Materials, products and services - the Green Guide Online provides details of the life cycle environmental impacts of construction materials and components, and the Green Book is a free online database of products and services.
Spermicides are used globally for birth control, with or without condoms. As the only means of birth control, spermicides are rarely effective. However, in conjunction with condoms, spermicides are somewhat effective in birth control.
How It Works. Progestin-only birth control methods, including pills (called mini-pills), implants, and shots, prevent the ovaries from releasing an egg (ovulation), thicken mucus at the cervix so sperm cannot enter the uterus, and in rare cases, prevent a fertilized egg from implanting in the uterus.