Changing risk factors for placental abruption: a case crossover study using routinely collected data from Finland, Malta and Aberdeen

Emma Anderson, Edwin Amalraj Raja, Ashalatha Shetty, Mika Gissler, Miriam Gatt, Siladitya Bhattacharya, Sohinee Bhattacharya* (Corresponding Author)

*Corresponding author for this work

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To evaluate the effects of changes in risk factors between the first two pregnancies on the occurrence of placental abruption (PA) in the same woman.

Routinely collected obstetric data from Aberdeen Maternity and Neonatal Databank, the Maltese National Obstetric Information System and the Finnish Medical Birth Register were aggregated. Records of the first two singleton pregnancies from women who had PA in one pregnancy but not the other, were identified from this pooled dataset. A case-crossover study design was used; cases were pregnancies with abruption and matched controls were pregnancies without abruption in the same woman. Conditional logistic regression was used to investigate changes in risk factors for placental abruption in pregnancies with and without abruption.

A total of 2,991 women were included in the study. Of these 1,506 (50.4%) had PA in their first pregnancy and 1,485 (49.6%) in a second pregnancy. Pregnancies complicated by preeclampsia {194 (6.5%) versus 115 (3.8%) adj OR 1.69; (95% CI 1.23–2.33)}, antepartum haemorrhage of unknown origin {556 (18.6%) versus 69 (2.3%) adjOR 27.05; 95% CI 16.61–44.03)} and placenta praevia {80 (2.7%) versus 21 (0.7%) (adjOR 3.05; 95% CI 1.74–5.36)} were associated with PA. Compared to 20 to 25 years, maternal age of 35–39 years {365 (12.2) versus 323 (10.8) (adjOR 1.32; 95% CI 1.01–1.73) and single marital status (adjOR 1.36; 95% CI 1.04–1.76) were independently associated with PA. Maternal smoking, BMI and fetal gender were not associated with PA.

Advanced maternal age, pregnancies complicated with unexplained bleeding in pregnancy, placenta praevia and preeclampsia were independently associated with a higher risk of placental abruption.
Original languageEnglish
Article numbere0233641
Number of pages15
JournalPloS ONE
Issue number6
Publication statusPublished - 11 Jun 2020

Bibliographical note


With thanks to the women from Malta, Finland and Aberdeen whose data is included and to all who contributed to the datasets used.

Data Availability: The dataset was created from three population based international datasets and permissions obtained from governing committees for the 3 databases. Therefore permission for public access to data will need to be given by all three committees. The Finnish register data have been given for this specific study, and the data cannot be shared without authorization from the register keepers. More information on the authorization application to researchers who meet the criteria for access to confidential data can be found at (THL). Similarly data from Aberdeen can be accessed by applying to the AMND steering committee found at The authors did not have special access privileges in accessing the data.

Funding: Funding was received from NHS Grampian Endowment Fund (Grant number RG14524-10) to cover data access and storage costs and for article processing charges for open access publication for this research project. The funders played no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.


  • placental abruption
  • abruptio placentae
  • risk factors
  • antepartum haemorrhage
  • case crossover study


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