Calvin E. Oyer

Reference Values for Singleton and Twin Placental Weights

The largest series of normal singleton placental weights was collected in the Collaborative Perinatal Study between the years 1959 and 1966 but values for normal twin placental weights were not published. In our study we examined 787 singleton and 514 twin normal placentas. Placentas with associated conditions known to affect the weights of placentas were excluded. After establishing the normal values for singleton and twin placental weights, we concluded that weight gain of twin placentas appears to accelerate between 24 and 36 weeks but reaches a plateau after 37 weeks, whereas singleton placentas appear to gain weight more uniformly throughout gestation. The mean values of twin placental weights for each gestational age are less than double those of singleton placental weights for the same duration of gestation. Our singleton and twin placentas are heavier than those from previously published data and may reflect a generational or nutritional change over the 30 years since the original numbers were compiled.

Reference Values for Second Trimester Fetal and Neonatal Organ Weights and Measurements

To establish accurate reference ranges for the entire second trimester, we documented organ weights, body weight, and linear measurements for 597 fetuses and neonates with gestational ages ranging from 12 to 26 wk. We determined the mean and standard deviation for weights and measurements at each week of gestation using the StatView™ SE + Graphics statistical program. The analyses revealed a linear correlation between the gestational age and, respectively, the toe-heel length, crown-rump length, and crown-heel length. Body and organ weights increase at varying rates throughout the second trimester. The data correlate well with weights and measurements previously published for the latter half of the second trimester, and extend these reference ranges to encompass the entire second trimester.

Ischemia-reperfusion injury in the intestines of newborn pigs.

Although the pathogenesis of necrotizing enterocolitis remains uncertain, ischemia appears to be an important contributing factor to the development of this disorder. Reperfusion plays a major role in ischemia-related injury, and oxygen free radicals produced during reperfusion most likely contribute to the injury. These oxidants can be generated during prostanoid metabolism, which increases during reperfusion of ischemic gut in adult subjects. The present study was designed to: 1) examine the effects of superior mesenteric artery occlusion, e.g. ischemia and reperfusion in vivo on the development of histopathologic intestinal injury; 2) determine whether products of arachidonic acid metabolism, e.g. prostanoids are increased during reperfusion of ischemic gut; and 3) determine whether oxygen free radical scavengers attenuate the injury in newborn pigs. Chronically catheterized placebo-pretreated newborn pigs exposed to ischemia-reperfusion, placebo-pretreated nonischemic control pigs, and polyethylene glycol-superoxide dismutase (SOD) plus polyethylene glycol-catalase (CAT)-pretreated, ischemic pigs were studied by examining changes in intestinal circulation, oxygenation, prostanoids, and tissue injury. In the placebo-pretreated pigs, intestinal blood flow decreased to very low levels during superior mesenteric artery occlusion. During reperfusion, blood flow increased, but remained below baseline. After ischemia, oxygen uptake returned to values that were similar to baseline. Intestinal efflux of the vasodilator 6-keto-prostaglandin F1α was evident (p < 0.05 versus no or zero efflux) during early reperfusion. Histopathologic scoring of terminal ileal samples showed significant mucosal necrosis, surface epithelial disruption, lamina propria congestion and hemorrhage, submucosal hemorrhage, edema, and increases in cells compared with the placebo-pretreated nonischemic pigs. In the SOD plus CAT-pretreated ischemic pigs, changes in intestinal blood flow, oxygen uptake, 6-keto-prostaglandin F1α efflux, and the pattern of the ileal tissue injury did not differ significantly from the placebo-pretreated ischemic pigs. In summary, superior mesenteric artery occlusion for 1 h and reperfusion for 2 h resulted in severe intestinal ischemia, early postocclusive limited increases in intestinal perfusion and oxygen uptake, efflux of vasodilating prostanoids during early reperfusion, and signs of ischemic tissue injury in the placebo- and SOD plus CAT-pretreated pigs. This study demonstrates that, after superior mesenteric artery occlusion and reperfusion, severe intestinal tissue injury is detected in vivo, prostanoid efflux increases, and SOD plus CAT given just before occlusion does not attenuate the extent of injury in newborn pigs.

Neonatal Hemochromatosis, Renal Tubular Dysgenesis, and Hypocalvaria in a Neonate

ABSTRACT We report a neonate with neonatal hemochromatosis (NH), renal tubular dysgenesis (RTD), and hypocalvaria. NH is a fatal condition of the newborn, characterized by severe idiopathic liver failure of intrauterine onset and siderosis, intra- and extrahepatic, with sparing of the reticuloendothelial system. RTD is characterized by short, abnormally developed cortical tubules that lack proximal tubule differentiation. Although both NH and RTD have been reported as entities with a genetic component, similar findings can be secondary to in utero insults. Hypocalvaria has been reported in association with fetal hypoxia including that secondary to angiotensin converting enzyme inhibitors. This 38-week-old infant died at 8.5 h. The small nodular liver weighed 44 g. Grossly, the kidneys were normal. Hypocalvaria was present. Microscopically, the hepatic parenchyma was distorted by fibrous tracts, proliferation of bile ducts, and abundant iron deposition in hepatocytes. Extrahepatic siderosis in the pancreas, myocardium, and other organs was consistent with NH. Proximal convoluted tubules were not seen on routine stains and markers for proximal tubules were negative. Previous reports have linked NH with RTD and RTD with hypocalvaria. This infant had all three of these rare conditions, which have been hypothesized or shown to be due to genetic factors, hypoxia, or drugs. The etiology in this case is unknown.

Hepatic subcapsular hematomas in fetuses and neonatal infants.

ABSTRACT In fetuses and neonates hepatic subcapsular hematomas are relatively common lesions and may be life-threatening. Conditions previously associated with these hematomas include trauma, coagulopathies, hypoxia, sepsis, pneumothorax, maternal diseases, and placental lesions. In this study of 755 perinatal autopsies, hepatic subcapsular hematomas were found in 52 (6.9%) cases, including 31 stillborn fetuses and 21 liveborn infants. The average body weight was 690 g. A comparison group consisted of 52 temporally proximal autopsies of fetuses and neonates without hematomas. Body weights, gender, maternal age, and stillbirth or postnatal survival were matched as closely as possible while evaluating the presence or absence of sepsis, pneumothorax, cerebral germinal matrix hemorrhage, trauma, coagulopathy, placental lesions, and maternal diseases. Sepsis was associated with 62% of the cases with hepatic subcapsular hematomas and with 25% of the comparison group (P = .0001). Group B streptococcus infection was the most common cause of sepsis, but many different organisms were isolated. Cerebral germinal matrix hemorrhages were present in 35% of the cases with hematomas and in 14% of the comparison group (P = .0001). No other lesions or conditions were statistically different in the study group versus the comparison group. The delicacy of the hepatic capsule and its connections to the collagen along the sinusoids provide insight for the pathogenesis of hematomas in premature fetuses and neonates. We conclude that sepsis is present in most perinatal cases of hepatic subcapsular hematomas and that such patients also frequently have cerebral germinal matrix hemorrhages. Each of these lesions is a greater hazard among very small premature fetuses or neonates than among older fetuses and neonates.

THE DETECTION OF NON-IMMUNE HYDROPS THROUGH SECOND-TRIMESTER MATERNAL SERUM SCREENING

The objective was to investigate whether non‐immune hydrops in euploid pregnancies is associated with alterations in the second‐trimester levels of maternal serum alpha‐fetoprotein (AFP), unconjugated oestriol (uE3), and human chorionic gonadotropin (hCG). Ten singleton cases of fetal non‐immune hydrops were identified. The aetiology and timing of onset of the earliest signs of non‐immune hydrops, including polyhydramnios, in relation to maternal serum screening for Down syndrome were assessed. There was no clear relationship between the aetiology of non‐immune hydrops and the analyte levels, as aetiologies varied widely. AFP levels were elevated overall (median=1·78 MOM) and uE3 levels were unremarkable (median=0·82 MOM). hCG levels were elevated (median=3·53 MOM) when non‐immune hydrops was present at the time of screening, but were unremarkable (median=0·82 MOM) when the non‐immune hydrops presented later. It is concluded that second‐trimester non‐immune hydrops is associated with elevated hCG levels.

Fatal intrauterine adenoviral endomyocarditis with aortic and pulmonary valve stenosis: diagnosis by polymerase chain reaction.

We report a case of fatal hydrops fetalis owing to adenoviral endomyocarditis with aortic and pulmonary valve stenosis. A 1850-g macerated male stillborn delivered 1 week after fetal ultrasonography showed hydrops, cardiomegaly, and possible aortic valve stenosis. Autopsy confirmed hydrops and showed thickened, fibrotic semilunar valves with stenosis. The myocardium was focally fibrotic with areas of calcification. Polymerase chain reaction study of myocardial and aortic valve tissue was positive for adenovirus. Intrauterine viral myocarditis has been reported only rarely, but cases owing to Coxsackie B virus, adenovirus, and parvovirus B19 have appeared in the literature. With the exception of rubella, viral causation of significant valvular lesions in humans has received scanty support in the literature. This report suggests a broader group of causative agents. HUM PATHOL 31:1433-1435.

The Histologic Fetoplacental Inflammatory Response in Fatal Perinatal Group B-Streptococcus Infection

OBJECTIVE: To determine the rate of histologic fetoplacental inflammation in fetuses and newborns with fatal perinatal Group B-Streptococcus (GBS) infection.STUDY DESIGN: Autopsy files (1990 to 2002) were searched for fetuses and newborns with GBS-positive post-mortem blood and/or lung cultures. The rate of histological fetoplacental inflammation in preterm (<36 weeks gestational age) and term (≥36 weeks) fetuses/infants was compared using χ 2 test.RESULTS: GBS infection was diagnosed in 4.9% (61/1236) of perinatal autopsies and was considered the exclusive cause of death in 58 cases (16 to 41 weeks gestation, median: 26 weeks). A total of 43 fetuses/infants (74%) were preterm, 24 (41%) were male and 33 (57%) stillborn. The histologic fetoplacental inflammatory response was age-dependent for the following variables: acute chorioamnionitis (seen in 67% of preterm vs 33% of term fetuses/infants, p < 0.05), multiple-vessel umbilical vasculitis (37 vs 7%, p < 0.05), funisitis (37 vs 13%, p < 0.05), and the presence of neutrophils in the gastrointestinal tract (35% vs none, p < 0.05). Neutrophils in the pulmonary airspaces (47 vs 33%) and pneumonia (16 vs 27%) were found with similar frequency in both groups.CONCLUSION: Histologic fetoplacental inflammation is a poor indicator of perinatal GBS infection; the sensitivity is 67% in preterm and 33% in term fetuses/newborns (overall sensitivity 59%). The higher rate of histologic inflammation in preterm fetuses/newborns suggests age-specific interactions between microorganism, host and placenta.

In Utero Development of Hypertensive Necrotizing Pulmonary Arterial Lesions: Report of a Case Associated with Premature Closure of the Ductus Arteriosus and Pulmonary Hypoplasia

Premature closure of the ductus arteriosus (PCDA) is an uncommon defect in which pulmonary hypertension (PH) has been documented by echocardiography in patients and by direct measurement after experimental PCDA in animals. The pulmonary vascular histology in human cases has received little attention but in the few recorded observations the vessels were either normal or showed increased muscularity. We report the case of a 31 week hydropic female stillborn monozygotic twin in whom postmortem examination disclosed PCDA and hypoplasia of the lungs. Atypical plexiform lesions with necrotizing pulmonary arteritis were present. These lesions represent vascular consequences of severe pulmonary hypertension produced by greatly enhanced blood flow through a restricted vascular bed resulting from the combined effects of these two abnormalities. The findings in this case of PCDA with presumed severe PH indicate that severe pulmonary vascular changes can develop in utero and that the interval of time needed for development of such chances in secondary PH is relatively short.

46,XX GONADAL AGENESIS IN A NEONATE WITH MULTIPLE CONGENITAL ANOMALIES: Case Report and Review of the Literature

We report a neonate with 46,XX gonadal agenesis, a rare disorder, confirmed by autopsy, karyotype determination, and fluorescent in situ hybridization examination of intact cells. Multiple other anomalies, including diaphragmatic hernia, a doomed bicuspid aortic valve, and müllerian derivative defects, were present. There was no sexual ambiguity. The age of this patient and the presence of anatomically dispersed congenital anomalies are unique among reported examples of 46,XX gonadal agenesis. Review of the literature reveals that all five previously reported cytogenetically confirmed patients with 46,XX gonadal agenesis were 17 to 25 years of age, none were diagnosed before their teens, all had female phenotype with sexual infantilism, three had müllerian derivative anomalies, and none had nongenitourinary anomalies. The abnormalities in this case may represent a polytopic field defect due to unknown insults occurring at approximately 6 weeks of developmental age.