G. Mielke

Cardiac output and central distribution of blood flow in the human fetus

BackgroundThe objectives of this study were to establish reference ranges for left and right cardiac output and to investigate blood flow distribution through the foramen ovale, ductus arteriosus, and pulmonary bed in human fetuses. Methods and ResultsA prospective study was performed in 222 normal fetuses from 13 to 41 weeks of gestation with high-resolution color Doppler ultrasound. Cardiac output and ductal flow were calculated by use of vessel diameter and the time-velocity integral. Pulmonary blood flow was expressed as the difference between right cardiac output and ductal flow. Foramen ovale flow was estimated as the difference between pulmonary flow and left cardiac output. Gestational age-specific reference ranges are given for left, right, and biventricular output and volume of ductal blood flow, showing an exponential increase with gestational age. Median ratio of right to left cardiac output was 1.42 and was not associated with gestational age. Right cardiac output was 59% and left cardiac output was 41% of biventricular cardiac output. Median biventricular cardiac output was estimated to be 425 mL · min−1 · kg−1 fetal weight. Ductal blood flow was 46%, estimated pulmonary flow was 11%, and estimated foramen ovale flow was 33% of biventricular output. ConclusionsThe study establishes reference ranges for fetal cardiac output and offers insights into the central blood flow distribution in human fetuses from 13 weeks to term. There is a clear right heart dominance. The estimated ratio of pulmonary blood flow to cardiac output is higher than in fetal lamb studies.

Blood flow velocity waveforms of the fetal pulmonary artery and the ductus arteriosus: reference ranges from 13 weeks to term

Objective To establish reference ranges for blood flow velocity waveforms of the fetal main pulmonary artery and the ductus arteriosus during the second and third trimesters of pregnancy.

Fetal sex determination by high resolution ultrasound in early pregnancy

OBJECTIVE Fetal sex determination by ultrasound, and its medical and ethical implications, has been predominantly discussed in mid and late gestation. The development of high resolution ultrasound equipment has provided the possibility of detailed visualization of the fetus in early pregnancy. The present prospective study investigates the feasibility and accuracy of fetal sex determination by transabdominal ultrasound in early pregnancy. METHODS Sonographic determination of fetal sex was attempted prospectively prior to genetic amniocentesis in 173 fetuses from 11 to 16 weeks of gestation. The result of ultrasound examination was compared with the karyotype obtained from amniotic fluid cells. RESULTS Sonographic sex determination was feasible in 80.3% of cases, and all these determinations proved to be correct. There was no difference in the identification rate between male (n=87) and female (n=86) sex. Fetal sex determination was also feasible and correct in all four sets of twins and in the one set of quadruplets. CONCLUSION Fetal sex assignment in the late first and early second trimester can be useful in pregnancies at risk for severe sex-linked diseases, in fetal disorders involving the genitalia, and in the individual identification of multiple fetuses. Prenatal sex assignment in early pregnancy implicates also far-reaching ethical problems because of the potential risk of sex-selected abortion.

Reference ranges for two‐dimensional echocardiographic examination of the fetal ductus arteriosus

Objectives To establish reference ranges for 2D‐echocardiographic examination of the fetal ductus arteriosus and its relationship to the main pulmonary artery and the aorta.

Qualitätsanforderungen der DEGUM zur Durchführung der fetalen Echokardiografie

Angeborene Herzfehler gehçren zu den h ufigsten Fehlbildungen und Erkrankungen des Menschen (ca. 5 – 8/1000 Lebendgeburten). Im ersten Lebensjahr sind sie die wesentliche Ursache f r Todesf lle. Die pr natale Diagnose fetaler Erkrankungen, insbesondere auch von Fehlbildungen des Herzens, f hrt zu einer Senkung der perinatalen Mortalit t und Morbidit t. Mittels Ultraschall kann bereits w hrend der Schwangerschaft eine zuverl ssige Diagnostik angeborener Herzfehler erfolgen. In den letzten Jahren haben verschiedene Fachgesellschaften Leitlinien und Qualit tsanforderungen an die kardiale Diagnostik in der Fetalzeit verçffentlicht [1 – 3]. Die Sektion Gyn kologie und Geburtshilfe der Deutschen Gesellschaft f r Ultraschall in der Medizin (DEGUM) hat bereits Qualit tsanforderungen an die geburtshilfliche Ultraschalldiagnostik (DEGUM-Stufe I) [4] sowie an die weiterf hrenden differenzialdiagnostischen Ultraschalluntersuchung in der pr natalen Diagnostik (DEGUMStufe II) [5] verçffentlicht. Hierbei sollen das fetale Herz im Vierkammerblick (DEGUM-Stufe I) bzw. zus tzlich die rechtsund linksventrikul ren Ausflusstrakte (DEGUM-Stufe II) untersucht werden. Finden sich Auff lligkeiten in der einen oder anderen Untersuchung, liegt ein erhçhtes Risiko f r das Vorliegen einer fetalen Herzerkrankung oder -fehlbildung vor. Ist das Herz nicht ausreichend im B-Bild zu beurteilen, so bedarf es der gezielten fetalen echokardiografischen Untersuchung. Die hier formulierten Qualit tsanforderungen der Sektion Gyn kologie und Geburtshilfe sowie des Arbeitskreises „fetale Echokardiografie“ der DEGUM sind eine Anleitung zur gezielten Untersuchung des fetalen Herzens. Sie richten sich an DEGUM-Stufe II und III qualifizierte Ultraschalluntersucher, welche Screeninguntersuchungen und weiterf hrende differenzialdiagnostische Untersuchungen im Rahmen der Schwangerschaftsbetreuung inklusive die gezielte fetale Echokardiografie durchf hren.

A New Formula for Prenatal Ultrasonographic Weight Estimation in Extremely Preterm Fetuses

A new formula for the prenatal estimation of the weight of extremely preterm fetuses was derived using ultrasound measurements and birth weights of 73 premature infants delivered before 30 completed weeks of pregnancy and weighing between 400 and 1,680 g at birth. The actual birth weight lay within +/- 15% of the estimated weight calculated with this formula in 92% of the cases. Preliminary testing of the reliability of the formula was performed on a further test group of 19 nonselected cases. The formula developed in this study offers a reliable and simple method of prenatal estimation of fetal weight between 23 and 30 weeks of gestation.

Resection of a large right atrial hemangioma in a neonate after prenatal diagnosis.

Cardiac hemangiomas are extremely rare benign tumors. We describe the case of a right atrial hemangioma in a neonate diagnosed prenatally and successfully operated 10 days after spontaneous delivery. This unusual case illustrates the importance of prenatal diagnosis and delivery of the baby next to a pediatric center with a department of appropriately specialized cardiovascular surgery.

SONOGRAPHIC ASSESSMENT OF THE FETAL PALPEBRAL FISSURE SLANT—AN ADDITIONAL TOOL IN THE PRENATAL DIAGNOSIS OF SYNDROMES

Several syndromes and aneuploidies are associated with ocular abnormalities including up‐ and down‐slanting palpebral fissures. We describe a technique for the sonographic assessment of the fetal palpebral fissure slant which was used in 70 normal pregnancies from 14 to 36 weeks of gestation. In a frontal view of the fetal face, the inferior angle between the palpebral fissure and the midline of the skull was determined. The median angle was 89°, with a range from 87° to 90°. In selected cases, sonographic assessment of the fetal palpebral fissure slant may be a helpful additional tool in the prenatal diagnosis of syndromes, as demonstrated in a fetus with Seckel syndrome associated with downslanting palpebral fissures and in a fetus with Downs syndrome associated with upslanting palpebral fissures.

An accurate method for sonographic estimation of the weight of very preterm fetuses.

This study was undertaken to test the accuracy of formulas we recently developed for the sonographic estimation of the weight of very preterm fetuses. The formulas were used to determine estimated weights from prenatal sonographic data for 62 premature infants born at 23-29 weeks of gestation, weight < or = 1,400 g. The mean absolute deviation of the actual birth weight from the estimated weight was 75.8 +/- (SD) 68.5 g, the mean percent deviation +0.60% and the absolute mean percent deviation 8.1 +/- (SD) 5.6%; 90.3% of the birth weights lay within 15% of the estimated weight. The model described represents an accurate method for prenatal estimation of the weight of very preterm fetuses.

Late Onset of Hydrops Fetalis following Intrauterine Parvovirus B19 Infection

We present a case of intrauterine parvovirus B19 infection, diagnosed by detection of B19 DNA in the amniotic fluid obtained at 15 weeks of gestation for chromosome analysis in an asymptomatic pregnancy, causing hydrops fetalis 7 weeks later. Following intrauterine transfusion, rapid resolution of hydrops could be observed and a healthy boy was born at 38 weeks of gestation. The respective laboratory data obtained from the examination of the amniotic fluid and maternal, fetal, and neonatal blood offer interesting insights into the dynamics of maternal-fetal parvovirus B19 infection.