My wife says her color of spotting has changed from pink to brown and dark red took a pregnancy test came back negative but this is usually when her cycle is on dates might have been a little too soon but we never really heard of the color changing

Color often changes during a cycle. Some women will experience spotting during ovulation once in awhile. Some during implantation. Some a bit after a period as her body continues to remove older tissue from a recent period. Sometimes there may be a bit of spotting before a period starts. It is very individual and none of it has to happen every cycle.

If she is having just spotting, even with some color change, have her wait until after she would have normally expected her period to see if it shows or not before trying a pregnancy test if no normal period occurs.