Alice is a 25 year old pregnant lady and has been found to have Placenta Praevia at her 20 week scan. This is her first pregnancy, and she has had no complications to date. Her past medical history is unremarkable, and she only takes Folic acid. She had an appendicectomy 10 years ago. She is trying to stop smoking and currently smokes 2 cigarettes a day, drinks no alcohol and has a BMI of 18.
Which one of the following factors in her history would increase the risk of Placenta Praevia?