Temperature shift and ovulation
Ovulation and the effect on body temperature
After ovulation, the hormone progesterone is produced. Progesterone has a warming influence on body temperature meaning that the body will heat up (slightly).
When tracking basal body temperature (BBT) a sustained rise can indicate that ovulation has now occurred. To accurately use BBT to help confirm ovulation, temps must rise by a minimum amount for at least 3 days (sometimes 4 depending on the temp values in the first 3 days). When subscribed to the Tempdrop premium features, a valid temp shift will be marked in the app chart for you. Use this fertility sign to help close your fertile window each cycle.
Ovulation day and temperature shift
Typically ovulation will occur in the 1-2 days before temps shift upwards but studies have shown progesterone can also start to be released before the egg is released. This means that temps may even rise a day or two before ovulation occurs. Confused? Don't be.
Cycle tracking at home isn't about determining the exact day of ovulation (we need ultrasounds to be that precise). Instead, your charting will help you confirm that ovulation did indeed occur and then, narrow that event down to a small window. You can then make an estimated guess based on your symptoms and start counting your days past ovulation to determine when your next period is due (the time from ovulation to period is usually fixed within 1-2 days for most women).
The Tempdrop app will set an ovulation indication (solid green dot) on the day before temps rise and then count the days of high temps as a luteal phase count.