Women with any number of births can use the diaphragm. The fit of the device should be checked after delivery or second-trimester abortion, however. The size and muscle tone of the upper vagina can change after pregnancy, however, so a new device may be needed. It is unclear whether the effectiveness of the diaphragm varies according to parity. Women of any parity can use the cervical cap, but the fit of the device should be checked after delivery or second-trimester abortion.
Parous women tend to have a much higher pregnancy rate than nulliparous women.
Yes, but not as effectively as with spermicide. Until better data on contraceptive effectiveness refute the conventional recommendations, users should be advised to add spermicide to fitted diaphragms. Two studies of nonfitted diaphragms without spermicide had conflicting results. Research on fitted diaphragm use without spermicide are also conflicting. In a randomized trial comparing fitted diaphragm use with versus without spermicide, the typical use and perfect use pregnancy rates were lower in the diaphragm with spermicide group, but the study was small, and the differences were not statistically significant.