Q: Is there something like an 'abnormal' BBT curve?
A: BBT chart cannot be classified as 'abnormal' or 'normal' and you should be more specific about what it is that you see. You should not try to make anything out of a one-day temperature. Some charts look more typical than others, but because there are so many variables, no two charts ever look alike. Most doctors prefer to take a look at the temperature curve at the end of the cycle, the first day when you get your period. At that time it becomes so much easier to interpret it as either 'ovulatory' (biphasic with ovulation) or 'anovulatory.'