von Willebrand factor multimeric levels and patterns in patients with severe preeclampsia

The clinical manifestations of severe preeclampsia and thrombotic thrombocytopenic purpura are similar. Patients with thrombotic thrombocytopenic purpura have been demonstrated to have larger than usual von Willebrand factor multimers. Serial serum samples were taken from patients with severe preeclampsia, all with platelet counts less than 50,000. Von Willebrand factor multimeric patterns were normal in all the patients except one, who later proved to have chronic relapsing thrombotic thrombocytopenic purpura. All patients had elevated levels of von Willebrand factor. Although the clinical presentations of thrombotic thrombocytopenic purpura and severe preeclampsia with thrombocytopenia have many similarities, the underlying pathophysiology of each disorder appears to be different.     

Cervical dimensions and risk of preterm birth: a prospective cohort study

OBJECTIVE: To examine the relation between cervical dilatation and length and the risk of spontaneous preterm birth, including its subtypes preterm labor and preterm premature rupture of membranes (PROM). METHODS: Cervical dimensions assessed by clinical examination were recorded prospectively at 24-29 weeks' gestation in 871 subjects with singleton pregnancies who were followed to delivery. Relative risks (RRs) of preterm birth, preterm labor, and preterm PROM were calculated for clinically distinguishable categories of cervical dilatation and length and for cervical score (length minus dilatation). Regression analysis was used to adjust for confounding. Time to delivery from baseline examination was summarized using survival analysis. RESULTS: There were 73 spontaneous preterm births (8.3%), 46 preterm labors and 27 cases of preterm PROM. All cervical measurements were associated with increased risks of preterm birth, with increasing abnormality more strongly predictive of risk. The adjusted RR for preterm birth with dilatation of at least 0.5 cm was 2.9 (95% confidence interval [CI] 1.2, 7.3); for length of 1.5 cm or less, the RR was 2.1 (95% CI 1.0, 4.5), and for cervical score less than 2.0, the RR was 2.8 (95% CI 1.4, 5.6). The association with cervical measurements was stronger for preterm PROM than for preterm labor, although precision was limited. These measurements had high specificity (93-99%) and low sensitivity (8-20%) for predicting preterm birth. CONCLUSION: In asymptomatic women at 24-29 weeks' gestation, greater cervical dilatation and shorter length were associated with increased risk of spontaneous preterm delivery, particularly preterm PROM.     

Stress and growth response of juvenile crayfish to rhythmic and arrhythmic temperature fluctuations

Growth, molting, and survival of juvenile crayfish,Procambarus a. acutus, were recorded under constant and variable temperature regimes. Crayfish were exposed to four rhythmic regimes: Constant temperatures of 10, 17.5, and 25°C, and a daily square-wave cyclic regime of 10 to 25°C (X = 17.5°C); and to one arrhythmic temperature regime: A daily square-wave acyclic regime varying within 10 to 25°C limits (X=17.8°C). The direction and magnitude of temperature changes in the acyclic variable temperature chamber were selected randomly to make temperature changes unpredictable within the specified range.Rhythmic and arrhythmic temperature regimes had different effects on growth, molting, and survival of crayfish. Growth under both variable regimes was similar to growth at a constant temperature (17.5°C) equal to the mean of the variable regimes. Molt frequency was directly related to temperature. Growth rates approximately paralleled changes in the adjusted molt rate for each regime. Mortality under variable regimes approximated mortality at a constant temperature (25°C) equal to the upper extreme of the variable regimes. The cyclic regime tended to be less optimal for growth and survival than the acyclic regime, possibly because of differences in average daily temperature fluctuations and relative time spent at temperature extremes.     

Predictors of vaginal bleeding during the first two trimesters of pregnancy

This study evaluates maternal age, race, cigarette smoking, prior spontaneous abortion, prior induced abortion, and prior preterm birth in relation to vaginal bleeding during the first two trimesters of pregnancy. Information on vaginal bleeding and predictors came from the Pregnancy, Infection, and Nutrition Study, which enrolled 2806 pregnant women at 24-29 weeks' gestation during 1995-2000 in central North Carolina, USA. Generalised estimating equations were applied to take into account repeated episodes of vaginal bleeding during pregnancy. Women with advanced maternal age and passive smoking exposure were more likely to experience more intense vaginal bleeding during pregnancy, as were women with prior preterm birth. More intense bleeding was also more likely to be reported among women with multiple prior spontaneous abortions or multiple prior induced abortions, but not among women with a single prior spontaneous or induced abortion. The combination of prior spontaneous and induced abortion showed a dose-response association with the occurrence of vaginal bleeding during pregnancy.     

Serum alphafetoprotein in multiple pregnancy.

The concentration of alpha-fetoprotein (AFP) was determined in paired umbilical cord and maternal sera in 42 multiple pregnancies. No concentrations above 1.4 microgram/ml were detected in maternal sera. Although there was a significant inverse correlation between cord AFP levels and gestational age, large intrapair discrepancies were common and these were not influenced by birth order, weight, or malformations. Intrapair AFP ratios were higher amongst dizygotic (DZ) than monozygotic (MZ) twins. In a pair discordant for neonatal hepatitis, the affected twin had the lower level of AFP in cord serum, but AFP was still detectable at 55 days.     

Somali refugee women speak out about their needs for care during pregnancy and delivery

More than half of all Somali refugees in the United States live in Minnesota. To obtain information to develop culturally sensitive health education materials, we conducted two focus groups with 14 Somali women who had each given birth to one child in Minnesota. Overall, women thought that their childbirth experience was positive. They also reported racial stereotyping, apprehension of cesarean births, and concern about the competence of medical interpreters. Women wanted more information about events in the delivery room, pain medications, prenatal visits, interpreters, and roles of hospital staff. The most desirable educational formats were a videotape, audiotapes, printed materials, and birth center tours. To increase their attendance at prenatal appointments, participants said they needed reminder telephone calls, transportation, and childcare.     

Twins and triplets: the effect of plurality and growth on neonatal outcome compared with singleton infants

OBJECTIVE: Information on outcome by gestational age from large numbers of twins and triplets is limited and is important for counseling and decision-making in obstetric practice. We reviewed one of the largest available neonatal databases to describe mortality and morbidity rates and growth in newborn infants from multiple gestations and compared these data with data for singletons. STUDY DESIGN: Data from a large prospectively recorded neonatal database that incorporated neonatal records from January 1997 to July 2002 were reviewed. We evaluated birth weight and neonatal mortality and morbidity rates that affected long-term outcome for each week of gestational age from 23 to 35 weeks of gestation for all nonanomolous inborn twins and triplets who were admitted to the neonatal intensive care unit and compared these data to all singletons who met similar criteria during the same time period. RESULTS: There were 12,302 twin and 2155 triplet births that met the entry criteria. The data for these newborn infants were compared with 36,931 singletons. Average birth weights at each gestational week were similar for all gestational ages until 29 weeks of gestation for triplets and 32 weeks of gestation for twins. After these gestational ages, the entire difference between twins and singletons was due to the weight of the smaller twin; the larger twins' mean weights were similar to singletons at all weeks that were studied. Birth order at each week also did not affect neonatal mortality rates, even when corrected for route of delivery and antenatal steroids. Neonatal morbidities associated with adverse long-term outcomes (intraventricular hemorrhage, retinopathy of prematurity, necrotizing enterocolitis) were also not different between multiple infants and singletons. Intrauterine growth restriction (IUGR) was associated with increased mortality rates at all gestational ages, but in the absences of IUGR, discordance was not. CONCLUSION: Data on a large number of twins and triplets provide reassurance that neonatal outcome at all viable premature weeks of gestation are similar to singletons. Intrauterine growth restriction and prematurity are therefore the principal issues that drive neonatal mortality and morbidity rates in multiple gestations. These data are important for obstetric decision-making and patient counseling.