PT - JOURNAL ARTICLE AU - Hickey, Martha AU - Agarwal, Sweta TI - Unscheduled bleeding in combined oral contraceptive users: focus on extended-cycle and continuous-use regimens AID - 10.1783/147118909789587411 DP - 2009 Oct 01 TA - Journal of Family Planning and Reproductive Health Care PG - 245--248 VI - 35 IP - 4 4099 - http://jfprhc.bmj.com/content/35/4/245.short 4100 - http://jfprhc.bmj.com/content/35/4/245.full SO - J Fam Plann Reprod Health Care2009 Oct 01; 35 AB - Combined oral contraceptives (COCs) are highly effective when correctly used but unscheduled bleeding, which occurs fairly commonly during the early months, is disruptive for many women. The mechanisms underlying this bleeding are not fully understood. Several studies have shown that extended-cycle or continuous-use COCs are typically associated with higher initial rates of unscheduled bleeding than are conventional 21-day cyclical COCs. Some medicines, herbal supplements and smoking may increase unscheduled bleeding by interfering with estrogen metabolism. The most common cause of unscheduled bleeding is non-adherence to a prescribed COC regimen. Compliance can be improved by appropriate counselling of women about the possibility of unscheduled bleeding and the importance of adherence to the pill regimen. If abnormal bleeding persists beyond 3–4 months and causes such as incorrect usage can be ruled out, other causes should be considered.