Conclusion
In this large register-based study we observed an increased risk of OASIS associated with primiparity, instrumental delivery, increasing maternal age, previous CS and low maternal height. Obesity was observed to slightly increase the risk of OASIS if adjustments for birth weight were not made, which might be the most clinically appropriate adjustment model to use in this case. A negative association with OASIS was seen with smoking and low maternal educational levels, however there are uncertainties whether this association represents a true protective effect or a potential difference in the provision of health care. Future studies will be able to use these results in a clinical setting aimed at individual risk assessment improving women’s health.
Acknowledgements : None
Disclosure of interest : None to declare
Contributions of authorship : KA, AS and KK contributed to the overall design of the study and the analysis and interpretation of the data. KA drafted the first manuscript. AS and KK then revised and critically appraised the draft before all authors approved of the final manuscript.
Details of ethics approval : The study was approved by the Regional Medical Ethics Committee, Lund, Sweden (2018/538).
Funding : None to declare