Incidence, risk factors and perinatal outcomes for placenta accreta in Australia and New Zealand: a case–control study

Abstract

ObjectiveEstimate the incidence of placenta accreta and describe risk factors, clinical practice and perinatal outcomes.DesignCase–control study.SettingSites in Australia and New Zealand with at least 50 births per year.ParticipantsCases were women giving birth (≥20 weeks or fetus ≥400 g) who were diagnosed with placenta accreta by antenatal imaging, at operation or by pathology specimens between 2010 and 2012. Controls were two births immediately prior to a case. A total of 295 cases were included and 570 controls.MethodsData were collected using the Australasian Maternity Outcomes Surveillance System.Primary and secondary outcome measuresIncidence, risk factors (eg, prior caesarean section (CS), maternal age) and clinical outcomes of placenta accreta (eg CS, hysterectomy and death).ResultsThe incidence of placenta accreta was 44.2/100 000 women giving birth (95% CI 39.4 to 49.5); however, this may overestimated due to the case definition used. In primiparous women, an increased odds of placenta accreta was observed in older women (adjusted OR (AOR) women≥40 vs <30: 19.1, 95% CI 4.6 to 80.3) and current multiple birth (AOR: 6.1, 95% CI 1.1 to 34.1). In multiparous women, independent risk factors were prior CS (AOR ≥2 prior sections vs 0: 13.8, 95% CI 7.4 to 26.1) and current placenta praevia (AOR: 36.3, 95% CI 14.0 to 93.7). There were two maternal deaths (case fatality rate 0.7%).Women with placenta accreta were more likely to have a caesarean section (AOR: 4.6, 95% CI 2.7 to 7.6) to be admitted to the intensive care unit (ICU)/high dependency unit (AOR: 46.1, 95% CI 22.3 to 95.4) and to have a hysterectomy (AOR: 209.0, 95% CI 19.9 to 875.0). Babies born to women with placenta accreta were more likely to be preterm, be admitted to neonatal ICU and require resuscitation.

Severe maternal morbidity during delivery hospitalisation in a large international administrative database, 2008–2013: a retrospective cohort

“…The incidence of placenta accreta in the USA is approximately 1 in 500 pregnancies, 22 which is higher than reported incidences of 1.7 per 1000 pregnancies in England 23 and 4.4 per 10 000 pregnancies in Australia. 24 The increased accreta rate in the USA likely also contributed to the increased rates of PPH and associated complications.…”

Prevalence and main outcomes of placenta accreta spectrum: a systematic review and meta-analysis

“…There were 22 retrospective studies 14, and seven prospective. 19, [47][48][49][50][51][52] Twenty-eight (28/29) were published after the year 2000 (Table 1). There were 18 studies from a single institution 14,[26][27][28][29][30][31]33,[36][37][38][39][40]42,44 , three involving two affiliated institutions 32,34,51 , two studies from the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network 48,50 , two regional studies 43,46 , three national studies 41,45,49 and two international studies involving four 19 and two 52 countries, respectively.…”

“…The clinical criteria described by the authors for the clinical diagnosis of placenta accreta spectrum at delivery felt into three categories (Table 2): basic description 32,34,35,[38][39][40]44,47,48,50,51 ; extended description 27,30,33 ; and World Health Organization (WHO) international classification. 19,36,43,46 More than a third of the studies (11/29) 14,26,29,31,37,41,42,45,49,52 did not describe the clinical criteria used for the diagnosis of placenta accreta spectrum at birth. Lateral extension of the accreta areas and detailed description of the uterine vasculature anatomical changes associated with invasive placentation were not reported by any of the 29 studies.…”

“…Three studies 34,35,38 reported on the invasion of the myometrium by placental villous tissue and four studies 20, 45,46,50 reported having confirmed the clinical diagnosis by pathologic examination at birth but with no description or reference to the criteria used. Detailed histopathologic data on the depth of villous invasiveness were only reported by ten studies 14,29,30,31,[36][37][38]42,49,52 and included 473/757 (62.5%) cases of placenta creta, 117/757 (15.4%) placenta increta and 167/757 (22.1%) placenta percreta (Table 3).…”

Placenta Praevia and Placenta Accreta: Diagnosis and Management

“…[New 2018] P All epidemiological studies of the last 2 decades have shown a direct association between the increase in caesarean deliveries and the incidence of placenta accreta spectrum (abnormally adherent and invasive placenta) in subsequent pregnancies worldwide. [111][112][113][114][115][116][117][118][119][120][121] The 2016 Nordic Obstetric Surveillance Study found that the risk of invasive placentation increases seven-fold after one prior caesarean section. 117…”