A Birth control implant is a capsule implanted in all women in the Silo to prevent them from conceiving an unauthorised child. Women are implanted with the device to prevent overpopulation by allowing Judicial to control who is able to conceive. When a woman is chosen to procreate—known as winning the 'lottery'—their implant is removed thus allowing them to naturally conceive[1].
For many within the Silo, however, when they were selected to have their implant remove, the implant was secretly left in, thus preventing them from conceiving a child. Allison Becker was subject to this and was forced to dig out her own implant after advice from Gloria Hildebrandt.