It is increasing available throughout pregnancy, and it's morally acceptable. It is scientifically established that during each menstrual cycle a woman normally becomes fertile and then naturally infertile. The fertile time is the part of her cycle when sexual intercourse can result in pregnancy. A woman's body provides certain physical signs to indicate her fertile and infertile times. The most used signs are a normal discharge of cervical mucus and changes in a woman's waking temperature.
Cervical mucus is nature's way of helping a man's sperm reach a woman's egg.
About the same time she ovulates, her mucus may be abundant and have a consistency something like raw egg-white. After ovulation, her mucus normally disappears. A woman's waking temperature is lower before ovulation and rises slightly but distinctly after ovulation. After it has been elevated for several days, it is a very positive sign that she is infertile. The Sympto-Thermal Method is a system of using the mucus and the temperature signs in a crosschecking way for the highest confidence and reliabilty in family planning.