Prenatal ultrasonic prediction of autopsy-proven pulmonary hypoplasia

Are non-invasive or minimally invasive autopsy techniques for detecting cause of death in prenates, neonates and infants accurate? A systematic review of diagnostic test accuracy

OBJECTIVES

To assess the diagnostic accuracy of non-invasive or minimally invasive autopsy techniques in deaths under 1 year of age.

DESIGN

This is a systematic review of diagnostic test accuracy. The protocol is registered on PROSPERO.

PARTICIPANTS

Deaths from conception to one adjusted year of age.

SEARCH METHODS

MEDLINE (Ovid), EMBASE (Ovid), CINAHL (EBSCO), the Cochrane Library, Scopus and grey literature sources were searched from inception to November 2021.

DIAGNOSTIC TESTS

Non-invasive or minimally invasive diagnostic tests as an alternative to traditional autopsy.

DATA COLLECTION AND ANALYSIS

Studies were included if participants were under one adjusted year of age, with index tests conducted prior to the reference standard.Data were extracted from eligible studies using piloted forms. Risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies-2. A narrative synthesis was conducted following the Synthesis without Meta-Analysis guidelines. Vote counting was used to assess the direction of effect.

MAIN OUTCOME MEASURES

Direction of effect was expressed as percentage of patients per study.

FINDINGS

We included 54 direct evidence studies (68 articles/trials), encompassing 3268 cases and eight index tests. The direction of effect was positive for postmortem ultrasound and antenatal echography, although with varying levels of success. Conversely, the direction of effect was against virtual autopsy. For the remaining tests, the direction of effect was inconclusive.A further 134 indirect evidence studies (135 articles/trials) were included, encompassing 6242 perinatal cases. The addition of these results had minimal impact on the direct findings yet did reveal other techniques, which may be favourable alternatives to autopsy.Seven trial registrations were included but yielded no results.

CONCLUSIONS

Current evidence is insufficient to make firm conclusions about the generalised use of non-invasive or minimally invasive autopsy techniques in relation to all perinatal population groups.PROSPERO registration numberCRD42021223254.

Assessment of the fetal lungs in utero

Antenatal diagnosis of abnormal pulmonary development has improved significantly over recent years because of progress in imaging techniques. Two-dimensional ultrasound is the mainstay of investigation of pulmonary pathology during pregnancy, providing good prognostication in conditions such as congenital diaphragmatic hernia; however, it is less validated in other high-risk groups such as those with congenital pulmonary airway malformation or preterm premature rupture of membranes. Three-dimensional assessment of lung volume and size is now possible using ultrasound or magnetic resonance imaging; however, the use of these techniques is still limited because of unpredictable fetal motion, and such tools have also been inadequately validated in high-risk populations other than those with congenital diaphragmatic hernia. The advent of advanced, functional magnetic resonance imaging techniques such as diffusion and T2* imaging, and the development of postprocessing pipelines that facilitate motion correction, have enabled not only more accurate evaluation of pulmonary size, but also assessment of tissue microstructure and perfusion. In the future, fetal magnetic resonance imaging may have an increasing role in the prognostication of pulmonary abnormalities and in monitoring current and future antenatal therapies to enhance lung development. This review aims to examine the current imaging methods available for assessment of antenatal lung development and to outline possible future directions.

Imaging of congenital lung malformations

Congenital lung malformations are a heterogeneous group of anomalies that involve the lungs and tracheobronchial tree (congenital airway pulmonary malformation, bronchial atresia, bronchogenic cyst, congenital lobar overinflation, pulmonary cyst, hamartoma, pulmonary isomerism and azygous lobe), vascular abnormalities (arteriovenous malformations, anomalous pulmonary venous return, pulmonary artery sling, interrupted pulmonary artery, pulmonary varix, pulmonary vein stenosis and pulmonary lymphangiectasia), or frequently both entities (pulmonary sequestration, pulmonary maldevelopment and scimitar syndrome). Advances in diagnostic imaging (including sonography, multi-detector computer tomography, magnetic resonance imaging and angiography) have increased their detection during both antenatal and postnatal periods, and radiological characterisation, which in turn influence patient counselling and management stratification. An educational illustration of the clinical application in characterisation of these malformations is presented.

Current Role of Fetal Magnetic Resonance Imaging in Body Anomalies

Fetal MR body applications have become more common in recent years as both in utero therapies, including fetoscopic surgery, and improvements in perinatal care have increased the demand for precise antenatal anatomic detail. This article discusses the variety of fast imaging sequences available to the fetal imager and describes their applications to both common and unusual congenital pathologies, including of the neck, chest, abdomen/pelvis and musculoskeletal systems.

Accuracy of imaging parameters in the prediction of lethal pulmonary hypoplasia secondary to mid-trimester prelabor rupture of fetal membranes: a systematic review and meta-analysis

In women who have suffered mid-trimester prelabor rupture of membranes (PPROM), prediction of pulmonary hypoplasia is important for optimal management. We performed a systematic review to assess the capacity of imaging parameters to predict pulmonary hypoplasia. We searched for published articles that reported on biometric parameters and allowed the construction of a 2 × 2 table, comparing at least one of these parameters with the occurrence of pulmonary hypoplasia. The selected studies were scored on methodological quality and we calculated sensitivity and specificity of the tests in the prediction of pulmonary hypoplasia and lethal pulmonary hypoplasia. Overall performance was assessed by summary receiver-operating characteristics (sROC) analyses that were performed with bivariate meta-analysis. We detected 13 studies that reported on the prediction of lethal pulmonary hypoplasia. The quality of the included studies was poor to mediocre. The estimated sROC curves for the chest circumference/abdominal circumference ratio and other parameters showed limited accuracy in the prediction of pulmonary hypoplasia. In women with mid-trimester PPROM, the available evidence indicates limited accuracy of biometric parameters in the prediction of pulmonary hypoplasia.

New anatomical landmarks to study the relationship between fetal lung area and thoracic circumference by three-dimensional ultrasonography

OBJECTIVE

To evaluate the relation between total lung area (TLA) and thoracic circumference (TC) ratio by three-dimensional (3D) ultrasonography applying new anatomical landmarks as the fetal aorta and inferior angle of the scapula.

METHODS

A longitudinal prospective study was conducted with 56 uncomplicated pregnancies between 24 and 32 weeks of gestation. Polynomial regressions were used to evaluate the correlation between TC and gestational age (GA) as well as TC and estimated fetal weight (EFW). A simple linear regression was used to evaluate the correlation between TLA and Total thoracic area (TTA) and GA. The intraclass correlation coefficient (ICC) was used to assess the intra and interobserver variability.

RESULTS

127 examinations were performed. TC values ranged from 150 to 174 mm (mean 166 mm) at 24 weeks and 215-248 mm (mean 231 mm) at 32 weeks. The TLA/TC ratio ranged from a mean of 0.64 at 24 weeks (range 0.56-0.70) to 0.90 at 32 weeks gestation (range 0.79-1.01). The intraobserver variability using the ICC was of 0.919 for TC; 0.916 for TTA; 0.860 for right lung area (RLA) and 0.910 for left lung area (LLA). Interobserver reproducibility was with an ICC of 0.970 for TC; 0.984 for RLA and 0.910 for LLA.

CONCLUSIONS

Measurement of fetal TC and the relationship between TLA and TC by 3D-ultrasonography applying new anatomical landmarks shows good reproducibility and allows a new assessment of thoracic and lung growth.

The management of preterm premature rupture of the membranes near the limit of fetal viability

Preterm premature rupture of the membranes near the limit of fetal viability is an uncommon complication of pregnancy, affecting approximately 4 in 1000 gravidas. However, maternal, fetal, and neonatal complications resulting from this condition are significant and include chorioamnionitis, pulmonary hypoplasia, restriction deformities, fetal loss, and complications of extreme prematurity among surviving infants. In this article, we review the literature regarding pregnancy outcomes after preterm premature rupture of the membranes near the limit of viability, and the data on traditional and nontraditional interventions to improve outcomes. An approach to patients who present with preterm premature rupture of the membranes near the limit of viability will be proposed.

Two- or three-dimensional ultrasonography to predict pulmonary hypoplasia in pregnancies complicated by preterm premature rupture of the membranes

OBJECTIVES

The purpose of this study was to compare 3D lung volume measurements with 2D biometric parameters in predicting pulmonary hypoplasia in pregnancies complicated by preterm premature rupture of the membranes (PPROM).

METHODS

In this prospective study, 18 pregnancies complicated by PPROMs at a mean 21 weeks' gestation (range 14-32 weeks) were examined. The 3D lung volume measurements and the following 2D biometric parameters were measured: thoracic circumference (TC) versus gestational age or femur length (FL), the TC/abdominal circumference (AC) ratio and the thoracic area/heart area (TA/HA) ratio. The sensitivity, specificity, positive and negative predictive value of each measurement to diagnose pulmonary hypoplasia were compared. Pulmonary hypoplasia was diagnosed on the basis of clinical, radiological and/or pathologic criteria.

RESULTS

The incidence of pulmonary hypoplasia was 33.3%. The best diagnostic accuracy for predicting pulmonary hypoplasia was achieved using the 3D lung volume measurements versus gestational age (sensitivity 83%, specificity 100%, positive predictive value 100% and negative predictive value 92%).

CONCLUSIONS

Three-dimensional lung volume measurements seem to be promising in predicting pulmonary hypoplasia prenatally in pregnancies complicated by PPROM.

Fetal Lung Volume Measurements: Determination with MR Imaging—Effect of Various Factors

PURPOSE

To retrospectively determine the effect of gestational age (GA), imaging plane, section thickness, and inter- and intraobserver variability on fetal lung volume (FLV) measurements obtained with magnetic resonance (MR) imaging in a cohort of fetuses without thoracic abnormalities.

MATERIALS AND METHODS

Institutional review board approval was obtained. Informed consent for this retrospective cohort study was waived, and the conduct of this study was HIPAA compliant. FLV was measured in 30 fetuses (GA, 17-36 weeks) referred for MR imaging for indications other than pulmonary abnormalities. Measurements were made on single-shot fast spin-echo images by tracing free-form regions of interest on individual consecutive sections in the transverse, sagittal, and coronal planes. Measurements were performed twice by two observers independently. Correlations between FLV and GA, imaging plane, and section thickness were assessed, as were intra- and interobserver variability. Time to perform FLV was assessed in a subset of fetuses.

RESULTS

Total FLV ranged from 2 to 110 mL. Mixed-effects regression model showed significant quadratic trend in FLV with increasing GA, with comparable strength of correlation (r = 0.89-0.91) in the three imaging planes of measurement. Intraobserver agreement was good in all three planes (r = 0.65-0.83) and was highest in the transverse plane. Interobserver agreement was good in all three planes (r = 0.68-0.76). FLV showed no significant dependence on section thickness (P = .23) or imaging plane (P = .82). Mean time to obtain FLV measurements ranged from 48 seconds at GA of 21 weeks to 77 seconds at GA of 29-30 weeks.

CONCLUSION

GA-based FLV measurements obtained with MR images are independent of section thickness and imaging plane and can be performed with good inter- and intraobserver agreement in less than 2 minutes.

Three- and 4-dimensional ultrasound in obstetric practice: does it help?

OBJECTIVE

The purpose of this article was to review the published literature on 3-dimensional ultrasound (3DUS) and 4-dimensional ultrasound (4DUS) in obstetrics and determine whether 3DUS adds diagnostic information to what is currently provided by 2-dimensional ultrasound (2DUS) and, if so, in what areas.

METHODS

A PubMed search was conducted for articles reporting on the use of 3DUS or 4DUS in obstetrics. Seven-hundred six articles were identified, and among those, 525 were actually related to the subject of this review. Articles describing technical developments, clinical studies, reviews, editorials, and studies on fetal behavior or maternal-fetal bonding were reviewed.

RESULTS

Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, especially facial clefts. There is also evidence that 3DUS provides additional diagnostic information in neural tube defects and skeletal malformations. Large studies comparing 2DUS and 3DUS for the diagnosis of congenital anomalies have not provided conclusive results. Preliminary evidence suggests that sonographic tomography may decrease the examination time of the obstetric ultrasound examination, with minimal impact on the visualization rates of anatomic structures.

CONCLUSIONS

Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations. Additional research is needed to determine the clinical role of 3DUS and 4DUS for the diagnosis of congenital heart disease and central nervous system anomalies. Future studies should determine whether the information contained in the volume data set, by itself, is sufficient to evaluate fetal biometric measurements and diagnose congenital anomalies.

Fetal lung volumetry using two- and three-dimensional ultrasound

OBJECTIVES

To compare methods of measuring fetal pulmonary volume and to establish nomograms of fetal pulmonary volume according to gestational age for the accurate diagnosis of pulmonary hypoplasia.

METHODS

Three methods of measuring fetal pulmonary volume in 39 normal fetuses were compared: two-dimensional (2D) ultrasound measurement assuming that the lung is a geometrical pyramid, three-dimensional (3D) ultrasound using the VOCAL rotational method, and the conventional multiplanar 3D mode. Linear regression was used to construct an equation for 3D volume calculation from 2D measurements (the re-evaluated pulmonary volume equation (RPVE)). Lung volume measurements were recorded from 622 singleton fetuses in order to construct nomograms.

RESULTS

There was no statistically significant difference between the lung volume values obtained using the two 3D modes. However, in comparison with the 2D measurements the volumes obtained were larger (mean difference = 11.99, P < 0.1 x 10(-6)). The relationship between the 2D and 3D volumes was determined using a statistical linear regression method: RPVE (mL) = 4.24 + (1.53 x 2DGPV), where 2DGPV (2D geometric pulmonary volume) = (surface area right lung base (cm2) + surface area left lung base (cm2)) x 1/3 height right lung (cm). Two nomograms were constructed, one for use with 2D and one for 3D technology.

CONCLUSION

2D pulmonary volume assessment can be used in clinical situations where fetal prognosis depends on lung volume and its growth potential. It is routinely available and easy to perform particularly when repeat measurements are required in evaluation of lung growth. We therefore propose this method as an alternative to magnetic resonance imaging or 3D ultrasound.

An Evidence-Based Approach to the Evaluation and Treatment of Premature Rupture of Membranes: Part II

Preterm premature rupture of membranes (PPROM) occurs in 3% of pregnancies and is responsible for one third of all preterm births. In part I of this series, the definition, pathophysiology, and diagnosis of PPROM was reviewed. In this part, treatment is discussed. Adjunctive antibiotic and corticosteroid therapy has the strongest evidence for improving neonatal outcome. Treatment is gestational age-dependent and will be influenced by local neonatal intensive-care unit (NICU) survival statistics. This review presents the available evidence and grades it according to the U.S. Preventative Task Force recommendations.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to summarize the data on the use of labor inhibition in the setting of PPROM, list potential antibiotics regimens that are recommended for prophylaxis in patients with PPROM, to describe the benefits of corticosteroid administration in patients with PPROM, and to outline potential management strategies for patients with PPROM based on gestational age.

Volumetric assessment of normal fetal lungs using three-dimensional ultrasound

We attempted to construct normal reference centiles of fetal lung volume (LV) for clinical application by using three-dimensional (3-D) ultrasound (US) during normal gestation. A prospective study was performed on 195 healthy fetuses with gestational age (GA) ranging from 20 to 40 weeks for the assessment of fetal LV using a 3-D US volume scanner with a mixture of cross-sectional and serial measurements. Polynomial regression analysis was calculated to find the best-fit model between GA, right lung volume (RLV), left lung volume (LLV) and total lung volume (TLV). In addition, common fetal growth parameters, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HCi), abdominal circumference (ACi), femur length (FL) and estimated fetal weight (EFW) were also measured to demonstrate the correlations between RLV, LLV, TLV and these parameters. Our results showed that RLV, LLV and TLV were highly correlated with GA. Using GA as the independent variable and RLV, LLV and TLV as the dependent variable, the best-fit regression equations were: RLV (mL) = 0.067 GA(2) - 1.2464 GA + 2.7825 (r = 0.95, n = 173, p < 0.0001), LLV (mL) = 0.0573 GA(2) - 1.599 GA + 12.454 (r = 0.95, n = 159, p < 0.0001) and TLV (mL) = 0.1263 GA(2) - 2.982 GA + 17.448 (r = 0.96, n = 152, p < 0.0001). For clinical use, a chart of normal growth centiles of fetal LV in utero was then calculated based on this equation. Furthermore, RLV, LLV and TLV were also highly correlated with the common fetal growth parameters during normal gestation (all p < 0.0001). In conclusion, the 3-D US nomograms of the fetal lung volume established in this study can be utilized as useful references in prenatal detection of fetal pulmonary pathologic status and relevant abnormalities.

Fetal imaging

Presently, MRI is an adjunct to prenatal sonography. It provides information that can aid in the diagnosis of fetal anomalies, affect prenatal counseling and management of the pregnancy, and guide prenatal intervention and delivery planning. With further advances in technology, particularly shorter scan times and better image resolution, the applications for fetal imaging are likely to increase.

Reliability of prenatal sonographic lung biometry in the diagnosis of pulmonary hypoplasia

OBJECTIVE

The purpose of the present study was to assess the value of biometric lung measurements for the diagnosis of severe fetal pulmonary hypoplasia by investigating whether a significant correlation between two-dimensional lung biometry measurements and autopsy findings could be established.

METHODS

This was a prospective study carried out between 1995 and 1997. Nomograms for normal fetuses of the anterior-posterior and transverse inner thoracic diameters, which describe the growth and shape of the lung, were used as a basis for diagnosis of pulmonary hypoplasia in fetuses at high risk of developing the condition (the fetuses had bilateral renal agenesis or multicystic kidneys; chronic PROM <25 gestational weeks or hydrothorax). Pregnancy was terminated by abortion or intrauterine death in 29/43 high-risk fetuses and autopsies were performed. Only the 29 fetuses for which there were autopsy findings were included in the study.

RESULTS

The best plane for diagnosing pulmonary hypoplasia was the four-chamber view. The diagnostic accuracy for this view as expressed by the sensitivity was 57% for the anterior-posterior diameter and 44% for the transverse diameter; as expressed by the specificity it was 42% for the anterior-posterior diameter and 50% for the transverse diameter. The results for the four-chamber view for the various high-risk conditions were as follows: for fetuses with chronic PROM we obtained sensitivities of 75% and 50% (anterior-posterior and transverse dimensions, respectively) and specificities of 80% and 60% (anterior-posterior and transverse dimensions, respectively). The sensitivities of lung biometry in fetuses with hydrothorax were 1% and 80% for the two diameters, but there was a low specificity. In fetuses with bilateral renal agenesis or multicystic kidneys we obtained sensitivities of 36% and 30% (anterior-posterior and transverse dimensions, respectively) and a specificity of 50% (anterior-posterior dimension).

CONCLUSIONS

The present results show that two-dimensional lung biometry is not a suitable method for antenatal detection of pulmonary hypoplasia. However, in individual cases with high risk for pulmonary hypoplasia, lung biometry might prove to be an additional diagnostic parameter.

Fetal magnetic resonance imaging

Ultrafast magnetic resonance imaging (MRI) sequences have changed the use of MRI to evaluate fetal abnormalities. Currently, the best application is the evaluation of suspected brain abnormalities found on ultrasound. MRI differentiates the various types of fetal ventriculomegaly. Superior posterior fossa visualization allows differentiation of Dandy-Walker malformation from a large cisterna magna. Anomalies of the corpus callosum can be seen. MRI also is valuable in the evaluation of fetal giant neck masses for planning delivery of the baby and surgery for life-threatening airway obstruction. In the chest, MRI differentiates masses such as diaphragmatic hernia, cystic adenomatoid malformation, and sequestration, and it aids in planning fetal surgery because MRI directly visualizes the position of the lung, liver, and bowel.

Magnetic resonance imaging of fetal thoracic abnormalities

Fetal thoracic abnormalities are increasingly being detected using prenatal ultrasound. Prenatal magnetic resonance imaging is an important adjunct in evaluation of fetal chest lesions. It can help differentiate different masses and is most helpful in evaluation of large or atypical masses. It also is very important in planning in utero interventional procedures, delivery, and immediate postnatal surgery.

The fetal lung. 2: Pulmonary hypoplasia

This review describes the pathogenesis of pulmonary hypoplasia and highlights its clinical, radiological and pathologic features, with emphasis on oligohydramnios-related pulmonary hypoplasia. Since pulmonary hypoplasia may lead to severe respiratory distress immediately after birth and even to neonatal death, an accurate and patient-friendly prenatal test for early detection and distinction between lethal and non-lethal pulmonary hypoplasia is still highly desirable. An extended overview of the proposed methods for the prenatal prediction of pulmonary hypoplasia is presented.

MRI for the assessment of the malformed fetus

Ultrafast MRI sequences have changed the use of MRI for evaluating fetal abnormalities. Currently, the best application is the demonstration of normal fetal brain development and the further definition of suspected brain abnormalities found on ultrasound. MRI differentiates well the various types of fetal ventriculomegaly. Superior posterior fossa visualization allows differentiation of Dandy Walker malformation from a large cisterna magna. Anomalies of the corpus callosum and some disorders of neuronal migration can be seen. MRI is also valuable in the evaluation of fetal giant neck masses for planning delivery of the baby and surgery for life threatening airway obstruction. In the chest, MRI differentiates masses such as diaphragmatic hernia, cystic adenomatoid malformation and sequestration, and aids in planning fetal surgery because MRI directly visualizes the position of the lung, liver and bowel. MRI defines abnormalities of the urinary tract by demonstrating dysplastic pathology in the renal cortex and dilation of the collecting systems. Oligohydramnios does not effect MRI.

[Prenatal diagnosis of chylothorax]

Chylothorax is defined as the presence of lymph in the pleural space. Congenital chylothorax is one of the most frequent causes of fetal pleural effusion. It may be primary or secondary. Careful assessment of the etiology and of possible associated anomalies is required. Main complications are pulmonary hypoplasia, hydrops fetalis and the risk of premature delivery. Management is still a mater of controversy, the diagnosis of fetal pulmonary hypoplasia being difficult in utero. Factors such as gestational age, evolution of pleural effusion on two weeks, signs of seriousness (hydrops fetalis), and pulmonary expansion after pleural puncture may help the physician to choose between abstention, pleural tapping or long-term in utero drainage. Post natal treatment consists of pleural drainage and assisted ventilation in cases of respiratory distress, correction of metabolic and immune disorders and exclusive parenteral nutrition. Once chylothorax is resolved, formula feeding without long-chain triglycerides is allowed. If pleural effusion persists despite a well conducted treatment, albumin infusion and diuretics may be used before considering surgical treatment.

Correlation of prenatal ultrasound diagnosis and pathologic findings in fetal anomalies

This retrospective study compared the prenatal ultrasound (US) diagnosis with autopsy findings in 61 intact fetuses following induced abortion and 36 fragmented fetuses from dilatation and evacuation (D&E). In intact fetuses, complete agreement between US diagnosis and autopsy findings was achieved in 65.6% of cases in the central nervous system (CNS) and 47.5% in other somatic organ systems (SOS). There were major differences between US and autopsy findings involving the CNS in 6.5% of cases and SOS in 27.9%. Correlation was better for evaluation of renal anomalies (complete agreement in 63.6% of 11 suspected cases, 2 false-positive and no false-negative cases) than congenital heart disease (complete agreement in 27.3% of 11 suspected cases, 5 false-positive and 3 false-negative cases). In D&E specimens, a prenatal diagnosis of neural tube defect (NTD) was confirmed in 90% of cases. However, due to fragmentation of fetal parts, the US diagnosis in the CNS could not be confirmed totally (69.4%) or partially (2.8%) in fetuses with chromosomal abnormalities (ChA) or multiple congenital anomalies (MCA). Nonetheless, the US diagnosis of SOS was confirmed in six cases on D&E, including Meckel-Gruber syndrome, cystic hygroma, renal agenesis with contralateral renal dysplasia, cardiac defect, fetal hydrops, and tracheal atresia. Our results show that a thorough autopsy of an intact fetus after abortion is necessary to confirm prenatal diagnosis and allow proper management and counseling. The pathologic examination of D&E specimens can reliably confirm the US diagnosis of NTD, but it is very limited in identifying other fetal anomalies.

Midtrimester premature rupture of the membranes

Midtrimester premature rupture of the membranes is an uncommon adverse complication of pregnancy with an occurrence of approximately 0.65%. Significant perinatal and maternal morbidity includes pulmonary hypoplasia, restriction deformities, and sequelae of prematurity as well as maternal chorioamnionitis and endometritis. Moreover, 31% of survivors are affected by long-term complications such as chronic lung disease, neurological and developmental abnormalities. Fetal survival is evident with increasing latency and good residual amniotic fluid (largest vertical pocket > or = 2 cm). In this article, we review the relevant literature regarding prognosis, counseling, and management of the patient with membrane rupture in the midtrimester.

The fetal thorax: noncardiac chest anomalies

Fetal thoracic anomalies often lead to pulmonary hypoplasia with subsequent fetal or neonatal demise. Therefore, in utero sonographic identification of these anomalies is important. Unlike cardiac anomalies, most noncardiac thoracic abnormalities are easily detected with ultrasound. An unusually small thorax is usually obvious to the experienced sonographer, and thoracic masses are commonly observed on the routinely obtained four-chamber view of the heart. This article reviews the many causes of pulmonary hypoplasia with an emphasis placed on thoracic masses. Many examples of pathological fetal thoracic conditions are provided as well as a listing of differential considerations with regard to sonographic appearances of chest masses.