SILCS diaphragm: postcoital testing of a new single-size contraceptive device

Contraception. 2008 Sep;78(3):237-44. doi: 10.1016/j.contraception.2008.04.118. Epub 2008 Jul 3.


Background: This study was conducted to compare the effectiveness of a new, single-size silicone contraceptive diaphragm used with either spermicide [2% nonoxynol-9 (N-9)] or lubricant in preventing sperm from penetrating midcycle cervical mucus.

Study design: A crossover postcoital test (PCT) in healthy, sexually active women not at risk for pregnancy due to tubal occlusion was conducted. Couples had a baseline PCT without a device to verify normal fertility parameters. Qualified couples underwent up to two test cycles using the SILCS diaphragm with a metal spring. A subgroup of couples underwent a third test cycle with the SILCS polymer spring diaphragm used with N-9 gel.

Results: Fifteen couples completed a baseline cycle and were randomized to order of study gel. Of these, 14 couples completed a baseline cycle and at least one test cycle, 12 couples completed a baseline cycle and two test cycles and 8 couples completed a third test cycle with the polymer spring prototype. Sperm was detected in the vaginal pool in all completed test cycles. The SILCS metal spring diaphragms used with N-9 gel reduced the average number of progressively motile sperm per high power field in the cervical mucus from a baseline of 12.5 to 0, while use of this device with lubricant reduced the number to 0.5. The SILCS polymer spring diaphragm used with N-9 performed the same as the metal spring used with N-9.

Conclusion: The SILCS diaphragm used with N-9 gel performed well. It is likely that the SILCS diaphragm will give acceptable results in a contraceptive effectiveness study but that adjunctive use of a chemical barrier such as N-9 gel will be necessary for it to be most effective.

Trial registration: NCT00561613.

Publication types

  • Clinical Trial, Phase I
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Cervix Mucus
  • Contraceptive Devices, Female*
  • Cross-Over Studies
  • Equipment Design
  • Female
  • Humans
  • Lubricants / therapeutic use
  • Male
  • Nonoxynol / therapeutic use*
  • Sperm Motility
  • Spermatocidal Agents / therapeutic use*
  • Treatment Outcome


  • Lubricants
  • Spermatocidal Agents
  • Nonoxynol

Associated data