Q: My BBT is up for 18 days but my pregnancy test was negative today. What does this mean?
A: Sometimes it takes longer for your hCG to reach levels high enough to trigger a positive urine test and you may want to check again in 2-3 days. And sometimes there is an abnormal pregnancy with lower hCG values. If you were on medication for fertility problems, that could cause an extended luteal phase without a pregnancy. It is also possible for a corpus luteum cyst to lead to a longer luteal phase. The best thing to do is see your doctor for an examination and maybe a blood pregnancy test, exam, and ultrasound.