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 ... -  《-》

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 ... -  《-》

Trends, characteristics, and outcomes of placenta accreta spectrum: a national study in the United States.

Although an infrequent occurrence, the placenta can adhere abnormally to the gravid uterus leading to significantly high maternal morbidity and mortality during cesarean delivery. Contemporary national statistics related to a morbidly adherent placenta, referred to as placenta accreta spectrum, are needed. This study aimed to examine national trends, characteristics, and perioperative outcomes of women who underwent cesarean delivery for placenta accreta spectrum in the United States. This is a population-based retrospective, observational study querying the National Inpatient Sample. The study cohort included women who underwent cesarean delivery from October 2015 to December 2017 and had a diagnosis of placenta accreta spectrum. The main outcome measures were patient characteristics and surgical outcomes related to placenta accreta spectrum assessed by the generalized estimating equation on multivariable analysis. The temporal trend of placenta accreta spectrum was also assessed by linear segmented regression with log transformation. Of 2,727,477 cases who underwent cesarean delivery during the study period, 8030 (0.29%) had the diagnosis of placenta accreta spectrum. Placenta accreta was the most common diagnosis (n=6205, 0.23%), followed by percreta (n=1060, 0.04%) and increta (n=765, 0.03%). The number of placenta accreta spectrum cases increased by 2.1% every quarter year from 0.27% to 0.32% (P=.004). On multivariable analysis, (1) patient demographics (older age, tobacco use, recent diagnosis, higher comorbidity, and use of assisted reproductive technology), (2) pregnancy characteristics (placenta previa, previous cesarean delivery, breech presentation, and grand multiparity), and (3) hospital factors (urban teaching center and large bed capacity hospital) represented the independent characteristics related to placenta accreta spectrum (all, P<.05). The median gestational age at cesarean delivery was 36 weeks for placenta accreta and 34 weeks for both placenta increta and percreta vs 39 weeks for non-placenta accreta spectrum cases (P<.001). On multivariable analysis, cesarean delivery complicated by placenta accreta spectrum was associated with increased risk of any surgical morbidities (78.3% vs 10.6%), Centers for Disease Control and Prevention-defined severe maternal morbidity (60.3% vs 3.1%), hemorrhage (54.1% vs 3.9%), coagulopathy (5.3% vs 0.3%), shock (5.0% vs 0.1%), urinary tract injury (8.3% vs 0.2%), and death (0.25% vs 0.01%) compared with cesarean delivery without placenta accreta spectrum. When further analyzed by subtype, cesarean delivery for placenta increta and percreta was associated with higher likelihood of hysterectomy (0.4% for non-placenta accreta spectrum, 45.8% for accreta, 82.4% for increta, 78.3% for percreta; P<.001) and urinary tract injury (0.2% for non-placenta accreta spectrum, 5.2% for accreta, 11.8% for increta, 24.5% for percreta; P<.001). Moreover, women in the placenta increta and percreta groups had markedly increased risks of surgical mortality compared with those without placenta accreta spectrum (increta, odds ratio, 19.9; and percreta, odds ratio, 32.1). Patient characteristics and outcomes differ across the placenta accreta spectrum subtypes, and women with placenta increta and percreta have considerably high surgical morbidity and mortality risks. Notably, 1 in 313 women undergoing cesarean delivery had a diagnosis of placenta accreta spectrum by the end of 2017, and the incidence seems to be higher than reported in previous studies.

Matsuzaki S ，Mandelbaum RS ，Sangara RN ，McCarthy LE ，Vestal NL ，Klar M ，Matsushima K ，Amaya R ，Ouzounian JG ，Matsuo 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 ... -  《-》

Incidence, risk factors and maternal outcomes of unsuspected placenta accreta spectrum disorders: a retrospective cohort study.

Zhao J ，Li Q ，Liao E ，Shi H ，Luo X ，Zhang L ，Qi H ，Zhang H ，Li J ... -  《BMC Pregnancy and Childbirth》