Purpose of the article. To explore the strength of association between different maternal and pregnancy characteristics and the occurrence of abnormally invasive placenta (AIP). Materials and methods: Pubmed, Embase, CINAHL databases were searched. The risk factors for AIP explored were: obesity, age >35 years, smoking before or during pregnancy, placenta previa, prior cesarean section (CS), placenta previa and prior CS, prior uterine surgery, abortion and uterine curettage, in vitro fertilization (IVF) pregnancy and interval between a previous CS, and a subsequent pregnancy. Random-effect head-to-head meta-analyses were used to analyze the data. Results: Forty-six were included in the systematic review. Maternal obesity (Odd ratio, OR: 1.4, 95% CI 1.0–1.8), advanced maternal age (OR: 3.1, 95% CI 1.4–7.0) and parity (OR: 2.5, 95% CI 1.7–3.6), but not smoking were associated with a higher risk of AIP. The presence of placenta previa in women with at least a prior CS was associated with a higher risk of AIP compared to controls, with an OR of 12.0, 95% CI 1.6–88.0. Furthermore, the risk of AIP increased with the number of prior CS (OR of 2.6, 95% CI 1.6–4.4 and 5.4, 95% CI 1.7–17.4 for two and three prior CS respectively). Finally, IVF pregnancies were associated with a high risk of AIP, with an OR of 2.8 (95% CI 1.2–6.8). Conclusion: A prior CS and placenta previa are among the strongest risk factors for the occurrence of AIP.

Objectives: The main aim of this systematic review was to evaluate the prevalence and type of associated anomalies in fetuses with heterotaxy diagnosed prenatally on ultrasound; the perinatal outcome of these fetuses was also studied.Methods: An electronic search of MEDLINE, EMBASE and CINAHL databases was performed. Only studies reporting the prenatal diagnosis of isomerism were included. Outcomes observed included associated cardiac and extracardiac anomalies, fetal arrhythmia, abnormal karyotype, type of surgical repair and perinatal mortality. The analysis was stratified according to the type of heterotaxy syndrome (left (LAI) or right (RAI) atrial isomerism). Meta‐analyses of proportions were used to combine data. Quality assessment of the included studies was performed using the Newcastle–Ottawa Scale for cohort studies.Results: Sixteen studies (647 fetuses) were included in the analysis. Atrioventricular septal defect was the most common associated major cardiac anomaly found both in fetuses with LAI (pooled proportion (PP), 59.3% (95% CI, 44.0–73.7%)), with obstructive lesions of the right outflow tract occurring in 35.5% of these cases, and in fetuses with RAI (PP, 72.9% (95% CI, 60.4–83.7%)). Fetal arrhythmias occurred in 36.7% (95% CI, 26.9–47.2%) of cases with LAI and were mainly represented by complete atrioventricular block, while this finding was uncommon in cases with RAI (PP, 1.3% (95% CI, 0.2–3.2%)). Abnormal stomach and liver position were found, respectively, in 59.4% (95% CI, 38.1–79.0%) and 32.5% (95% CI, 11.9–57.6%) of cases with LAI, and in 54.5% (95% CI, 38.5–70.1%) and 45.9% (95% CI, 11.3–83.0%) of cases with RAI, while intestinal malrotation was detected in 14.2% (95% CI, 2.5–33.1%) of LAI and 27.1% (95% CI, 7.9–52.0%) of RAI cases. Hydrops developed in 11.8% (95% CI, 2.9–25.6%) of fetuses diagnosed prenatally with LAI. Biventricular repair was accomplished in 78.2% (95% CI, 64.3–89.4%) of cases with LAI, while univentricular repair or palliation was needed in 17.0% (95% CI, 9.7–25.9%); death during or after surgery occurred in 26.8% (95% CI, 4.6–58.7%) of LAI cases. Most children with RAI had univentricular repair and 27.8% (95% CI, 15.5–42.1%) died during or after surgery.Conclusions: Fetal heterotaxy is associated with a high prevalence of cardiac and extracardiac anomalies. Approximately one quarter of fetuses with heterotaxy died during or after surgery. Abnormal heart rhythm, especially heart block, is common in fetuses with LAI, while this finding is uncommon in RAI. Biventricular repair was common in LAI while univentricular repair was required in the majority of children affected by RAI. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.