Hello, Light brown bleeding can occur for a variety of reasons, including hormonal fluctuations, changes in medication, or certain medical conditions. In the context of birth control, missing or delaying pills can sometimes cause irregular bleeding or spotting. Here are some possible explanations for light brown bleeding when there were still 4 active birth control pills pending to be taken: * Hormonal changes: Birth control pills work by regulating hormones in the body, and any changes to the timing or dose of the pills can sometimes cause irregular bleeding. * Missed pills: Missing or delaying birth control pills can sometimes cause irregular bleeding or spotting. In this case, the light brown bleeding may be due to missing or delaying one or more pills. * Medication interactions: Some medications can interact with birth control pills and affect their effectiveness or cause irregular bleeding. It is important to discuss any new medications with your healthcare provider if you are taking birth control pills. * Medical conditions: Certain medical conditions, such as polyps or infections in the reproductive system, can cause irregular bleeding. It is recommended to continue taking the birth control pills as directed and to use an additional form of contraception, such as condoms, if there has been a missed pill or delay. If the light brown bleeding persists or is accompanied by other symptoms, such as pain or fever, it is important to consult a healthcare provider for further evaluation. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. H. Kay, General & Family Physician