Spotting refers to light blood shed that occur in between two menstruation.  There are basically 3 type of spotting: -

1)   Midcycle Spotting – Generally, an indicator of high fertility. This type will normally occur around ovulation as a result of    shedding of excessive layers of endometrium which have built up under the influence of estrogen. 

2)   Implantation Spotting – An indicator of a possible pregnancy. This type will usually occur within 7-10 days after Ovulation.

3)   Pre-Menstrual Spotting – This is early shedding of endometrium as progesterone level drops, which may begin a day or two before the actual menstruation.