Abnormal Placenta

Abnormally invasive placenta—prevalence, risk factors and antenatal suspicion: results from a large population-based pregnancy cohort study in the Nordic countries


'A total of 205 cases of AIP in association with laparotomy were identified, representing 3.4 per 10 000 deliveries. 

The single most important risk factor, which was reported in 49% of all cases of AIP, was placenta praevia. 

The risk of AIP increased seven-fold after one prior caesarean section (CS) to 56-fold after three or more CS. 

Prior postpartum haemorrhage was associated with six-fold increased risk of AIP (95% confidence interval 3.7–10.9). 

Approximately 70% of all cases were not diagnosed antepartum. 

Of these, 39% had prior CS and 33% had placenta praevia.'

• How do you define and diagnose abnormally invasive placenta (AIP)?
• How common is AIP in your practice?
• What are the benefits of prospective registration of rare complications of pregnancy (compared to existing retrospective registration systems based on ICD-10 codes)?
• What are the strengths and pitfalls of amalgamating data from multiple countries?
• What are the major risk factors of AIP identified in this study? How much more likely are women with these risk factors to have AIP?
• Is antenatal suspicion of AIP associated with improved maternal and neonatal outcomes?
• How would the results of this study influence your daily practice?

Thurn L, Lindqvist PG, Jakobsson M, Colmorn LB, Klungsoyr K, Bjarnadóttir RI, Tapper AM, Børdahl PE, Gottvall K, Petersen KB, Krebs L, Gissler M, Langhoff-Roos J, Källen K. Abnormally invasive placenta—prevalence, risk factors and antenatal suspicion: results from a large population-based pregnancy cohort study in the Nordic countries. BJOG 2015; DOI: 10.1111/1471-0528.13547.