ABSTRACT
Background
Placenta accreta spectrum (PAS) refers to morbidly adherent trophoblastic tissue invading
into the gravid uterus and is associated with significant maternal morbidity. The
majority of PAS is suspected antenatally, and most patients undergo planned, late-preterm
cesarean hysterectomy to reduce the risk of morbidity. Rarely, however, PAS can be
incidentally diagnosed at vaginal delivery, but there is a scarcity of data regarding
these events.
Objective
To examine the incidence, characteristics and outcomes of pregnant individuals with
incidentally diagnosed PAS at term vaginal delivery.
Study Design
This is a retrospective cohort study querying the Healthcare Cost and Utilization
Project's National Inpatient Sample. The study population was 8,694,669 term vaginal
deliveries from 1/2016-12/2019. Exclusion criteria included prior uterine scar, placenta
previa, and preterm delivery. Exposure was assigned by the diagnosis of PAS. The main
outcomes were (i) incidence rate, (ii) clinical and pregnancy characteristics, and (iii) maternal morbidity related to unsuspected PAS at vaginal delivery. Multivariable
binary logistic regression analysis and inverse probability of treatment weighting
were fitted for statistical analysis.
Results
Unsuspected PAS was reported in one in 3,797 vaginal deliveries. In a multivariable
analysis, (i) patient characteristics of older age, (ii) uterine factors such as uterine anomaly and uterine myoma, (iii) pregnancy factors including early-term delivery and prior recurrent pregnancy losses,
and (iv) fetal factors of in-utero growth restriction and demise were associated with increased
likelihood of encountering unsuspected PAS (all, P<0.05). Of those, uterine anomaly had the greatest association to unsuspected PAS
(adjusted-odds ratio [aOR] 6.23, 95% confidence interval [CI] 4.20-9.26). In a propensity
score-weighted model, patients in the unsuspected PAS 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
to those without PAS. Patients in the unsuspected PAS group were also more likely
to receive manual placental removal compared to those in the non-PAS group (25.1%
vs 0.6%).
Conclusion
The current study suggests that although encountering unsuspected PAS among patients
undergoing term vaginal delivery is rare, unsuspected PAS is associated with significant
morbidity. The observed association between uterine anomalies and PAS warrants further
investigation.
Keywords
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Article info
Publication history
Accepted:
November 5,
2022
Received in revised form:
October 31,
2022
Received:
September 6,
2022
Publication stage
In Press Accepted ManuscriptIdentification
Copyright
© 2022 Elsevier Inc. All rights reserved.
