Cervical CapvsDiaphragm

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	Cervical Cap A small silicone cap that fits over the cervix by suction, used with spermicide before sex.	Diaphragm A reusable silicone dome that covers the cervix to block sperm, used with spermicide each time you have sex.
Efficacy	Least effective see details Least effective: under 90 out of 100 people successfully prevent pregnancy per year.	83% typical use Least effective: under 90 out of 100 people successfully prevent pregnancy per year.
Cost	$73–$97 Insurance: Usually	$60–$112 Insurance: Usually
Duration	Reusable for 2 years (replace every 2 years or sooner if damaged)	Reusable for 1-2 years (replace every 1-2 years or sooner if damaged)
Reversibility	Reversible	Reversible
STI Protection	No	No
How it works	A small silicone cap fits snugly over the cervix and stays in place by suction, blocking sperm from entering the uterus. Used with spermicide inside the cap.	A reusable silicone dome covers the cervix to block sperm from entering the uterus. Used with spermicide for added effectiveness.
Prescription	Required Prescription required	Required Prescription required
Side effects	Vaginal irritation from spermicide Discomfort if not fitted correctly Unusual vaginal discharge if left in too long	Increased risk of urinary tract infection Vaginal irritation from spermicide Discomfort if not fitted correctly
Who shouldn't use this	Cervical anomaly preventing fit Active pelvic infection Sensitivity to silicone or spermicide Inability to insert or remove reliably	Uterine or cervical anomaly preventing fit Sensitivity to silicone or spermicide Inability to insert or remove reliably

Key differences

Cervical Cap duration: Reusable for 2 years (replace every 2 years or sooner if damaged). Diaphragm duration: Reusable for 1-2 years (replace every 1-2 years or sooner if damaged). Cervical Cap: costs $73–$97. Diaphragm: costs $60–$112.