Some women experience a period like bleeding during their pregnancy.
It isn't common.

Many women can experience episodes of bleeding and spotting during pregnancy. Bleeding is especially common in the first trimester and about 30% of pregnant women experience bleeding during this time. Although fewer women bleed during the second and third trimesters, spotting is still possible and not all that uncommon. However, though this bleeding may resemble menstruation, it actually is something different altogether.

One of the most common causes of period-like bleeding during pregnancy is called decidual bleeding. Sometimes, during pregnancy, your body’s hormones can get out of whack, causing you to lose parts of the lining of your uterus. This is especially common in the early stages of pregnancy, before the lining has completely attached to the placenta. While it can be troublesome to think about shedding part if your uterine lining, decidual bleeding is generally not thought to be a health threat to you or your baby.

Right I get it...

As a follow up question: during what weeks of pregnancy does this happen? Approximately? Any idea?