The study was renewed in 1995 to continue data collection to establish the effect of triphasic OCs on MI risk, with particular attention to the joint effect with heavy smoking. The new data collection also permitted more definitive analysis of the effect of monophasic OCs. Triphasic formulations have become popular and in 1995 accounted for about half of OC use. There were not enough users of triphasic OCs in the present study for informative analysis, nor were there any data from other studies on this issue. The study ended in December, 1999.