The phrase "uterus wall" refers to the thick muscular layer surrounding the uterus, which is a part of the female reproductive system. It helps support and protect the growing baby during pregnancy. Full definition
And about the kid it is possible not to worry, uterus walls well protect bubble in which it is. (infobaby.org)
For people who believe that life begins at conception, that means that life begins when the egg is fertilized, not when it attaches to the uterus wall. (religion.blogs.cnn.com)
Implantation, as widely understood by women, is an event happening during a woman's pregnancy where the egg adheres to the uterus wall. (shrewdmommy.com)