A systematic review and meta-analysis of cesarean delivery and other uterine surgery as risk factors for placenta accreta.

BACKGROUND

The incidence of placenta accreta has increased in recent years and it has been suggested that the rising trend in cesarean delivery and other uterine surgery is the underlying cause.

OBJECTIVE

To explore the magnitude of the effect of performing single and repeat cesarean deliveries or other uterine surgery on the incidence of placenta accreta.

SEARCH STRATEGY

Relevant databases were searched for papers published before August 1, 2018, using terms including "accreta" and "cesarean."

SELECTION CRITERIA

Cohort studies assessing the risk of placenta accreta according to women's history of uterine surgery.

DATA COLLECTION AND ANALYSIS

Meta-analyses were performed to assess the risks associated between uterine surgery and placenta accreta, hysterectomy, and uterine rupture. The I statistic was used to examine between-study heterogeneity.

MAIN RESULTS

The risk of placenta accreta in a second pregnancy increased for women who had undergone a cesarean in their first pregnancy compared with vaginal delivery (OR 3.02; 95% CI, 1.50-6.08). Absolute risk of placenta accreta increased with the number of previous cesareans. The risk of uterine rupture and hysterectomy was also associated with the number of cesareans.

CONCLUSIONS

Risk of placenta accreta, hysterectomy, and uterine rupture increases with the number of previous cesarean deliveries.

PROSPERO

CRD42016050646.