Accuracy of sonographic chorionicity classification in twin gestations.

Objectives: To evaluate the accuracy of sonographic classification of chorionicity in a large cohort of twins and investigate which factors may be associated with sonographic accuracy.

Methods: We conducted a secondary analysis of a randomized trial of preterm birth prevention in twins. Sonographic classification of chorionicity was compared with pathologic examination of the placenta.

Maternal 25-hydroxyvitamin d and preterm birth in twin gestations.

Objective: To assess whether there was an independent association between maternal 25-hydroxyvitamin D concentrations at 24-28 weeks of gestation and preterm birth in a multicenter U.S. cohort of twin pregnancies.

Impact of smoking during pregnancy on functional coagulation testing.

Compounds that are systemically absorbed during the course of cigarette smoking, and their metabolites, affect the coagulation system and cause endothelial dysfunction, dyslipidemia, and platelet activation leading to a prothrombotic state. In addition, smoking increases the activity of fibrinogen, homocysteine, and C-reactive protein. We hypothesize that smoking may affect functional coagulation testing during pregnancy.

Second trimester cervical length and risk of preterm birth in women with twin gestations treated with 17-α hydroxyprogesterone caproate.

Objective: To compare rates of preterm birth before 35 weeks based on cervical length measurement at 16-20 weeks in women with twin gestations who received 17-α hydroxyprogesterone caproate (17OHPC) or placebo.

Methods: This is a secondary analysis of a randomised, double-blind, placebo-controlled trial of twin gestations exposed to 17OHPC or placebo. Baseline transvaginal ultrasound evaluation of cervical length was performed prior to treatment assignment at 16-20 weeks.

Family history of venous thromboembolism and identifying factor V Leiden carriers during pregnancy.

Objective: To estimate whether there is a correlation between family history of venous thromboembolism and factor V Leiden mutation carriage in gravid women without a personal history of venous thromboembolism.

Methods: This is a secondary analysis of a prospective observational study of the frequency of pregnancy-related thromboembolic events among carriers of the factor V Leiden mutation. Family history of venous thromboembolism in either first- or second-degree relatives was self-reported.

Neonatal outcomes in twin pregnancies delivered moderately preterm, late preterm, and term.

We compared neonatal outcomes in twin pregnancies following moderately preterm birth (MPTB), late preterm birth (LPTB), and term birth. A secondary analysis of a multicenter, randomized controlled trial of multiple gestations was conducted. MPTB was defined as delivery between 32 (0)/(7) and 33 (6)/(7) weeks and LPTB between 34 (0)/(7) and 36 (6)/(7) weeks.

Avascular villi, increased syncytial knots, and hypervascular villi are associated with pregnancies complicated by factor V Leiden mutation.

There is controversy about whether pathologic abnormalities are associated with pregnancies complicated by factor V Leiden (FVL) mutation. The purpose of this study was to evaluate 105 placentas delivered to mothers heterozygous for FVL mutation to determine if there are pathologic changes suggestive of hypoxia or thrombosis, which correlate with mutation status. We examined placentas obtained as part of a prospective study of 5188 pregnancies analyzed for the presence of FVL mutation in either the mother or the infant.

The effect of active and passive household cigarette smoke exposure on pregnant women with asthma.

Background: The article was designed to estimate the effect of active and passive household cigarette smoke exposure on asthma severity and obstetric and neonatal outcomes in pregnant women with asthma.

Methods: We used a secondary observational analysis of pregnant women with mild and moderate-severe asthma enrolled in a prospective observational cohort study of asthma in pregnancy and a randomized clinical trial (RCT) comparing inhaled beclomethasone and oral theophylline. A baseline questionnaire detailing smoking history and passive household smoke exposure was given to each patient.

The effect of 17-alpha hydroxyprogesterone caproate on the risk of gestational diabetes in singleton or twin pregnancies.

Objective: To compare the rates of gestational diabetes among women who received serial doses of 17-alpha hydroxyprogesterone caproate vs placebo.

Study Design: Secondary analysis of 2 double-blind randomized placebo-controlled trials of 17-alpha hydroxyprogesterone caproate given to women at risk for preterm delivery. The incidence of gestational diabetes was compared between women who received 17-alpha hydroxyprogesterone caproate or placebo.

Prevention of preterm birth in triplets using 17 alpha-hydroxyprogesterone caproate: a randomized controlled trial.

Objective: To assess whether 17 alpha-hydroxyprogesterone caproate reduces the rate of preterm birth in women carrying triplets.

Methods: We performed this randomized, double-blinded, placebo-controlled trial in 14 centers. Healthy women with triplets were randomly assigned to weekly intramuscular injections of either 250 mg of 17 alpha-hydroxyprogesterone caproate or matching placebo, starting at 16-20 weeks and ending at delivery or 35 weeks of gestation.

Sample bias among women with retained DNA samples for future genetic studies.

Objective: To evaluate whether women who agree to future use of their biologic specimens for genetic studies reflect the larger study population from which they are derived.

Methods: Women were questioned as to the future disposition of their maternal and fetal DNA samples upon enrollment in a multicenter, observational study originally designed to identify factor V Leiden mutation carriers and prospectively ascertain the estimated rate of pregnancy-related venous thromboembolism and adverse pregnancy outcome. Univariate and multivariate analyses was carried out on the 5,003 of 5,188 enrolled women who indicated their desire regarding future disposition of their DNA samples.

Association of obesity with pulmonary and nonpulmonary complications of pregnancy in asthmatic women.

Objective: To evaluate whether maternal obesity is associated with pulmonary and nonpulmonary pregnancy complications in asthmatic women.

Methods: This is a secondary analysis of the prospective cohort Asthma During Pregnancy Study. Asthma patients were classified as having either mild or moderate to severe disease at the beginning of the study.

Spirometry is related to perinatal outcomes in pregnant women with asthma.

Objective: The purpose of this study was to test the hypothesis that maternal asthma symptoms and pulmonary function are related to adverse perinatal outcomes.

Study Design: Asthmatic patients were recruited from the 16 centers of the Maternal Fetal Medicine Units. Forced expiratory volume in 1 second was obtained at enrollment and at monthly study visits, and the frequency of asthma symptoms was assessed from enrollment to delivery.

The relationship of asthma medication use to perinatal outcomes.

Background: Maternal asthma has been reported to increase the risk of preeclampsia, preterm deliveries, and lower-birth-weight infants, but the mechanisms of this effect are not defined.

Objective: We sought to evaluate the relationship between the use of contemporary asthma medications and adverse perinatal outcomes.

Methods: Asthmatic patients were recruited from the 16 centers of the National Institute of Child Health and Human Development Maternal Fetal Medicine Units Network from December 1994 through February 2000.

Asthma during pregnancy.

Objective: To determine neonatal and maternal outcomes stratified by asthma severity during pregnancy by using the 1993 National Asthma Education Program Working Group on Asthma and Pregnancy definitions of asthma severity. The primary hypothesis was that moderate or severe asthmatics would have an increased incidence of delivery at <32 weeks of gestation compared with nonasthmatic controls.

Methods: This was a multicenter, prospective, observational cohort study conducted over 4 years at 16 university hospital centers.

Risk factors and outcome of varicella-zoster virus pneumonia in pregnant women.

To determine the factors associated with an increased risk of developing varicella-zoster virus (VZV) pneumonia during pregnancy, a case-control analysis was done in which 18 pregnant women with VZV pneumonia were compared with 72 matched control subjects. VZV infection was identified clinically, and VZV pneumonia was diagnosed by dyspnea and findings on chest radiographs. Of 347 pregnant women with VZV infection, 18 (5.