Breastfeeding Birth ControlvsCopper IUD

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	Breastfeeding Birth Control A natural postpartum method (lactational amenorrhea method, LAM) that relies on exclusive breastfeeding to suppress ovulation, effective for up to 6 months.	Copper IUD A small copper device placed in the uterus that works for up to 10 years and is over 99% effective.
Efficacy	98% typical use Moderately effective: over 90 out of 100 people successfully prevent pregnancy per year.	99.2% typical use Most effective: over 99 out of 100 people successfully prevent pregnancy per year.
Cost	$0–$300 Insurance: Varies	$0–$1,424 Insurance: Usually
Duration	Up to 6 months postpartum	Up to 10 years
Reversibility	Reversible	Reversible
STI Protection	No	No
How it works	Exclusive breastfeeding suppresses the hormones that trigger ovulation. High prolactin from frequent nursing keeps estrogen and progesterone low, preventing the return of menstrual cycles.	Releases copper ions into the uterus that make the environment toxic to sperm and may prevent implantation if fertilization occurs.
Prescription	OTC No prescription / OTC	Required Prescription required
Side effects	None reported	Heavier or longer periods (especially first few months) Increased cramping Spotting between periods Small risk of uterine perforation at insertion
Who shouldn't use this	Baby over 6 months old Periods have returned Not exclusively or nearly exclusively breastfeeding Use of supplemental formula or solid foods	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)

Key differences

Copper IUD is more effective (99.2% vs 98% typical use). Breastfeeding Birth Control duration: Up to 6 months postpartum. Copper IUD duration: Up to 10 years. Copper IUD requires a prescription; Breastfeeding Birth Control does not. Breastfeeding Birth Control: costs $0–$300. Copper IUD: costs $0–$1,424.