Fferent surveys using the date of filling in the questionnaire. We then grouped the surveys as follows: 6?8 months = 1-year follow-up, 19?8 months = 2-year follow-up, 29?2 months = 3year follow-up, 43?9 months =4-year follow-up. Women who left one or more follow-up surveys unanswered formed a separate group (intermittent surveys). We classified women into those who had or had not had symptoms in t