Harm-Gerd Karl Blaas

Harm-Gerd Karl Blaas
Norwegian University of Science and Technology | NTNU · Department of Laboratory Medicine, Children's and Women's Health

PhD

About

112
Publications
15,748
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Introduction
Harm-Gerd Karl Blaas currently works at the Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology. Harm-Gerd does research in Obstetrical Ultrasound and Fetal Medicine.

Publications

Publications (112)
Article
Objectives Central nervous system (CNS) anomalies are the second most frequent category of congenital anomalies after congenital heart defects (CHDs). In this study, the aim was to investigate the distribution of different CNS anomalies with associated anomalies and karyotype in a fetal autopsy population of terminated pregnancies over a 30-year pe...
Chapter
Viele Indikationen geben zu einer Ultraschalluntersuchung in der Frühschwangerschaft Anlass. Ziel der Diagnostik ist primär Nachweis von Vitalität, Alter, korrekter Lage des Konzeptus und evtl. Mehrlinge inkl. Chorionizität und Amnionizität. Man soll auch beurteilen, ob die Schwangerschaft sich normal entwickelt. Die Voraussetzung dafür sind gute K...
Chapter
Holoprosencephaly (HPE) is a heterogeneous central nervous system (CNS) anomaly that results from a primary defect in induction and patterning of the rostral neural tube (basal forebrain), leading to varying degrees of incomplete separation of the cerebral hemispheres and facial anomalies. HPE is graded as alobar, semilobar, and lobar, and a mild v...
Article
Full-text available
Purpose To investigate the variability of the normal-sized fetal renal pelvis (≤5 mm) over time and to analyze repeatability of measurements. Materials and Methods 98 fetal renal pelvises and 49 fetal urinary bladders were analyzed at a gestational age of 17–20 weeks at St. Olavs Hospital, Trondheim, Norway. The anterior-posterior diameter (APD) of...
Article
A human embryo in the palm of your hand (R1) Based on histological examinations of embryos and fetuses Wilhelm His established classic human embryology. Already in the 1880s he emphasized the need for 3D models.1 In 1883 the laborious "Plattenmodellirmethode" was used to generate (enlarged) 3D models of embryos, which markedly improved understandin...
Article
Full-text available
OBJECTIVES: To investigate the intra- and inter-observer variation of the manual 3D Virtual Organ Computer-aided Analysis (VOCAL) in calculating fetal bladder volume and compare results from VOCAL with Sonography-based Automated Volume Count (SonoAVC) and a mathematical calculation based on three radiuses. METHODS: Forty-five women attending the se...
Article
ObjectivesA prenatal ultrasound examination together with a postmortem examination provide the basis for correct diagnosis in fetuses terminated due to congenital anomalies. The aim of this study is to correlate fetal anomalies detected by ultrasound examination with autopsy findings following termination of pregnancy (TOP) over a 30-year period, a...
Article
To evaluate two algorithms for prediction of preeclampsia in a population of nulliparous women in Norway. Prospective screening study. National Centre for Fetal Medicine in Trondheim, Norway. Five hundred and forty-one nulliparous women. The women were examined between 11(+0) and 13(+6) weeks with interviews for maternal characteristics and measure...
Article
Objective To investigate the prediction of preeclampsia and gestational hypertension with the use of maternal characteristics, mean arterial pressure (MAP), uterine artery pulsatility index (UtAPI), pregnancy-associated plasma protein-A (PAPP-A) and placental growth factor (PlGF) at gestational weeks 11-13 in a Scandinavian population with a medium...
Article
Objective This study compares prenatal ultrasound examination and autopsy findings in fetuses and infants with gastroschisis and omphalocele. Method Criteria for inclusion in the study were an autopsy of fetuses/infants with gastroschisis or omphalocele performed between January 1985 and December 2009 and prenatal ultrasound examination performed i...
Article
During the past 25 years, embryonic and early fetal ultrasound and diagnosis have increasingly gained attention in pregnancy care. Modern high-frequency ultrasound transducers make it possible to obtain detailed images of the early conceptus and its organs, and thus move part of the anatomy and anomaly scan from the second to the first trimester. T...
Chapter
Es gibt viele Indikationen, die zu einer Ultraschalluntersuchung in der Frühschwangerschaft Anlass geben. Die Zielsetzung solcher Diagnostik ist primär der Nachweis von Vitalität, Alter, korrekter Lage und eventueller Mehrlinge. Darüber hinaus ist es wünschenswert zu beurteilen, ob die Schwangerschaft sich auch normal entwickelt. Die Voraussetzunge...
Article
To compare detection rates of small-for-gestational-age fetuses, large-for-gestational-age fetuses, congenital anomalies and adverse perinatal outcomes in pregnancies randomized to third trimester routine ultrasound or ultrasound on clinical indication. Design Randomized controlled trial. National Center for Fetal Medicine in Norway between 1989 an...
Article
Full-text available
Abstract ABSTRACT Objective The aim of our study was to retrospectively assess morphological findings in thanatophoric dysplasia, particularly in how many cases cerebral manifestations with temporal lobe dysplasia was identified. We also wanted to register and analyse the proportions between lung, brain and body weight. DesignCriteria for inclusion...
Article
Background: Treatment with radioiodine for Graves' disease regularly increases the level of antithyroid antibodies, and transplacental passage of stimulating thyrotropin receptor antibodies (TRAb) may cause fetal hyperthyroidism. Case presentation: A 21-year-old woman with Graves' disease received radioiodine treatment to avoid use of antithyroi...
Article
Autopsies of fetuses with thanatophoric dysplasia (TD) have shown abnormal gyration of the temporal lobes. In addition, the head is relatively large compared with the abdomen. We evaluated by ultrasound six consecutive cases of TD at 19 + 0 to 19 + 6 gestational weeks based on last menstrual period. We observed abnormal and deep transverse sulci in...
Article
To determine if postmortem examinations of fetuses and infants change the diagnosis obtained at prenatal ultrasound and affect counseling of future pregnancies, and if there has been a change over recent years in the accuracy of prenatal ultrasound diagnosis. This was a retrospective review of 455 autopsies of fetuses and infants with developmental...
Article
All cases of ichthyosis prematurity syndrome (IPS), registered at the National Center for Fetal Medicine in Trondheim, Norway between 1987 and 2010 were identified and the findings analyzed. Five fetuses with IPS were identified between 1988 and 2000. All five developed polyhydramnios between 28 and 31 weeks. The fetal stomach appeared to be empty...
Article
The introduction of diagnostic ultrasound into clinical practice 40 years ago provided a new safe and non-invasive method for in vivo studies of early pregnancy development. The initial studies primarily focused on biometrical descriptions of early pregnancy, while later work was more concerned with normal and abnormal morphological features of emb...
Article
Full-text available
Ichthyosis prematurity syndrome (IPS) is classified as a syndromic congenital ichthyosis based on the presence of skin changes at birth, ultrastructural abnormalities in the epidermis, and extracutaneous manifestations. Recently, mutations in the fatty acid transporter protein 4 gene have been identified in patients with IPS. We sought to perform a...
Article
In the following review, the early development of the central nervous system (CNS), as described by embryologists and anatomists in modern embryological textbooks, is compared with sonoanatomic descriptions from two-dimensional (2D) and three-dimensional (3D) ultrasound studies, week by week in the first trimester. The anatomic descriptions are lim...
Article
To assess the contribution of the second-trimester routine ultrasound examination and maternal age (>or= 38 years) to the prenatal detection of trisomy 21 in a large non-selected population in which no other screening methods were carried out. A prospective follow-up study was carried out in a non-selected Norwegian population from 1987 to 2004, in...
Article
In the following review, the development of the thorax and abdomen, as described by embryologists and anatomists in modern embryological text books, is compared with sonoanatomic descriptions from 2D and 3D ultrasound studies, week by week in the first trimester. The anatomic descriptions are limited to details that are of interest for the understa...
Article
To evaluate prenatal detection of facial clefts by ultrasound examination in a large non-selected population, and to study trends in detection rates over 18 years, as well as the prevalence of isolated cases and those with associated anomalies. This prospective follow-up study from January 1987 to December 2004 was divided into two 9-year periods....
Article
To evaluate prenatal ultrasound detection of talipes equinovarus (TEV) in a large non-selected population and to study trends in detection rates over time, as well as the prevalence and outcome of isolated TEV and TEV with associated anomalies. All cases of pre- or postnatally diagnosed TEV between 1987 and 2004 within a non-selected population of...
Article
Prenatal diagnosis of esophageal obstruction is believed to improve the outcome for the affected newborn. However, the prenatal detection rate is only 10-40%, the diagnosis is usually not made before the third trimester and the false-positive rate has been high. This study investigated the prenatal detection rate and time of prenatal diagnosis at o...
Article
Standardization of the display of ultrasound images has so far only been achieved in transabdominal two-dimensional (2D) sonography. In contrast, there is a lack of uniformity in the demonstration of transvaginal 2D ultrasound images. The described non-uniformity frequently leads to confusion in the assessment of an image, in particular with regard...
Article
Despite the relatively common occurrence of imperforate anus, prenatal diagnosis is rarely reported. In this study, we investigated the presence and diagnosis of imperforate anus along with strategies for improving prenatal diagnosis of the condition. Fetuses and infants with imperforate anus who had been examined prenatally by ultrasound at the Na...
Article
To evaluate volumetry with three-dimensional (3D) ultrasonography in the assessment of the size of human embryos and fetuses. Forty-four healthy embryos/fetuses with crown-rump length (CRL) ranging from 9 mm to 58 mm were studied using a 7.5-MHz annular array transvaginal 3D probe. EchoPAC 3D software was used to calculate the volumes of the head,...
Article
To evaluate the detection rate of congenital heart defects (CHD) in a non-selected population and to follow outcome after diagnosis. All 30,149 fetuses/newborns that were scheduled to deliver at our hospital between February 1991 and December 2001 were registered prospectively. Of these, 29,460 (98%) fetuses had a prenatal ultrasound scan at our ce...
Article
The aim of this study was to describe the outcome of a case series of fetuses with omphalocele. Ninety fetuses with omphalocele at the National Center for Fetal Medicine (NCFM) between January 1985 and January 2004 were followed from the time of prenatal diagnosis. Follow-up times ranged from 6 months to 17 years. Omphaloceles were subdivided into...
Article
Full-text available
We report on two siblings who presented prenatally with a ductus venosus (DV) that was abnormally located between the middle hepatic vein (mHV) and the proximal inferior vena cava (IVC), and with hepatomegaly. The first case presented with polyhydramnios at 33 weeks and therapeutic amniocentesis resulted in premature delivery soon after admission....
Article
Infants with gastroschisis have a high survival rate. However, the rate (10-15%) of intrauterine fetal death (IUFD) is considerable, and the association with fetal distress is well known. The aim of this study was to describe the outcome of fetuses with a prenatal diagnosis of gastroschisis. The impact of correct prenatal diagnosis, surveillance an...
Article
The aim of this study was to describe the outcome of fetuses with duodenal obstruction diagnosed prenatally and to compare the outcome with the results of studies of newborns. All fetuses with a prenatal diagnosis of duodenal obstruction were registered and evaluated prospectively from January 1985 to December 2000. Duodenal obstruction was found i...
Article
To investigate the prenatal appearance of the holoprosencephaly spectrum. A database of 1750 fetuses with congenital anomalies identified by ultrasound was prospectively collected from 1987 to 2000. Among them, 30 cases (1.7%) with holoprosencephaly were prenatally identified and described. The prevalence of holoprosencephaly in the Health Region o...
Article
Diagnostic ultrasound in the early pregnancy deals with the recognition of normal anatomy and/or the detection of anomalies in very early viable pregnancies. There are clinical situations where the position of the embryo does not allow imaging of the optimal section of a certain organ. This is often the case with the transvaginal approach, where mo...
Article
In the growing embryo, the brain is the first organ system to develop in such a way that it can be imaged in detail with transvaginal ultrasound. The extension of the transvaginal ultrasound technique to 3D imaging makes it possible to obtain new ultrasound images of the developing embryonic brain in planes not available in the original scan plane,...
Article
Purpose: The aim of this study was to describe the outcome of a cohort of fetuses with duodenal obstruction diagnosed prenatally. Most previous studies are based on results from newborns and have shown a good outcome with a survival rate up to 95–100%.Methods: Fetuses with prenatally diagnosed duodenal obstruction were registered and prospectively...
Article
Three-dimensional (3D) imaging by ultrasound was proposed in the 1950s. Since the end of the 1980s, 3D ultrasound has become a major field of research in obstetrics and gynaecology. The technique of acquiring 3D data involves making a set of consecutive 2D ultrasound slices by moving the transducer and continuously storing the images. These ultraso...
Article
We present three cases of spina bifida during the embryonic period detected by ultrasound before 10 weeks' gestational age. The last-menstrual-period-based ages ranged from 9 weeks 1 day to 9 weeks 4 days and the crown rump lengths ranged from 22 mm to 28 mm. The cases were identified prospectively in a program of targeted ultrasound examination of...
Article
To compare ultrasound and post-mortem findings in 98 fetuses and infants with an abnormal karyotype. Criteria for inclusion were an ultrasound examination at the National Center for Fetal Medicine (NCFM), an abnormal karyotype, and an autopsy performed during the period 1985-94. Trisomy 18 and 21 were the two most common abnormal karyotypes. The hi...
Article
Detection of congenital urinary system anomalies is an important part of the prenatal ultrasound examination. The present study compares prenatal ultrasonographic findings and postmortem examinations of fetuses and infants with renal and urinary tract anomalies. Criteria for inclusion were an ultrasound examination at the National Center for Fetal...
Article
We describe an ultrasound probe for three-dimensional transvaginal imaging. The transducer was an annular array with a center frequency of 7.5 MHz which was rotated with an internal stepper motor. The probe had no external moving parts, and the total volume covered by a full rotation defined a half sphere. The raw digital data from the scanner were...
Article
Major characteristics of the acrocallosal syndrome include severe mental retardation, agenesis or hypoplasia of the corpus callosum, and polydactyly of fingers and toes. In the past few years, anencephaly has also been noted, together with other midline defects. We report on a nonconsanguineous, Norwegian couple with a history of two pregnancies wi...
Article
We present the ultrasound detection of alobar holoprosencephaly (HPE) with cyclopia in an embryo of 9 weeks 2 days last menstrual period (LMP)-based gestational age; the crown-rump length (CRL) was 22 mm. The use of three-dimensional (3-D) ultrasound made additional diagnostic ultrasound tomograms possible, and the volume reconstructions improved t...
Article
Embryological and sonoembryological studies have shown the uniform development of the human embryos with small differences in size and age at the different development stage. This fact can be used as the basis for diagnostic ultrasound in the early pregnancy, which deals with the recognition of pregnancy loss, and the recognition of normal anatomy...
Thesis
Full-text available
Summary Introduction Embryology is the description of the anatomy, the normal anatomic relations and the development of abnormalities of the embryo. The developmental steps of the human embryo have been described and staged by the classical human embryologists. More than 30 years ago ultrasound was introduced as a mean to evaluate the pregnancy. I...
Article
The uniform development of the human embryo, as described by classic human embryology, has been confirmed by sonoembryological studies. In particular, the embryonic brain is suitable for transvaginal ultrasound examination, because the large 'cystic' cavities of the brain can easily be imaged. Sonoembryology not only describes normal embryonic anat...
Article
Detection of congenital heart defects by prenatal ultrasound examination has been one of the great challenges since the investigation for fetal anomalies became part of the routine fetal examination. This prospective study was designed to evaluate the concordance of prenatal ultrasound findings with autopsy examination in a population consisting of...
Article
Longitudinal studies of multiple parameters in the first trimester for assessment of embryonic growth are lacking. This study's aim was to register changes in growth over time, by taking several measurements of embryos on successive occasions and evaluating these changes by longitudinal analysis. This prospective longitudinal study describes the no...
Article
Three-dimensional (3D) imaging of the living human embryo has become possible in the monitoring of embryological development, as described by classic human embryology. We aimed to create 3D images of organs in embryos on early pregnancy. We used a specially developed 7.5 MHz annular array 3D transvaginal probe to examine embryos. We included 34 wom...
Article
Description of the development of the human embryonic brain visualized by transvaginal ultrasound. Methods. In two studies, healthy pregnant women without any pregnancy complications and normal outcomes were examined by transvaginal ultrasound in the early pregnancy between seven and twelve weeks of gestation. The hypoechogenic brain cavities were...