Triphasic Temperature Pattern

To understand what a triphasic temperature pattern is, you must first know the basics of charting.

Fig.1 - A triphasic chart, however this one did not result in pregnancy.

After an embryo implants in the uterus, it immediately beings to produce hCG, which is a chemical signal to the corpus luteum cyst to continue progesterone production, instead of dissolving when there is no pregnancy. As hCG levels rise, they stimulate the CL cyst more. This sometimes causes a third level of temperatures. About 30% of triphasic charts have confirmed pregnancy. The later the triphasic shift happens, the more likely it's a good pregnancy symptom. Sometimes the triphasic shift doesn't happen until after the luteal phase has been extended by pregnancy. Charts with the triphasic shift before 8dpo, are most likely the result of progesterone levels naturally or artificially peaking, and may or not be a symptom.