Although there is some halachic debate on this matter, the consensus is that once the seven clean days have been fully observed, no further bedikot are required prior to immersion and colored undergarments may be worn.
A kallah, however, may not go a full week before her wedding without performing any bedikah, regardless of when she immersed during that week. This halacha relates to a special concern with a kallah, that the excitement of the upcoming wedding might lead to unexpected uterine bleeding.
Please note that there is a separate halacha permitting up to four days between a kallah's immersion and her wedding. Whether she is required to perform bedikot between immersion and the wedding in such a case is also debated; here we also follow the lenient opinions.
We usually suggest that, when possible, a kallah delay performing her hefsek taharah until nine or ten days before the wedding. This avoids a long break between the clean days and immersion or between immersion and the wedding, but still leaves a little extra time in case of difficulty.