How much my BBT temperature shift upon ovulation?

A BBT chart helps determine the fertile time window. In order to obtain records for a BBT chart, basal body temperature should be taken every morning before anything is done. A temperature increase is normally observed 48 hours after ovulation, to the extent of 0.4F to 1F (0.25C to 0.55C). A slight dip of basal temperature could occur before the temperature shift to a higher level.

The shift is caused by the manufacturing of hormone progesterone which starts to be secreted at the moment of the release of the ovum from ovarian follicle into fallopian tube. The follicle experiences a transformation and turns to "corpus luteum". During the luteal phase of menstrual cycle, the corpus luteum produces and emits progesterone.

By taking BBT charting, infertile factors may be acknowledged, if there is any. Your doctor can further utilize this chart to interpret any abnormalities.