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Dichorionic placentation is observed in both monozygotic (MZ) and dizygotic (DZ) twinning, while monochorionic placentation is unique to MZ twinning. Examinations of monochorionic twin placentas frequently reveal the presence of vascular anastomoses between the two fetal circulations; such anastomoses rarely occur in dichorionic placentas. Consequently, abnormalities resulting from placental vascular communications are almost exclusively observed in MZ twin pairs with monochorionic placentas. We report opposite-sex DZ twins in which vascular anastomoses occurred within a fused dichorionic placenta and were associated with vascular disruptions in one twin. The liveborn male twin had amelia, cutis aplasia, and XX/XY blood chimerism; the female twin died in utero.

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Two newborn infants with fetal akinesia sequence were noted to have multiple perinatal fractures of the long bones. The radiographic manifestations are characterized by gracile ribs, thin long bones, and multiple diaphyseal fractures. Consistent histopathologic changes of bone are irregular with focal areas of extreme diaphyseal thinning, thin and long marrow spicules, and with or without callous formation at fracture sites. Pathogenic mechanisms of bone fractures in fetal akinesia sequence and the differential diagnoses of congenital/perinatal bone fractures are discussed.

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Because of the increasing prenatal use of high-resolution ultrasonography to assess fetal growth and because growth aberration is one of the principal manifestations of abnormal intrauterine development, a more precise definition of normal growth is desirable. Our data set from autopsies of fetuses/neonates (50-4,000 g), collected with systematic attention to precision of measurement, is analyzed and presented. Previous computations of fetal growth curves appear to overstate the variation about the mean. Through the identification and exclusion of outliers and the use of appropriate curve fitting techniques, the problem of overestimation of variation about the mean has been largely eliminated. The new growth standards we present can be used to assess aberration from proportional growth and correlate it with gestational circumstances and particular morphological features of the fetus.

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Normal fetal and newborn prostates were studied to evaluate growth patterns, histogenesis, and secretory activity. Whole cross-sectioned prostates harvested from 107 necropsies of fetuses and newborns ages 20 weeks gestation to 1 month of age were used. Development of the prostate occurred in three stages: bud stage (20-30 weeks gestation), bud-tubule stage (31-36 weeks gestation), and acinotubular stage (37-42 weeks gestation). Squamous metaplasia often appeared in the urethra, utricle, and primary lobular ducts, and occasional microcysts were noted. PAS and alcian blue-PAS positive secretion were present in 65% of the specimens by 20-30 weeks gestation and in over 87% of the specimens by 37 or more weeks gestation. Secretory activity was most prominent in the lateral regions of the peripheral zone. Prostate-specific antigen was only weakly detected throughout the prenatal period and was not related to secretory activity as evidenced by the PAS technique.

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Lethal perinatal osteogenesis imperfecta (OI Type II) is a biochemically diverse collagen disorder characterized by short, crumpled long bones, beaded ribs, blue sclerae and thin, fragile skin. Cardiovascular abnormalities are rarely described. Using morphometry and light and electron (SEM and TEM) microscopy, we analyzed the hearts and great vessels from 2 fetuses with OI Type IIA and compared the findings with age-matched controls. The heart weights and atrioventricular valve (AVV) circumferences were reduced in OI. The chordae tendineae were short and fragile; both the AVVs and the chordae tendineae were hypercellular. TEM showed relatively little organized collagen in the chordae tendineae of OI fetuses. Furthermore, quantitative evaluation of collagen fibril size revealed a decrease in the cross-sectional diameter. There was also a marked decrease in the adventitial and intramural collagen of the intramyocardial arteries and great vessels in OI. Our study reports, for the first time, specific lesions in the cardiovascular systems of patients with OI Type II and reviews the cardiovascular pathology in other forms of OI.

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This study investigated the influence of the location of the sampling site during elemental analyses of 21 human term placentae. The levels of iron, zinc, copper and calcium in fetal membranes, umbilical cords and placental discs were measured by atomic absorption spectrophotometry and compared. The disc samples were obtained from central (peri-insertion and mid-disc fetal and maternal halves), and peripheral regions. Significant variations were found. Copper was present in highest levels (17.2 +/- 2.0 micrograms/g dry weight) in the fetal membranes. Calcium levels were highest (712 +/- 47 micrograms/g dry weight) in the periphery of the placental disc. Iron levels were highest (558 +/- 14 micrograms/g dry weight) in the central regions of the disc. Zinc levels were lower (50.3 +/- 1.4 micrograms/g dry weight) in the fetal half of the mid-disc regions than in the maternal half (56.0 +/- 1.2 micrograms/g dry weight). This study demonstrates the importance of defining the location of the sampling site in studies involving elemental analysis of the placenta.

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Smoking habits, prenatal health, and pregnancy outcome were surveyed among 1700 nulliparous women. During pregnancy, increases in levels of hemoglobin and hematocrit and the frequency of women reporting bleeding and decreases in diastolic pressure and frequency of toxemia were observed with increased maternal smoking. A higher frequency of fetal bradycardia was detected among women smoking greater than or equal to one-half pack per day. With increased smoking there was an increased frequency of abnormal placentas. Mean birth weight and crown-heel length decreased with increased smoking, and neonates born to women smoking greater than or equal to one-half pack per day had a higher frequency of jaundice. The association between smoking and reduced birth weight and crown-heel length persisted after controlling for gestational age, maternal weight gain, prenatal visits, and other confounding variables.

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Four cases are reported, along with a review of the literature, to demonstrate the radiographic and clinial spectrum of bilateral anteromedial defect of the diaphragm in infants and children. Bilateral anteromedial defect of the diaphragm produces a characteristic radiographic pattern on herniation of abdominal structures through a single midline opening. The usually solid herniated structures elevate the heart and thymus producing a three-tiered snowman appearance. The lateral chest view substantiates the anterior location differentiating anteromedial herniation from eventration, partial or complete. Diagnosis can be confirmed by pneumoperitoneography but the high incidence of liver herniation allows less invasive determination by radionuclide scanning. While many patients will be asymptomatic, clinical symptoms can be severe due to pulmonary compression and hypoplasia or associated cardiovascular abnormalities.

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Adrenocortical insufficiency was produced in rat fetuses by surgical decapitation. These animals show low plasma corticosterone levels compared to littermate controls. Lung slices from anencephalic fetuses were found to have reduced incorporation of [14C]choline into phosphatidylcholine, hence diminished choline pathway activity; this abnoramlity was present at 21 days of gestation but not at term. Cholinephosphotransferase (CPT), the terminal catalyst of the choline pathway, also showed diminished activity in lungs of anencephalic fetuses, with a mean of 120 pmol/min/mg protein compared to a control value of 190. Dexamethasone treatment of these animals for 6-12 hr led to enhanced choline incorporation rates. Corticosteroid administration also restored CPT activity and even elevated the enzyme to a mean level (340 pmol/min/mg protein) greater than that found in normal fetuses at 21-22 days of gestation. The early pulmonary biochemical effects of dexamethasone in this model were not accompanied by recognizable ultrastructural changes.

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Although it has long been known that the lack of androgen dependent differentiation in patients with testicular feminization is secondary to end organ insensitivity, the molecular basis of this genetic disorder has not been elucidated. In the present report a rodent model for testicular feminization is described. The Stanley-Gumbreck pseudohermaphroditic rat has an inherited disorder characterized by a female phenotype, a male genotype and tissue insensitivity to androgens. Even though male differentiation does not occur when these animals are treated with physiologic doses of testosterone, some androgen dependent growth is evident when 100-fold larger doses of testosterone are given. Studies of androgen metabolism in the psuedohermaphroditic animals indicate that testosterone transport and metabolism to dihydrotestosterone are normal. However, intranuclear retention of dihydrotestosterone is defective. These findings suggest that the androgen insensitivity of the pseudohermaphroditic rat is due to an inherited abnormality of a regulatory protein which renders the nucleus of the cell incapable of concentrating androgens at their proposed intracellular site of action. The pseudohermaphroditic rats also have a defect of testicular and adrenal steroid synthesis in addition to the androgen insensitivity. The relation of these two abnormalities in rat and in man are discussed.

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