Definition - What does Triphasic Chart mean?
A triphasic chart is basal body temperature (BBT) chart that shows three distinct levels of temperature rises. Charting BBT is a method to track ovulation and time intercourse to maximize the chances of conception. A triphasic pattern is considered by some to be an early sign of possible pregnancy.
FertilitySmarts explains Triphasic Chart
A BBT chart typically will show a biphasic (or two-phase) temperature chart with a pattern of relatively low preovulatory temperatures, followed by a single shift to higher postovulatory temperatures for around 12-16 days, until the start of menstruation. The temperature switch typically occurs after ovulation, which is around the middle of a cycle.
A triphasic chart includes two distinct temperature shifts. An increase in temperature after ovulation and an additional shift in the middle of the luteal phase (occurring around 7-10 days after ovulation). A temperature shift is confirmed when the elevated temperature is sustained for at least three days.
Some women believe a triphasic chart is considered a sign of possible pregnancy because the second shift can be associated with a spike in progesterone, a heat-inducing hormone responsible for raising temperatures after ovulation. Progesterone levels generally increase after the implantation of an embryo ( around 7-10 days past ovulation).
A triphasic chart is not considered a definite sign of pregnancy and pregnancy is possible without a triphasic chart.