The single-size (70 mm) SILCS silicone diaphragm
A reader’s query: This was posted as a reader’s comment and my reply on my October 23, 2010 Entry “Gas guards for high school girls”. It concerns a new design for a cervical barrier that still has to be approved by the FDA. I haven’t discussed SILCS before so I thought I would re-post this discussion where more readers can read it.
The reader wrote: “SILCS is an intravaginal barrier device currently under development. It is made of silicone with an arcing ring. SILCS has a pre-shaped rim to cling high in the vaginal vault and a finger cup on one edge for easy removal. It will be a one-size-fits-all device. I would appreciate your expert opinion on this new contraceptive Diaphragm. http://www.path.org/projects/silcs.php”
My reply: Actually, SILCS is a single size (70 mm) one-size-fits-most device of advanced design. I like the design, but I hate the fact that it will be available in only a single size. Current thinking is that SILCS may be available as early as 2011. The FDA has yet to approve it for use in the U.S. I am very skeptical about the effectiveness of one-size-fits-most contraceptive devices.
The intention of PATH is to develop a simple inexpensive device that poor women in under-developed countries can use without the attendant costs of medical providers, pelvic exams and fitting visits and in this they may be successful. The four most prescribed diaphragm sizes in the U.S and Europe are 65 mm, 70 mm, 75 mm and 80 mm. Currently diaphragms are made in sizes from 60 mm to 90 mm.
That SILCS will only be available in a single 70 mm size is worrying. A single 70 mm size is too small in a traditionally shaped diaphragm for many women and using a too small device would decrease its overall effectiveness for users. That’s because a traditionally shaped diaphragm that is too small will expose the anterior rim to the likelihood of being thrust underneath by a partner’s thrusting penis. With the penis under the dome at ejaculation sperm is deposited against the cervix protected only by the spermicide which should be applied in the dome. The curved relief arch (on the anterior rim) of the SILCS design may (or may not) go some way to minimizing the problem of under-thrusting, but we won’t know about that for years.
I have no doubt that if SLICS becomes easily available in under-developed areas where it will give women something to use where previously they had nothing, then it is a major step forward. I’m not at all certain that it is as good as or better than a properly fitted and correctly inserted traditionally shaped diaphragm.