Contraceptive (“against conception”) devices and methods aim to prevent pregnancy. The various contraceptive devices and methods use one of two techniques to avoid pregnancy: preventing sperm and ova from meeting or making the environment unsuitable for fertilization. Hormonal methods may either prevent the ovary from releasing an egg into the uterine tubes or cause changes in the cervix or uterus, making it difficult for sperm to enter the uterus or implant a fertilized egg in the uterus. Barrier methods, withdrawal, natural family planning, and sterilization prevent sperm and ova from meeting. Intrauterine devices interfere and prevent the implantation of a fertilized ovum in the uterus.