Most women are already well acquainted with spotting by the time they become pregnant. You’ve probably experienced spotting before or after your period, or after switching, stopping or starting a new birth control. For the most part, spotting is completely harmless, but it’s crucial that you know the difference between spotting and bleeding when you become pregnant.

The term spotting refers to a light vaginal bleeding that is usually brown or pink. If you’re spotting, a single panty liner will be enough to catch the stain. Spotting during your first trimester is completely normal. The most common time that women notice spotting during their pregnancy is actually before they even realize that they’re pregnant. Spotting usually occurs after implantation bleeding. So, after you conceive but before you take your pregnancy test, you’ll likely experience some spotting. Although, sometimes spotting occurs randomly between periods with no explanation, so don’t let this alone persuade you that you’re pregnant. In general, spotting during your first trimester is nothing to worry about. Spotting late in your pregnancy though could actually be a sign of going into labor.

On the other hand, you need to be diligently on the lookout for any vaginal bleeding. Unlike spotting, blood will look bright red and it will probably soak through a panty liner or pad. If you have any vaginal bleeding during your pregnancy, it’s usually a sign something is wrong and you need to see your doctor immediately. Bleeding could be a sign that there’s a serious problem with your placenta. If you have vaginal bleeding in the first trimester and your doctor doesn’t see anything immediately wrong, studies show that this often leads to serious complications later in the pregnancy due to abnormal placental changes. However, bleeding could also be a sign of something even more serious, such as an infection, an ectopic pregnancy or a miscarriage. These are all serious and potentially fatal complications, so make sure you call your doctor right away if you notice any bleeding.

If you’re unsure whether you’re bleeding or spotting, it’s better to err on the side of safety. Call your pregnancy doctor if you notice any unusual coloration in your discharge. If it’s blood, it’s better to catch any problem immediately, so you should get a check up. However, if you know that you’re spotting, especially during your first trimester, there’s no need to panic, as this is common.

Source: Reem Hasan et al: Patterns and Predictors of Vaginal Bleeding in the First Trimester of Pregnancy. Annals of Epidemiology Volume 20 Issue 7 pp. 524-531 July 2010