Trends, Characteristics, and Outcomes of Placenta Accreta Spectrum: A National Study in the United States

Placenta accreta spectrum (PAS) describes the phenomenon wherein the trophoblastic placental tissue morbidly attaches to the myometrium of the gravid uterus, preventing normal detachment and causing morbidity. Depending on the degree of invasion, PAS is categorized as accreta if attached to the myometrium without decidua, increta if invasion occurs into the myometrium, and percreta if invasion through the myometrium into surrounding organs occurs. The incidence of PAS has increased over the last few decades; however, national statistics related to pregnancies with PAS and outcomes related to PAS are limited. This retrospective, population-based study aimed to examine national trends, characteristics, and perioperative outcomes related to cesarean delivery (CD) for PAS in the United States. Data were obtained from the National Inpatient Sample, a publicly available inpatient database sponsored by the Agency for Healthcare Research and Quality. Women undergoing CD from October 2015 to December 2017 were included in this analysis and grouped based on the diagnosis of PAS. There were 2 primary study outcomes: patient, pregnancy, and facility characteristics related to PAS; and perioperative outcomes related to PAS measured using the generalized estimating equation on multivariable analysis. Temporal trend of PAS during the study period was evaluated by linear segmented regression with log transformation. A total of 2,727,477 women underwent CD during the study period, 8030 (0.29%) of whom were diagnosed with PAS. The most common PAS subtype was placenta accreta (6205 [0.23%]), followed by percreta (1060 [0.04%]), and increta (765 [0.03%]). The number of cases with PAS increased by 2.1% (95% confidence interval [CI], 0.9-3.3) every quarter year during the study period. Independent characteristics associated with PAS included older age (median, 33 vs 30; adjusted odds ratio [aOR] per year, 1.08; 95% CI, 1.07-1.09), recent year (2.2% increase every 3-month increment; aOR, 1.02; 95% CI, 1.01-1.04), tobacco use (8.3% vs. 5.6%; aOR, 1.26; 95% CI, 1.03-1.54), increased comorbidity (Charlson comorbidity index of >= 1; 16.6% vs 9.0%; aOR, per unit, 1.18; 95% CI, 1.10-1.26), and assisted reproductive technology (2.4% vs 0.6%; aOR, 2.40; 95% CI, 1.59-3.62). Cases related to PAS had earlier gestational age at the time of delivery compared with non-PAS cases (median 36 vs 39 weeks; P < 0.001). Pregnancy characteristics associated with increased risk of PAS included placenta previa (41.4% vs 1.5%; aOR, 32.1; 95% CI, 28.5-36.2), previous CD (66.4% vs 48.1%; aOR, 2.99; 95% CI, 2.64-3.37), breech presentation (17.1% vs 10.6%; aOR, 1.70; 95% CI, 1.46-1.98), and grand multiparity (2.1% vs 0.7%; aOR, 1.67; 95% CI, 1.13-2.47). Undergoing CD at urban teaching and large bed capacity centers was associated with PAS (P < 0.05). Women undergoing CD complicated by PAS were at higher risk of surgical morbidity (78.3% vs 10.6%; aOR, 29.1; 95% CI, 25.7-32.9) and severe maternal morbidity (60.3% vs 3.1%; aOR, 37.2; 95% CI, 33.3-41.5) compared with CD without PAS. Risks of hemorrhage, coagulopathy, shock, and death were increased sequentially from placenta accreta, increta, to percreta. The results of this national-scale retrospective trial demonstrate the diagnosis of PAS at the time of CD has increased in recent years, the incidence of PAS varies based on patient and pregnancy factors, and PAS is associated with high surgical morbidity and mortality.