Tubal Ligation Failure Risk Calculator

Tubal ligation is very effective, but failures can occur—and when they do, ectopic pregnancy is more likely. This calculator estimates your annual and cumulative risk bands based on procedure type, time since surgery, and whether a reversal was done. Use it for education only; if you have pregnancy symptoms, test early and contact a clinician.

Used to show emergency contraception windows if you are worried now.
Methodology and Sources

What this estimates

This tool provides an educational estimate of (1) an annual failure rate after tubal sterilization and (2) an approximate cumulative probability of pregnancy since the procedure. It blends large cohort failure rates by technique with simple time-since-procedure math. It is not a diagnosis and does not replace clinical advice.

Baseline failure rates by method

We seed the calculator with method-specific ten-year failure rates from the U.S. Collaborative Review of Sterilization (CREST), a large prospective cohort. CREST observed different risks by technique: lower with postpartum partial salpingectomy and unipolar coagulation; higher with spring clip and bipolar coagulation. We use these method bands to set the model’s baselines. Key source (CREST cohort): Peterson et al., 1996.

Annual vs cumulative risk

Failure accumulates over time. For a simple educational approximation, we convert each method’s long-term rate into a flat annual hazard and compute cumulative probability as 1 − (1 − annual_rate)years. This keeps results intuitive while acknowledging that real-world hazards may vary over time and by patient factors.

Method and clinical modifiers

Technique drives most of the baseline difference (e.g., clip vs band vs coagulation vs postpartum partial salpingectomy). We also surface warning flags if users report expulsion-type symptoms or uncertainty about the procedure. When “reversal performed” is indicated, sterilization protection no longer applies; users should treat pregnancy risk according to current fertility and contraception, not sterilization baselines.

What to do now

If intercourse occurred recently and pregnancy is not desired, we show the emergency contraception window using current guidelines: oral ulipristal acetate up to 120 hours after sex; levonorgestrel is most effective within 72 hours; a copper IUD can be used for emergency contraception within 5 days (and continues as ongoing contraception). Source: CDC Selected Practice Recommendations, 2024.

Ectopic pregnancy warning

Pregnancies after sterilization have a higher chance of being ectopic than pregnancies in the general population. Any positive test with pain or bleeding warrants urgent care to rule out ectopic pregnancy. Background discussion from CREST: Peterson et al., CREST analyses.

Limitations

Estimates reflect population averages and simplified assumptions. Real failure risk can differ with age at sterilization, surgical details, device type, surgical skill, and time since procedure. Use your surgeon’s documentation and your clinician’s guidance to interpret results.

Educational use only; not medical advice.

How we estimate risk

The calculator turns a method-specific annual failure band into a multi-year estimate using:
cumulative risk ≈ 1 − (1 − annual risk)^(years). It’s a simplification for education—not a diagnosis.

Method profiles (relative, not exact)

TechniqueTypical profileNotes
Total salpingectomy Lowest observed failure Entire tube removed; failures are rare but still possible.
Postpartum partial salpingectomy (e.g., Pomeroy) Very low Done soon after delivery; long track record.
Ring or clip (e.g., Filshie/Hulka) Low–moderate Small risk of clip/ring failure or recanalization over time.
Electrocautery/bipolar coagulation Low–moderate Effect depends on segment length sealed and technique.
Essure (legacy) Varies Device no longer marketed; outcomes depend on placement and follow-up testing.
Age at procedure matters. Failures are more likely when the procedure is done at younger ages. Risk does not fall to zero with time.

What to do if you’re concerned

  • Test early if your period is late or you have pregnancy symptoms.
  • Call a clinician urgently for severe one-sided pain, shoulder pain, dizziness/fainting, or heavy bleeding—signs can suggest ectopic pregnancy.
  • If you had a reversal, your situation is different—you’re relying on natural fertility rather than failure of a ligation.

Educational only. This tool can’t account for all surgical details. Confirm any positive test promptly to rule out ectopic pregnancy.

FAQs

Can tubes “grow back” after ligation? ▾

Very rarely, a small channel (recanalization) or tubal fistula can form and allow sperm/egg to meet. This is one reason failures can occur years later.

Is pregnancy after ligation more likely to be ectopic? ▾

Yes—among pregnancies that occur after ligation, a higher proportion are ectopic. Test early and seek care promptly for concerning symptoms.

Does failure risk drop to zero over time? ▾

No. Risk is low but persists. Cumulative risk increases with time since the procedure.

Which technique is least likely to fail? ▾

Complete removal of the tubes (total salpingectomy) is generally associated with the lowest observed failure, but actual outcomes depend on surgical details and patient factors.

What if I had a reversal? ▾

After a successful reversal, you’re no longer relying on the ligation to prevent pregnancy. Your chances then depend on age and fertility factors rather than “failure.”

What’s next?

When can I test? Late Period Probability Daily Chance Calendar Due Date if Positive

Within 120 hours (5 days) of sex and worried? See Morning-After Pill Effectiveness.