Yes. According to the American College of Obstetricians and Gynecologists (ACOG), early pregnancy loss, meaning the loss of a pregnancy before 13 completed weeks, happens in about 10 of every 100 known pregnancies. The risk rises with age: for women over 40, about 1 in 3 pregnancies end in miscarriage.
About half of early miscarriages happen because the embryo does not develop properly, often due to an abnormal number of chromosomes. ACOG notes that miscarriage is usually a random event and that working, exercising, stress, arguments, sex, or past use of birth control pills do not cause it. Bleeding is the most common sign, and anyone with symptoms should contact their obstetrician-gynecologist.
Source: ACOG, Early Pregnancy Loss FAQ
Image: Littmann Stethoscope by Hanabishi, CC0, via Wikimedia Commons.