Assessment of placenta accreta spectrum at vaginal birth after cesarean delivery.

Previous cesarean delivery is a risk factor for developing placenta accreta spectrum in a subsequent pregnancy and patients with antenatally suspected placenta accreta spectrum frequently undergo planned cesarean hysterectomy. There is a paucity of data regarding unsuspected placenta accreta spectrum among patients undergoing trial of labor after cesarean delivery for attempted vaginal birth after cesarean delivery. This study aimed to investigate the incidence, characteristics, and delivery outcomes of patients with placenta accreta spectrum diagnosed at the time of vaginal birth after cesarean delivery. The Healthcare Cost and Utilization Project's National Inpatient Sample was retrospectively queried to examine 184,415 patients with a history of low transverse cesarean delivery who had vaginal delivery in the current index hospital admission between 2017 and 2020. Those with placenta previa, previous vertical cesarean delivery, other uterine scars, and uterine rupture were excluded. This study identified placenta accreta spectrum cases using the World Health Organization International Classification of Disease, Tenth Revision, codes of O43.2. Coprimary outcomes were (1) the incidence rate of placenta accreta spectrum at vaginal birth after cesarean delivery; (2) clinical and pregnancy characteristics related to placenta accreta spectrum, assessed with multivariable binary logistic regression model; and (3) delivery outcomes associated with placenta accreta spectrum by fitting propensity score adjustment. The secondary outcome was to conduct a systematic literature review using 3 public search engines (PubMed, Cochrane, and Scopus). Data on incidence rate and maternal morbidity related to placenta accreta spectrum at vaginal birth after cesarean delivery were evaluated. The incidence rate of placenta accreta spectrum at vaginal birth after cesarean delivery was 8.1 per 10,000 deliveries. Most placenta accreta spectrum cases were placenta accreta (83.3%). In a multivariable analysis, older maternal age, tobacco use, preeclampsia, multifetal pregnancy, fetal anomaly, preterm premature rupture of membrane, chorioamnionitis, low-lying placenta, and preterm delivery were associated with an increased risk of placenta accreta spectrum (all, P<.05). Of these factors, low-lying placenta had the largest odds for placenta accreta spectrum (526.3 vs 7.3 per 10,000 deliveries; adjusted odds ratio, 35.02; 95% confidence interval, 18.19-67.42). Patients in the placenta accreta spectrum group were more likely to have postpartum hemorrhage (80.0% vs 5.5%), blood product transfusion (23.3% vs 1.0%), shock or coagulopathy (20.0% vs 0.2%), and hysterectomy (43.3% vs <0.1%) than those without placenta accreta spectrum (all, P<.001). In a systematic literature review, a total of 212 studies were screened, and none of these studies examined the incidence and morbidity of placenta accreta spectrum at vaginal birth after cesarean delivery. This nationwide assessment suggests that although placenta accreta spectrum with vaginal birth after cesarean delivery is uncommon (1 of 1229 cases), the diagnosis of placenta accreta spectrum at vaginal birth after cesarean delivery is associated with significant maternal morbidity. In addition, the data suggest that low-lying placenta in the setting of previous low transverse cesarean delivery warrants careful evaluation for possible placenta accreta spectrum before a trial of labor.

Matsuzaki S ，Rau AR ，Mandelbaum RS ，Tavakoli A ，Mazza GR ，Ouzounian JG ，Matsuo K ... -  《-》

Unsuspected placenta accreta spectrum at vaginal delivery: assessment of incidence, characteristics, and maternal morbidity.

Placenta accreta spectrum refers to morbidly adherent trophoblastic tissue invading into the gravid uterus and is associated with significant maternal morbidity. Most cases of placenta accreta spectrum are suspected antenatally, and most patients undergo planned, late-preterm cesarean hysterectomy to reduce the risk of morbidity. Rarely, however, placenta accreta spectrum is incidentally diagnosed at vaginal delivery, but there is a scarcity of data regarding these events. This study aimed to examine the incidence, characteristics, and outcomes of pregnant individuals with incidentally diagnosed placenta accreta spectrum at term vaginal delivery. This was a retrospective cohort study investigating the Healthcare Cost and Utilization Project's National Inpatient Sample. The study population was 8,694,669 term vaginal deliveries from January 2016 to December 2019. Exclusion criteria included previous uterine scar, placenta previa, and preterm delivery. Exposure was assigned by the diagnosis of placenta accreta spectrum. The main outcomes were: (1) incidence rate, (2) clinical and pregnancy characteristics, and (3) maternal morbidity related to unsuspected placenta accreta spectrum at vaginal delivery. Multivariable binary logistic regression analysis and inverse probability of treatment weighting were fitted for statistical analysis. Unsuspected placenta accreta spectrum was reported in 1 in 3797 vaginal deliveries. In a multivariable analysis, the following were associated with increased likelihood of unsuspected placenta accreta spectrum (all, P<.05): (1) patient factor with older age, (2) uterine factors such as uterine anomaly and uterine myoma, (3) pregnancy factors including early-term delivery and previous recurrent pregnancy losses, and (4) fetal factors of in utero growth restriction and demise. Of those, uterine anomaly had the greatest association with unsuspected placenta accreta spectrum (adjusted odds ratio, 6.23; 95% confidence interval, 4.20-9.26). In a propensity score-weighted model, patients in the unsuspected placenta accreta spectrum group were more likely to have hemorrhage (65.2% vs 4.1%), blood product transfusion (21.3% vs 0.6%), hysterectomy (14.9% vs <0.1%), coagulopathy (2.9% vs 0.1%), and shock (2.9% vs <0.1%) compared with those without placenta accreta spectrum. Patients in the unsuspected placenta accreta spectrum group were also more likely to receive manual removal of the placenta compared with those in the non-placenta accreta spectrum group (25.1% vs 0.6%). This study suggests that although unsuspected placenta accreta spectrum among patients undergoing term vaginal delivery is rare, it is associated with significant morbidity. The observed association between uterine anomalies and placenta accreta spectrum warrants further investigation.

Rau AR ，Youssefzadeh AC ，Matsuzaki S ，Mandelbaum RS ，Ouzounian JG ，Matsuo K ... -  《-》

Emergency delivery in pregnancies at high probability of placenta accreta spectrum on prenatal imaging: a systematic review and meta-analysis.

Placenta accreta spectrum disorders are associated with a high risk of maternal morbidity, particularly when surgery is performed under emergency conditions. This study aimed to investigate the incidence of emergency cesarean delivery in patients with a high probability of placenta accreta spectrum disorders on prenatal imaging and to compare the maternal and neonatal outcomes between patients requiring emergency cesarean delivery and those not requiring emergency cesarean delivery. MEDLINE, Embase, Cochrane, and ClinicalTrials.gov databases were searched. This study included case-control studies reporting the outcomes of pregnancies with a high probability of placenta accreta spectrum on prenatal imaging confirmed at birth delivered via unplanned emergency cesarean delivery vs those delivered via planned elective cesarean delivery for maternal or fetal indications. The outcomes observed were the occurrence of emergency cesarean delivery; incidence of placenta accreta and placenta increta/placenta percreta; preterm birth at <34 weeks of gestation; and indications for emergency delivery. This study analyzed and compared the outcomes between patients who underwent emergency cesarean delivery and those who underwent elective cesarean delivery, including estimated blood loss; number of packed red blood cell units transfused and blood products transfused; transfusion of more than 4 units of packed red blood cell; ureteral, bladder, or bowel injury; disseminated intravascular coagulation; relaparotomy after the primary surgery; maternal infection or fever; wound infection; vesicouterine or vesicovaginal fistula; admission to the neonatal intensive care unit; maternal death; composite neonatal morbidity; fetal or neonatal loss; Apgar score of <7 at 5 minutes; and neonatal birthweight. Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale for case-control and cohort studies. Random-effect meta-analyses of proportions, risks, and mean differences were used to combine the data. A total of 11 studies with 1290 pregnancies complicated by placenta accreta spectrum were included in the systematic review. Emergency cesarean delivery was reported in 36.2% of pregnancies (95% confidence interval, 28.1-44.9) with placenta accreta spectrum at birth, of which 80.3% of cases (95% confidence interval, 36.5-100.0) occurred before 34 weeks of gestation. The main indication for emergency cesarean delivery was antepartum bleeding, which complicated 61.8% of the cases (95% confidence interval, 32.1-87.4). Patients who underwent emergent cesarean delivery had higher estimated blood loss during surgery (pooled mean difference, 595 mL; 95% confidence interval, 116.10-1073.90; P<.001), higher number of packed red blood cells transfused (pooled mean difference, 2.3 units; 95% confidence interval, 0.99-3.60; P<.001), and higher number of blood products transfused (pooled mean difference, 3.0; 95% confidence interval, 1.10-4.90; P=.002) than patients who underwent scheduled cesarean delivery. Patients who underwent emergency cesarean delivery had a higher risk of requiring transfusion of more than 4 units of packed red blood cell (odds ratio, 3.8; 95% confidence interval, 1.7-4.9; P=.002), bladder injury (odds ratio, 2.1; 95% confidence interval, 1.1-4.0; P=.003), disseminated intravascular coagulation (odds ratio, 6.1; 95% confidence interval, 3.1-13.1; P<.001), and admission to the intensive care unit (odds ratio, 2.1; 95% confidence interval, 1.4-3.3; P<.001). Newborns delivered via emergency cesarean delivery had a higher risk of adverse composite neonatal outcomes (odds ratio, 2.6; 95% confidence interval, 1.4-4.7; P=.019), admission to the neonatal intensive care unit (odds ratio, 2.5; 95% confidence interval, 1.1-5.6; P=.029), Apgar score of <7 at 5 minutes (odds ratio, 2.7; 95% confidence interval, 1.5-4.9; P=.002), and fetal or neonatal loss (odds ratio, 8.2; 95% confidence interval, 2.5-27.4; P<.001). Emergency cesarean delivery complicates approximately 35% of pregnancies affected by placenta accreta spectrum disorders and is associated with a higher risk of adverse maternal and neonatal outcomes. Large prospective studies are needed to evaluate the clinical and imaging signs that can identify patients with a high probability of placenta accreta spectrum at birth, patients at risk of requiring emergency cesarean delivery or peripartum hysterectomy, and patients at high risk of experiencing intrapartum hemorrhage.

Lucidi A ，Janiaux E ，Hussein AM ，Nieto-Calvache A ，Khalil A ，D'Amico A ，Rizzo G ，D'Antonio F ... -  《-》

Comparison of maternal outcomes and clinical characteristics of prenatally vs nonprenatally diagnosed placenta accreta spectrum: a systematic review and meta-analysis.

This study aimed to compare maternal outcomes of prenatally and nonprenatally diagnosed placenta accreta spectrum. A systematic literature search was performed in PubMed, the Cochrane database, and Web of Science until November 28, 2022. Studies comparing the clinical presentation of prenatally and nonprenatally diagnosed placenta accreta spectrum were included. The primary outcomes were emergent cesarean delivery, hysterectomy, blood loss volume, number of transfused blood product units, urological injury, coagulopathy, reoperation, intensive care unit admission, and maternal death. In addition, the pooled mean values for blood loss volume and the number of transfused blood product units were calculated. The secondary outcomes included maternal age, gestational age at birth, nulliparity, previous cesarean delivery, previous uterine procedure, assisted reproductive technology, placenta increta and percreta, and placenta previa. Study screening was performed after duplicates were identified and removed. The quality of each study and the publication bias were assessed. Forest plots and I2 statistics were calculated for each study outcome for each group. The main analysis was a random-effects analysis. Overall, 415 abstracts and 157 full-text studies were evaluated. Moreover, 31 studies were analyzed. Prenatally diagnosed placenta accreta spectrum was associated with a significantly lower rate of emergency cesarean delivery (odds ratio, 0.37; 95% confidence interval, 0.21-0.67), higher hysterectomy rate (odds ratio, 1.98; 95% confidence interval, 1.02-3.83), lower blood loss volume (mean difference, -0.65; 95% confidence interval, -1.17 to -0.13), and lower number of transfused red blood cell units (mean difference, -1.96; 95% confidence interval, -3.25 to -0.68) compared with nonprenatally diagnosed placenta accreta spectrum. The pooled mean values for blood loss volume and the number of transfused blood product units tended to be lower in the prenatally diagnosed placenta accreta spectrum groups than in the nonprenatally diagnosed placenta accreta spectrum groups. Nulliparity (odds ratio, 0.14; 95% confidence interval, 0.10-0.20), previous cesarean delivery (odds ratio, 6.81; 95% confidence interval, 4.12-11.25), assisted reproductive technology (odds ratio, 0.19; 95% confidence interval, 0.06-0.61), placenta increta and percreta (odds ratio, 3.97; 95% confidence interval, 2.24-7.03), and placenta previa (odds ratio, 6.81; 95% confidence interval, 4.12-11.25) showed statistical significance. No significant difference was found for the other outcomes. Despite its severity, the positive effect of prenatally diagnosed placenta accreta spectrum on outcomes underscores the necessity of a prenatal diagnosis. In addition, the pooled mean values provide a preoperative preparation guideline.

Sugai S ，Yamawaki K ，Sekizuka T ，Haino K ，Yoshihara K ，Nishijima K ... -  《-》

Focal-occult placenta accreta: a clandestine source of maternal morbidity.

Focal-occult placenta accreta spectrum is known to cause adverse obstetrical morbidity outcomes, however, direct comparisons with previa-associated placenta accreta spectrum morbidity are lacking. We sought to compare the baseline characteristics, surgical and obstetrical morbidity, and subsequent pregnancy outcomes of patients with focal-occult placenta accreta spectrum with those of patients with previa-associated accreta. A retrospective review was conducted of all pathologically confirmed placenta accreta spectrum cases from 2018 to 2022 at a tertiary care center. The baseline characteristics, surgical, obstetrical, and subsequent pregnancy outcomes were recorded. Cases of focal-occult placenta accreta spectrum was compared with cases of previa-associated placenta accreta spectrum across a range of morbidity characteristics including hemorrhagic factors, interventions, postdelivery reoperations, infections, and intensive care unit admission. Statistical comparison was performed using Kruskal-Wallis or chi-square tests, and a P value of <.05 was considered significant. A total of 74 cases were identified with 43 focal-occult and 31 previa-associated placenta accreta spectrum cases. Of those, 25.6% of the patients with focal-occult placenta accreta spectrum and 100% of the patients with previa-associated placenta accreta spectrum underwent a hysterectomy. One case of focal-occult placenta accreta spectrum and 29 cases of previa-associated placenta accreta spectrum were diagnosed antenatally. Patients with focal-occult placenta accreta spectrum did not differ from those with previa-associated placenta accreta spectrum in mean maternal age (33.0 vs 33.1 years), body mass index, or the incidence of previous dilation and curettage procedures (16.3% vs 25.8%). Patients with focal-occult placenta accreta spectrum were significantly more likely to have a lower mean parity (1.5 vs 3.6 gestations), higher gestational age at delivery (36.1 vs 33.9 weeks' gestation), and were less likely to have had a previous cesarean delivery (12/43, 27.9% vs 30/31, 96.8%). In addition, patients with focal-occult placenta accreta spectrum had less previous cesarean deliveries (mean, 0.5 vs 2.3), were more likely to have undergone in vitro fertilization (20.9% vs 3.2%), and less likely to have anterior placentation. When contrasting the clinical outcomes of patients with focal-occult placenta accreta spectrum with those with previa-associated placenta accreta spectrum, the postpartum hemorrhage rates (71.0% vs 67.4%), mean quantitative blood loss (2099 mL; range, 500-9516 mL vs 2119 mL; range 350-12,220 mL), mean units of red blood cells transfused (1.4 vs 1.7), massive transfusion rate (9.3% vs 3.2%), and intensive care unit admission rates (11.6% vs 6.5%) were not significantly different, but there was a nonsignificant trend toward higher morbidity among patients with focal-occult accreta. Patients with focal-occult accreta had a higher incidence of reoperations or return to the operating room (30.2 vs 6.5%; P=.01). When comparing focal-occult with previa-associated placenta accreta spectrum, the composite outcomes, including hemorrhagic morbidity (77.4% vs 74.4%), any maternal morbidity (83.9% vs 76.7%), and severe maternal morbidity (64.5% vs 65.1%), were not significantly different between the groups. Nine focal-occult placenta accreta spectrum patients had a subsequent pregnancy, and 3 of those had recurrent placenta accreta spectrum. Focal-occult placenta accreta spectrum presents with fewer identifiable risk factors than placenta previa-associated placenta accreta spectrum but may be associated with an in vitro fertilization pregnancy. Patients with focal-occult placenta accreta spectrum was observed to have a higher incidence of reoperation when compared with patients previa-associated placenta accreta spectrum, and no other statistically significant differences in morbidity outcomes were observed. The absence of differences in morbidity outcomes may be attributable to a lack of antenatal detection of focal-occult accreta and merits further investigation.

Larish A ，Horst K ，Brunton J ，Schenone M ，Branda M ，Mehta R ，Packard A ，VanBuren W ，Norgan A ，Shahi M ，Missert A ，Pompeian R ，Greenwood J ，Theiler R ... -  《-》