The statistical truth is that pills are 99.9% effective when taken perfectly, with imperfect use (ie. Not taking at the same time every day, mixing with other meds) the 'real' truth is that they are about 95%... Still a pretty damn good stat if you ask me. Since she's not ovulating you can have as much sex as you want, and no amout of sperm *should* get her pregnant... But it is theoretically possible... Even the clinical studies with 99.9% effectiveness show that 1 in 1000 women will get pg through perfect use. So it's possible... But slim