Birth Control & Fertility

Updated: August 2025

See how each method changes pregnancy odds — then get your personal estimate.

Different contraceptives change your pregnancy odds in very different ways — and how you use them matters just as much as the method. Use the tools above to see your numbers, or skim the quick guide below for what most people get wrong about condoms, pills, IUDs, implants, and “natural” methods.

Method snapshots

Barrier methods (condoms, diaphragms)

  • Best when used consistently and correctly; slips/breaks/late withdrawal drive most risk.
  • See your personal odds: Condom Risk Calculator

Hormonal methods (pill, patch, ring, shot)

  • Missed or delayed doses are the main leak—use reminders or continuous packs if appropriate.
  • Quick check while on the pill: Pill Risk Calculator

Long-acting reversible contraception (IUDs, implant)

Fertility awareness & withdrawal

  • Highly user-skill dependent—accurate tracking helps, but there’s little buffer for mistakes.
  • Consider a backup barrier on higher-risk days.

Combining Methods

Using two methods can dramatically reduce risk — but not every combo helps.

Best/Worst Pairs — Guide Combine Methods Calculator Advanced Calculator

Tip: Compare typical vs perfect use in the calculators for realistic results.

FAQ

Does hormonal birth control harm long-term fertility?
No clear evidence of permanent harm; cycles may take time to normalize after stopping. Timing varies by method.
What actually causes most “failures”?
Missed/late doses, late/incorrect condom use, device timing (insertion/replacement), and intercourse on high-risk days without backup.
Should I use perfect or typical use in your tools?
If you sometimes slip on timing/technique, choose typical; if you’re consistently precise, choose perfect. You can compare both.
What if I use two methods?
Use the Combine Methods Calculator to see the combined effect. Some pairings help a lot; others add little.

Educational content only; not medical advice. For personalized guidance, consult a qualified clinician.

Check Out Our Latest Contraceptives and Fertility Posts

  • Contraceptive Use Quality Feature Image
    How Use Quality Impacts Contraceptive Effectiveness
    by Sam Gorman
    When choosing birth control, it’s easy to focus on the method—but how you use it matters just as much. The gap between perfect use (no mistakes) and typical use (real life) can change your odds in a big way. What “perfect” vs “typical” use means Perfect use Taking the pill at the same time daily … Read more
  • Contraceptive Methods You Should Never Mix
    by Sam Gorman
    Some contraceptive pairs reduce protection or add risk. If you want to “double up,” choose methods that complement each other—not ones that fight or cancel out. Below are combinations most people should avoid, plus better substitutes. Pairs you shouldn’t mix Don’t mix Why it’s a bad combo Better instead Two external condoms or an external … Read more
  • How Effective is Using Two Contraceptives at Once?
    by Sam Gorman
    Using two methods at the same time can lower pregnancy risk, especially if at least one method protects against user error. The calculator below estimates protection when you combine methods under typical or perfect use. Check your combined protection How the estimate works (plain math) Convert each method’s effectiveness to a failure rate. Example: 95% … Read more
  • Top Contraceptive Method Combinations for Maximum Protection
    by Sam Gorman
    Some pairs of birth control work especially well together. Below are evidence-based combinations that increase pregnancy protection while keeping STI protection in mind. When you want precise numbers for your situation, use our Combined Contraceptive Effectiveness Calculator. How “combined effectiveness” works (in plain English) Each method has a small chance of failure in a given … Read more
  • Implanon effectiveness after 3 years: what the research shows
    by Sam Gorman
    Implanon NXT is the etonogestrel contraceptive implant. The product label says to replace it at 3 years. Some studies followed users for longer and found very low pregnancy rates in years four and five. That extended use is off-label in many countries, so decisions should be made with a clinician who knows your situation. What … Read more
  • Pullout method: what the 5 hour rule and research show
    by Sam Gorman
    Withdrawal can lower pregnancy risk when done perfectly. In real life it fails often. Two findings matter here: pre-ejaculate usually has little or no sperm when there has not been a recent ejaculation, and residual sperm in the urethra seems short-lived and often clears with urination. This is where the informal “5-hour rule” comes from. … Read more