<s>[INST] Hello doctor, My fiancee has had a weird in-between period thing for about a week, and this just about a week ago. She had very slight bleeding for about a week with red to dark red to pink and sometimes brown. She had constant cramps for nine days during this as well. A week later her period is supposed to come on the 26th. She is fine and on birth control and tells me she feels good but her upper back has been hurting for the past four days and she is starting to get cramps on and off again. We had sex two days before her last period and I have a strong feeling that it is just the birth control doing this. I used a condom and made sure there were no holes. Before I finished I pulled out but the condom slipped off and it got stuck inside of her and she said nothing was coming out of her after this happened. Is birth control the cause of all of this? [/INST] Hello. Any type of hormonal contraception may cause irregular bleeding that can be unpredictable in nature. If a birth control method is changed or if pills are missed, unscheduled bleeding can also occur. All birth control methods can fail, even with perfect use and unusual bleeding can also be a sign of pregnancy. A home pregnancy test is a good idea to make sure this is not the case. Upper back pain an unusual side effect of birth control, but cramping may be normal if it is during a period. Cramping or pelvic pain in the setting of abnormal or irregular bleeding could be caused by many things including ovarian cysts, early or abnormal pregnancy, urinary tract infections, sexually transmitted infections or PID (pelvic inflammatory disease). She would need an exam and further testing in order to confirm the exact cause of her symptoms. </s>