Evaluation of routine prenatal diagnosis by a registry of congenital anomalies

Prenatal diagnosis performed by ultrasound scan is now a routine part of prenatal care in many countries. How many fetal anomalies are actually detected by these procedures? We have used our registry of congenital malformations to answer this question. In a previous study (Prenat. Diagn., 12 , 263–270, 1992), considering the period 1979–1988, we have shown that prenatal diagnosis was performed in 23.1 per cent of fetuses with a chromosomal aberration and in 20.1 per cent of fetuses with non-chromosomal anomalies. In 1991 and 1992, the percentatge of termination for Down syndrome was 44.4 and 41.9 per cent, respectively. From 1989 to 1992, the detection rate and the specificity of prenatal diagnosis by ultrasonographic examination were improved. The detection rate for isolated malformations (fetuses with only one anomaly) and for multiple malformed children was 26.2 and 66.0 per cent, respectively. The detection rate of congenital anomalies by ultrasonography was variable for the different categories of malformation. A high detection rate was observed for anencephaly (100 per cent) and urinary tract malformation. A low detection rate was seen for cleft lip (17.5 per cent) and limb reduction defects (18.2 per cent).     

Evaluation of prenatal diagnosis of limb reduction defects by a registry of congenital anomalies

Prenatal diagnosis performed by ultrasound scan is now a routine part of antenatal care in our region. How many fetal anomalies are actually detected by this procedure? We have used our registry of congenital malformations to answer this question regarding limb reduction defects (LRDs). The mean time of detection of LRDs was 26 weeks of pregnancy (range 16–32 weeks). The sensitivity of prenatal diagnosis of LRDs by ultrasonographic examination was much lower for isolated malformations (fetuses with only one anomaly) than for multiply malformed children with LRDs, 4·0 and 18·2 per cent, respectively. For all cases of LRDs, the percentage of prenatal detection was 11·5. Termination of pregnancy was performed in 6·7 per cent of the cases.     

Evaluation of prenatal diagnosis of associated congenital heart diseases by fetal ultrasonographic examination in Europe

Ultrasound scans in the mid trimester of pregnancy are now a routine part of antenatal care in most European countries. With the assistance of Registries of Congenital Anomalies a study was undertaken in Europe. The objective of the study was to evaluate prenatal detection of congenital heart defects (CHD) by routine ultrasonographic examination of the fetus. All congenital malformations suspected prenatally and all congenital malformations, including chromosome anomalies, confirmed at birth were identified from the Congenital Malformation Registers, including 20 registers from the following European countries: Austria, Croatia, Denmark, France, Germany, Italy, Lithuania, Spain, Switzerland, The Netherlands, UK and Ukrainia. These registries follow the same methodology. The study period was 1996–1998, 709 030 births were covered, and 8126 cases with congenital malformations were registered. If more than one cardiac malformation was present the case was coded as complex cardiac malformation. CHD were subdivided into ‘isolated’ when only a cardiac malformation was present and ‘associated’ when at least one other major extra cardiac malformation was present. The associated CHD were subdivided into chromosomal, syndromic non-chromosomal and multiple. The study comprised 761 associated CHD including 282 cases with multiple malformations, 375 cases with chromosomal anomalies and 104 cases with non-chromosomal syndromes. The proportion of prenatal diagnosis of associated CHD varied in relation to the ultrasound screening policies from 17.9% in countries without routine screening (The Netherlands and Denmark) to 46.0% in countries with only one routine fetal scan and 55.6% in countries with two or three routine fetal scans. The prenatal detection rate of chromosomal anomalies was 40.3% (151/375 cases). This rate for recognized syndromes and multiply malformed with CHD was 51.9% (54/104 cases) and 48.6% (137/282 cases), respectively; 150/229 Down syndrome (65.8%) were livebirths. Concerning the syndromic cases, the detection rate of deletion 22q11, situs anomalies and VATER association was 44.4%, 64.7% and 46.6%, respectively. In conclusion, the present study shows large regional variations in the prenatal detection rate of CHD with the highest rates in European regions with three screening scans. Prenatal diagnosis of CHD is significantly higher if associated malformations are present. Cardiac defects affecting the size of the ventricles have the highest detection rate. Mean gestational age at discovery was 20–24 weeks for the majority of associated cardiac defects. Copyright © 2001 John Wiley & Sons, Ltd.     

Unusual case of a fetus with congenital cystic adenomatoid malformation of the lung associated with trisomy 13

Congenital cystic adenomatoid malformation of the lung can be detected with antenatal ultrasound as hyperechogenic areas in the fetal chest. Associated extrapulmonary malformations as well as chromosomal aberrations are described as very rare. We present a case report of a fetus in the 23rd week of gestation who showed in the course of a routine ultrasound screening a large number of malformations: holoprosencephaly, arrhinencephaly, cleft palate, CCAM type III of the right inferior pulmonary lobe, ventricular septal defect and bilateral clubfeet. Chromosome analysis confirmed the suspicion of trisomy 13. The present case shows how important it is—even with malformations that are rarely accompanied by associated anomalies and which have a very good prognosis—to carry out a directed diagnosis including a fetal karyotyping. Copyright © 2003 John Wiley & Sons, Ltd.     

Prenatal diagnosis of a mosaic supernumerary marker iso (8p) (tetrasomy 8p): discordance between chorionic villi culture and amniotic fluid karyotypes

We describe the first case of mosaic supernumerary marker iso (8p) displaying a karyotype discordance between chorionic villi (CV) and amniotic fluid (AF) cultures during prenatal cytogenetic diagnosis. In the first trimester, cytogenetic analysis after chorionic villi sampling (CVS) was normal in all metaphases in the short-term cytotrophoblast cell culture, but an undefined supernumerary marker was detected in 60% of mesenchymal cells in the long-term CV culture. Informed of the mosaicism, the couple selected amniotic fluid sampling as a second-trimester confirmatory diagnostic procedure. The supernumerary marker was absent in all of the 25 available AF cells metaphases. The prospective parents received genetic counselling and were informed that the discordance could be interpreted as a placental confined mosaicism or as a true foetal mosaicism with low percentage of affected cells. The couple opted to continue the pregnancy. In the second month of life, the child had abnormal development with severe psychomotor delay and frequent episodes of epilepsy. Postnatal cytogenetic extensive re-evaluation discovered that the previously detected supernumerary marker was indeed an isochromosome (8p) rearrangement present at low frequency in 5% of the blood lymphocytes. Copyright © 2006 John Wiley & Sons, Ltd.     

Prenatal diagnosis of cerebral lesions acquired in utero and with a late appearance

Although no precise figures are available, many congenital brain lesions arise from intrauterine disruption, frequently due to obstetric complications. The most common entities include intracranial hemorrhage, ischemic lesions, thrombosis of venous vessels and infections. Accurate prenatal diagnosis is possible in many of these cases. However, the findings may be subtle, particularly in the early stage of the disruptive process. Identification of these conditions requires therefore specific expertise, the combination of fetal neurosonography and magnetic resonance, and frequently there is a need for serial examinations. Targeted diagnostic imaging should be offered to obstetric patients with conditions predisposing to prenatal cerebral insults. Copyright © 2009 John Wiley & Sons, Ltd.