Before Ovulation (low chance of pregnancy):
The first few days following menstruation, there will be little or no discharge present. You will feel dryness around your vulva. During this time, chances of getting pregnant are low.
Approaching Ovulation (chance of pregnancy):
The first discharge that does appear should be moist or sticky and should be white or cream in color. In the finger test, the mucus should break easily. You will only be able to pull your fingers about 1 cm apart before it breaks. During this transition time, first the mucus will become cloudy and slightly stretchy during the finger test (this means that it will still break before the fingers are stretched all the way). As time progresses, the mucus will become greater in volume.
Right around ovulation (high chance of pregnancy):
At this stage, mucus resembles egg whites. It is the thinnest, clearest and most abundant at this point in the cycle. Finger testing will allow the mucus to stretch quite a ways (several centimeters) before it breaks (if it breaks at all). ) The amount of this thin mucus will steadily increase until you experience your 'mucus peak'. This is the last day of this period where the chance of conception is high. It is closely tied to ovulation. During this phase, the sperm's survival rate is higher. It can survive in cervical mucus for up to 72 hours, a significantly longer time than during the rest of the cycle.
After Ovulation (low chance of pregnancy):
After ovulation, there is a marked change in mucus appearance. It returns to the sticky stage (does not stretch during finger test) and there is again a feeling of dryness around the vulva.
One caution for this test is that sperm can be confused with the mucus secretions and you could make wrong assumptions. Also, vaginal infections, medication, and birth control can alter conditions and should be taken into consideration when examining any vaginal secretions.
There are several cases where you may not be able to collect an adequate sample of cervical mucus. Medications, being over 35, & not ovulating can have a dramatic effect on your body's ability to produce the fertile cervical mucus.