The Risk of Postpartum Hemorrhage Following Prior Prelabor Cesarean Delivery Stratified by Abnormal Placentation: A Multicenter Historical Cohort Study.

Background: Prior prelabor cesarean delivery (CD) was associated with an increase in the risk of placenta previa (PP) in a second delivery, whether it may impact postpartum hemorrhage (PPH) independent of abnormal placentation. This study aimed to assess the risk of PPH stratified by abnormal placentation following a first CD before the onset of labor (prelabor) or intrapartum CD. Methods: This multicenter, historical cohort study involved singleton, pregnant women at 28 weeks of gestation or greater with a CD history between January 2017 and December 2017 in 11 public tertiary hospitals within 7 provinces of China. PPH was analyzed in the subsequent pregnancy between women with prior prelabor CD and women with intrapartum CD. Furthermore, PPH was analyzed in pregnant women stratified by complications with PP alone [without placenta accreta spectrum (PAS) disorders], complications with PP and PAS, complications with PAS alone (without PP), and normal placentation. We performed multivariate logistic regression to calculate adjusted odds ratios (aOR) and 95% CI controlling for predefined covariates. Results: Out of 10,833 pregnant women, 1,197 (11%) women had a history of intrapartum CD and 9,636 (89%) women had a history of prelabor CD. Prior prelabor CD increased the risk of PP (aOR 1.91, 95% CI 1.40-2.60), PAS (aOR 1.68, 95% CI 1.11-2.24), and PPH (aOR 1.33, 95% CI 1.02-1.75) in a subsequent pregnancy. After stratification by complications with PP alone, PP and PAS, PAS alone, and normal placentation, prior prelabor CD only increased the risk of PPH (aOR 3.34, 95% CI 1.35-8.23) in a subsequent pregnancy complicated with PP and PAS. Conclusion: Compared to intrapartum CD, prior prelabor CD increased the risk of PPH in a subsequent pregnancy only when complicated by PP and PAS.

Shilei B ，Lizi Z ，Yulian L ，Yingyu L ，Lijun H ，Minshan H ，Baoying H ，Jinping J ，Yinli C ，Shaoshuai W ，Xiaoyan X ，Ling F ，Yangyu Z ，Xianlan Z ，Qiying Z ，Hongbo Q ，Suiwen W ，Lanzhen Z ，Hongtian L ，Jingsi C ，Zhijian W ，Lili D ，Dunjin C ... -  《Frontiers in Medicine》

The risk of abnormal placentation and hemorrhage in subsequent pregnancy following primary elective cesarean delivery.

Chen S ，Cheng W ，Chen Y ，Liu X ... -  《-》

Risk Factors for Severe Postpartum Hemorrhage After Cesarean Delivery: Case-Control Studies.

Butwick AJ ，Ramachandran B ，Hegde P ，Riley ET ，El-Sayed YY ，Nelson LM ... -  《-》

Association between Number of Prior Cesareans and Early Preterm Delivery in Women with Abnormal Placentation.

Delivery timing at 34 to 36 weeks is nationally recommended for pregnancies complicated by placenta accreta spectrum (PAS). However, it has recently been suggested that those with ≥2 prior cesarean deliveries (CD) and PAS should be delivered earlier than 34 weeks because of a higher risk of unscheduled delivery and complications. We sought to evaluate whether the number of prior CD in women with PAS is associated with early preterm delivery (PTD) (<34 weeks). We also evaluated the same relationship in women with placenta previa alone (without PAS). This is a secondary analysis of a multicenter and observational study that included women with prior CD (maternal-fetal medicine unit cesarean registry). Women with a diagnosis of PAS (regardless of placenta previa) were included for our primary analysis, and women with known placenta previa (without a component of PAS) were independently analyzed in a second analysis. Two groups of patients from the registry were studied: patients with PAS (regardless of placenta previa) and patients with placenta previa without PAS. The exposure of interest was the number of prior CD: ≥2 CD compared with <2 CD. The primary outcome was PTD <34 weeks. Secondary outcomes included preterm labor requiring hospitalization or tocolysis, transfusion of blood products, composites of maternal and neonatal morbidities, and NICU admission. Outcomes by prior CD number groups were compared in both cohorts. Backward selection was used to identify parsimonious logistic regression models. There were 194 women with PAS, 97 (50%) of whom had <2 prior CD and 97 (50%) of whom had ≥2 prior CD. The rate of PTD <34 weeks in women with ≥2 prior CD compared with <2 in the setting of PAS was 23.7 versus 29.9%, p = 0.27; preterm labor requiring hospitalization was 24.7 versus 13.5%; p = 0.05. The rates of plasma transfusion were increased with ≥2 prior CD (29.9 vs. 17.5%, p = 0.04), but there were no differences in transfusion of other products or in composite maternal or neonatal morbidities. After multivariable adjustments, having ≥2 CDs was not associated with PTD <34 weeks in women with PAS (adjusted odds ratio (aOR): 0.73, 95% confidence interval [CI]: 0.39-13.8) despite an association with preterm labor requiring hospitalization (aOR: 2.69; 95% CI: 1.15-6.32). In our second analysis, there were 687 women with placenta previa, 633 (92%) with <2 prior CD, and 54 (8%) with ≥2 prior CD. The rate of PTD <34 weeks with ≥2 CD in the setting of placenta previa was not significantly increased (27.8 vs. 22.1%, aOR: 1.49; 95% CI: 0.77-2.90, p = 0.08); the maternal composite outcome (aOR: 4.85; 95% CI: 2.43-9.67) and transfusion of blood products (aOR: 6.41; 95% CI: 2.30-17.82) were noted to be higher in the group with ≥2 prior CD. Women with PAS who have had ≥2 prior CD as compared with women with <2 prior CD did not appear to have a higher risk of complications leading to delivery prior to 34 weeks. As such, considering the associated morbidity with early preterm birth, we would not recommend scheduled delivery prior to 34 weeks in this population. · We do not recommend delivery prior to 34 weeks of gestational age in PAS.. · PTD was not significantly increased in PAS with ≥2 CDs.. · PTD < 34 weeks of gestational age was not increased in placenta previa with ≥2 prior CDs..

Oben A ，Ausbeck EB ，Gazi MN ，Subramaniam A ，Harper LM ，Szychowski JM ，Tita AT ... -  《-》

Previous prelabor or intrapartum cesarean delivery and risk of placenta previa.

The purpose of this study was to examine the association between previous cesarean delivery and subsequent placenta previa while distinguishing cesarean delivery before the onset of labor from intrapartum cesarean delivery. We conducted a retrospective cohort study of electronic medical records from 20 Utah hospitals (2002-2010) with restriction to the first 2 singleton deliveries of nulliparous women at study entry (n=26,987). First pregnancy delivery mode was classified as (1) vaginal (reference), (2) cesarean delivery before labor onset (prelabor), or (3) cesarean delivery after labor onset (intrapartum). Risk of second delivery previa was estimated by previous delivery mode with the use of logistic regression and was adjusted for maternal age, insurance, smoking, comorbidities, previous pregnancy loss, and history of previa. Most first deliveries were vaginal (82%; n=22,142), followed by intrapartum cesarean delivery (14.6%; n=3931), or prelabor cesarean delivery (3.4%; n=914). Incidence of second delivery previa was 0.29% (n=78) and differed by previous delivery mode: vaginal, 0.24%; prelabor cesarean delivery, 0.98%; intrapartum cesarean delivery, 0.38% (P<.001). Relative to vaginal delivery, previous prelabor cesarean delivery was associated with an increased risk of second delivery previa (adjusted odds ratio, 2.62; 95% confidence interval, 1.24-5.56). There was no significant association between previous intrapartum cesarean delivery and previa (adjusted odds ratio, 1.22; 95% confidence interval, 0.68-2.19). Previous prelabor cesarean delivery was associated with a >2-fold significantly increased risk of previa in the second delivery, although the approximately 20% increased risk of previa that was associated with previous intrapartum cesarean delivery was not significant. Although rare, the increased risk of placenta previa after previous prelabor cesarean delivery may be important when considering nonmedically indicated prelabor cesarean delivery.

Downes KL ，Hinkle SN ，Sjaarda LA ，Albert PS ，Grantz KL ... -  《-》