Spotting is light vaginal bleeding, usually involving a small amount of blood that will not wet the panty liner. The color of the spotting may be bright red or appear pink or brown.
What is the reason of this?
Although any bleeding during pregnancy should be taken seriously, spotting during the first trimester is quite normal. Pink or brown spotting during the first few weeks of pregnancy is likely implantation bleeding. Spotting in the first trimester can be a side effect of pregnancy-related hormone changes or uterine polyps and fibroids. However, spotting in the first twelve weeks of pregnancy can also be caused by more serious conditions such as infection, miscarriage, ectopic or molar pregnancy, or cervical insufficiency.
Spotting is less common in the later stages of pregnancy. Any color or amount of spotting could be a sign of a pregnancy complication such as preterm birth or placenta or uterine problems, all of which require medical treatment. Towards the end of pregnancy, pink spotting can be a bloody show.
Normal activities during pregnancy, such as sexual intercourse or pap smears, can also cause spotting.
Tips
Any spotting during pregnancy should always be discussed with your doctor. It's not always a sign of a problem, but to be on the safe, you'll want to let your healthcare provider know when you're experiencing this symptom. If you notice extremely light spotting that disappears within a few hours, you can report this to your provider within 24 hours. Any other type of detection – especially after the first trimester – should be reported to your healthcare provider immediately so he or she can rule out an underlying condition and make sure everything is progressing normally.

