Project Impact By Country Project Impact By CountryProject Impact By Country
Learn about PSI's models Learn about PSI's modelsLearn about PSI's models

Tubal Ligation

Tubal ligation is a surgical procedure to close a woman’s fallopian tubes. This type of voluntary female sterilization is a safe, highly effective, relatively simple, surgical means of contraception that can usually be provided in an outpatient setting and is intended to be permanent. Female sterilization is the most widely used modern method in the world, including developing regions and many developed countries such as the United States.

Unit of intervention1 tubal ligation

TypePermanent contraceptive method

Target populationWomen of reproductive age (15-49)

Increased access to family planning helps women prevent unintended and high-risk pregnancies, contributes to the overall health of women and their children, and reduces the need for abortion. For more information about how PSI is empowering women and couples to lead healthier lives, visit our website at:

Model Overview

PSI’s estimates for the health impact of family planning use a methodology developed by Marie Stopes International (MSI) in the Impact 2 model (version 4). Please see for detailed methodology. PSI’s current approach for estimating the impact on child mortality is based on assumptions about changes in mortality risk for children under-five years of age with lengthening birth intervals. PSI is working with modelers from partner organizations to integrate new evidence and adopt a set of common assumptions across impact models for family planning.

PSI uses USAID’s couple years of protection (CYP) conversion factors to represent the estimated protection against unintended pregnancy provided by contraceptive methods during one year. PSI does not modify these conversion factors when estimating CYPs provided.

Service provision:

When a client directly receives a family planning method from a PSI or PSI-affiliated provider during a consultation, PSI claims 100% of the impact of that service.


When PSI distributes a family planning method but does not provide it directly to a client, PSI claims 90% of the impact of that product, to take into account supply chain wastage.


When a client is referred by PSI to a non-PSI service provider, such as the public sector, instead of providing the service itself, PSI claims 50% of the impact of that service. This impact is only attributed to PSI when the referral is confirmed with appropriate documentation.

Model Outputs (impact metrics)

Estimates of DALYs averted, deaths averted, CYPs provided, and unintended pregnancies averted represent the projected health impact of the intervention. It is projected because it has not been directly measured.

Examples based on a tubal ligation intervention in Myanmar in 2015

* We are able to produce deaths averted coefficients for maternal deaths and child deaths individually. Within PSI’s Impact Calculator, these estimates are aggregated into a single deaths averted estimate. Estimates of maternal deaths averted are available via the export function within the calculator in most cases. Please contact for more information.

Examples of Statement of modeled results:

If 10,000 tubal ligations were performed in Myanmar in 2015, an estimated 100,000 CYPs would be provided and 182 deaths, 14,794 DALYs, and 37,917 unintended pregnancies would be averted over the effective life span of the intervention.