A basal body temperature reading reports the temperature of the body when it is fully rested. The methods for checking this temperature require using a digital thermometer, which may be inserted vaginally, orally, or rectally. When checking basal body temperature, women should take a reading immediately upon waking up.
The basal body temperature is useful in helping women determine the days on which sex is most likely to lead to pregnancy. Checking basal body temperature can help a woman either to prevent a pregnancy or to become pregnant. Women who track their basal body temperature for contraception or fertility are not at risk of any side effects. Checking basal body temperature is also one way to confirm a pregnancy.
Women may choose to insert the thermometer into their mouth, vagina, or rectum. It is not recommended to change the location into which the thermometer is inserted during the same cycle. Switching from one area to another can be done after the current cycle has ended. Checking basal body temperature vaginally will produce higher temperatures than oral readings.
Experts recommend checking basal body temperature at the same time every morning. Checking the temperature at the same time throughout the cycle allows those just beginning to record, to learn about their cycles. A basal body temperature reading is not capable of alerting women in advance that they will soon ovulate. These temperature readings can only indicate ovulation after it has occurred.
Women should avoid physical activity before taking their temperature. Eating and drinking should also be postponed until after the temperature has been checked. If a woman has not had at least three to four hours of sleep upon awakening, the temperature reading will not be valid.
Several factors can affect the outcome of a basal body temperature reading. Drinking alcohol or taking medications the night before can cause temperature fluctuations. The temperature of the home can also affect the readings because it may cause a women to become warmer or colder than usual. Women checking basal body temperature must note that the reading will be lower from the time menstruation ends until ovulation begins. The temperature increases after ovulation and remains so during menstruation.
