How does a Medical Abortion Work? It works by blocking the hormone progesterone, which is necessary to sustain pregnancy. Without this hormone, the lining of the uterus breaks down, the cervix (opening of the uterus or womb) softens, and bleeding begins. Within a few hours days after taking the medication medication it will cause the uterus to contract and empty. This ends the pregnancy. If you are pregnant and cannot afford surgical abortion which is very expensive then consider medical termination with a pill. You will achieve exactly the same results, safely, quickly and cheaply.