Basal Body Temperature
Abbreviated BBT. Indirect evidence of ovulation can be obtained with the basal body temperature chart. The temperature can be taken orally with a digital thermometer immediately upon awakening and before any activity. This is recorded on a special graph that enables you to visualize the different temperature shifts. The temperature will drop to its lowest point, 1-2 days prior to ovulation, and then rises and remains elevated until a couple of days before impending menstruation. If the individual is pregnant the temperature will remain elevated. This elevation is not considered a fever because it will never exceed 38ºC (100ºF). This test is unfortunately not very reliable in every woman, and is therefore not used universally. Urine ovulation prediction testing is a better way to document ovulation and to determine prospectively when ovulation will occur.