Susan Shen-Schwarz

Standards of birth weight in twin gestations stratified by placental chorionicity

Objective To establish fetal growth nomograms for twin gestations, categorized by placental chorionicity, and to compare them with those of published singleton and twin nomograms. Methods Computerized data files of live births of all twins delivered between January 1990 and October 1996 at Saint Peters Medical Center were used. Birth weight curves corresponding to the fifth, tenth, 50th, 90th, and 95th percentiles were derived separately for twins with monochorionic and dichorionic placentation. We generated the curves by applying the method of generalized estimating equations, after adjusting for the potential intracluster correlation due to twinning. The curves were then smoothed on the basis of nonparametric restricted cubic splines to derive (smoothed) birth weight percentiles. We then compared our twin birth weight nomogram to six previously published singleton and two twin nomograms published previously for predicting small for gestational age infants (defined as birth weight below the tenth percentile). Results Among 1302 twin fetuses, 272 (21%) were monochorionic. Twins from monochorionic gestations weighed, on average, 66.1 g (standard deviation 28.4 g, P = .02) less than twins from dichorionic gestations after correcting for gestational age. Twin curves based on parity (nulliparity versus multiparity) were not different from each other. Analyses indicate that all previously published singleton nomograms approximate twin growth reasonably well between 32 and 34 weeks, but they underestimate twin growth at earlier gestational ages (between 25 and 32 weeks) and overestimate twin growth beyond 34 weeks gestation. Similarly, a comparison of previously published twin nomograms with those of ours indicates that the growth standards in our population were similar to those in other published twin nomograms. Conclusion We recommend that future epidemiologic and clinical studies use twin nomograms to identify growthrestricted twin fetuses. Moreover, because fetal growth is influenced by placental chorionicity, we recommend that fetal growth assessment in twin gestations consider placental chorionicity, whenever the information is available.

Clinical Chorioamnionitis and Histologic Placental Inflammation

OBJECTIVEnTo estimate the rate of histologic chorioamnionitis in the presence of diagnosed clinical chorioamnionitis and determine whether clinical markers of maternal and neonatal infection are associated with histologic chorioamnionitis.nnnMETHODSnWe identified singleton pregnancies from 1996 in which discharge diagnoses included clinical chorioamnionitis and reviewed maternal and neonatal records for clinical evidence of chorioamnionitis and suspected or confirmed neonatal infections. Placentas were examined for acute histologic chorioamnionitis.nnnRESULTSnOne hundred thirty-nine pregnancies with the discharge diagnosis of maternal clinical chorioamnionitis were included. Eighty-six (61.9%) had the clinical diagnosis supported by histologic chorioamnionitis. Histologic chorioamnionitis was associated with an earlier gestational age at delivery (35.7+/-6.5 weeks versus 38.6+/-2.9 weeks, P = .002), lower epidural usage (72.1% versus 92.5%, P = .004), less internal monitoring (47.7% versus 75.5%, P = .001), and possible neonatal sepsis (60.5% versus 35.8%, P = .005). For 19 of 71 (26.8%) infants with possible neonatal sepsis, placentas did not show histologic chorioamnionitis.nnnCONCLUSIONnClinical chorioamnionitis and possible neonatal infection were not supported by histologic evidence for infection in 38.1% and 26.8% of cases, respectively, suggesting other noninflammatory causes of signs and symptoms.

Umbilical vein interleukin 6 and tumor necrosis factor alpha plasma concentrations in the very preterm infant

Objective. To examine the relationship between umbilical vein plasma concentrations of interleukin 6 (IL‐6) and tumor necrosis factor (TNF)‐alpha and early neonatal sepsis in the very preterm infant, and the histopathologic findings of chorioamnionitis in the placentas from these pregnancies. Methods. A prospective study was conducted in 43 very preterm, singleton infants delivered at or before 32 weeks of gestation. IL‐6 and TNF‐alpha were measured by enzyme‐linked immunoassay. Placentas from these pregnancies were histologically examined for the presence of chorioamnionitis. Infants were prospectively classified as confirmed sepsis group, clinical sepsis group or control group. IL‐6 and TNF‐alpha plasma concentrations were not normally distributed, so they were transformed to their natural log values for statistical analysis. Results. The enrolled infants had a mean gestational age of 27.2 ± 2.7 weeks and a mean birth weight of 956 ± 325 g. Three (7%) infants had confirmed sepsis, 18 (42%) were in the clinical sepsis group and 22 (51%) were in the control group. IL‐6 concentrations but not TNF‐alpha were significantly higher (P < 0.05) in the confirmed (8.9 ± 1.7) and clinical sepsis (5.5 ± 2.4) groups in comparison with the control group (2.1 ± 1.6). We examined 42 placentas. Twenty‐three (55%) had no evidence of chorioamnionitis, 1 (2%) had mild grade, 8 (19%) had a moderate grade and 10 (24%) had a severe grade of chorioamnionitis. IL‐6 was significantly elevated in the moderate (5.9 ± 1.6 vs. 1.9 ± 1.6) and severe grade (7.2 ± 2.3 vs. 1.9 ± 1.6) of chorioamnionitis, in the presence of acute deciduitis (6.0 ± 2.7 vs. 2.1 ± 1.8), chorionic vasculitis (6.8 ± 2.1 vs. 2.2 ± 1.9) and funisitis (7.3 ± 1.9 vs. 2.7 ± 2.3) (P < 0.05) TNF‐alpha plasma concentrations were not significantly different. Conclusion. An elevated umbilical vein IL‐6 concentration is a good indicator of sepsis syndrome in the very preterm infant and also correlates with histologic chorioamnionitis in these pregnancies.

Neonatal morbidity and placental pathology.

Objective: To investigate the association between gestational age, placental pathology and outcome among preterm births.Methods: Medical records and placental pathology results of 165 preterm infants (gestational age ≤34 weeks) were used to analyze the development of intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP), patent ductus arteriosus (PDA) and sepsis, in association with placental findings in the gestational age categories of 22–27 (n=71) and 28–33 (n=93) weeks.Results: Significant differences were found in placental findings based on gestational age and neonatal morbidity. Lower gestational age was associated with increased infection-related lesions such as chorionic vasculitis (47.9%, P<0.001) and acute chorioamnionitis (67.6%, P<0.001). Placental lesions reflecting disturbances of fetal-placental blood flow (infarction, chorionic plate thrombi and basal perivillous fibrin) were predominantly seen in the 28–33 week gestational age category (P<0.05–0.01). Despite the high prevalence of chorioamnionitis (38.8%), no significant association was found between this lesion and the tested preterm morbidity after controlling for gestational age. Only, villous edema and chorionic vasculitis were identified as independent predictors for the development of IVH (49.2%, ORA 2.57, 95% CI 1.01, 6.58 and 39.3%, ORA 1.95, 95% CI 1.01, 4.21, respectively).Conclusion: Villous edema and chorionic vasculitis are significant risk factors for the development of the IVH among neonates born at gestational age ≤34 weeks.

The relationship between placental histology and cervical ultrasonography in women at risk for pregnancy loss and spontaneous preterm birth

OBJECTIVEnOur objective was to determine whether there were any differences in the placental lesions of high-risk patients with versus without ultrasonographic evidence of cervical shortening between 15 and 24 weeks gestation.nnnSTUDY DESIGNnWomen who were at risk for pregnancy loss and spontaneous preterm birth were followed by serial transvaginal cervical ultrasonography with transfundal pressure between 15 and 24 weeks gestation. Two groups of women were identified: those in whom progressive cervical shortening developed to below 2 cm, either spontaneously or induced by transfundal pressure, and those in whom it did not. A perinatal pathologist who was blinded to the pregnancy outcome retrospectively examined placental histologic slides. The histologic placental lesions were categorized as acute or chronic inflammatory lesions, decidual vascular lesions, and coagulation-related lesions.nnnRESULTSnThere were 278 women who were followed during the study. Placentas were submitted for histologic examination in 189 cases (125 singleton, 45 twin, and 19 triplet gestations). There were 72 pregnancies with and 117 pregnancies without an ultrasonographic diagnosis of cervical shortening, respectively. Overall, there were significantly more acute inflammatory lesions in patients in whom cervical shortening developed, as determined by ultrasonographic examination. However, there were significantly more decidual vascular lesions in women in whom cervical shortening did not develop. When we examined the distribution of the placental histologic lesions in the 64 cases of multiple gestations, the only significant finding was again a greater frequency of acute inflammatory lesions in patients in whom cervical shortening developed. There was no difference in the distribution of the placental histologic lesion categories among women treated with bed rest versus cervical cerclage because of the ultrasound diagnosis of cervical shortening.nnnCONCLUSIONnAcute inflammatory lesions of the placenta were more frequent in patients with second-trimester cervical shortening. These findings support that patients with cervical shortening in the second trimester are prone to acute placental inflammation.

Value of a complete sonographic survey in detecting fetal abnormalities: correlation with perinatal autopsy.

Objective. To determine the sensitivity of using a complete anatomic sonographic survey in detecting fetal abnormalities via correlation with perinatal autopsy results. Methods. All perinatal autopsies (1994–2001) with positive findings for at least 1 fetal abnormality and performed by a single perinatal pathologist at our institution were retrospectively reviewed. From these cases, singleton fetuses who received prenatal sonography solely in our unit were identified. The sensitivity of sonography in detecting anomalous fetuses as well as fetal abnormalities and abnormalities by organ system was determined. Abnormalities were classified as major or minor. In addition, findings from sonography and autopsy were compared, and their correlation was assigned to 1 of 3 categories. Results. Of 88 fetuses identified, 85 had 1 or more abnormal structural sonographic findings (sensitivity for fetuses with anomalies, 97%). A total of 372 separate abnormalities were found on autopsy; of the 299 major and 73 minor abnormalities, prenatal sonography showed 224 (75%) and 13 (18%), respectively. There was either complete agreement or only minor differences between sonographic and autopsy findings in 57 (65%) of 88. The sensitivity of sonography in identifying abnormalities was greater than 70% in these systems: central nervous system, cardiac system, urinary system, extremities, genitalia, ribs, and hydrops. Conclusions. In experienced hands, sonography has 97% sensitivity in detecting anomalous fetuses when compared with perinatal autopsy results. Although the sensitivity of sonography in detecting major fetal abnormalities is 75%, the sensitivity for minor abnormalities is poor, even when using a complete anatomic sonographic survey. Although it has limitations, this type of survey is invaluable for both patients and physicians in diagnosing fetal abnormalities.

Prenatal Sonographic Appearance of Hemorrhagic Cerebellar Infarction

To date, the prenatal diagnosis of cerebellar hemorrhage has been limited to isolated case reports, which have demonstrated either a hyperechoic cerebellar hemisphere or a hyperechoic mass within the cerebellum in near‐term fetuses. We demonstrate the ultrasonographic findings of intracerebellar hemorrhagic infarction in a fetus at approximately 21 weeks gestation. In contrast to previous case reports, the hemorrhagic infarcts seen in our case were hypoechoic.

A clinicohistopathologic comparison between HELLP syndrome and severe preeclampsia.

OBJECTIVEnTo determine whether differences in the clinical entities of HELLP syndrome and severe preeclampsia are associated with different placental lesions.nnnSTUDY DESIGNnThis was a case control study of singleton pregnancies with HELLP syndrome or severe preeclampsia. Archived pathology slides were retrieved and reviewed. Clinical and histopathological features were compared between the two groups.nnnRESULTSnThere were 31 women with HELLP syndrome and 56 with severe preeclampsia. HELLP syndrome was associated with epigastric pain and higher levels of LDH, bilirubin, liver enzymes and fibrin degradation products. Hemoglobin, hematocrit and platelet counts were lower. Abruption lesions of the placenta were less common with HELLP syndrome (Odds Ratio 0.1 95% Confidence Interval 0.01,0.8). None of the other 22 placental features examined were different between the two conditions.nnnCONCLUSIONnThe significant overlap between HELLP syndrome and severe preeclampsia for both clinical and placental features suggests that the two conditions represent a spectrum of essentially the same pathophysiologic process.