Faculty Bibliography

OBJECTIVE: The purpose of this study was to define normal second-trimester cervical length (CL) measurements and to estimate the association between second-trimester CL and spontaneous preterm birth (SPTB) in twin pregnancies. METHODS: A retrospective cohort of 309 asymptomatic patients with twin pregnancies who had routine outpatient CL assessment in the second trimester was studied. We looked at the gestational age periods of 16 to 17 6/7, 18 to 19 6/7, 20 to 21 6/7, and 22 to 23 6/7 weeks. We estimated the association between the CL measurement during each period and SPTB. A short CL was defined both as a CL at or below the 10th percentile for gestational age and 25 mm or less. We also performed regression analyses controlling for a number of clinically important factors: maternal age, chorionicity, in vitro fertilization, multifetal reduction, prior term births, prior preterm births, prepregnancy body mass index, and cerclage. RESULTS: The CL measurement at 16 to 17 6/7 weeks was not associated with gestational age at delivery or SPTB. At 18 to 19 6/7 and 20 to 21 6/7 weeks, the CL measurement was not significantly associated with gestational age at delivery or SPTB before 28 and 32 weeks. There was an association with SPTB before 35 weeks. At 22 to 23 6/7 weeks, the CL measurement had a significant association with gestational age at delivery and SPTB before 28, 32, and 35 weeks (P < .05). A short CL at 22 to 23 6/7 weeks was significantly associated with SPTB before 32 and 35 weeks (P < .05). CONCLUSIONS: In second-trimester twin pregnancies, the strongest association between CL and SPTB is at 22 to 23 6/7 weeks.

OBJECTIVE: To estimate whether the weight gain recommendations for twin pregnancies in the 2009 Institute of Medicine (IOM) guidelines are associated with improved perinatal outcomes. METHODS: A cohort of 297 twin pregnancies was identified from a single practice with measured prepregnancy body mass index (BMI) and weight gain during pregnancy. Recommended IOM guidelines were applied to our cohort based on prepregnancy BMI categories (normal weight, overweight, obese). Pregnancy outcomes were compared between patients whose weight gain met or exceeded the IOM recommendations and patients who did not meet these recommendations. RESULTS: Patients with normal prepregnancy BMIs whose weight gain met the IOM recommendations had significantly improved outcomes compared with patients who did not meet the IOM recommendations. They were less likely to have preterm birth before 32 weeks (5.0% compared with 13.8%) and spontaneous preterm birth before 32 weeks (3.4% compared with 11.5%). They also delivered significantly larger neontates (larger twin birth weight 2,582.1+/-493.4 g compared with 2,370.3+/-586.0 g; smaller twin birth weight 2,277.0+/-512.1 g compared with 2,109.3+/-560.9 g) and were significantly more likely to have both neonates weigh more than 2,500 g (38.8% compared with 22.5%) and more than 1,000 g (97.5% compared with 91.2%) and were less likely to deliver any twin with a birth weight lower than the fifth percentile for gestational age (21.5% compared with 35.0%). CONCLUSION: In women with twin pregnancies and normal starting BMIs, weight gain during pregnancy is significantly associated with improved outcomes, including a decreased risk of prematurity and larger birth weights. LEVEL OF EVIDENCE: II.

Omega-3 fatty acids are essential fatty acids that must be consumed in the diet. Adequate consumption of omega-3 fatty acids is vitally important during pregnancy as they are critical building blocks of fetal brain and retina. Omega-3 fatty acids may also play a role in determining the length of gestation and in preventing perinatal depression. The most biologically active forms of omega-3 fatty acids are docosahexaenoic acid and eicosapentaenoic acid, which are primarily derived from marine sources such as seafood and algae. Recent surveys, however, indicate that pregnant women in the United States and in other countries eat little fish and therefore do not consume enough omega-3 fatty acids, primarily due to concern about the adverse effects of mercury and other contaminants on the developing fetus. This review discusses the benefits of omega-3 fatty acid consumption during pregnancy and provides guidelines for obstetricians advising patients.

Continuous observations, such as reaction and run times, and binary observations, such as correct/incorrect responses, are recorded routinely in behavioral learning experiments. Although both types of performance measures are often recorded simultaneously, the two have not been used in combination to evaluate learning. We present a state-space model of learning in which the observation process has simultaneously recorded continuous and binary measures of performance. We use these performance measures simultaneously to estimate the model parameters and the unobserved cognitive state process by maximum likelihood using an approximate expectation maximization (EM) algorithm. We introduce the concept of a reaction-time curve and reformulate our previous definitions of the learning curve, the ideal observer curve, the learning trial and between-trial comparisons of performance in terms of the new model. We illustrate the properties of the new model in an analysis of a simulated learning experiment. In the simulated data analysis, simultaneous use of the two measures of performance provided more credible and accurate estimates of the learning than either measure analyzed separately. We also analyze two actual learning experiments in which the performance of rats and of monkeys was tracked across trials by simultaneously recorded reaction and run times and the correct and incorrect responses. In the analysis of the actual experiments, our algorithm gave a straightforward, efficient way to characterize learning by combining continuous and binary measures of performance. This analysis paradigm has implications for characterizing learning and for the more general problem of combining different data types to characterize the properties of a neural system.

OBJECTIVE: The objective of the study was to determine the relationship between fetal fibronectin (fFN) testing prior to ultrasound-indicated cerclage and obstetric outcome. STUDY DESIGN: Singleton pregnancies between 18 and 24 weeks' gestation with an ultrasound-diagnosed short cervix (< 25 mm) and funneling (> 25%) of the chorioamniotic membranes into the endocervical canal were analyzed. The fFN testing was performed and patients were randomized to cerclage or no-cerclage. Groups were stratified by fFN result. Cerclage patients were compared with no-cerclage patients. The primary outcome was delivery prior to 35 weeks' gestation. RESULTS: Spontaneous preterm birth prior to 35 weeks' gestation occurred in 15 (44.1%) fFN-positive-cerclage patients and 16 (55.2%) fFN-positive no-cerclage patients (P = .45). Similarly, it occurred in 16 (17.8%) fFN-negative cerclage patients and 11 (17%) fFN-no-cerclage patients (P = .99). CONCLUSION: fFN did not identify optimal candidates for cerclage. However, fFN testing before an ultrasound-indicated cerclage aids in counseling patients, anticipating the outcome of pregnancies complicated by cervical shortening

Continuous (reaction times) and binary (correct/ incorrect responses) measures of performance are routinely recorded to track the dynamics of a subject's cognitive state during a learning experiment. Current analyses of experimental data from learning studies do not consider the two performance measures together and do not use the concept of the cognitive state formally to design statistical methods. We develop a mixed filter algorithm to estimate the cognitive state modeled as a linear stochastic dynamical system from simultaneously recorded continuous and binary measures of performance. The mixed filter algorithm has the Kalman filter and the more recently developed recursive filtering algorithm for binary processes as special cases. In the analysis of a simulated learning experiment the mixed filter algorithm provided a more accurate and precise estimate of the cognitive state process than either the Kalman or binary filter alone. In the analysis of an actual learning experiment in which a monkey's performance was tracked by its series of reaction times, and correct and incorrect responses, the mixed filter gave a more complete description of the learning process than either the Kalman or binary filter. These results establish the feasibility of estimating cognitive state from simultaneously recorded continuous and binary performance measures and suggest a way to make practical use of concepts from learning theory in the design of statistical methods for the analysis of data from learning experiments.

BACKGROUND: Postpartum ovarian vein thrombosis is a rare diagnosis with a significant associated risk of pulmonary embolism. The mainstay of therapy consists of intravenous antibiotics and anticoagulation. CASE: A 30-year-old woman presented with fever and abdominal pain 3 days after cesarean section and was found to have an ovarian vein thrombosis on computed tomography. Given her history of cerebral arteriovenous malformation and the attendant risk for cerebral hemorrhage with the use of anticoagulation, she was successfully treated with a removable suprarenal inferior vena cava (IVC) filter and intravenous antibiotics. CONCLUSION: For patients who fail to respond to anticoagulation alone or in whom anticoagulation is contraindicated, placement of a retrievable suprarenal IVC filter is a viable treatment option in the setting of postpartum ovarian vein thrombosis

OBJECTIVE: Discussion of isolated ultrasound (US) markers for fetal aneuploidy can provoke significant patient anxiety. The objective of this study is to quantify maternal anxiety associated with the detection of these markers. METHODS: All patients undergoing routine second-trimester US examination for fetal anatomical survey over a one-year period were administered the State-Trait Anxiety Inventory (STAI) for Adults before and after the procedure. Women with isolated fetal markers for aneuploidy were notified of the findings but discouraged from pursuing amniocentesis. Rates of normal US examination, aneuploidy markers, anomalies, amniocentesis, and pregnancy outcomes were assessed across the ethnic groups. Pre- and post-ultrasound STAI surveys were scored and standardized with previously established norms. Student t-tests, Chi-square, and analysis of variance (ANOVA) were used where appropriate. RESULTS: Among the 798 patients tested, 57% were Hispanic, 30% were Asian, 6% were Black, and 7% were White. Maternal anxiety level was decreased in women after a normal US. The anxiety level increased with aneuploidy markers and was the highest with anomalies. Aneuploidy markers were more common among Hispanic and Asian fetuses, without any associated aneuploidy. Women with isolated aneuploidy markers underwent amniocentesis as often as women with advanced maternal age. CONCLUSION: The detection and communication of isolated aneuploidy markers is associated with increased maternal anxiety and unnecessary amniocentesis

OBJECTIVE: The objective of this study was to determine the effect of omega-3 fatty acids (eicosapentaenoic acid [EPA]; docosahexaenoic acid [DHA]) on prostaglandin production and prostanoid enzyme expression in cultured decidual cells exposed to interleukin-1beta (IL-1beta), a cytokine that plays a major role in inflammation. STUDY DESIGN: Decidua was obtained from human placentas of nonlaboring patients at term cesarean delivery (N = 6) and cultured by using standard cell culture techniques. Cells were preincubated in defined media with various concentrations of vehicle, DHA, or EPA for 1 hour. IL-1beta (10 ng/mL) was then added to the media, and experiments were terminated 12 hours after exposure to IL-1beta. Prostaglandin E2 (PGE2) and PGF2alpha concentrations in conditioned media were measured by enzyme-linked immunosorbent assay; cyclooxygenase-1 (COX-1), COX-2, microsomal prostaglandin E synthase (mPGES)-1, mPGES-2, and 15-hydroxy prostaglandin dehydrogenase (PGDH) expression were quantified by real-time polymerase chain reaction and immunoblotting. Groups were compared with the use of Student t test, with significance defined as P < .05. RESULTS: Preincubation with DHA decreased prostaglandin production by up to 80% when compared with controls. DHA decreased both mPGES-1 and -2 messenger RNA expression by approximately 50% (P = .02). Preincubation in DHA or EPA had no effect on COX-1, COX-2, and PGDH messenger RNA or protein expression. CONCLUSION: Under conditions simulating inflammation, supplementation with omega-3 fatty acids decreases PGE2 and PGF2alpha production in cultured decidual cells. The reduction in prostaglandin production was associated with a decreased expression of mPGES-1 and -2. These findings suggest a mechanism by which omega-3 fatty acid supplementation decreases the incidence of preterm birth in high-risk patients