227 research outputs found
Association of Cervical Effacement With the Rate of Cervical Change in Labor Among Nulliparous Women
OBJECTIVE: To assess the association of cervical effacement with the rate of intrapartum cervical change among nulliparous women.
METHODS: We conducted a secondary analysis of a prospective trial of intrapartum fetal pulse oximetry. For women who had vaginal deliveries, interval-censored regression was used to estimate the time to dilate at 1-cm intervals. For each given centimeter of progressive cervical dilation, women were divided into those who had achieved 100% cervical effacement and those who had not. The analysis was performed separately for women in spontaneous labor and those who were given oxytocin.
RESULTS: A total of 3,902 women were included in this analysis, 1,466 (38%) who underwent labor induction, 1,948 (50%) who underwent labor augmentation (combined for the analysis), and 488 (13%) who labored spontaneously. For women in spontaneous labor, the time to dilate 1 cm was shorter for those who were 100% effaced starting at 4 cm of cervical dilation (P=.01 to <.001). For women who received oxytocin, the time to dilate 1 cm was shorter for those who were 100% effaced throughout labor (P<.001).
CONCLUSION: The rate of cervical dilation among nulliparous women is associated with not only the degree of cervical dilation, but also with cervical effacement.
CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00098709
ADI splitting schemes for a fourth-order nonlinear partial differential equation from image processing
We present directional operator splitting schemes for the numerical solution of a fourth-order, nonlinear partial differential evolution equation which arises in image processing. This equation constitutes the H−1-gradient flow of the total variation and represents a prototype of higher-order equations of similar type which are popular in imaging for denoising, deblurring and inpainting problems. The efficient numerical solution of this equation is very challenging due to the stiffness of most numerical schemes. We show that the combination of directional splitting schemes with implicit time-stepping provides a stable and computationally cheap numerical realisation of the equation
On the fourth-order accurate compact ADI scheme for solving the unsteady Nonlinear Coupled Burgers' Equations
The two-dimensional unsteady coupled Burgers' equations with moderate to
severe gradients, are solved numerically using higher-order accurate finite
difference schemes; namely the fourth-order accurate compact ADI scheme, and
the fourth-order accurate Du Fort Frankel scheme. The question of numerical
stability and convergence are presented. Comparisons are made between the
present schemes in terms of accuracy and computational efficiency for solving
problems with severe internal and boundary gradients. The present study shows
that the fourth-order compact ADI scheme is stable and efficient
Haptoglobin Phenotype, Preeclampsia Risk and the Efficacy of Vitamin C and E Supplementation to Prevent Preeclampsia in a Racially Diverse Population
Haptoglobin's (Hp) antioxidant and pro-angiogenic properties differ between the 1-1, 2-1, and 2-2 phenotypes. Hp phenotype affects cardiovascular disease risk and treatment response to antioxidant vitamins in some non-pregnant populations. We previously demonstrated that preeclampsia risk was doubled in white Hp 2-1 women, compared to Hp 1-1 women. Our objectives were to determine whether we could reproduce this finding in a larger cohort, and to determine whether Hp phenotype influences lack of efficacy of antioxidant vitamins in preventing preeclampsia and serious complications of pregnancy-associated hypertension (PAH). This is a secondary analysis of a randomized controlled trial in which 10,154 low-risk women received daily vitamin C and E, or placebo, from 9-16 weeks gestation until delivery. Hp phenotype was determined in the study prediction cohort (n = 2,393) and a case-control cohort (703 cases, 1,406 controls). The primary outcome was severe PAH, or mild or severe PAH with elevated liver enzymes, elevated serum creatinine, thrombocytopenia, eclampsia, fetal growth restriction, medically indicated preterm birth or perinatal death. Preeclampsia was a secondary outcome. Odds ratios were estimated by logistic regression. Sampling weights were used to reduce bias from an overrepresentation of women with preeclampsia or the primary outcome. There was no relationship between Hp phenotype and the primary outcome or preeclampsia in Hispanic, white/other or black women. Vitamin supplementation did not reduce the risk of the primary outcome or preeclampsia in women of any phenotype. Supplementation increased preeclampsia risk (odds ratio 3.30; 95% confidence interval 1.61-6.82, p<0.01) in Hispanic Hp 2-2 women. Hp phenotype does not influence preeclampsia risk, or identify a subset of women who may benefit from vitamin C and E supplementation to prevent preeclampsia
Fish Consumption, Erythrocyte Fatty Acids, and Preterm Birth
To estimate the association between fish consumption and erythrocyte omega-3 long chain polyunsaturated fatty acids and preterm birth in a high-risk cohort
Maternal 25-Hydroxyvitamin D and Preterm Birth in Twin Gestations
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
Flux-splitting schemes for parabolic problems
To solve numerically boundary value problems for parabolic equations with
mixed derivatives, the construction of difference schemes with prescribed
quality faces essential difficulties. In parabolic problems, some possibilities
are associated with the transition to a new formulation of the problem, where
the fluxes (derivatives with respect to a spatial direction) are treated as
unknown quantities. In this case, the original problem is rewritten in the form
of a boundary value problem for the system of equations in the fluxes. This
work deals with studying schemes with weights for parabolic equations written
in the flux coordinates. Unconditionally stable flux locally one-dimensional
schemes of the first and second order of approximation in time are constructed
for parabolic equations without mixed derivatives. A peculiarity of the system
of equations written in flux variables for equations with mixed derivatives is
that there do exist coupled terms with time derivatives
Second-stage labor duration in nulliparous women: relationship to maternal and perinatal outcomes
To assess maternal and perinatal outcomes as a function of second stage labor duration
Accuracy of Sonographic Chorionicity Classification in Twin Gestations
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
Change in Mononuclear Leukocyte Responsiveness in Midpregnancy and Subsequent Preterm Birth
To estimate the associations of change in immune response with preterm delivery, omega-3 supplementation, and fish diet
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