What Causes Bleeding in the First Half of Pregnancy?

...and when to be concerned.

How common is bleeding in pregnancy?

Bleeding in pregnancy is considered according to when in pregnancy it occurs: prior to 20 weeks or after 20 weeks of pregnancy. Vaginal spotting or bleeding occurs in approximately 25% of pregnancies in the first trimester (up to 13+6 weeks [ie, 13 weeks plus 6 days of gestation dated from the first day of the LMP]). …