Nomogram based on clinical characteristics and ultrasound indicators for predicting severe postpartum hemorrhage in patients with anterior placenta previa combined with previous cesarean section: a retrospective case-control study.

BACKGROUND: Placental accreta spectrum disorders (PAS) are a high-risk group for severe postpartum hemorrhage (SPPH), with the incidence of PAS increasing annually. Given that cesarean section and anterior placenta previa are the primary risk factors for PAS, therefore, our study aims to investigate the predictive value of clinical characteristics and ultrasound indicators for SPPH in patients with anterior placenta previa combined with previous cesarean section, providing a theoretical basis for early prediction of SPPH. METHODS: A total of 450 patients with anterior placenta previa combined with previous cesarean section were retrospectively analyzed at Shengjing Hospital affiliated with China Medical University between January 2018 and March 2022. Clinical data and ultrasound indicators were collected. Patients were categorized into SPPH (blood loss >2000mL, 182 cases) and non-SPPH (blood loss ≤ 2000mL, 268 cases) groups based on the blood loss within 24 h postpartum. The population was randomly divided into training and validation cohorts at a 7:3 ratio. LASSO and multifactorial logistic regression analyses were utilized to identify independent risk factors for SPPH. Accordingly, a nomogram prediction model was constructed, the predictive performance was assessed using receiver operating characteristic (ROC) curves, calibration curves and decision curve analysis (DCA). RESULTS: Among the 450 patients, 182 experienced SPPH (incidence rate, 40.44%). Preoperative systemic immune-inflammatory index, preoperative D-dimer level, preoperative placenta accreta spectrum ultrasound scoring system (PASUSS) score, and one-step-conservative surgery were identified as independent risk factors for SPPH in patients with anterior placenta previa combined with previous cesarean section. A nomogram was constructed based on these factors. The areas under the ROC curves for the training and validation cohorts were 0.844 (95%CI: 0.801-0.888) and 0.863 (95%CI: 0.803-0.923), respectively. Calibration curves and DCA indicated that this nomogram demonstrated good predictive accuracy. CONCLUSIONS: This nomogram presents an effective and convenient prediction model for identifying SPPH in patients with anterior placenta previa combined with previous cesarean section. It can guide surgical planning and improve prognosis.

Effect of placenta location detected by ultrasound on the severity of placenta accreta spectrum in patients with placenta previa and placenta accreta spectrum.

BACKGROUND: To evaluate the effect of placental location on the severity of placenta accreta spectrum (PAS). METHODS: We analyzed 390 patients with placenta previa combined with placenta accreta spectrum who underwent cesarean section between January 1, 2014 and December 30, 2020 in the electronic case database of the Second Hospital of Hebei Medical University. According to the position of the placenta, 390 placentas were divided into the posterior group (n = 89), the anterior group (n = 60) and the non-central group (n = 241). RESULTS: The history of cesarean delivery rates in the anterior group (91.67%) and the non-central group (85.71%) were statistically different from the posterior group (63.74%)(P < 0.001). Univariate logistic regression results showed that employment, urban living, gestational age, complete placenta previa, fetal presentation shoulder, gravidity, cesarean section and vaginal delivery were all predictors for the severity of placenta accreta (P < 0.05). The anterior group (P = 0.001, OR = 4.13, 95%CI: 1.84-9.24) and the non-central group (P = 0.001, OR = 2.90, 95%CI: 1.55-5.45) had a higher incidence of invasive accreta placentation than the posterior group, and were independent risk factors for invasive accreta placentation. CONCLUSION: Compared with posterior placenta, anterior and non-central placenta are independent risk factors for invasive PAS in patients with placenta previa, during which we should be more cautious in treatment.

Placental Location in Maternal-Fetal Surgery for Myelomeningocele.

INTRODUCTION: Uterine incision based on the placental location in open maternal-fetal surgery (OMFS) has never been evaluated in regard to maternal or fetal outcomes. OBJECTIVE: The aim of this study was to investigate whether an anterior placenta was associated with increased rates of intraoperative, perioperative, antepartum, obstetric, or neonatal complications in mothers and babies who underwent OMFS for fetal myelomeningocele (fMMC) closure. METHODS: Data from the international multicenter prospective registry of patients who underwent OMFS for fMMC closure (fMMC Consortium Registry, December 15, 2010-June 31, 2019) was used to compare fetal and maternal outcomes between anterior and posterior placental locations. RESULTS: The placental location for 623 patients was evenly distributed between anterior (51%) and posterior (49%) locations. Intraoperative fetal bradycardia (8.3% vs. 3.0%, p = 0.005) and performance of fetal resuscitation (3.6% vs. 1.0%, p = 0.034) occurred more frequently in cases with an anterior placenta when compared to those with a posterior placenta. Obstetric outcomes including membrane separation, placental abruption, and spontaneous rupture of membranes were not different among the 2 groups. However, thinning of the hysterotomy site (27.7% vs. 17.7%, p = 0.008) occurred more frequently in cases of an anterior placenta. Gestational age (GA) at delivery (p = 0.583) and length of stay in the neonatal intensive care unit (p = 0.655) were similar between the 2 groups. Fetal incision dehiscence and wound revision were not significantly different between groups. Critical clinical outcomes including fetal demise, perinatal death, and neonatal death were all infrequent occurrences and not associated with the placental location. CONCLUSIONS: An anterior placental location is associated with increased risk of intraoperative fetal resuscitation and increased thinning at the hysterotomy closure site. Individual institutional experiences may have varied, but the aggregate data from the fMMC Consortium did not show a significant impact on the GA at delivery or maternal or fetal clinical outcomes.

Association of external cephalic version before term with late preterm birth.

INTRODUCTION: While evidence suggests that beginning an external cephalic version (ECV) before term (340/7 to 366/7 weeks) compared with after term may be associated with an increase in late preterm birth (340/7 to 366/7 weeks), it remains unknown what might account for this risk. The objective of the present study is to further investigate the association between ECV before term and late preterm birth. MATERIAL AND METHODS: Secondary analysis of data collected from the international, multicenter Early ECV trials. We evaluated the relation between ECV exposure and late preterm birth (340/7 to 366/7 weeks), as well as whether additional risk factors for preterm birth (such as maternal age, height, body mass index, parity, placental location, and perinatal mortality rate) moderated this relation. Generalized linear mixed methods were used to account for center effect and adjust for covariates. RESULT: Among 1765 women with breech pregnancies and without a prior preterm birth, 749 (42.4%) received at least one ECV before term. Exposure to an ECV before term was not associated significantly independently with odds of preterm birth. However, placenta location moderated the association between early ECV exposure and late preterm birth. The odds of preterm birth in women who were exposed to an ECV before term and who also had an anterior placenta were doubled (OR 2.05; 95% CI 1.12-3.71; p = 0.02). CONCLUSION: In a large cohort of women without known risks for preterm birth, those with an anterior placenta who undergo an ECV before term constitute a subgroup at particular risk for late preterm birth.

Association between placental location and cord insertion site with pre-eclampsia: a retrospective cohort study.

OBJECTIVE: The relationship between placental location in pregnancies without previa and adverse pregnancy outcomes has not been well studied. Additionally, the impact of abnormal cord insertion sites remains controversial. Therefore, the objective of this study was to explore the adverse outcomes associated with placental location and abnormal cord insertion in nulliparous women and to assess their impact on pregnancy outcomes. METHODS: This retrospective cohort study was conducted at a single tertiary hospital between January 2019 and June 2022. The study included nulliparous women with singleton pregnancies who delivered live infants and had available data on placental location and umbilical cord insertion site from a second- or third-trimester ultrasound. Placental location was categorized as anterior or posterior using transabdominal ultrasonography. The association between placental location/cord insertion site and pre-eclampsia was evaluated using multivariate logistic regression analysis. We compared the area under the curve to evaluate the impact of placental location and cord insertion site on pre-eclampsia. RESULTS: A total of 2219 pregnancies were included in the study. Pre-eclampsia occurred significantly more frequently in the anterior group than in the posterior group (8.21% vs. 3.04%, p < .001). In multivariate analysis investigating the association between placental location and pre-eclampsia, anterior placenta and marginal cord insertion showed increased odds ratios for pre-eclampsia of 3.05 (95% confidence interval [CI] 1.68-6.58) and 3.64 (95% CI 1.90-6.97), respectively. Receiver operating characteristic (ROC) curves were constructed to predict pre-eclampsia using independent factors from multivariate analyses. Model I, including maternal age, pre-pregnancy body mass index, in vitro fertilization, chronic hypertension, overt diabetes, kidney disease, and hematologic diseases, achieved an area under the ROC curve of 0.70 (95% CI 0.65-0.75). Adding cord insertion site and placental location to the model (Model II) improved its predictive performance, resulting in an area under the ROC curve of 0.749 (95% CI 0.70-0.79, p = .02). CONCLUSIONS: Anterior placenta and marginal cord insertion were associated with an increased risk of pre-eclampsia. Further studies on prospective cohorts are necessary to validate these findings.

Type and location of placenta previa affect preterm delivery risk related to antepartum hemorrhage.

PURPOSE: To evaluate whether type and location of placenta previa affect risk of antepartum hemorrhage-related preterm delivery. METHODS: We retrospectively studied 162 women with singleton pregnancies presenting placenta previa. Through observation using transvaginal ultrasound the women were categorized into complete or incomplete placenta previa, and then assigned to anterior and posterior groups. Complete placenta previa was defined as a placenta that completely covered the internal cervical os, with the placental margin >2 cm from the os. Incomplete placenta previa comprised marginal placenta previa whose margin adjacent to the internal os and partial placenta previa which covered the os but the margin situated within 2 cm of the os. Maternal characteristics and perinatal outcomes in complete and incomplete placenta previa were compared, and the differences between the anterior and the posterior groups were evaluated. RESULTS: Antepartum hemorrhage was more prevalent in women with complete placenta previa than in those with incomplete placenta previa (59.1% versus 17.6%), resulting in the higher incidence of preterm delivery in women with complete than in those with incomplete placenta previa [45.1% versus 8.8%; odds ratio (OR) 8.51; 95% confidence interval (CI) 3.59-20.18; p < 0.001]. In complete placenta previa, incidence of antepartum hemorrhage did not significantly differ between the anterior and the posterior groups. However, gestational age at bleeding onset was lower in the anterior group than in the posterior group, and the incidence of preterm delivery was higher in the anterior group than in the posterior group (76.2% versus 32.0%; OR 6.8; 95% CI 2.12-21.84; p = 0.002). In incomplete placenta previa, gestational age at delivery did not significantly differ between the anterior and posterior groups. CONCLUSION: Obstetricians should be aware of the increased risk of preterm delivery related to antepartum hemorrhage in women with complete placenta previa, particularly when the placenta is located on the anterior wall.

Placental Lesions and Pregnancy Outcome in Anterior as Compared to Posterior Placenta Previa.

The uterine location of placenta previa (PP), anterior vs. posterior has an impact on pregnancy outcome. We aimed to study maternal and neonatal outcome and placental histopathology lesions in anterior vs. posterior PP. The medical records and histopathology reports of all singleton cesarean deliveries (CD) performed due to PP, from 24 to 41 weeks, between 12.2008 and 10.2018, were reviewed. Placental lesions were classified into maternal and fetal vascular malperfusion lesions (MVM, FVM), maternal and fetal inflammatory responses (MIR, FIR). Gestational age (GA) at delivery was similar between the anterior PP (n = 67) and posterior PP (n = 105) groups. As compared to the posterior PP group, the anterior PP group had higher rate of previous CD (p < 0.001), placental accreta spectrum (p = 0.04), lower neonatal Hb at birth (p = 0.03), higher rate of neonatal blood transfusion (p = 0.007) and prolonged maternal hospitalization (p = 0.02). Placentas from the anterior PP group had lower weights (p = 0.035), with increased rate of MVM lesions (p = 0.017). The anterior PP location is associated with increased adverse maternal and neonatal outcome, lower placental weights and increased rate of malperfusion lesions. Abnormal placentation in the scarred uterine wall probably has an impact on placental function.

Temporary balloon occlusion of the internal iliac arteries to prevent massive hemorrhage during cesarean delivery among patients with placenta previa.

OBJECTIVE: To evaluate the effectiveness of temporary balloon occlusion of the internal iliac artery before uterine incision to prevent massive obstetric hemorrhage during cesarean delivery among patients with anterior placenta previa. METHODS: In a retrospective cohort study conducted at Amphia Hospital Breda (Breda, Netherlands), data were analyzed from women with anterior placenta previa who delivered by cesarean between January 1, 2001, and September 30, 2012. Cases with and without balloon occlusion of the internal iliac artery were included. The primary outcomes were the amount of blood loss during cesarean delivery, drop of hemoglobin level, and blood loss of more than 1000 mL. RESULTS: Of 68 eligible women, 42 (62%) had temporary balloon occlusion and 26 (38%) had no balloon occlusion. Median blood loss was 800 mL (interquartile range [IQR] 488-1113) in the balloon group and 1000 mL (IQR 694-1307) in the no balloon group (P=0.06). Blood loss of 1000 mL or more was recorded in 16 (38%) women in the balloon group and 18 (69%) in the no balloon group (P=0.01). CONCLUSION: Temporary balloon occlusion of the internal iliac artery before uterine incision during cesarean delivery could potentially reduce blood loss among patients with anterior placenta previa. Large, randomized controlled trials are needed to confirm the results.