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Diaphragm vs Spermicide

A side-by-side comparison of two birth control methods — efficacy, cost, how they work, and who shouldn't use them.

Last verified October 11, 2026Updated October 11, 2026

Side-by-side comparison

Diaphragm A reusable silicone dome that covers the cervix to block sperm, used with spermicide each time you have sex.
Spermicide A chemical gel, foam, or film inserted into the vagina before sex to disable sperm, available over the counter.

Method	Diaphragm A reusable silicone dome that covers the cervix to block sperm, used with spermicide each time you have sex.	Spermicide A chemical gel, foam, or film inserted into the vagina before sex to disable sperm, available over the counter.
Efficacy	Diaphragm 83% typical use Least effective: under 90 out of 100 people successfully prevent pregnancy per year.	Spermicide 79% typical use Least effective: under 90 out of 100 people successfully prevent pregnancy per year.
Cost	Diaphragm $0–$250 Insurance: Usually	Spermicide $16–$18 per package Insurance: Varies
Duration	Diaphragm Reusable for up to 2 years (replace sooner if damaged)	Spermicide Single use, one dose before each act of sex (gel works for up to 1 hour; film goes in 15 minutes to 3 hours before sex)
Reversibility	Diaphragm Reversible	Spermicide Reversible
STI protection	Diaphragm No	Spermicide No
How it works	Diaphragm A reusable silicone dome covers the cervix to block sperm from reaching an egg. Used with spermicide for added effectiveness.	Spermicide A chemical (usually nonoxynol-9) immobilizes or kills sperm on contact. Inserted into the vagina before sex.
Prescription	Diaphragm Required Hybrid (Fitting or Ship)	Spermicide Not required Over-the-Counter
Side effects	Diaphragm Increased risk of urinary tract infection Vaginal irritation from spermicide Toxic shock syndrome risk (rare)	Spermicide Vaginal or penile irritation Increased risk of UTI Allergic reaction
Who shouldn't use this	Diaphragm Uterine or cervical anomaly preventing fit Sensitivity to silicone or spermicide Inability to insert or remove reliably History of toxic shock syndrome High risk of HIV exposure (because of the spermicide)	Spermicide Sensitivity to nonoxynol-9 High risk of HIV exposure, or HIV in you or a partner (frequent use may increase transmission risk)

Key differences

With typical use, 17 in 100 people using Diaphragm get pregnant in a year, vs 21 in 100 with Spermicide (both least effective). How long it lasts: Diaphragm, reusable for up to 2 years (replace sooner if damaged); Spermicide, single use, one dose before each act of sex (gel works for up to 1 hour; film goes in 15 minutes to 3 hours before sex). A prescription is needed for Diaphragm, not for Spermicide. Diaphragm: costs $0–$250. Spermicide: costs $16–$18 per package.