The Basis of the Justisse Method

Cervical Mucus Cycle Wheel

The basis of the Justisse Method is the observation of cervical mucus in the menstrual cycle. Basal body temperature, cervical changes, and other cycle events and signs of fertility are used to support the information provided by cervical mucus observations. All events and signs are important in understanding reproductive health and fertility.

The 1st day of the cycle is the 1st day of menstruation. Menstrual flow lasts about three to seven days. A healthy menstrual flow begins as heavy or moderate and subsides to light or very light.

After menstruation, you will usually notice a few days where the sensation at the vulva is and no cervical mucus is observed (except in shorter cycles).

After those dry days, you may notice some discharge at the vulva. You may notice it on your undergarments or as a sensation of extra smoothness or lubrication when you wipe yourself after going to the bathroom. You may first notice a sticky white mucus discharge. After a few days, the discharge becomes clear and/or stretchy, accompanied by a sensation of lubrication or slipperiness at the vulva. The last day of mucus that is clear, stretchy, or lubricative is called the Peak Day.

Following the Peak Day, there is a dramatic change. The mucus changes to a sticky white discharge or disappears altogether. The sensation at the vulva returns to dry. From the 4th day after peak until the beginning of the next menstrual flow, you will notice you are dry.

Fertile days include the menstrual flow and all mucus days, from the first day mucus appears through to the Peak Day and for 3 days following.

Infertile days include the dry days after menstruation and from the fourth day after Peak Day until the beginning of the next menstruation.

In the diagram of the “cervical mucus cycle wheel” you will notice that the days between the Peak Day and the onset of menstruation are numbered from 1 to 14. No numbers appear from the start of menstruation and up to and including the Peak Day. This is because the phase before Peak Day may vary in length. The phase after Peak Day is stable in length. Fourteen (14) days is the average length of this post-Peak-phase. Peak Day correlates very closely with the time of ovulation.

Occasionally women experience a cycle that is shorter cycle than they would normally expect. When this happens, ovulation may occur earlier in the cycle. The clue to an early ovulation is that there are no dry days following menstruation. Instead, mucus will be present during the light and very light days of menstrual flow. Taking this possibility into consideration, and being aware that you cannot predict when a cycle will be short, the menstrual flow is considered fertile. However, the light and very light days of the menstrual flow can be observed for mucus as any other day. If there is no mucus on the light and very light days then these days are infertile.

All days of menstruation are considered fertile until a woman can confidently identify her light days of bleeding as dry. As well, she must be confident that her bleeding is a true menstrual bleed and not another type of bleeding. When she is confident of these two things then she may consider days 1-5 (the first 5 days) of her menstrual cycle as infertile. Such confidence generally comes after having charted for at least one year.

The Count of 3 after Peak Day is necessary because ovulation can possibly occur on those days. On average, ovulation occurs on Peak Day. However, statistics have shown that ovulation can occur on the first, second or third day after peak, or the day before Peak. Even though you are dry on the days after peak your vaginal environment is still alkaline enough to support sperm life. Thus if ovulation were to occur on one of those dry days within the Count of 3 intercourse might result in a pregnancy. That is why those days are considered fertile, and it is important for a woman who is avoiding pregnancy or wanting to become pregnant to consider this.