Meeting Paper
SMFM Papers
The effect of placental location in cases of placenta accreta spectrum

Presented as a poster at the Society for Maternal-Fetal Medicine 39th Annual Pregnancy Meeting, Las Vegas, NV, Feb. 13−16, 2019.
https://doi.org/10.1016/j.ajog.2019.07.028Get rights and content

Background

Placenta accreta spectrum affects approximately 3 in 1000 pregnancies. There is a paucity of data evaluating the effect of placental location on diagnosis, risk factors, and resultant outcomes in cases of placenta accreta spectrum.

Objective

We analyzed placenta accreta spectrum cases to assess whether risk factors or maternal outcomes varied based on placental location.

Materials and Methods

We performed a retrospective chart review of pathology-confirmed cases of placenta accreta spectrum from patients delivering at 2 large urban hospitals in the same healthcare system from 2007 to 2017. Placental location was defined by ultrasound images and confirmed by pathology reports. Location was categorized as anterior, posterior, or anterior/posterior for those with placental location at both sites. Fisher exact tests and analysis of variance were used to examine associations with measures of diagnosis, risk factors, and maternal outcomes.

Results

A total of 86 pathology-confirmed placenta accreta spectrum cases were reviewed. The distribution of placental location on ultrasound was as follows: 19% posterior, 59% anterior, and 22% anterior/posterior. We found that prior cesarean delivery was lower with posterior placenta accreta spectrum (63% vs 94% vs 84% in the anterior and anterior/posterior groups respectively; (P = .007); however, in vitro fertilization rates were significantly higher (38% vs 2% vs 5% in the anterior and anterior/posterior groups respectively; P = .001). There was also lower incidence of percreta with posterior placenta accreta spectrum compared to the anterior and anterior/posterior groups (19% vs 47% vs 58% respectively; P = .055). Posterior cases were less likely to have placenta accreta spectrum suspected prenatally (50%) compared to anterior (80%) and anterior/posterior (89%) cases (P = .019). Despite late diagnosis, ureteral injury was the only surgical complication that was more common in patients with posterior placenta accreta spectrum (13% vs 0% vs 5% for anterior and anterior/posterior groups respectively; P = .037).

Conclusion

Placenta accreta spectrum with posterior placental location is associated with delayed diagnosis, surgical complications, assisted reproductive technology, and lower numbers of prior cesarean deliveries relative to anterior location. These differences in outcomes and risk factors based on placental location may allow for heightened clinical awareness, and improved diagnosis and management.

Section snippets

Study context

Cases were identified from Abbott Northwestern and United Hospitals in the Twin Cities, part of the Allina Health system. Minnesota Perinatal Physicians (MPP) provides care for high-risk pregnancies at both hospital campuses that serve as regional perinatal health care centers, pulling in patient referrals from across the state. Prior to referral to MPP, patients may have received prenatal care at an Allina Health−owned clinic or may have been referred from a clinic outside the Allina Health

Results

There were 76,048 deliveries with consent to use medical records for research from 2007 to 2017 at the 2 hospitals. Of those women, 137 had a hysterectomy performed at the time of delivery. After reviewing pathology reports, 95 case patients were confirmed to have a diagnosis of PAS. Nine patients were excluded from the current analysis because they were missing documentation of placenta location on the ultrasound. This resulted in a final sample of 86 histology-confirmed PAS cases, which were

Comment

Although there has been a proliferation in the literature devoted to PAS,12, 13 these studies remain limited to relatively small case series because of the rarity of the disease process. In our study, we aimed to examine a large cohort of patients to further describe how contributory risk factors, diagnosis-related measures, and resultant outcomes differ based on placenta location.

We found that PAS with posterior placenta location is associated with delayed identification of PAS, surgical

References (18)

There are more references available in the full text version of this article.

Cited by (0)

The authors report no conflict of interest.

This study was funded partially by the Abbott Northwestern Foundation.

Cite this article as: Morgan EA, Sidebottom A, Vacquier M, et al. The effect of placental location in cases of placenta accreta spectrum. Am J Obstet Gynecol 2019;221:357.e1-5.

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