximal intercalary LRD, 8.3% (1 out of 12) for longitudinal LRD and 0 for split hand/foot; for multipli-malformed children with LRD those percentages were 46.1% (30 out of 65), 66.6% (6 out of 9), 57.1% (8 out of 14) and 0 (0 out of 2), respectively. The prenatal detection rate of LRDs varied in relation with the ultrasound screening policies from 20.0% to 64.0% in countries with at least one routine fetal scan.