Menu Healthy Lifestyle Diseases & Conditions First Aid Symptoms Tests & Procedures Videos Definitions FAQs MiscarriageUpdated: 2017-06-13OverviewA miscarriage is the loss of a pregnancy before the 20th week. Most occur before the 12th week. Most happen because the fetus isn't developing normally.SymptomsSymptoms include fluid, blood, or tissue passing from the vagina and pain in the belly or lower back. © 1998-2022 Mayo Foundation for Medical Education and Research(MFMER). All rights reserved. Terms of Use