There is still much to learn about the virus. Studies from the USA showed that pregnant women with swine flu were four times more likely to be hospitalised for complications compared to the non-pregnant population. In separate studies pregnant women are over represented in the group of patients admitted to hospital requiring Level 2 (High Dependency Care) or Level 3 care (Critical/Intensive Care). Observations from the USA, Canada and Australasia showed that pregnant women formed between 7 and 9% of admissions to Intensive Care Units (ICU).