I took my birth control pill this evening at 8:30pm, and at 8:45pm I had diarrhea. Does having diarrhea decrease the effectiveness of the pill?
No. No The pill replaces the estrogen and progesterone amounts in your body. It then can fool the body into stopping ovulation. Loose stools will not change the absorption of the pill in your stomach. The pills effectiveness will not be changed by diarrhea as long as you take it daily according to label directions.
No. unless you vomited the pill.