Placental ultrasonographic biochemical and histochemical studies in human fetuses affected with Niemann-Pick disease type A

Placental ultrasonographic, bio- and histochemical studies were performed on four unrelated fetuses affected with Niemann-Pick disease Type A, following prostaglandin-induced abortion at about the 19th week of gestation. An accumulation of sphingomyelin in the placentae of affected fetuses indicates the essential role of the enzyme sphingomyelinase, even during the early stages of gestation. A fair correlation between histochemical localization of sphingomyelin in the placentae and ultrasonographic findings was found, indicating the value of ultrasonic echo wave information in the diagnosis of metabolic disorders.     

First-trimester fetal nuchal translucency and inherited metabolic disorders

OBJECTIVES: To assess the association between inherited metabolic disorders and nuchal translucency (NT) measurements. METHODS: The NT measurements obtained from 66 fetuses at high risk for metabolic diseases prior to chorionic villus sampling (CVS) were retrospectively analysed. RESULTS: NT was found to be within the normal range in all of the 13 affected fetuses, which included three with Gaucher disease, two with glycogenosis type II, two with mucopolysaccharidosis type I and six others with Krabbe disease, metachromatic leukodystrophy, mucopolysaccharidosis type II, Niemann-Pick A disease, Pelizaeus-Merzbacher disease and sialidosis, respectively. An increased nuchal thickness was found only in one fetus affected with trisomy 21 but not affected with mucopolysaccharidosis type II. CONCLUSION: NT appears to have a limited role in identifying affected fetuses in pregnancies at high risk for inherited metabolic disorders. NT may be normal in early pregnancy even for fetuses affected with conditions known to be associated with non-immune hydrops fetalis.     

Prenatal diagnosis of Pompe's disease (type II glycogenosis) in chorionic villus biopsy using maltose as a substrate.

Uncultured trophoblasts obtained from chorionic villus biopsy during the gestation period of 8-12 weeks were assayed for alpha-glucosidase activity using maltose as the substrate. Only one major form of maltase activity with a pH optimum at 4.0 was demonstrated. Using this method, we performed prenatal diagnosis on three pregnancies at risk for the infantile form of type II glycogen storage disease. Two affected fetuses and one unaffected fetus were predicted and the diagnosis was subsequently confirmed. The maltose assay offered a direct, simple, and sensitive method for prenatal diagnosis of Pompe's disease in the first trimester.     

A characteristic cluster of fetal sonographic markers that are predictive of fetal Turner syndrome in early pregnancy

OBJECTIVE: The purpose of this study was to describe a characteristic cluster of sonographic features of fetuses with Turner syndrome in early pregnancy. STUDY DESIGN: A targeted transvaginal ultrasound examination of all fetal organs was performed for 40123 consecutive pregnant women at 14 to 16 weeks of gestation. Both low- and high-risk pregnancies were included. Fetal karyotyping was performed in 9348 cases. The main indications were major fetal anomalies, advanced maternal age, abnormal biochemical markers, maternal anxiety, and request. RESULTS: Turner syndrome was detected in 13 fetuses (0.03%, 1/3086 early pregnancies). Huge septated cystic hygroma, severe subcutaneous edema, and hydrops were observed in all cases. A short femur was detected in 12 of 13 fetuses. A narrow aortic arch was visualized in all 8 fetuses who were scanned after 1995, when scanning of the aortic arch became mandatory in our institution. Four other fetuses had three or four of the five markers, 2 of the fetuses had trisomy 21, 1 fetus was normal, and one case of missed abortion occurred without a karyotype. CONCLUSION: A reliable diagnosis of Turner syndrome by sonographic means is possible in early pregnancy.     

Isoxsuprine-induced release of pulmonary surfactant in the rabbit fetus

Rabbit fetuses were injected intramuscularly with 0.5 mg. of isoxsuprine on the twenty-eighth day of gestation. They were killed in utero four hours after the injection, and fetal pulmonary fluid (FPF) was collected through a tracheal catheter. The quantity of FPF and the lung weight/body weight ratio were both significantly less in the isoxsuprine-treated fetuses than in control fetuses. Surface activity, evaluated with pulsating bubble, and the lecithin/sphingomyelin (L/S) ratio were greater in FPF from isoxsuprine-treated animals than in control samples. We concluded that isoxsuprine is able to dehydrate the fetal lung and cause a release of surfactant stored in type II pneumocytes. This latter conclusion was supported by a significant decrease in the number of lamellar inclusions observed in these cells.     

Prenatal diagnosis of Niemann-Pick diseases types A,B and C

Prenatal diagnosis of Niemann-Pick disease types A and B is routinely accomplished by sphingomyelinase assay. For Niemann-Pick type C disease, demonstration of an abnormal intracellular cholesterol trafficking is a complex procedure, and mutational analysis (NPC1 or NPC2/HE1 gene), whenever feasible, represents a major advance.     

Prenatal diagnosis of glycogen storage disease type IV

BACKGROUND: Glycogen storage disease type IV (GSD-IV) is a rare autosomal recessive disorder due to mutations in the GBE1 gene causing deficiency of the glycogen branching enzyme (GBE). Prenatal diagnosis has occasionally been performed by the measurement of the GBE activity in cultured chorionic villi (CV) cells. METHODS: Two unrelated probands with severe hypotonia at birth and death during the neonatal period were diagnosed with GSD-IV on the basis of postmortem histological findings. DNA analysis revealed truncating GBE1 mutations in both families. RESULTS: Prenatal diagnosis was performed in subsequent pregnancies by determination of branching enzyme activity and DNA analysis of CV or cultured amniocytes. Detailed autopsies of the affected fetuses at 14 and 24 weeks of gestation demonstrated intracellular inclusions of abnormal glycogen characteristic of GSD-IV. CONCLUSION: Prenatal diagnosis of GSD-IV by DNA analysis is highly accurate in genetically confirmed cases.     

Hypertriglyceridemia and hypoxemia in small-for-gestational-age fetuses

Plasma triglyceride concentration and blood oxygen tension were measured in samples obtained by cordocentesis from 35 small- and 54 appropriate-for-gestational-age fetuses at 18 to 36 weeks' gestation. In the appropriate-for-gestational-age fetuses there was an exponential decrease in plasma triglycerides with gestation. Some small-for-gestational age fetuses were hypertriglyceridemic and the degree of this biochemical disturbance was significantly correlated with the degree of fetal hypoxemia.     

Sonographic diagnosis of limb reduction defects in a fetus with haemoglobin Bart's disease at 12 weeks of gestation.

Limb reduction defect is a rare event but is found in eight per cent of fetuses affected by haemoglobin Bart's disease. We present a case of haemoglobin Bart's disease with terminal transverse limb reduction defects of all four limbs diagnosed by abdominal ultrasound examination at 12 weeks of gestation. The pregnancy was terminated by suction curettage. Just prior to the procedure, transabdominal needle embryoscopy was performed and this confirmed the sonographic diagnosis. The present case demonstrates the need and feasibility of a detailed anatomic survey of a fetus affected by haemoglobin Bart's disease at 12 weeks. This is particularly relevant if the patient is considering the option of intra-uterine therapy.     

Assessment of fetal circulation in the late first trimester--preliminary study

OBJECTIVES: to confirm that fetal echocardiography is indeed possible in late first trimester and that it improves the standard of the so-called "genetic" ultrasound scan. MATERIAL AND METHODS: Early echocardiography was performed in 75 fetuses from high and low risk pregnancies. All fetuses underwent echocardiography examination in 18-22 weeks of gestation and established follow up. RESULTS: The most suitable method of visualization seems to be transabdominal examination, between 13.0-13.6 weeks of gestation, an transvaginal one, between 12.0-12.6 weeks of gestation, with 90% effectiveness. In researched group of 75 fetuses (with established follow up) there were four heart defects (5.3%). Three of them were diagnosed before 14th week of gestation. One case (tetralogy of Fallot) was overlooked. There were two false positive diagnosis verified at 20th week of gestation. CONCLUSIONS: Early echocardiography, especially between 12.0-13.6 weeks of gestation, is a possible and valuable method of diagnosis. Reference evaluation should be performed between 18 and 22 weeks of gestation. In cases with suspected anomalies karyotyping is recommended. Congenital heart disease diagnosed at late first trimester should be treated as the next potential marker of genetic disorder.     

Cross-correlation of fetal cardiac and somatic activity as an indicator of antenatal neural development

OBJECTIVE: In this study, we wanted to model the emergence of coupling between fetal cardiac and somatic activity in normal and at-risk fetuses. STUDY DESIGN: One hundred six fetuses of uncomplicated pregnancies were longitudinally monitored at 20, 24, 28, 32, 36, and 38 weeks of gestation by using a fetal actocardiograph and computerized data collection. Twenty-six fetuses of complicated pregnancies were also included. Statistical time series analysis techniques were used to examine the relation between fetal movement and fetal heart rate. RESULTS: A linear increase was found in the magnitude of the cross-correlation function between fetal movement and fetal heart rate as gestation advanced, with coalescence around a peak lag of 5 seconds by 32 weeks. Fetuses that delivered before term evidenced accelerated fetal movement and fetal heart rate coupling, whereas fetuses affected by deleterious conditions showed a decline in developmental trajectory. CONCLUSIONS: The cross-correlation between fetal cardiac and somatic activity is an indicator of neuroregulation in human fetuses.     

Cadmium uptake by the rat embryo as a function of gestational age.

Maternal blood, liver, kidney, and placental and fetal (embryo) accumulation of cadmium (Cd), a known embryotoxic trace element, was investigated following a single oral dose of various amounts of Cd (10 to 1,000 microgram/rat) as CdCl2 containing 109Cd at days 6, 10, 14, and 17 of gestation. Twenty-four hours after Cd administration the rats were killed and the various tissues were counted in a gamma well counter for determination of 109Cd activity. Maternal liver and kidneys were the main target organs of Cd accumulation at all stages of gestation. Embryo levels of Cd were highest prior to formation of the functional placenta. After placental formation, fetal Cd levels were decreased, while placental accumulation of Cd increased with increasing gestational age. The results indicate that the embryo accumulates the greatest percentage of ingested Cd between implantation and placentation, the early period of organogenesis. The placenta apparently protects the fetus from exposure to this element during the last third of gestation.     

Ultrastructure of the human placenta in metabolic storage disease

Eleven placentae and one fibroblast cell culture from pregnancies complicated by various inherited metabolic disorders, together with five chorionic villus biopsies from pregnancies at risk, were examined for ultrastructural evidence of accumulation of metabolites. Abnormal ultrastructural features were present as early as 10 weeks gestation. Myelin bodies were found in all placental cell types in a case of Niemann-Pick disorder and stromal cells showed marked vacuolation in Hurler's disease. Membranous arrays were occasionally identified in the lysosomes of stromal cells in a case of Sandhoff's disease, together with some myelin body formation in the trophoblast and endothelium. In Pompe's disease, intralysosomal accumulations of glycogen were present in all cell types except syncytiotrophoblast, while in sialic acid storage disorder all placental cells were affected except for the cytotrophoblast. Collagen fibre disorientation and excess associated proteoglycan was seen in a formalin-fixed placenta with Sanfilippo mucopolysaccharidosis, and syncytial vacuolation, caused possibly by delays in fixation, was evident in many specimens. The specimens were collected from different centres and the fixation procedure varied significantly. The most satisfactory results were obtained from chorionic villus sampling in vivo and from pregnancies terminated using aspiration followed by immediate fixation. The importance of liaison with clinicians is stressed in order to obtain optimal preservation of the tissue. This is particularly vital in immature specimens of placenta where abnormal storage product material may not have had time to accumulate.     

Ultrasonic evaluation of fetal body movements over twenty-four hours in the human fetus at twenty-four to twenty-eight weeks' gestation

Continuous 24-hour observations of fetal gross body movements were performed in 20 women between 24 and 28 weeks of gestation by means of real-time ultrasound examination. At 24 to 26 weeks, fetuses moved 13.1% +/- 0.3% of the time, which was not significantly different from the incidence of 12.4% +/- 0.8% at 26 to 28 weeks' gestation. An examination of the number of movements per hour demonstrated that fetuses at 24 to 26 weeks' gestation moved on the average 53.4 +/- 1.6 times/hr, which was significantly different from 26 to 28 weeks' gestation when fetuses made 46.2 +/- 1.4 movements/hr. When examined on an hourly basis, fetuses in both age groups demonstrated a significant increase in the number of movements overnight from 2300 to 0800 hours. Intermovement intervals were also examined. Ninety-nine percent of intervals less than 6 minutes in both age groups contained movement. The longest observed quiescent interval was 24 minutes in both age groups. These data suggest that the incidence of fetal body movements is different than that observed in fetuses during the last 10 weeks of gestation. Fetuses at 24 to 28 weeks' gestation exhibit a diurnal pattern of fetal movement and move more frequently than do older fetuses. However, these movements are of a sporadic nature and relatively short duration. Thus these fetuses do not appear to have well-defined periods of rest and activity.     

Middle cerebral artery Doppler study in fetuses with homozygous alpha-thalassaemia-1 at 12-13 weeks of gestation.

OBJECTIVE: Fetuses affected by homozygous alpha-thalassaemia-1 are anaemic from the first trimester of pregnancy. We investigated middle cerebral artery Doppler velocimetry in these affected fetuses at 12-13 weeks of gestation to assess its use in predicting fetal anaemia. METHODS: Women referred for the prenatal diagnosis of homozygous alpha-thalassaemia-1 before 14 weeks of gestation were recruited. All fetuses underwent pulsed Doppler examinations following colour flow mapping at 12 or 13 weeks of gestation. Homozygous alpha-thalassaemia-1 was diagnosed by DNA or haemoglobin study. The middle cerebral artery Doppler indices were compared between the affected fetuses and fetuses unaffected by homozygous alpha-thalassaemia-1. RESULTS: Between 1998 and 2000, 80 eligible women were recruited. Of these, 19 fetuses were affected by homozygous alpha-thalassaemia-1. Two of them showed hydropic changes at the time of Doppler study. The affected fetuses had significantly higher middle cerebral artery peak systolic velocity (V(max)) (36% increase) and time-averaged maximum velocity (V(tamx)) (33% increase). CONCLUSION: The increase of cerebral blood flow in affected fetuses is consistent with our previous finding of an increased forward flow in the ductus venosus, cardiac dilatation and an increase of cardiac output to preferentially shunt more oxygenated blood to the brain as a compensatory mechanism. However, extensive overlap of the middle cerebral artery flow velocity values between affected and unaffected fetuses precludes its use in predicting anaemia at 12-13 weeks' gestation.     

Analysis of pulmonary venous blood flow in growth retarded fetuses above 30 weeks of gestation

Abnormal spectra of blood flow are observed in many fetal vessels in pregnancy complicated by intrauterine growth restriction. Redistribution of blood flow to the most important organs causes a diminished perfusion of the others. The disturbances of lung perfusion in utero are related to abnormal growth and development of the fetal lung. The aim of this study was to describe blood flow velocity waveforms in fetal pulmonary veins in normally grown and growth restricted fetuses above 30 weeks of gestation. Doppler studies were performed in 53 normally grown and 39 growth restricted fetuses. The subjects of analysis were: peak systolic (VS), peak diastolic (VD), end-diastolic (VA), and pulsatility index for veins (PIV). Analysis was performed for two gestational intervals: 31-36, 37-41 wks. The pulmonary venous flow in growth retarded fetuses demonstrates the similar pattern to that observed in normally grown fetuses above 30 weeks of gestation. There were no statistically significant differences between normally grown and growth restricted fetuses in all analyzed indices in both gestational intervals.     

Intrauterine fetal activity in at term and prolonged pregnancies

Fetal body movements and breathing movements were recorded with a real time ultrasound scanner in 26 fetuses. There were two recording periods of 25 min each, before and half and hour after maternal IV administration of 50 gr glucose. Six fetuses were at 280 days of gestation (Group A), twelve fetuses were at 294 days of gestation (group B), eight fetuses at 294 days gestation were classified as stage I postmature (group C). The incidence of fetal body movements was not significantly different in the three groups. Maternal glucose administration had no significant influence on fetal body movements in any group. On the other hand fetal breathing activity was significantly increased in all three groups after maternal glucose administration. Breathing activity was significantly greater in group A when compared to group C in both recording periods, and when compared to group B in the period which followed maternal glucose administration. It is concluded that fetal breathing activity is reduced in prolonged pregnancies.     

Effect of dexamethasone on amniotic fluid absorbance in Rh-sensitized pregnancy

Five Rh-sensitized pregnant women between 23 and 30 weeks gestation, with a poor obstetric history and initially high delta A450 values, were treated with weekly doses of 24 mg of dexamethasone over a period of 2-7 weeks to enhance fetal lung maturation. Four women showed a gradual decline in delta A450 during the treatment. All five deliveries were delayed until fetal lung maturity was confirmed by amniotic fluid lecithin/sphingomyelin (L/S) ratio and all five fetuses survived. It is possible that high doses of dexamethasone delayed the anticipated intrauterine deterioration of the fetuses and may have prevented the need for intrauterine transfusions.     

Evaluation of fetal lung maturity in diamniotic twins

Objective: This study was undertaken to evaluate the correspondence in fetal lung development between diamniotic twins. Study Design: Lecithin/sphingomyelin ratios were determined for amniotic fluid specimens collected from each sac in 58 diamniotic twin pregnancies. Results: Overall, the lecithin/sphingomyelin ratios of twin A and twin B and those of the larger and smaller twins of each pair were closely correlated (r ≥ 0.83, P < .001). When stratified by gestational age, however, the percentage disparity in lecithin/sphingomyelin ratios between members of twin pairs was significantly greater at ≤32 weeks’ gestation (25%) than at >32 weeks’ gestation (15%, P = .027). An analysis of the lecithin/sphingomyelin ratios of twins with a large lecithin/sphingomyelin ratio disparity (≥20%) suggested that this disparity was a result of 1 twin having a lecithin/sphingomyelin ratio that was advanced for gestational age with respect to that of the co-twin. Disparities in lecithin/sphingomyelin ratio were not significantly affected by fetal sex or by discordance in size between the twins. Conclusion: At relatively early stages of diamniotic twin gestation (≤32 weeks’ gestation), lecithin/sphingomyelin ratios should be obtained for both amniotic sacs to ensure accurate assessment of fetal lung maturity in both twins. (Am J Obstet Gynecol 1999;180:1438-41.)     

Non-invasive first trimester fetal gender assignment in pregnancies at risk for X-linked recessive diseases

OBJECTIVES: Prenatal diagnosis in families affected by X-linked recessive disorders should ideally be limited to the subjects at increased risk, i.e. male fetuses, in order to avoid the risk of fetal loss due to the invasive procedure in healthy female fetuses. The aim of the study was to assess the fetal sex within the first trimester of gestation by two non-invasive approaches, using ultrasonography and a molecular analysis of fetal DNA extracted from whole maternal blood with specific markers, in order to avoid invasive sampling in female fetuses. METHODS: A total number of 18 fetuses at risk for an X-linked recessive disease were included in the present investigation. Maternal peripheral blood was analysed between 7 and 12 weeks of gestation by nested PCR for the detection of fetal DNA and the prediction of fetal gender. In addition, when the biparietal diameter (BPD) was between 21 and 23 mm, an ultrasonographic examination was carried out to assess the fetal gender. CVS was then performed in male fetuses only. RESULTS: Fetal gender was correctly assigned by ultrasonography between 21 and 23 mm of BPD in all the cases studied, whereas DNA extracted from whole maternal blood accurately predicted the gender in all the female cases (10), but failed in 4 out of 8 male fetuses, erroneously assigned as females. CONCLUSION: The present study shows that sonography is able to accurately predict the fetal gender within the first trimester of pregnancy, whereas the molecular analysis of DNA extracted from whole maternal blood is biased by false-Y-negative results in 50% of the cases.