The sympto-thermal method of NFP is a well-researched method of family-planning and the term “Sympto-thermal” means that at least two indicators are used to define the fertile time.

1. The “Symptom” is the mucus which reveals the onset of ovarian activity and the start of the fertile phase.

2. “Thermal” refers to the temperature rise in the cycle. It indicates that the ovum (human egg) has been released into the fallopian tube, which is the end of the fertile phase.

How does the method work?

The sympto-thermal method of contraception is a double check method that is based on detection of both the beginning and end of the fertile phase. It was recommended and introduced into Europe by Dr Anna Flynn and John Kelly.

By recording first the temperature each day and then the changes in quality and quantity of the mucus, it is possible to determine the beginning and end of fertile and infertile days of the menstrual cycle.

A third optional sign, checking the lower opening of the uterus, the cervix, can be another useful indicator of ovulation, as also breast tenderness and abdominal pain. These can be very useful during breast feeding, the menopause and times of illness when the temperature is fluctuating.

The sympto-thermal method caters for each married couple as each woman is unique and has her own pattern of fertility. With guidance, it is possible to learn to record and interpret the chart and be confident of knowing the infertile and fertile times and so to choose or avoid pregnancy.