External CondomvsFertility Awareness

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	External Condom A non-hormonal barrier method that also lowers the risk of STIs, available over the counter.	Fertility Awareness Tracking body signs like temperature and cervical mucus to identify fertile days and avoid unprotected sex then.
Efficacy	87% typical use Least effective: under 90 out of 100 people successfully prevent pregnancy per year.	Least effective see details Least effective: under 90 out of 100 people successfully prevent pregnancy per year.
Cost	$0.5–$3 /per unit Insurance: Varies	$0–$100 /monthly Insurance: Varies
Duration	Single use	Ongoing daily tracking
Reversibility	Reversible	Reversible
STI Protection	Yes	No
How it works	A physical sheath worn over the penis that blocks semen from entering the vagina and reduces skin-to-skin contact that transmits STIs.	Track basal body temperature, cervical mucus, and cycle length to identify the fertile window. Avoid unprotected sex or use backup contraception on fertile days.
Prescription	OTC No prescription / OTC	OTC No prescription / OTC
Side effects	Rare local irritation from latex or lubricants	None reported
Who shouldn't use this	Known allergy to latex (use polyisoprene or polyurethane instead)	Irregular cycles that make fertile window prediction unreliable Inability to track consistently Recent childbirth, breastfeeding, or perimenopause (cycles unstable)

Key differences

External Condom duration: Single use. Fertility Awareness duration: Ongoing daily tracking. Only External Condom protects against STIs. External Condom: costs $0.5–$3 per unit. Fertility Awareness: costs $0–$100 monthly.