SpongevsVaginal pH Modulator

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

Side-by-side comparison

Method	Sponge A soft foam disc placed deep in the vagina before sex. It covers the cervix and contains spermicide.	Vaginal pH Modulator A prescription gel used before sex that keeps vaginal pH acidic to disable sperm.
Efficacy	Least effective see details Least effective: under 90 out of 100 people successfully prevent pregnancy per year.	86.3% typical use Least effective: under 90 out of 100 people successfully prevent pregnancy per year.
Cost	$15–$20 /per package Insurance: No	$0–$400 /per package Insurance: Usually
Duration	Single use (can be left in place up to 24 hours and for multiple acts of sex)	Single use (effective for 1 hour)
Reversibility	Reversible	Reversible
STI Protection	No	No
How it works	A polyurethane foam disc impregnated with spermicide is placed over the cervix before sex. The spermicide kills or disables sperm and the physical barrier blocks sperm from entering the uterus.	A gel containing lactic acid, citric acid, and potassium bitartrate maintains an acidic vaginal pH that disables sperm and reduces their motility. It also acts as a physical barrier to sperm movement.
Prescription	OTC No prescription / OTC	Required Prescription required
Side effects	Vaginal irritation or dryness Increased risk of urinary tract infection Rare allergic reaction	Vaginal burning or irritation Increased risk of urinary tract infection Rare allergic reaction
Who shouldn't use this	Allergy to nonoxynol-9, benzalkonium chloride, or other spermicide ingredients History of toxic shock syndrome Active vaginal infection Inability to insert or remove reliably High risk of HIV exposure (frequent nonoxynol-9 use may increase vaginal irritation; CDC cautions)	Recurrent UTIs or urinary tract abnormalities (FDA label says avoid use)

Key differences

Sponge duration: Single use (can be left in place up to 24 hours and for multiple acts of sex). Vaginal pH Modulator duration: Single use (effective for 1 hour). Vaginal pH Modulator requires a prescription; Sponge does not. Sponge: costs $15–$20 per package. Vaginal pH Modulator: costs $0–$400 per package.