Barriers & Spermicide
Some contraceptive methods work by creating a barrier that prevents sperm from entering the uterus. The diaphragm and similar devices are inserted before relations and cover the opening of the cervix. These methods are permitted by some halachic authorities under certain circumstances. Condoms are not permitted, although an individual question can be asked in very extreme circumstances.
Spermicides are used together with some barrier methods to increase their effectiveness. When used alone, spermicides present few halachic problems (where contraception itself is permitted), but are only about 80% effective.
This section provides information on barrier methods of contraception and spermicides.