The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jay D Iams - One of the best experts on this subject based on the ideXlab platform.
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a prospective masked observational study of Uterine Contraction frequency in twins
American Journal of Obstetrics and Gynecology, 2006Co-Authors: Roger B Newman, Steve N. Caritis, Jay D Iams, Anita F Das, Robert L Goldenberg, Paul J Meis, Atef H Moawad, Bahaeddine M Sibai, Menachem Miodovnik, Richard H PaulAbstract:Objective This study was undertaken to compare Uterine Contraction frequency in twins versus singletons and to determine if Contraction frequency can be an efficient predictor of spontaneous preterm birth in twin gestations. Study design Fifty-nine twin and 306 singleton gestations were enrolled between 22 and 24 weeks at 11 centers. Contraction frequency was recorded with a home Uterine activity monitor (HUAM) 2 or more times per day on 2 or more days per week until delivery or 36-6/7 weeks. Masked HUAM data were interpreted according to standard protocol. Repeated measures analyses were used to determine whether mean or maximum Uterine Contraction frequency per hour differed between singleton and twin gestations across gestational age, by time of day, and by delivery before 35 weeks or beyond. Uterine Contraction frequency was also evaluated by logistic regression and receiver operator characteristic (ROC) curves as tests to predict spontaneous preterm birth. Results There were 34,908 hours of HUAM data recorded by the 306 singleton gestations and 5,427 hours by the 59 women with twins. Uterine Contraction frequency was significantly greater in twins ( P = .002) compared with singletons, regardless of gestational age. Contraction frequency in twins increased significantly with gestational age and time of day (1600-0359 hours); but was not associated with spontaneous preterm birth. Maximum Uterine Contraction frequency was associated with preterm birth less than 35 weeks but only in the morning (am) recording (0400-1559) and at the 29- to 30-week gestational age interval. This relationship was modest (odds ratio 1-2) and not consistent across gestational age or between the am and afternoon/evening (pm) monitoring sessions. ROC analysis revealed no Contraction frequency that efficiently identified twins who delivered prematurely at any 2-week gestational age interval. Conclusion Mean Uterine Contraction frequency was significantly higher for twin gestations than singletons throughout the latter half of pregnancy and between 1600 and 0359 hours but was not higher among twins who delivered less than 35 weeks' gestation. Neither maximum am or pm Contraction frequency predicted spontaneous preterm birth less than 35 weeks' gestation in twin pregnancies.
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prediction and early detection of preterm labor
Obstetrics & Gynecology, 2003Co-Authors: Jay D IamsAbstract:Studies of cervical sonography, fetal fibronectin, and Uterine Contraction monitoring during pregnancy have improved our understanding of how preterm labor occurs, but their use in practice remains uncertain. This article reviews the use of these tests to improve the accuracy of diagnosis of preterm labor and to estimate the likelihood of preterm birth in women with historical risk factors. Because the clinical criteria for a diagnosis of preterm labor are inaccurate until labor is well established, over-diagnosis is common. A cervical length measurement of more than 30 mm or a negative fibronectin obtained from a patient with possible preterm labor can avoid over-diagnosis and unnecessary treatment. There is no role for routine use of either cervical sonography or fibronectin to screen pregnant women for preterm birth risk, but women thought to be at increased risk may be reassured by negative test results. Uterine Contraction monitoring has low sensitivity for detecting women at risk of preterm birth. Current use of cervical length and fetal fibronectin in pregnancy is limited to situations where a negative result can avoid unnecessary interventions.
Richard H Paul - One of the best experts on this subject based on the ideXlab platform.
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a prospective masked observational study of Uterine Contraction frequency in twins
American Journal of Obstetrics and Gynecology, 2006Co-Authors: Roger B Newman, Steve N. Caritis, Jay D Iams, Anita F Das, Robert L Goldenberg, Paul J Meis, Atef H Moawad, Bahaeddine M Sibai, Menachem Miodovnik, Richard H PaulAbstract:Objective This study was undertaken to compare Uterine Contraction frequency in twins versus singletons and to determine if Contraction frequency can be an efficient predictor of spontaneous preterm birth in twin gestations. Study design Fifty-nine twin and 306 singleton gestations were enrolled between 22 and 24 weeks at 11 centers. Contraction frequency was recorded with a home Uterine activity monitor (HUAM) 2 or more times per day on 2 or more days per week until delivery or 36-6/7 weeks. Masked HUAM data were interpreted according to standard protocol. Repeated measures analyses were used to determine whether mean or maximum Uterine Contraction frequency per hour differed between singleton and twin gestations across gestational age, by time of day, and by delivery before 35 weeks or beyond. Uterine Contraction frequency was also evaluated by logistic regression and receiver operator characteristic (ROC) curves as tests to predict spontaneous preterm birth. Results There were 34,908 hours of HUAM data recorded by the 306 singleton gestations and 5,427 hours by the 59 women with twins. Uterine Contraction frequency was significantly greater in twins ( P = .002) compared with singletons, regardless of gestational age. Contraction frequency in twins increased significantly with gestational age and time of day (1600-0359 hours); but was not associated with spontaneous preterm birth. Maximum Uterine Contraction frequency was associated with preterm birth less than 35 weeks but only in the morning (am) recording (0400-1559) and at the 29- to 30-week gestational age interval. This relationship was modest (odds ratio 1-2) and not consistent across gestational age or between the am and afternoon/evening (pm) monitoring sessions. ROC analysis revealed no Contraction frequency that efficiently identified twins who delivered prematurely at any 2-week gestational age interval. Conclusion Mean Uterine Contraction frequency was significantly higher for twin gestations than singletons throughout the latter half of pregnancy and between 1600 and 0359 hours but was not higher among twins who delivered less than 35 weeks' gestation. Neither maximum am or pm Contraction frequency predicted spontaneous preterm birth less than 35 weeks' gestation in twin pregnancies.
Witoon Prasertcharoensuk - One of the best experts on this subject based on the ideXlab platform.
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success rate in preterm Uterine Contraction inhibition with tocolytic agents in a tertiary care center
International Journal of Women's Health, 2016Co-Authors: Duangsamorn Kiatsuda, Jadsada Thinkhamrop, Witoon PrasertcharoensukAbstract:Objective This study aims to assess the success rate of inhibiting preterm Uterine Contraction with tocolytic agents to delay delivery for at least 48 hours and risk factors of failure inhibition. Materials and methods Between January 2013 and July 2014, medical records of all singleton pregnant women between 24 0/7 and 33 6/7 weeks of gestation with the diagnosis of preterm labor (with cervical dilatation) or threatened preterm labor (without cervical dilatation) who received tocolytic agents were reviewed. The success rate of preterm Uterine Contraction inhibition was accounted in patients with 48 hours delayed delivery. The risk factors of the inhibition failure and neonatal outcomes were also investigated in this study. Results Among 424 pregnant women diagnosed of preterm labor or threatened preterm labor, 103 singleton pregnant women met the study criteria. Overall success rate of preterm Uterine Contraction inhibition to prolong pregnancy for at least 48 hours was 86.4% (95% confidence interval [CI]: 78.3, 92.3). However, the success rate among the threatened preterm labor group was 93.8% (95% CI: 88.3, 99.1) while the preterm labor group was 60.9% (95% CI: 39.3, 82.4). The significant factor associated with inhibition failure was preterm labor (adjusted odds ratio 7.22; 95% CI: 1.99, 26.20). Conclusion The success rate of preterm Uterine Contraction inhibition with tocolytic agents to delay delivery for at least 48 hours was high in threatened preterm labor and low in preterm labor. A significant risk factor for inhibition failure was the preterm Uterine Contraction with cervical change.
Rita Lochcaruso - One of the best experts on this subject based on the ideXlab platform.
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stimulation of Contraction of pregnant rat uterus in vitro by non dechlorinated and microbially dechlorinated mixtures of polychlorinated biphenyls
Environmental Health Perspectives, 2001Co-Authors: Jeehyeon Bae, John F Quensen, Stephen A Boyd, Mahmoud A Mousa, Rita LochcarusoAbstract:A previous study of six polychlorinated biphenyl (PCB) congeners showed that PCBs with four or fewer chlorines and ortho substitution stimulate Uterine Contraction frequency in vitro, whereas congeners with a greater number of chlorines or non-ortho substitution are inactive in vitro. We tested the hypothesis that PCB mixtures stimulate Uterine Contractions in a manner inversely related to the degree of chlorination and the presence of chlorines in the ortho- position of the biphenyl constituents of the mixtures. Uterine strips from pregnant rats were suspended in standard muscle baths and analyzed for changes in isometric Contractions in response to in vitro exposure to commercial PCB mixtures (Aroclors) and their dechlorinated products after microbial degradation. The PCB mixtures Aroclor 1242, 1248, and 1254 significantly stimulated Uterine Contraction frequency, and the least chlorinated mixture, Aroclor 1242, was the most potent stimulant. Microbes from Hudson River sediment dechlorinated Aroclor 1242 and Aroclor 1254 under reducing conditions to produce mixtures with an increased proportion of ortho-substituted congeners with one or two chlorine substitutions. The PCB mixtures that had undergone microbial reductive dechlorination stimulated Uterine Contraction frequency to a significantly greater extent than the parent mixtures. These results show that increased uterotonic activity was associated with decreased chlorination and increased ortho substitution of the biphenyl constituents of the mixtures.
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stimulation of pregnant rat Uterine Contraction by the polychlorinated biphenyl pcb mixture aroclor 1242 may be mediated by arachidonic acid release through activation of phospholipase a2 enzymes
Journal of Pharmacology and Experimental Therapeutics, 1999Co-Authors: Jeehyeon Bae, Marc Petersgolden, Rita LochcarusoAbstract:The polychlorinated biphenyl (PCB) mixture Aroclor 1242 (A1242) increases frequency of Contractions of pregnant rat uteri, suggesting a possible mechanism for decreased gestational age and increased spontaneous abortion in women and animals exposed to PCBs. In the present study, we hypothesized that A1242-induced stimulation of Uterine Contraction is mediated by arachidonic acid released by phospholipase A2 (PLA2) enzymes. Isometric Uterine Contraction was measured in longitudinal Uterine strips isolated from gestation day 10 rat. Pretreatment of Uterine strips with the PLA2 inhibitor (E)-6-(bromomethylene)tetrahydro-3-(1-naphthalenyl)-2H-pyran-2-one (HELSS) or manoalide, or an inhibitor of the G protein of PLA2, isotetrandrine, completely prevented the increase of contractile frequency induced by 50 microM A1242. However, the phospholipase C inhibitors 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate (NCDC) and neomycin were unable to block stimulation of Uterine Contraction by A1242. In accordance, A1242 (100 microM) did not release inositol phosphates from myo-[3H]inositol-labeled myometrial cells, whereas myometrial cells prelabeled with [3H]arachidonic acid released arachidonic acid in a concentration- and time-dependent manner after exposure to A1242 (10-100 microM). A1242 significantly stimulated arachidonic acid release in the absence of extracellular calcium, although the release was attenuated. Analysis of the eicosanoids released by A1242 indicated that only 0.83% of released [3H]arachidonic acid was metabolized to eicosanoids and 99.07% remained as free arachidonate. Uterine Contraction increased in strips exposed to exogenous arachidonic acid (1-100 microM). This study suggests that A1242 stimulates Contraction in pregnant rat uterus by a mechanism involving PLA2-mediated arachidonic acid release, and that arachidonic acid, rather than eicosanoids, may mediate A1242 uterotonic action in the uterus.
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stimulation of oscillatory Uterine Contraction by the pcb mixture aroclor 1242 may involve increased ca2 i through voltage operated calcium channels
Toxicology and Applied Pharmacology, 1999Co-Authors: Jeehyeon Bae, Edward L Stuenkel, Rita LochcarusoAbstract:Abstract Polychlorinated biphenyls (PCBs) are persistent environmental pollutants associated with spontaneous abortion and shortened gestation length in women and animals. In previous studies, we showed that PCB mixtures and noncoplanar ortho -substituted PCB congeners increased Contractions in pregnant rat uterus. In the present study, we hypothesized that the PCB mixture Aroclor 1242 (A1242) stimulates oscillatory Uterine Contraction in pregnant uterus by increasing intracellular calcium concentration ([Ca 2+ ] i ). Pretreatment of Uterine strips with ryanodine or thapsigargin, to deplete specific intracellular calcium stores, did not prevent the increased frequency of oscillatory Contraction due to 50 μM A1242, whereas thapsigargin effectively blocked carbachol-induced stimulation of Uterine Contraction. However, 100 μM A1242 was unable to increase Contraction in the absence of extracellular calcium or in the presence of the voltage-operated L-type calcium channel blocker nifedipine. A1242 (100 μM) was observed to partially depolarize the cell membrane of myometrial cells from pregnant rats, as measured with a potential-sensitive carbocyanine dye. Changes of [Ca 2+ ] i were monitored in single myometrial cells loaded with the fluorescent calcium-sensitive probe fura-2. Cells exposed to 100 μM A1242 showed a delayed and sustained increase of [Ca 2+ ] i , and this increase was completely blocked in the absence of extracellular calcium or the presence of nifedipine. Therefore, the data suggest that depolarization of the cell membrane by A1242 enabled myometrial cells to increase [Ca 2+ ] i through activation of voltage-operated calcium channels, and the increased [Ca 2+ ] i consequently stimulated Contraction of Uterine smooth muscle.
Roger B Newman - One of the best experts on this subject based on the ideXlab platform.
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a prospective masked observational study of Uterine Contraction frequency in twins
American Journal of Obstetrics and Gynecology, 2006Co-Authors: Roger B Newman, Steve N. Caritis, Jay D Iams, Anita F Das, Robert L Goldenberg, Paul J Meis, Atef H Moawad, Bahaeddine M Sibai, Menachem Miodovnik, Richard H PaulAbstract:Objective This study was undertaken to compare Uterine Contraction frequency in twins versus singletons and to determine if Contraction frequency can be an efficient predictor of spontaneous preterm birth in twin gestations. Study design Fifty-nine twin and 306 singleton gestations were enrolled between 22 and 24 weeks at 11 centers. Contraction frequency was recorded with a home Uterine activity monitor (HUAM) 2 or more times per day on 2 or more days per week until delivery or 36-6/7 weeks. Masked HUAM data were interpreted according to standard protocol. Repeated measures analyses were used to determine whether mean or maximum Uterine Contraction frequency per hour differed between singleton and twin gestations across gestational age, by time of day, and by delivery before 35 weeks or beyond. Uterine Contraction frequency was also evaluated by logistic regression and receiver operator characteristic (ROC) curves as tests to predict spontaneous preterm birth. Results There were 34,908 hours of HUAM data recorded by the 306 singleton gestations and 5,427 hours by the 59 women with twins. Uterine Contraction frequency was significantly greater in twins ( P = .002) compared with singletons, regardless of gestational age. Contraction frequency in twins increased significantly with gestational age and time of day (1600-0359 hours); but was not associated with spontaneous preterm birth. Maximum Uterine Contraction frequency was associated with preterm birth less than 35 weeks but only in the morning (am) recording (0400-1559) and at the 29- to 30-week gestational age interval. This relationship was modest (odds ratio 1-2) and not consistent across gestational age or between the am and afternoon/evening (pm) monitoring sessions. ROC analysis revealed no Contraction frequency that efficiently identified twins who delivered prematurely at any 2-week gestational age interval. Conclusion Mean Uterine Contraction frequency was significantly higher for twin gestations than singletons throughout the latter half of pregnancy and between 1600 and 0359 hours but was not higher among twins who delivered less than 35 weeks' gestation. Neither maximum am or pm Contraction frequency predicted spontaneous preterm birth less than 35 weeks' gestation in twin pregnancies.
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Uterine Contraction assessment
Obstetrics and Gynecology Clinics of North America, 2005Co-Authors: Roger B NewmanAbstract:Few approaches to preterm birth prevention have been as thoroughly studied yet as enigmatic as Uterine Contraction assessment. Despite multiple randomized clinical trials (level 1 evidence), the effectiveness of home Uterine Contraction assessment as an adjunct to the clinical management of women at risk for preterm birth remains controversial. This article reviews these trials with particular attention to study design and patient inclusion criteria. The data are absolutely clear that home Uterine Contraction monitoring with or without frequent perinatal nursing contact can reduce the risk of preterm birth and improve perinatal outcomes and that both are independently superior to standard preterm birth prevention education and care.
