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

Abstract

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 I2 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.

Effectiveness of contingent screening for placenta accreta spectrum disorders based on persistent low‐lying placenta and previous uterine surgery

“…16-99.88%) and specificity, 100% (95% CI, 99.07-100%)). Univariate analysis demonstrated that parity ≥ 2 (odds ratio (OR), 35.50 (95% CI, 6.90-649.00)), two or more previous Cesarean sections (OR,94.20 (95% CI,22.00-656.00)) and placenta previa (OR,20.50 (95% CI,.00)) were the strongest risk factors for PAS. In the diagnostic cohort, there were 173 referrals, with one false-positive and three false-negative diagnoses, resulting in a sensitivity…”

“…The incidence of PAS is increasing worldwide, which is attributed to the rising rate of Cesarean section 2–5 . Previous Cesarean birth is associated with an almost three‐fold increase in the risk of PAS in the next pregnancy, as compared with previous vaginal delivery 6 . The main risk factor for PAS in the current pregnancy is a diagnosis of placenta previa, with more than 90% of PAS cases being associated with placenta previa combined with a history of uterine surgery 7–10 .…”

Magnitude e determinantes da mortalidade neonatal e pós-neonatal em Goiânia, Goiás: um estudo de coorte retrospectivo, 2012

“…11,12,23,24 This protective effect of cesarean delivery may be related to the fact that in Goiânia 75% of childbirths were via cesarean section, performed in an operating theater, under the care of an obstetrician and with less risk of complications related to normal childbirth -such as amniotic fluid and meconium inhalation, macrosomia and infections. 25 For the purposes of comparison, a study conducted in Florianópolis, SC, found that cesarean sections accounted for 53% of childbirths, with no statistically significant difference in relation to the 'infant death' outcome. 1 A case-control study of determinants of infant mortality in 27 Brazilian state capitals, which also has as its study population infant deaths occurring in 2012, found that cesarean delivery was a protective factor in its analysis of the capital cities of Brazil's Midwest region and for all the Brazilian state capitals.…”

Time to reconsider elective Cesarean birth

“…Evidence from large epidemiological studies has demonstrated that the majority of the risk factors are confounders by virtue of being proxy markers for either previous Cesarean birth or placenta previa. The combination of a low-lying placenta and previous Cesarean section has been found to be the strongest risk factor for AIP [10][11][12][13][14][15] (Table 1). It is likely that maternal age, obesity and parity are proxies for increased risk of Cesarean birth, whilst embryo replacement in IVF predisposes to low uterine implantation and subsequent placenta previa 13,14 .…”