The high temperature phase lasts more than 14 days is pregnancy, this is due to the appearance of the high temperature phase of women is ovulation after the body’s progesterone level is relatively high, the progesterone can adjust the body temperature center, so that the body temperature rises 0.3-0.5 ℃. If there is no pregnancy after the egg is discharged, the corpus luteum in the body will atrophy and the secretion of progesterone will decline, and after 14 days, with the decline in progesterone levels, the body temperature will also decline and menstruation will occur. If the discharged egg is fertilized, the corpus luteum will continue to increase in size, transforming into the corpus luteum of pregnancy, and continue to secrete estrogen and progesterone, thus sustaining high temperatures for more than 14 days, by which a woman can be identified as pregnant or not.