Michele R. Lauria

Pulmonary hypoplasia : pathogenesis, diagnosis, and antenatal prediction

Objective To review published data pertaining to the pathogenesis, antenatal prediction, and neonatal diagnosis of pulmonary hypoplasia. Data Sources A computerized search of articles published through February 1995 was performed on the MEDLINE data base. Additional sources were identified through crossreferencing. Methods of Study Selection All available references were reviewed initially by the authors, and their impact on the clinical significance of this condition was summarized. Data Extraction and Synthesis Pulmonary hypoplasia can be understood best by first defining the embryology of lung development. Although pulmonary hypoplasia can occur as a primary event, most cases are secondary to congenital anomalies or pregnancy complications. Several methods have been proposed to predict the subsequent occurrence of pulmonary hypoplasia, but no single criterion has adequately confirmed sensitivity and specificity for clinical decision making. Conclusion For patients with premature rupture of membranes, the gestational age at time of rupture carries the highest risk correlation with subsequent pulmonary hypoplasia.

Effects of tumor necrosis factor-alpha on human trophoblast cell adhesion and motility

PROBLEM: Adhesive interaction between trophoblast cells and uterine endometrial basement membrane is one of the critical processes in embryo implantation. This interaction is directly or indirectly regulated by hormones, growth factors, and cytokines. Since tumor necrosis factor‐alpha (TNF‐α) is synthesized by both decidual and trophoblast cells, we hypothesized that TNF‐α may play a regulatory role in trophoblast cell invasion. To test this hypothesis, we have used in vitro models to determine the effect of TNF‐α on human trophoblast cell adhesion and motility, two major steps in trophoblast invasion.

Amniotic fluid lamellar body count : Cost-effective screening for fetal lung maturity

OBJECTIVE To create a highly specific cascade testing scheme for fetal lung maturity using the lamellar body count, lecithin/sphingomyelin ratio (L/S), and phosphatidylglycerol. METHODS A nondedicated hematology analyzer (Sysmex NE 1500, Toa Medical Electronics, Los Angeles, CA) was used to determine the lamellar body counts of 209 unspun amniotic fluid specimens. Maximally specific lamellar body count cutoffs for biochemical maturity and immaturity were determined using receiver operating characteristic curves. Biochemical lung maturity was defined as either a mature L/S ratio or phosphatidylglycerol. Biochemical lung immaturity was defined as both an immature L/S ratio and an immature phosphatidylglycerol. RESULTS A lamellar body count of less than 8000 (n = 17) was 100% specific for biochemical lung immaturity (positive predictive value = 100%, negative predictive value = 86%). A lamellar body count of greater than 32,000 was 98% specific for biochemical lung maturity (positive predictive value = 99%, negative predictive value = 63%). CONCLUSION Testing only specimens where the lamellar body count was greater than 8000 and less than or equal to 32,000 for the L/S ratio and phosphatidylglycerol would preclude the need for 76% of all L/S and phosphatidylglycerol assays. Because the lamellar body count is quick, simple, and universally available, it could serve as an extremely cost-effective screening test for fetal lung maturity.

Severe Oligohydramnios with Intact Membranes: An Indication for Diagnostic Amnioinfusion

Objective: To quantify the improvement in ultrasonographic fetal imaging following diagnostic amnioinfusion for the indication of unexplained midtrimester oligohydramnios. Methods: Patients referred for unexplained midtrimester oligohydramnios were retrospectively reviewed. Videotapes of those undergoing diagnostic antenatal amnioinfusion were analyzed for quality of visualization of routinely imaged structures before and after the infusion procedure. Results: The overall rate of adequate visualization of fetal structures improved from 50.98 to 76.79% (p < 0.0001). In fetuses having preinfusion-identified obstructive uropathy, there was improvement in identification of associated anomalies from 11.8 to 31.3%. Conclusions: Several authors have suggested that diagnostic amnioinfusion can facilitate fetal imaging and increase diagnostic precision in the setting of unexplained severe oligohydramnios. We have quantified the improvement in the rate of optimal visualization of fetal structures which likely translates, in experienced hands, into this observed improved diagnostic precision. Of particular importance is the improvement in appreciation of associated anomalies in cases of obstructive uropathy in which such findings may determine whether or not invasive fetal therapy is indicated.

Adrenomedullin Levels in Normal and Preeclamptic Pregnancy at Term

Objective: To describe maternal plasma levels of adrenomedullin (AM), a hypotensive and natriuretic peptide, in normal and preeclamptic women at term. Study design: Maternal plasma AM levels were determined in 13 preeclamptic and 15 normotensive primigravidas by radioimmunoassay. Plasma samples were obtained with the patients in the lateral recumbent position before the administration of any medications. Results: Women with preeclampsia had significantly elevated AM levels when compared with normotensive controls (42.3 ± 10.5 pg/mL versus 16.9 ± 3.1 pg/mL, P < .011). Conclusion: In this pilot study, AM levels were significantly increased at term in preeclamptic women.

Newborn care and safety: the black box of obstetric practices and residency training.

Certain causes of newborn mortality such as sudden unexpected infant death, which includes sleep-related infant death and sudden unexplained infant death syndrome, are potentially preventable. Obstetricians are uniquely positioned to counsel new parents about safe practices regarding newborn sleep, feeding, and transportation. Patients often do not develop a relationship with their pediatricians until the neonate has been discharged, and the newborn period is a time of particular vulnerability. Newborn safety should be routinely taught in obstetric curricula, and the American College/Congress of Obstetricians and Gynecologists and the American Academy of Pediatrics (AAP) should partner to disseminate updated literature and guidelines to health care providers regarding newborn safety. Current guidelines from the Academy of Pediatrics Task Force on Sudden Infant Syndrome are summarized in this article.

Pathologic uterine ring associated with fetal head trauma and subsequent cerebral palsy

BACKGROUND: Pathologic uterine rings, also called Bandl’s ring, are historically associated with obstructed labor and good neonatal outcomes. CASE: Two cases are presented involving a pathologic uterine ring identified at cesarean delivery, which led to fetal cranial trauma. At delivery, pathologic uterine rings were found to encompass the heads of both fetuses, with gross features of traumatic head deformity. Radiologic studies demonstrated intracranial hemorrhage predating delivery. Both infants developed cerebral palsy, which was initially attributed to hypoxic-ischemic encephalopathy from delivery despite normal umbilical arterial pH. Further investigation linked the intracranial bleeding to compressive trauma from the uterine rings. CONCLUSION: Although rare, pathologic uterine rings may cause traumatic cranial deformity and subsequent cerebral palsy.

Brain natriuretic peptide and cyclic guanosine‐3′,5′ monophosphate in pre‐eclampsia

The objective of this study is to determine the possibility that pre-eclampsia, a disease characterized by altered vascular tone, may result in altered levels of fetal BNP and cGMP, and to determine whether pre-eclampsia alters the maternal-fetal relationship of BNP and cGMP. Paired maternal and umbilical venous plasma levels of BNP and cGMP were determined in 13 pre-eclamptic and 9 normotensive primigravidas in the third trimester. Statistical analysis was performed using multivariate analysis of variance, linear regression, and canonical correlation. Overall, levels of cGMP were lower in pre-eclampsia (P < 0.03). Pre-eclampsia was also associated with an altered maternal-fetal relationship for BNP and cGMP (P < 0.008, P < 0.02, respectively). With pre-eclampsia, the maternal:fetal ratio was reduced for BNP and was increased for cGMP. Because of its role as a second messenger for many vasoactive hormones, we hypothesize that fetal cGMP levels may better reflect overall vascular tone than do individual hormones. Altered BNP and cGMP maternal-fetal homeostasis raises the possibility of maternal-fetal coordination of vascular control.

Meconium Does Not Guarantee Fetal Lung Maturity

OBJECTIVE In utero passage of meconium may represent a response to hypoxic stress or a normal maturational event. When found during the third trimester, one may be tempted to use its presence as prima facie evidence of fetal lung maturity. The purpose of our study was to determine the frequency of meconium-stained fluid in the third trimester and the incidence of biochemical and physiologic lung immaturity in these fetuses. METHODS Amniotic fluid specimens obtained at our institution from 1991 through 1993 (n = 2,377) were analyzed for maturity and visually inspected for meconium. Perinatal outcome was obtained for intramural deliveries occurring within 3 days of amniotic fluid collection (n = 905). Gestational age was defined as the best obstetric estimate based on menstrual dates, clinical examination, and ultrasound results. RESULTS Meconium staining was present in 2.7% (n = 64) of specimens. Although meconium-stained specimens were more likely to have mature lecithin-sphingomyelin (L:S) ratios (OR 2.1, 95% confidence interval [CI] = 1.2-3.6) and phosphatidylglycerol (PG) concentrations (OR 3.8, CI 2.2-6.7), 17.2% were immature for both L:S and PG (n = 11, CI = 9.9-28.2%). When analysis was limited to fetuses delivering intramurally within 3 days of amniotic fluid collection, respiratory distress syndrome occurred in 3.0% (CI = 0.5-15%) with meconium-stained fluid. CONCLUSIONS The presence of meconium in amniotic fluid does not guarantee lung maturity. The same consideration of the risks of prematurity must be given to the fetus with meconium-stained fluid as given to the fetus with clear fluid.