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

Abstract

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.

Development of antepartum risk prediction model for postpartum hemorrhage in Lagos, Nigeria: A prospective cohort study (Predict‐PPH study)

“…Prior history of cesarean delivery has the strongest link to PPH in this study. This is because of its association with possible pelvic and peritoneal adhesions, abnormal placentation, including placenta previa and placenta accreta, and uterine scar dehiscence and rupture 39 . The observed link between obesity and PPH, as reported in our study, has been attributed to the increased risk of cesarean section and the impaired uterine response to control bleeding due to the possible disruption of the hormonal balance in obese women 40 .…”

The prenatal diagnostic indicators of placenta accreta spectrum disorders

“…There was a dose-response relationship between the number of prior cesarean deliveries and PAS when stratified by that metric [ 9 ]. Interestingly, the timing of the initial cesarean delivery also affects the occurrence of PAS in subsequent pregnancies, and it was found that elective CS was associated with a high risk of subsequent pregnancies with placenta previa combined with PAS (OR 3.0, 95% CI 1.47–6.12) [ [11] , [12] , [13] ]. A plausible explanation could be that changes in the structure of the uterus during labor make the tissue more adaptable to injury, and the activation of immune function also facilitates the repair of the myometrium [ [14] , [15] , [16] , [17] ].…”