Barrier Methods (Chemical, Mechanical, Hormonal and IUDs)

Barrier Methods (Chemical, Mechanical, Hormonal and IUDs)

All barrier methods share one underlying idea — physically, chemically or hormonally keep the sperm from reaching the ovum — but they achieve it through very different mechanisms.

Chemical barrier: Foaming tablets, melting suppositories, jellies and creams are inserted into the vagina, where they chemically inactivate sperm on contact.

Mechanical barrier: Condoms are thin sheaths — made of polyurethane, latex or lambskin — worn over the penis (or, for the female equivalent, covering the vagina and cervix) before coitus, physically blocking semen from entering the reproductive tract. They are single-use and are also the only contraceptive method in this chapter that additionally protects against AIDS and other STDs. Diaphragms, cervical caps and vaults are rubber devices inserted to cover the cervix before coitus, physically stopping sperm from entering the uterus; being reusable, they differ from condoms in that regard even though both are mechanical, not chemical, barriers.

Hormonal barrier (oral contraceptives): Pills prevent ovulation by inhibiting the pituitary's secretion of FSH and LH — no egg is released, so there is nothing for sperm to fertilize — and they additionally thicken cervical mucus to further block sperm. The 'combined pill,' containing synthetic progesterone and estrogen, is the most widely used version. Saheli, developed by the Central Drug Research Institute (CDRI) in Lucknow, is a distinctive Indian alternative: a non-steroidal pill built around a compound called centchroman. …