Nexplanon is a form of contraceptive that is placed in a capsule and inserted under the skin of the upper arm and protects you from becoming pregnant for three years. It is a hormone that is close to, but not exactly the same as the natural hormone that is made by your body in the second half of your menstrual cycle.
It works by preventing ovulation so that an egg is not released by the ovary during your monthly cycle. With no egg to be fertilized, pregnancy cannot occur. It also causes changes in the cervical mucus that interferes with sperm reaching the egg. There are some occasions when neither of these actions prevent fertilization of the ovum (egg).
Most of the time when this occurs, the fertilized egg is prevented from implanting in the uterus because the birth control hormones change the lining of the uterus so that it rejects the fertilized egg.
