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803: The association of Montevideo units and uterine rupture during trial of labor after cesarean delivery
Poster Session V
ajog.org 803 The association of Montevideo units and uterine rupture during trial of labor after cesarean delivery Lindsay Maggio1, Rosemary J. Froehlich1, Joshua D. Dahlke2, Phinnara Has1, Dwight J. Rouse1, Christina M. Davidson3 1 The Warren Alpert Medical School of Brown University, Women & Infants Hospital of Rhode Island, Providence, RI, 2Methodist Women’s Hospital and Perinatal Center, Omaha, NE, 3Baylor College of Medicine, Houston, TX
OBJECTIVE: To evaluate whether there is an association between the attainment of at least 200 Montevideo units (MVU) and uterine rupture in women undergoing a trial of labor after cesarean delivery (TOLAC). STUDY DESIGN: Secondary analysis of a prospective multi-center study. Data on women with a singleton gestation with at least one prior cesarean delivery (CD) undergoing a TOLAC were abstracted by trained, certified research personnel. We included only women whose labor was managed with an intrauterine pressure catheter and compared the rates of attainment of 200 MVU (defined by ACOG as adequate) in women who experienced a uterine rupture (defined as a through and through disruption or tear of the uterine muscle and serosa) and those who did not. Multivariable logistic regression was performed to control for factors associated with uterine rupture. RESULTS: A total of 5,941 women were included, of whom 63 (1%) experienced uterine rupture. Of the remaining, 3,976 (67%) had a vaginal birth after cesarean (VBAC) and 1,902 (32%) had a failed TOLAC. In a bivariate analysis, there was no difference in the proportion of women with MVU 200 in those with and without uterine rupture (73% vs 72%, p¼1.0). After controlling for factors associated with uterine rupture (BMI at deliver, > 1 cesarean, tobacco, prostaglandin use -Table), there was no difference in adequate MVU achieved between those with uterine rupture and those without (aOR 1.08 (0.60-1.92), p¼0.8). CONCLUSION: Most women undergoing a TOLAC achieved at least 200 MVU. MVU at and above this threshold were not associated with uterine rupture, suggesting that the standard threshold for uterine activity in non-progressive labor need not be modified in women undergoing TOLAC.
STUDY DESIGN: Fetal membrane samples were collected from term
patients not in labor (TNIL; n¼11) and in labor (TL; n¼9) after cesarean and vaginal deliveries respectively. Extracted proteins were subjected to multiplex assays for the following antioxidants: peroxiredoxin (PRX2), super oxide dismutase (SOD1 and 2), catalase (CAT), and thioredoxin (TRX1). Multiple phosphorylated MAPKs (ATF2, p90RSK, Hsp27, MEK, P-p38MAPK, Stat3, ERK1, JNK) and p53 were assayed using Bio-Plex Pro Cell Signaling MAPK Panel for semi-quantitative estimation of cell signaling markers. Median fluorescence intensities (MFI) were recorded in both assays and data were normalized to total protein concentrations. Analysis was performed using Student t-test and p 0.05 was considered significant. RESULTS: Concentrations of PRX2, SOD1 and CAT were significantly lower in TL vs TNIL (Figure 1). Increased phosphorylation of MEK and Hsp27 was seen in TNIL compared to TL (Figure 2). Activation/ Phosphorylation of ATF and p38MAPK was significantly increased in TL compared to TNIL (Figure 2). Activation of p38MAPK in TL was confirmed with Western blot analysis. CONCLUSION: Term labor is associated with increased oxidant and decreased anti-oxidant function, resulting in activation of p38MAPK, a pro-senescence protein. Fetal membrane senescence at term does not involve p53 (pro-apoptotic factor) activation. Our findings confirm the role of membrane senescence as a mechanism for term labor.
804 Antioxidant reduction and p38MAPK signaling: mechanistic activators of fetal membrane senescence Faranak Behnia1, Eryn H. Dutta1, Christopher L. Dixon1, Talar Kechichian1, George Saade1, Ramkumar Menon1 1
University of Texas Medical Branch Galveston, Galveston, TX
OBJECTIVE: Term Labor is associated with oxidative stress (OS)
induced fetal membrane senescence. Our objective was to test the hypothesis that term labor is associated with reduction in fetal membrane antioxidant status and activation of stress-associated signals (mitogen activated protein kinases [MAPK]). Supplement to JANUARY 2016 American Journal of Obstetrics & Gynecology
S419
ajog.org 803 The association of Montevideo units and uterine rupture during trial of labor after cesarean delivery Lindsay Maggio1, Rosemary J. Froehlich1, Joshua D. Dahlke2, Phinnara Has1, Dwight J. Rouse1, Christina M. Davidson3 1 The Warren Alpert Medical School of Brown University, Women & Infants Hospital of Rhode Island, Providence, RI, 2Methodist Women’s Hospital and Perinatal Center, Omaha, NE, 3Baylor College of Medicine, Houston, TX
OBJECTIVE: To evaluate whether there is an association between the attainment of at least 200 Montevideo units (MVU) and uterine rupture in women undergoing a trial of labor after cesarean delivery (TOLAC). STUDY DESIGN: Secondary analysis of a prospective multi-center study. Data on women with a singleton gestation with at least one prior cesarean delivery (CD) undergoing a TOLAC were abstracted by trained, certified research personnel. We included only women whose labor was managed with an intrauterine pressure catheter and compared the rates of attainment of 200 MVU (defined by ACOG as adequate) in women who experienced a uterine rupture (defined as a through and through disruption or tear of the uterine muscle and serosa) and those who did not. Multivariable logistic regression was performed to control for factors associated with uterine rupture. RESULTS: A total of 5,941 women were included, of whom 63 (1%) experienced uterine rupture. Of the remaining, 3,976 (67%) had a vaginal birth after cesarean (VBAC) and 1,902 (32%) had a failed TOLAC. In a bivariate analysis, there was no difference in the proportion of women with MVU 200 in those with and without uterine rupture (73% vs 72%, p¼1.0). After controlling for factors associated with uterine rupture (BMI at deliver, > 1 cesarean, tobacco, prostaglandin use -Table), there was no difference in adequate MVU achieved between those with uterine rupture and those without (aOR 1.08 (0.60-1.92), p¼0.8). CONCLUSION: Most women undergoing a TOLAC achieved at least 200 MVU. MVU at and above this threshold were not associated with uterine rupture, suggesting that the standard threshold for uterine activity in non-progressive labor need not be modified in women undergoing TOLAC.
STUDY DESIGN: Fetal membrane samples were collected from term
patients not in labor (TNIL; n¼11) and in labor (TL; n¼9) after cesarean and vaginal deliveries respectively. Extracted proteins were subjected to multiplex assays for the following antioxidants: peroxiredoxin (PRX2), super oxide dismutase (SOD1 and 2), catalase (CAT), and thioredoxin (TRX1). Multiple phosphorylated MAPKs (ATF2, p90RSK, Hsp27, MEK, P-p38MAPK, Stat3, ERK1, JNK) and p53 were assayed using Bio-Plex Pro Cell Signaling MAPK Panel for semi-quantitative estimation of cell signaling markers. Median fluorescence intensities (MFI) were recorded in both assays and data were normalized to total protein concentrations. Analysis was performed using Student t-test and p 0.05 was considered significant. RESULTS: Concentrations of PRX2, SOD1 and CAT were significantly lower in TL vs TNIL (Figure 1). Increased phosphorylation of MEK and Hsp27 was seen in TNIL compared to TL (Figure 2). Activation/ Phosphorylation of ATF and p38MAPK was significantly increased in TL compared to TNIL (Figure 2). Activation of p38MAPK in TL was confirmed with Western blot analysis. CONCLUSION: Term labor is associated with increased oxidant and decreased anti-oxidant function, resulting in activation of p38MAPK, a pro-senescence protein. Fetal membrane senescence at term does not involve p53 (pro-apoptotic factor) activation. Our findings confirm the role of membrane senescence as a mechanism for term labor.
804 Antioxidant reduction and p38MAPK signaling: mechanistic activators of fetal membrane senescence Faranak Behnia1, Eryn H. Dutta1, Christopher L. Dixon1, Talar Kechichian1, George Saade1, Ramkumar Menon1 1
University of Texas Medical Branch Galveston, Galveston, TX
OBJECTIVE: Term Labor is associated with oxidative stress (OS)
induced fetal membrane senescence. Our objective was to test the hypothesis that term labor is associated with reduction in fetal membrane antioxidant status and activation of stress-associated signals (mitogen activated protein kinases [MAPK]). Supplement to JANUARY 2016 American Journal of Obstetrics & Gynecology
S419