Phase 1 · Understand the Body — Why the disease behaves the way it does.
The One-Line Truth
The whole disease in one chain
Everything on this page exists to explain this line.
A pregnancy that stops growing and ends before 20 weeks, most often because of a chromosome error the embryo could not survive.
A House That Cannot Hold Its Foundation
Imagine a newly built house with a blueprint so flawed that the walls crack as they go up—that blueprint error is like the chromosome mistake that stops the embryo from building itself correctly. The builder (hCG hormone) is sending signals to the lumber yard (corpus luteum ovary) to keep delivering support materials (progesterone), but once the builder realizes the structure is failing, those signal calls stop coming. The foundation crew (uterine lining) suddenly loses its supply orders, so the foundation begins to crumble and detach from the ground. The house's support system then starts convulsing (uterine cramping) to shake out the broken pieces, and the front door (cervix) swings open to let rubble pour out as debris and dust (tissue and blood). If chunks remain stuck inside the walls, water damage (infection) sets in because the door cannot fully seal and clean out the cavity.
ACOG Practice Bulletin No. 200: Early Pregnancy Loss, 2018 (reaffirmed 2020) · American College of Radiology Appropriateness Criteria: First Trimester Bleeding · NICE Guideline: Ectopic Pregnancy and Miscarriage, 2019 · UpToDate Clinical Guidelines (Obstetrics & Gynecology) · reviewed 2026-07-07