The Hormone which forms the basis for 'Basal Body Temperature' as a method of detecting ovulation is :
Estrogen
Progesterone
HCG
Oxytocin
This Method is based on the fact that after ovulation, progesterone level in the blood increases Progesterones have a Thermogenic effect, increasing the basal metabolic rate and causing the rise of temperature by 0.5degF the luteal phase. Day of 'temperature shift' indicates the time of ovulation.
Contraceptives