Syndromic associations with congenital anomalies of the fetal thorax and abdomen

Anomalies of the thorax and abdomen can be found in a number of genetic syndromes. Whilst it may not be possible to make a definitive diagnosis before birth, knowledge of the potential associations can be useful for the prenatal diagnostician when examining the fetus and counselling the parents. In this article, we describe conditions where other features may be detectable using prenatal ultrasound. We describe the features, potential diagnostic aids and prognosis. The tables list other potential features that may be identified. The range of conditions that can occur emphasises the value of genetic input in the management of a fetus with an apparently normal karyotype and multiple anomalies, the need to save material for future molecular analysis and the requirement of a detailed examination after delivery. These are needed in order to make accurate diagnoses and advise parents with regard to recurrence risks and the potential for prenatal diagnosis in future pregnancies.     

Changes in the transfer of nutrients across the placenta during normal gestation in the rat.

Transfer of labeled glucose and alpha-amino isobutyric acid from the maternal circulation into the fetus was studied in the rat at various times during gestation and the results were correlated with placental and fetal growth. It was found that the rate of transfer of both substances per gram of placental tissue increase markedly near term in coincidence with a simultaneous fetal growth spurt. The data suggest a bimodal sequence of growth of the conceptus with a first phase of rapid placental growth and reduced placental transfer and a second phase of slow placental growth, increased transfer, and rapid fetal growth.     

Sonographic features of hemivertebra at 13 weeks' gestation

Hemivertebra is a rare congenital spinal disorder where only one side of the vertebral body develops, leading to deformation of the spine, such as scoliosis or kyphosis. Previous reports suggest that the diagnosis may be based on antenatal sonographic examination after 14 weeks. We present the sonographic features of a fetus with solitary hemivertebra at 13 weeks' gestation confirmed by postmortem babygram, magnetic resonance imaging (MRI) and pathological examination. It shows that the condition may manifest in the first trimester of pregnancy.     

Sonographic markers of exencephaly below 10 weeks' gestation

We report two cases of exencephaly diagnosed by transvaginal ultrasonography at 8 weeks 4 days and at 9 weeks 3 days of gestation. Both cases presented an irregular cephalic pole, and, in the case seen at 8 weeks 4 days, brain vesicles were also absent, whereas in the case seen at 9 weeks 3 days, the midline echo was indistinguishable with disorganized choroid plexuses. In both cases, anencephaly was evident at 11 and 12 weeks' gestation and the postmortem confirmed the diagnosis.     

Sonographic evaluation of growth discordance and chorionicity in twin gestation.

Ninety-four twin gestations had serial ultrasound examinations for evaluation of fetal growth, with special attention to prediction of weight discordance and chorionicity. Fetal weight estimations were made a mean of 3.2 days before birth and then compared to actual birthweights. The average error in intertwin discordance prediction was 1 +/- 9%. In 56 patients ultrasonic detection of membrane thickness was compared with placental pathologic conditions. If a membrane was seen between twins, it was confirmed by placental pathologic study in all cases. No membrane was seen in four twin pairs, but only one of these actually had monochorionic monoamniotic membranes. The three cases with false-positive diagnoses of monoamniotic twin gestation were initially seen late in pregnancy. If clinical decisions in twin gestations are based on ultrasound determination of discordance and chorionicity, the level of accuracy demonstrated by these data must be considered.     

Sonographic determination of fetal sex from twelve weeks of gestation

Fetal sex was sonographically determined in 1879 pregnant women between 12 and 40 weeks of gestation by obtaining transverse, frontal, and sagittal sections of the fetal lower pelvic region. The success rates of producing echoimages that were sufficient to determine fetal sex were 97.1% for both sexes (7783 correct diagnoses out of 8010 sonograms), 97.1% for males (3986/4103), and 97.1% for females (3797/3907). Postnatal confirmation of the sex of 1886 newborn infants delivered of 1879 pregnant women revealed that the rate of correct diagnosis before delivery was 99.9% (1885/1886)-100% for males (957/957) and 99.8% for females (928/929). The method of ultrasonic examination of the fetal sex reported here appears to be feasible in obstetric practice with consistent reproducibility and a high incidence of correct determinations at 12 weeks of gestation and thereafter.     

Sonographic diagnosis of exencephaly: omphalocele at 11 weeks of gestation

This report presents a sonographic diagnosis of exencephaly combined with omphalocele at 11 weeks of gestation. The transvaginal ultrasound showed frog-eye appearance face with no skull, abnormal shape of disorganized brain with covering membrane separated from brain mass by anechoic fluid in some area, and omphalocele of 8 mm diameter. Therapeutic abortion was successfully done with misoprostol. Postabortal macroscopic findings confirmed the prenatal diagnosis. The combination of exencephaly and omphalocele is rare, and this is one of the earliest diagnosis of not only exencephaly but also omphalocele. To our best knowledge, this represents the earliest diagnosis of the combination. In conclusion, transvaginal ultrasound proved highly informative for both exencephaly and omphalocele as early as in first trimester.     

Prenatal sonographic assessment of the fetal thorax: normal values

Fetal thoracic circumference and thoracic length measurements were obtained by ultrasonographic examination on 576 women between 16 and 40 weeks gestation. Nomograms for thoracic circumference and thoracic length with respect to gestational age were developed. Growth of both thoracic parameters was observed to be linear throughout gestation. In normal pregnancy the ratios of thoracic circumference to abdominal circumference and thoracic length to humerus length remained virtually constant at 0.89 and 0.93, respectively.     

Meconium-stained amniotic fluid across gestation and neonatal acid-base status

OBJECTIVE: To estimate whether the acid-base status of neonates born to women with meconium-stained amniotic fluid varies across gestation. METHODS: We carried out a retrospective cohort study of all pregnancies that were complicated by meconium-stained amniotic fluid in 2004. Cases were identified from a perinatal pathology database that contained data on all pregnancies complicated by meconium-stained amniotic fluid. Data abstracted from the charts included gestational age at delivery, umbilical arterial pH, birth weight, and the presence or absence of labor. Cases were stratified according to gestational age at delivery. The distribution of meconium-stained amniotic fluid across gestation was computed. The mean umbilical arterial pH values (with 95% confidence intervals) across gestation were assessed by analysis of variance. RESULTS: The mean umbilical arterial pH in women with meconium-stained amniotic fluid did not differ across gestation. The overall incidence of meconium-stained amniotic fluid was 12.0% (766 of 6,403 deliveries). The rates of meconium-stained amniotic fluid increased from 1.2% at 32 weeks to 100% at 42 weeks. CONCLUSION: The rising incidence of meconium-stained amniotic fluid with gestational age is consistent with the hypothesis that fetal maturation is a major etiologic factor in meconium passage. Also, the lack of variation of mean umbilical arterial pH across gestation suggests that fetal acidemia is not increased when meconium passage occurs earlier in pregnancy rather than at later gestational ages.     

Sonographic and molecular diagnosis of thanatophoric dysplasia type I at 18 weeks of gestation

Thanatophoric dysplasia is the most common type of lethal skeletal dysplasia. It can usually be diagnosed with ultrasound, but differential diagnosis with other osteochondrodysplasias is not always possible. Mutations in the fibroblast growth factor receptor 3 (FGFR3) gene have been demonstrated to cause two distinct subtypes of the disorder. We describe a case of thanatophoric dysplasia type I diagnosed at 18 weeks of gestation by ultrasonography. Genomic DNA obtained by chorionic villus sampling showed a C to G substitution at position 746 in the FGFR3 gene, resulting in a Ser249Cys substitution already known to be associated with type I disease. Implications for perinatal management are discussed.     

Immunological responsiveness of maternal and foetal lymphocytes during normal pregnancy in the ewe

Peripheral blood lymphocytes collected from ewes before and during pregnancy manifested constant reactivity to concanavalin A and to paternal and third party peripheral blood lymphocytes. However, in some instances, the reactivity of these maternal cells against lipopolysaccharide and lymphatic lymphocytes from paternal, foetal and third-party donors increased markedly during pregnancy. Apart from an indication that plasma from some pregnant ewes acquired the capacity to depress lymphocyte reactivity non-specifically, no evidence was obtained to suggest that maternal lymphocyte reactivity observed in vitro did not accurately reflect the capacity of these cells in the donor ewe. In particular, there was no indication that populations of maternal peripheral blood lymphocytes returning from the gravid uterus had undergone any modification of reactivity against foetal determinants.     

Reference ranges of Doppler parameters of foetal pulmonary artery segments between 19 and 39 weeks of gestation

Objective: To determine reference ranges of Doppler parameters of foetal pulmonary artery segments.

Methods: A prospective cross-sectional study was conducted to evaluate 150 healthy singleton pregnancies between 19 and 39 weeks of gestation. The proximal, middle and distal segments of the foetal pulmonary artery were assessed. The following Doppler parameters were evaluated: pulsatility index (PI) and peak systolic velocity (PSV). The mean, standard deviation (SD) and maximum and minimum values were determined for each Doppler parameter. Pearson’s correlation coefficient (r) was used to assess the correlation between the foetal pulmonary artery segments. Polynomial regression was performed, and adjustments were made using the coefficient of determination (R²).

Results: The mean PI values (mean?±?SD) in the proximal, middle and distal arterial segments were 2.99?±?0.61, 2.25?±?0.96 and 1.31?±?0.58, respectively. The mean PSVs in the proximal, middle and distal segments were 50.68?±?16.63, 24.396?±?11.86 and 12.08?±?3.66?cm/s, respectively. Significant differences were observed between the PI and PSV values from the different segments (p?<?0.0001). A correlation between each Doppler parameter and gestational age was observed, and it was better represented using linear equations.

Conclusion: We successfully determined the reference ranges for Doppler parameters of foetal pulmonary artery segments between 19 and 39 weeks of gestation.