Abstract

PIP: The vaginal contraceptive sponge, approved on April 1, 1983 by the US Food Administration (FDA) for sale in the US as a single use, disposable, over-the-counter contraceptive, is made of polyurethane and designed to be biocompatible with the vaginal environment. The sponge is available in a single size, is round, and about 5.5 cm in diameter and 2.5 cm thick. An indentation on 1 side helps to ensure the sponge's correct placement against the cervix. A polyester retrieval loop attached to the sponge facilitates removal. Postcoital tests of the sponge without the spermicide indicated that it was ineffective in preventing sperm from entering the cervical canal. Before insertion, the contraceptive sponge is moistened with tap water to activate the spermicide and is inserted into the vagina with the indentation placed against the cervis. The sponge has been designed to provide continuous protection against pregnancy for at least 24 hours after insertion. Following a successful phase ii clinical trail of the sponge, in 1979 comparative phase iii clinical trials were initiated by Family Health International. The following trials were conducted: sponge versus the diaphragm (arcing-spring) used with a spermicide (nonoxynol-9) at 13 clinics in the US (1439 subjects) and at 2 clinics in Canada and the UK (502 subjects); sponge versus a foaming spermicidal (menfegol) suppository at 5 clinics in Yugoslavia, Taiwan, and Bangladesh (1386) subjects); and sponge versus spermicidal (nonoxynol-9) foam at 2 clinics in Israel and Thailand (366 subjects). In all trials the contraceptive methods were raondomly assigned. Clinics were required to follow up subjects for 1 year. Only the US study has been completed. In the comparative trials of the sponge and diaphragm (both US based and overseas) the pregnancy rates were significantly higher for the sponge. In the comparative trials of the sponge and foaming suppositories or spermicidal foam there were no significant differences between the pregnancy rates of the sponge and the other contraceptive methods. In the US based trial of the sponge the differences between cumulative 12 month pregnancy rates were relatively small--16.8 and 12.5 pregnancies/100 women for sponge and diaphragm users, respectively. No cases of toxic shock syndrime (TSS) or other serious omplications have occurred among 1848 women who have participated in the clinical trials of the sponge and who have accounted for 1068 woman years of sponge use. Advantages of the sponge include: it can be purchased without prescription and is easy to use and is not messy; sexual spontaneity is enhanced in that it may be inserted up to 24 hours before sexual intercourse; a single size fits all women; and after insertion, it immediately provides protection against pregnancy for at least 24 hours.