No significant difference could be shown in the development of abnormal vaginal flora in women fitted with an IUCD compared with IUS users, in a study from the UK. A total of 172 women requesting IUCD or IUS contraception were recruited to the study from contraceptive clinics between August 2000 and April 2003. In all, 78 women had a copper IUCD inserted and 94 had a progesterone-incorporated IUS. The women were assessed before and twice after fitting, using high vaginal swabs and Ison-Hay criteria for grading vaginal flora.