Couple-Years of Protection Indicator: New Global Guidance for Updating Existing Methods and Adding New Methods

Couple-years of protection is an important indicator for measuring coverage of family planning programs. Method-specific updates are required when a new method is introduced, a regulatory body changes the duration of use, or a significant change in presentation occurs.

The introduction of this indicator in 1973 1 marked an important shift in how FP programs were measured and evaluated.Previously, programs depended on the number of acceptors, regardless of the method.The limitation of this approach is that contraceptive methods vary in the level of protection they offer.For example, a couple accepting a supply of condoms may receive limited pregnancy protection for a short period of time, while a couple choosing sterilization will benefit from near-perfect pregnancy protection until menopause.With the introduction of the CYP indicator, however, programs were able to calculate the protection from pregnancy afforded by a specific method or sum all methodspecific CYPs to obtain an aggregate total figure.The reason the CYP indicator was so revolutionary for FP programs lies in its simplicity: programs can use readily available data, such as service statistics or data from the health management information system, and simply multiply the number of units distributed over a 1-year period by a conversion factor that quantifies the duration of contraceptive protection provided per unit distributed.2][3][4][5] As detailed by Stover et al., 4 the conversion factor does not take the reason for use into account; for example, condoms used for HIV prevention are assigned the same conversion factor as condoms used for contraception.Along with other commonly used FP indicators, such as contraceptive prevalence rate, 2 CYP can help program managers, governments, donors, and other entities obtain a comprehensive picture of program performance.
As new methods or new data on existing methods become available, the CYP indicator must be updated to ensure it reflects the current landscape of contraception options and enables accurate monitoring and evaluation of FP programs.The indicator has been updated 3 times since its inception: in 2000, by the U.S. Agency for International Development (USAID)funded EVALUATION Project 4 ; in 2011, by the USAID-funded RESPOND Project 5 ; and in 2022, by FHI 360, Avenir Health, and USAID 3 (Box).Due to the COVID-19 pandemic, we were unable to hold a consensus meeting to validate the new CYP factors.However, a series of virtual meetings to gain consensus were held in 2021 and 2022 with a wide variety of international FP stakeholders representing donor organizations, implementing partners, and academic institutions.For additional

BOX. Summary of Couple-Years of Protection Updates Conducted in 2000 and 2011
2000 Update Highlights Country or regional conversion factors for sterilization were added as the age at sterilization varies substantially across contexts.
Couple-years of protection (CYP) figures for condoms and spermicide were reduced due to new data from the Demographic and Health Surveys, which showed a lower coital frequency than previously estimated.

Update Highlights
Evidence Considered in CYP Calculations U.S.-based clinical trials would no longer be used to estimate contraceptive continuation rates as these rates are typically higher than continuation rates from studies in low-and middle-income countries.
Studies with specific/special populations, such as women using barrier methods primarily for sexually transmitted infection prevention, would no longer be considered for inclusion in the evidence to estimate CYP factors.

CYP Calculation Changes
Final CYP factors will no longer be rounded to the nearest whole number.
Overlapping coverage-defined as use of a method while the woman is less than 6 months postpartum, currently amenorrheic, and breastfeeding, or when more than 1 method of contraception is used-will no longer be included in the calculation, as a very small percentage of women fall into this category.Method effectiveness will no longer be included as a separate component in the CYP calculation for long-acting reversible contraception, as effectiveness is already accounted for in method continuation data.

Methods With Updated CYP
IUDs, implants, sterilization, and fertility awareness methods had new CYPs calculated.
Diaphragm was dropped as the product was marginally used.
New methods-vaginal ring and hormonal patch-were added.
Levoplant (formerly called Sino-Implant (II)) was added post-2011 with a 4-year duration of efficacy.
The CYP indicator must be updated to ensure it reflects the current landscape of contraception options and enables accurate monitoring and evaluation of FP programs.
information on this and previous updates, refer to the report that provides a more detailed explanation. 3In this article, we discuss the 2022 updates and propose a standardized process for future CYP updates.

STANDARDIZED PROCESS FOR COUPLE-YEARS OF PROTECTION UPDATES
Since the advent of the indicator, CYP updates have occurred as needed at USAID's request, and documentation of the process and methods used to conduct the updates has varied.We reviewed the methods used and documentation available for previous CYP updates. 4,5In an effort to streamline and standardize the process moving forward, we determined that processes used in past CYP updates should be adhered to as closely as possible and methodological assumptions should not be changed without strong justification.As such, the CYP update outlined in this article closely follows prior processes.We also propose a standard process for determining if a CYP update is needed in the future and, if so, how to calculate updated CYP factors.
The Figure outlines the following 3 criteria that should trigger a CYP update and provides a simple flowchart to guide the decision-making process.Once the decision is made that a method needs an updated CYP factor, we recommend following the process outlined in the methods section to calculate the updated CYP factor.

A Contraceptive Method Is New or Becoming Available in Low-and Middle-Income Countries
New methods do not have a CYP assigned and, thus, need a CYP for use moving forward.A new method of contraception is one that recently received regulatory approval and is now being distributed for use in the general population.A newly available method is one that has been available in select countries (usually higher-income countries) for any period of time and has recently become available in lowand middle-income countries (LMICs) for a number of possible reasons, including manufacturers offering the product at a more affordable price, regulatory approval by a Stringent Regulatory Authority or prequalification by the World Health Organization (WHO) making the product available for order by funders, social marketing organizations introducing the product in country, and/or significant pilot projects by organizations that have led to the product being available in LMICs.

The Labeled Duration of Use for a Method Has Been Changed by a Regulatory Body
At times, due to new evidence, a regulatory body may change the labeled duration of use of a method that necessitates a change in CYP for the method.For example, as discussed in this article, the hormonal intrauterine device (IUD) was changed from a 5-to a 7-year method by the WHO and U.S. Food and Drug Administration (FDA) in 2019 and subsequently to an 8-year method by the FDA in 2022.

The Method Presentation Has Changed Significantly
A significant change in the method presentation is defined as a change that affects the CYP calculation and is a scenario that was not present in previous CYP updates.For example, as outlined in this update, the progestin-only pill (POP) blister pack procured by USAID now consists of 35 pills rather than the standard 28 pills.To calculate the updated CYP for the Caya diaphragm, we drew upon approaches used for similar products, in this case, previous iterations of the diaphragm to determine the CYP.For Levoplant, which changed in duration of efficacy from 4 to 3 years, we used the past approach to calculate CYP for a 3-year implant.For the hormonal IUD, which changed in duration of efficacy from 5 to 7 years, we maintained the same approach used previously for the hormonal IUD but extended the modeled continuation curve by 2 years.For CYP calculations that account for method effectiveness, we relied on the widely used method-specific effectiveness rates from the WHO Family Planning -A Global Handbook for Providers. 8Further details on the calculations per method are described in the Results section.

Methods That Are New or Becoming Available in Low-and Middle-Income Countries
Diaphragm Diaphragm use has historically been low in LMICs.However, the Caya diaphragm offers several benefits over previous models and presents an opportunity to expand the method mix by increasing method choice.Aside from design improvements to increase comfort and usability, Caya comes in just 1 size, thereby eliminating the need for a fit exam-a key barrier to use in low-resource settings. 6,9wo studies conducted post-2011 were identified in our literature search.In 2015, a randomized controlled trial was conducted with a single-size diaphragm used with a contraceptive gel. 10 Approximately 54% of participants completed the 6-month study, and the trial found a 10.4% typical use pregnancy probability (at 6 months) that was extrapolated to a 17.8% 12-month probability, which nearly matches the widely used rate (17%) from the WHO Global Handbook. 8The only additional data source is a study conducted from 2019-2021 in Niger that estimated a 76.7% 6-month continuation rate. 6he 2000 CYP update conducted by Stover et al. assigned 1 CYP to the diaphragm based on how long a woman may typically use it in combination with other factors, such as wastage and discontinuation. 4The diaphragm was subsequently removed from the CYP Chart in 2011 because of limited use in USAID-funded programs.Given the desire to add the diaphragm back to the CYP chart and the sparse data post-2011, the updated CYP factor is 1 CYP per diaphragm.

Levoplant
Levonorgestrel implants are an effective longacting reversible contraception option.Levoplant is a levonorgestrel implant that was prequalified by the WHO in 2017 11 based on a Phase 3 trial conducted in the Dominican Republic. 12The predecessor to Levoplant, Sino-Implant (II), was labeled as a 4-year product, and the CYP was initially based on this duration of efficacy.However, based on the trial results that showed markedly higher pregnancy rates in the fourth year, 12 Levoplant is now labeled as a 3-year product and registered as a 3-year product in all countries where USAID procures the implant.
As the approved duration of use for Levoplant changed from 4 to 3 years, we recalculated its CYP to reflect the duration of efficacy and align with the CYP for the 3-year etonogestrel implant Implanon/ ImplanonNXT.The updated CYP is 2.5 per Levoplant implant inserted.

Hormonal IUD
4][15][16][17][18][19] This, coupled with product introduction efforts in multiple LMICs, will increase access to and use of the product. 20In 2019 and 2020, respectively, the FDA extended the duration of use for the Mirena and Liletta hormonal IUDs from 5 to 7 years.In the coming years, national drug authorities in LMICs will update approvals accordingly.In 2022, the FDA again extended the duration of use for Liletta and Mirena to 8 years; however, this update was made after this current CYP update was completed.Future updates should take this duration of efficacy into account.
In 2011, the CYP calculation for the hormonal IUD with a 5-year duration of use relied on the continuation rates of the Copper-T 380-A IUD and resulted in 3.3 CYP per inserted hormonal IUD.At that time, continuation rate data of the hormonal IUD were limited to U.S.-based clinical trials.Based on data available at that time, there was consensus that the hormonal IUD had continuation rates similar to copper IUDs. 21However, since then, data comparing continuation rates of hormonal and copper IUDs have emerged.
3][24] These data indicated higher 1-and 2-year continuation rates for the hormonal IUD (88%, 79%, respectively) than for the Copper-T 380-A (84%, 77%, respectively) and equivalent 3-year continuation rates (70% for both methods).Additionally, the continuation rates for the hormonal IUD are nearly equivalent to the continuation rates for contraceptive implants in the 2011 CYP update.
Additional studies conducted in LMICs further support these findings.A prospective cohort study conducted in Zambia and Nigeria showed higher continuation rates for the hormonal IUD (95%) compared to the Copper-T 380-A (89%) in Zambia in the first year and the same continuation rate (87%) for both IUDs in Nigeria. 16Two additional studies were considered: a prospective observational study in China 25 and a 9-country randomized trial with a majority of participants from China (56%). 26he prospective observational study had a relatively high 1-year continuation rate for hormonal IUD users (93%) 25 while the other reported higher continuation rates for the Copper-T 380-A over 1, 3, and 5 years (90%, 80%, 69%, respectively) than the hormonal IUD (84%, 62%, 48%, respectively). 26The extent to which study design and copper IUD popularity in China 27 affected the results is unknown, but they may explain the lower continuation rates for the hormonal IUD in the randomized trial.
Based on this recent evidence, hormonal IUDs in LMICs likely have continuation rates that more closely align with those of hormone-releasing implants and higher continuation rates than the Copper-T-380-A.Because the continuation rates for both IUDs and implants are calculated using the same methodology, just relying on different input To reflect the change in duration of efficacy from 4 to 3 years for Levoplant, we recalculated its CYP to 2.5 per Levoplant implant inserted.
data, it was decided to extend the modeled continuation curve for hormone-releasing implants to account for the 7-year duration of efficacy of the hormonal IUDs to determine the CYP, resulting in 4.3 CYPs per device inserted.
The continuation curves created for the 2011 update for IUDs and implants are based on articles that represent real-world usage, with a tendency toward using Demographic and Health Survey data whenever possible.Thus, the focus was on the quality of the data rather than the quantity of articles included in the analysis.9][30][31] Data on continuation rates from these articles were used to calculate a curve that is then used to estimate the average duration of use.
The average duration of use was calculated by fitting an exponential decay curve to the continuation data: R ¼ ae Àrt where R is retention at time t, a is constant that allows for immediate expulsion, r is constant that measures the annual rate of discontinuation, and t is time expressed in years.This equation was transformed by taking the natural logarithm of both sides.Then, a regression was run using the log of the continuation rates as the dependent variable and the year as the independent variable.Regression results were transformed back and used to estimate annual retention rates.These annual retention rates were then used to estimate life years of use, which were summed to get the average duration of use.
It is important to remember that with this approach the number of years that are included in the estimates impacts the average duration of use.For example, the same curve was used for estimating continuation for all implants by truncating the data at 3, 4, and 5 years, and now for the 7-year hormonal IUD.Also, as mentioned previously, the effectiveness of the methods is included in the continuation estimates because discontinuations for all reasons, including pregnancy, are looked at together.

U.S. Agency for International Development-Supplied Progestin-Only Pills
POPs and combined oral contraceptives (COCs) are both highly effective methods of contraception 8 supplied by USAID and used worldwide.Before this update, all oral contraceptive pills (POPs and COCs) were provided in 28-pill packs and were both assigned the same CYP-15 cycles, or pill packs, per CYP.USAID currently supplies POPs in packets of 35 pills and no longer provides POPs in 28-day packs.Therefore, it is necessary to differentiate COCs from POPs in the CYP calculation.
To remain consistent with the recommendations from 2011, we eliminated the proportion overlapping from the calculation.To calculate the CYP for POPs, we relied on the following formula:

DISCUSSION Standardized Process for Couple-Years of Protection Updates
As contraceptive methods continue to evolve, the CYP indicator will require regular updates to remain current.However, to date, the process for updating the indicator has been ad hoc and lacking standardization.To address this, we have proposed a formal process to both trigger an update and conduct them in the future.Colleagues from Data for Impact have highlighted the importance of standardized indicators, noting that without them, health interventions cannot be compared in an evidence-based fashion, leading to "poor decision making on a large scale, resulting in incorrect assessments and potential investment in less effective programming." 32Global standardization of the CYP indicator will ensure that all programs are measuring this indicator consistently and thus allow for greater comparability and improved decision-making by funders, policymakers, and program implementers.As programmatic data needs change and new evidence is generated, future changes to the standardized process for CYP updates may be needed.However, in the interest of consistency, we recommend following the guidance in this article until any future adjustments are formalized and documented.

Importance and Use of Couple-Years of Protection
CYP is an important indicator for measuring the method-specific coverage of contraceptives provided by FP programs.FP2030 includes CYP as one of the core indicators countries should use to monitor their programs and track trends and progress over time. 33t is the only FP2030 core indicator with data that comes directly from routine data systems in countries, such as the health management information system. 33However, CYP has limitations, as it cannot be used to estimate actual method use or impact, the number of individuals using a method, whether contraceptive methods are accessible and acceptable to all individuals, and the quality of contraceptive services.Programs should look to other indicators such as contraceptive prevalence rate, discontinuation rate, method information index, and unintended pregnancies to measure such outcomes.When CYP is used in conjunction with other indicators, including the broader set of FP2030 core indicators, a more comprehensive picture of FP programs emerges that enables donors, policymakers, and implementers to make evidence-based decisions to improve programs.
As noted earlier, this update is focused on USAIDprocured commodities, though both the CYPs and the process for producing the CYPs are broadly applicable, as the commodities are the same across programs except for the 35-day POP pill pack.Notably, procurement has shifted almost exclusively to the 35-day POP pill pack apart from 2 countries, so this exception is negligible.

CONCLUSION
Since its inception 50 years ago, CYP has been an integral indicator for FP programs worldwide.As the field of contraceptive research and development continues to generate new evidence on current FP methods and develop new methods, the CYP indicator will need to be updated accordingly.This article not only documents the most recent CYP update but also provides essential guidance to ensure a harmonized and standardized approach to updating CYP.
Using the new CYP factors is required for USAID programs and, in the interest of standard reporting and data-driven decision-making, is strongly recommended for all FP programs.USAID and other international FP stakeholders should regularly monitor FP methods for any changes that require a CYP update and ensure that updates are conducted as needed, thereby ensuring the indicator remains relevant in the future.

FIGURE.
FIGURE.Flowchart to Determine if Couple-Years of Protection Update Is Needed

TABLE .
Updated Couple-Years of Protection Indicator