Nicole Jastrow

Prediction of complete uterine rupture by sonographic evaluation of the lower uterine segment.

OBJECTIVE The purpose of this study was to establish the validity of sonographic evaluation of lower uterine segment (LUS) thickness for complete uterine rupture. STUDY DESIGN A prospective cohort study of women with previous cesarean delivery was conducted. LUS thickness (full thickness and myometrial thickness only) was measured between 35 and 38 weeks gestation, and the thinnest measurement was considered to be the dependent variable. Receiver operating curve analyses and logistic regression were used. RESULTS Two hundred thirty-six women were included in the study. Nine uterine scar defects (3 cases of complete rupture during a trial of labor and 6 cases of dehiscence) were reported. Receiver operating curve analyses showed that full thickness of <2.3 mm was the optimal cutoff for the prediction of uterine rupture (3/33 vs 0/92; P = .02). Full thickness was also identified as an independent predictor of uterine scar defect (odds ratio, 4.66; 95% confidence interval, 1.04-20.91) CONCLUSION Full LUS thickness of <2.3 mm is associated with a higher risk of complete uterine rupture.

Prediction of complications in pregnant women with cardiac diseases referred to a tertiary center

BACKGROUND Prediction of adverse maternal and neonatal events in women with heart disease is not well established. We aimed to assess cardiac, obstetrical and neonatal complications in pregnant women with heart disease referred to our tertiary care center and validate a previously proposed risk index. METHODS We included 227 women with cardiac disease followed for 312 pregnancies at our tertiary center from 1992 to 2007. Cardiac risk was assessed using the previously proposed Cardiac Disease in Pregnancy (CARPREG) score and its association with maternal and neonatal outcomes was determined. RESULTS Maternal cardiac lesions were predominantly congenital (81.4%). CARPREG risk was low (score=0) in 66.3% and intermediate (score=1) in 33.7% pregnancies. Maternal cardiac events complicated 7.4% pregnancies, with pulmonary edema occurring most frequently (3.8%). An intermediate score was associated with a higher rate of cardiac events (19.0% vs. 1.4%, odds ratio [OR] 15.6, 95% confidence interval (95%CI) 4.5-54.4, p<0.0001). Adverse events occurred in 27.5% neonates. Preterm deliveries occurred in 16.7% pregnancies, more commonly in patients with intermediate scores (OR 2.4, 95%CI 1.2-4.6, p=0.01). The sensitivity and negative predictive values of a low score were respectively 87% and 99% for total cardiac events and both 100% for primary cardiac events including pulmonary edema and sustained arrhythmia. CONCLUSION The CARPREG risk index has a high sensitivity and negative predictive value with regards to cardiac complications in pregnant women with heart disease. It may, therefore, be routinely used to improve the assessment of cardiac risk before and during pregnancy.

Impact of labor at prior cesarean on lower uterine segment thickness in subsequent pregnancy.

OBJECTIVE The objective of the study was to identify the factors associated with sonographic lower uterine segment (LUS) thickness near term in women with prior low transverse cesarean. STUDY DESIGN A prospective cohort study of women with a single prior low transverse cesarean was conducted. LUS thickness was quantified by transabdominal ultrasound with repeated transvaginal measurement when necessary. The thinnest measurement was considered as the dependent variable. Potential related factors were evaluated with nonparametric analyses and multivariate logistic regressions. RESULTS Two hundred thirty-five women were recruited at a mean gestational age of 36.7 +/- 1.3 weeks. The full LUS was thicker in women who had their previous cesarean during the latent phase (2.8 mm; interquartile [IQ], 2.0-3.3 mm) or the active phase of labor (3.1 mm; IQ 2.5-3.9 mm) than in women with previous cesarean prior to labor (2.4 mm; IQ 2.0-3.2 mm). The association remained significant after adjustment for potential confounders. CONCLUSION Presence of labor at previous cesarean is associated with a thicker LUS in a subsequent pregnancy.

Assessment of the rate of uterine rupture at the first prenatal visit: A preliminary evaluation

We read, with great interest, the paper by Shipp et al., who reported that a simple scoring system could better estimate the patient-specific risk of uterine rupture after prior cesarean section [1]. Most of the risk factors evaluated in their score were extracted from studies of their patient population. Since external validation of this score has not yet been demonstrated, we tested it in our own patient population. Analyzing all available data on 2493 women who underwent a trial of labor after prior cesarean section at Sainte-Justine Hospital, Montreal, between 1993 and 2004, we calculated the score for each patient and the corresponding rate of uterine rupture according to the study of Shipp et al. Although we found a similar trend in uterine rupture rates, the scoring system did not discriminate well those women at low risk for uterine rupture (Table I). As suggested by the authors, additional factors, such as type of closure, could improve the score [2]. As a demonstration, we repeated the calculation after adding 1 point for women with single-layer closure and removing the variable ‘age between 30 and 39 years’ [3]. In our series, this modified scoring system better discriminated lowversus high-risk populations with almost 70% of the population having a 50.8% risk of uterine rupture (Table I). In addition, we believe that it is important to mention the utility of measuring lower uterine

OP15.08: Comparison between transvaginal and abdominal sonography of lower uterine segment thickness near term

(UtR), and estimate the fraction of CO distributed to the uteroplacental circulation during the second half of pregnancy. Methods: Fifty-three low risk-pregnancies were evaluated longitudinally at approximately 4-weekly intervals from 22 weeks until term (a total of 253 observations). Mean arterial blood pressure (MAP), CO and SVR were measured using impedance cardiography, and the uterine artery blood flow velocities and diameter using Doppler and B-mode ultrasonography, respectively. Quta of both uterine arteries was estimated as the product of time-averaged intensity weighted mean velocity and cross-sectional area of the uterine artery. UtR was calculated as: MAP/sum of right and left Quta. Results: CO increased from 5.5 to 5.8 L/min (p = 0.006) despite a significant increase in SVR from 1046 to 1135 dyne s cm-5 (p = 0.0077) during 22–40 weeks. The UtR decreased from 0.26 to 0.13 mmHg/mL/min (p < 0.00001) and the total utero-placental blood flow more than doubled during the same period increasing from 299 ml/min to 673 ml/min which represented 5.6% to 11.7% of the maternal CO. Conclusion: We have established longitudinal reference intervals for the fraction of maternal CO distributed to the utero-placental circulation at 22–40 weeks of gestation. Increments in uteroplacental blood flow are relatively higher than that of the CO in the second half of pregnancy suggesting redistribution of maternal circulation due to continuous reduction in UtR.

P30.10: Factors associated with the location of uterine scar defect in women with previous low‐transverse Cesarean

Objectives: The objective of the study was to evaluate differences in post partum bleeding, transfusion requirement and length of hospital stay in women with focal vs. diffuse placenta accreta. The same parameters were compared in women undergoing balloon occlusion vs. no occlusion of the iliac arteries at Caesarean delivery for accreta. Methods: Prospective observational study of women with suspected focal or diffuse placenta accreta on routine sonography. Follow up scans were performed as required. Surgical and histologic correlation was performed after Caesarean delivery. Independent groups t-tests and non-parametric Mann-Whitney U were used in the statistical analysis. Results: 25 women were diagnosed on ultrasound with placenta accreta, 9 with focal accreta and 16 with diffuse involvement. On average, women in the diffuse group exhibited significantly greater blood loss (P < 0.001) than the focal group and had a higher transfusion requirement (P = 0.12). There was no significant difference in hospital stay between the groups. 12 women underwent balloon iliac occlusion at Caesarean delivery, 2 of whom had focal accreta diagnosed prenatally and 10 had diffuse accreta. There were no significant differences in blood loss, transfusion requirement or length of hospital stay between the balloon vs. no-balloon occlusion groups. Conclusions: Prenatal diagnosis of extent of placenta accreta is clinically important and should guide management around delivery. Although the numbers in this study are small, no significant differences in blood loss or transfusion requirement were observable between the balloon occlusion vs. no occlusion group. Further studies are required to assess whether this is a worthwhile and cost-effective intervention in management of placenta accreta.