One of the most effective methods of contraception among natural methods in preventing pregnancy and natural family planning is the thermal method. It is based on periodic sexual abstinence depending on the partner’s body temperature.
In the second phase of the monthly cycle, there is a constant increase in body temperature by about 0,2 – 0,6 degrees Celsius, conditioned by the action of the main hormone of this phase, i.e. progesterone. The infertile days are counted from the fourth day after the increase in body temperature, i.e. from the moment of ovulation. Safe days are counted until the onset of menstruation. It is an effective method, but it is burdened with requirements. First, the patient must cycle regularly and the temperature curve must follow the correct course. Any cold, illness, long journey or significant change in lifestyle can affect your basal body temperature reading. In addition, this method is very rigorous because it allows for intercourse only in the second phase of the cycle, which additionally, after subtracting the first four days, gives a total of about 10 infertile days. A couple using this method must be determined and motivated to follow it.
The so-called The “extended form” of this method, which consists in increasing the number of infertile days also from the beginning of menstruation to 6 days before the rise in body temperature, which is an indicator of ovulation. The version of this method is less effective because “unplanned” pregnancies are observed during its use.
To evaluate the effectiveness of each contraceptive method, the so-called Pearl Index, defined as the number of known pregnancies per 100 women using a given method for 1 year. For the discussed thermal method, the Pearl Index in the “extended” scheme is above 3, which in turn in the “strict or strict” scheme does not reach 1,4.
Text: Katarzyna Kuśmierczyk