Copper IUDvsDiaphragm

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
Copper IUD

Copper IUD

A small copper device placed in the uterus that works for up to 10 years and is over 99% effective.
Diaphragm

Diaphragm

A reusable silicone dome that covers the cervix to block sperm, used with spermicide each time you have sex.
Efficacy99.2% typical use

Most effective: over 99 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$0–$1,424

Insurance: Usually

$60–$112

Insurance: Usually

DurationUp to 10 yearsReusable for 1-2 years (replace every 1-2 years or sooner if damaged)
ReversibilityReversibleReversible
STI ProtectionNoNo
How it works

Releases copper ions into the uterus that make the environment toxic to sperm and may prevent implantation if fertilization occurs.

A reusable silicone dome covers the cervix to block sperm from entering the uterus. Used with spermicide for added effectiveness.

PrescriptionRequired Prescription requiredRequired Prescription required
Side effects
  • Heavier or longer periods (especially first few months)
  • Increased cramping
  • Spotting between periods
  • Small risk of uterine perforation at insertion
  • Increased risk of urinary tract infection
  • Vaginal irritation from spermicide
  • Discomfort if not fitted correctly
Who shouldn't use this
  • Active pelvic infection or PID (FDA label)
  • Uterine anomaly preventing insertion (FDA label)
  • Wilson's disease (copper metabolism disorder) (FDA label)
  • Known copper allergy (FDA label)
  • Current pregnancy (FDA label)
  • Uterine or cervical anomaly preventing fit
  • Sensitivity to silicone or spermicide
  • Inability to insert or remove reliably

Key differences

Copper IUD is more effective (99.2% vs 83% typical use). Copper IUD duration: Up to 10 years. Diaphragm duration: Reusable for 1-2 years (replace every 1-2 years or sooner if damaged). Copper IUD: costs $0–$1,424. Diaphragm: costs $60–$112.