Contraceptive Discontinuation

First-year contraceptive discontinuation rates

Definition

Among women who experienced episode of contraceptive use within the 5 years preceding the survey, percentage of episodes discontinued within 12 months by reason for discontinuation, according to specific method.

The discontinuation rates are based on episodes of use of particular methods. An individual woman may contribute more than one episode to the calculation. The calculation procedure is based on life table methods.

Coverage:

Population base: Contraceptive use episodes of all interviewed women who used a contraceptive method in the 5 years preceding the survey (IR file)

Time period: Method use in the 3-62 months preceding the survey

Discontinuation rate: Users who discontinue using a contraceptive method within 12 months of beginning use during a specific episode of use. Users who switch to another method are considered to have discontinued the previous method at the time of switching.

Exposure: Duration of use of a specific method within one episode of use. Exposure begins with initial month of use and ends with discontinuation or with the month of interview if method was still being used at the time of the interview.

Variables: IR file.

Calculation

In the DHS standard recode file, the data for contraceptive discontinuation rates come from the reproductive calendar (vcal). The reproductive calendar in the questionnaire consists of two or more columns of boxes, where each box represents a specific calendar month. The reproductive calendar usually begins with the first month of the fifth calendar year before the date of the start of fieldwork. For example, if the fieldwork began in July 2018, the calendar would start in January 2013. In the first column, episodes of use of contraception are indicated by placing a method code in the boxes that correspond to the calendar months when used. Pregnancies, births, and non-live birth terminations are also represented in this column by placing the corresponding codes in the appropriate months. Months with codes “0” are those in which the woman did not use contraception, was not pregnant, did not give birth, or did not have a fetal loss or stillbirth. In the second column, the reason for contraceptive discontinuation is noted in the box that corresponds to the last month of use.

In the standard recode file, the reproductive calendar is represented by character strings of fixed length. Each position within the character string represents a calendar month with the first position in the string representing the most recent point in time, and the last representing the beginning of the calendar (e.g. January 2013. Thus the third position from the end may represent March 2013, while the fifth position from the end represents May 2013. To calculate the durations of the episodes of use, each position is examined in chronological order (starting at the end of the string and moving towards the beginning) for a contraceptive code. The first code following a position without that code indicates the start of a new episode of use. The last position (e.g. January 2013) is ignored in this examination, since a code in that position may represent an episode of use that began before the calendar start date. The number of continuous positions with the same contraceptive code indicates the number of months of use in the episode. An episode ends if the following month does not have the same contraceptive code (a discontinuation) or corresponds to the month of interview (a censored duration). The episodes are then tabulated by duration and reasons for ending for each contraceptive method and for all methods combined. Standard life table calculations are then applied to the terminations to calculate months of exposure and number of discontinuations by month of episode. The cumulative proportion that discontinued by 12 months is taken as the 12-month discontinuation rate. See the Contraceptive Calendar Tutorial at https://www.dhsprogram.com/data/Calendar-Tutorial/index.cfm for a description of the calendar, how the data are stored and how to analyze the calendar data, and videos on Completing the Contraceptive Calendar and the Data Structure of the Contraceptive Calendar.

The discontinuation rate is categorized by reason for discontinuation, which is noted in the second column of the reproductive calendar in the box that corresponds to the month of discontinuation. Discontinuation, by reason of contraceptive failure, is given if the woman became pregnant while using contraception. In this case, the box in the first column corresponding to the month following the termination should include a “P” for pregnancy or a “T” for pregnancy termination (very unlikely to occur). Discontinuation to switch to another method is determined if the box for the month following the discontinuation of the specific method contains another contraceptive method. Discontinuation for switching is also indicated by a code in the second calendar column that indicates that the woman wanted a more effective method, and that the new method began within two months of discontinuation (i.e., only one month with a ‘0’, indicating no contraceptive use, between episodes of use). Discontinuation of a method, by reason of desire to become pregnant, is indicated in column 2 by the appropriate code.

The life table calculated for the contraceptive discontinuation rates is a true multiple decrement table producing net discontinuation rates. In formulas, the monthly rate of discontinuation, qij, where i is the number of months since the start of the episode and j is the reason for discontinuation, is calculated by dividing the number of episodes discontinued in month i, dij, by the total number of episodes that reached duration, i.e.:

 (and  for “any reasons” combined).

and the cumulative probability of not discontinuing at each month i for reason j is:

where any is “any reasons” combined and l_0j = 1 and l_0,any = 1.

The cumulative probability of discontinuing by 12 months duration for reason j is:

Note that this is mathematically equivalent to the cumulative probability of discontinuing by 12 months duration for any reasons given as:

Example:

Using the DHS-VI Model Datasets, we first sum each month of exposure in the period of interest (3 to 62 months preceding the survey) according to the duration of use of the method in that month. Late entries will first enter the table at the duration of use when they entered the period of interest. In the month of discontinuation of the method, the discontinuations are tallied according to the reason for discontinuation. The “Any reason” column is the sum of the individual reasons for discontinuation. The “Switched to another method” column is tallied separately from the reasons for discontinuation.

We now convert the counts of discontinuations and the months of exposure into monthly rates of discontinuation (qij) by dividing the discontinuation columns by the exposure column, as below:

Next we convert the monthly discontinuation rates into the cumulative probabilities of not discontinuing at each month, using the formula , where l_0j = 1 and l_0,any = 1. To carry out these calculations, first calculate l_1,any, then l_2,any, etc. for “any reason”, and then calculate l_1j, l_2j, etc. for each separate reason for discontinuation j.

Finally, the 12 month discontinuation rates are simply 1 minus the rates of continuing at 12 months:

Handling of Missing Values

Use of contraception is generally not allowed to be missing in any month in the calendar. In the few surveys where it is missing, these are treated as months of non-use of contraception. Missing and unknown reasons for discontinuation are treated as “Other” reasons.

Notes and Considerations

The life table calculated is a true multiple decrement table producing net discontinuation rates. The various reasons for discontinuation are treated as competing risks, and the monthly probabilities of discontinuation are additive across the reasons for discontinuation. In the DHS tables, only episodes that began within the calendar period and ended three months before the interview are included. Episodes that began before the beginning of the calendar are excluded. Episodes that ended in the month of interview or the two months prior are treated as censored at three months before the interview rather than terminated afterwards to avoid bias due to unrecognized pregnancies.

For methods that are not followed by another method or a pregnancy, it is assumed that the method episode started on average in the middle of the first month of use and ended in the middle of the month after the last noted month of use. If the month following the last noted method indicates a pregnancy or a different method, then it is assumed that the episode ended on average in the middle of that following month. Thus, the duration of exposure is taken as the difference between the month of first use and the month of last use (i.e., equal to the number of months during that episode with a notation for the method).

It is worth noting that different assumptions can be made to the calculation of the at risk component of the life table for contraceptive discontinuation. These assumptions are related to the fact that contraceptive information is usually collected using a calendar that collects information on use in calendar months, whereas the life table refers to actual months of use. One consequence of this approach is that censored observations actually contribute a full month of exposure in the last month of observation included in the analysis rather than half a month of exposure. In many life table analyses the number at risk is often taken as the number continuing to the month minus half of the censored observations. For the calculation of discontinuation rates The DHS Program assumes that all observations are at risk for the full month, rather than excluding half the censored observations.

Methods that have less than 125 months of exposure (unweighted) in the first month of the life table are not shown because of large sampling variance, and methods that have 125-249 months of exposure (unweighted) are shown in parentheses to caution the reader that estimates of the discontinuation rates are based on small sample sizes.

The reasons for discontinuation are exclusive categories, and as the discontinuation rates are net rates the discontinuation rates by reason sum to the total discontinuation rates for any reason. The discontinuation rates for switching to another method are calculated separately and are not exclusive of other reasons.

A woman is considered to have switched to another method if she used a different method in the month following discontinuation or if she gave “wanted a more effective method” as the reason for discontinuation and started another method within two months of discontinuation.

Changes over Time

The list of specific methods and their categorization has changed.

In DHS I and II surveys, modern methods included pill, IUD, injection, vaginal methods, condom, female sterilization, and male sterilization. The vaginal methods included in a single group diaphragm, foam, and jelly. Traditional methods included periodic abstinence (of any kind), withdrawal, and all respondent- mentioned other methods.

In DHS III surveys, modern methods included pill, IUD, injection, vaginal methods, condom, female sterilization, male sterilization, and implants. Traditional methods included periodic abstinence (of any kind), withdrawal, and lactational amenorrhea. Folk methods included respondent-mentioned other methods and were categorized separately from traditional methods.

In DHS IV surveys, emergency contraception was added to the list of contraceptive methods but is not included as a separate method for current use (i.e., included in “other”). The questionnaire allowed for more than one method to be currently used but restricted the calendar to only one code (method) in each box according to the following hierarchy: female sterilization, male sterilization, contraceptive pill, intrauterine contraceptive device (IUD), contraceptive injection, contraceptive implants (Norplant), condoms, diaphragm, form or jelly, lactational amenorrhea method (LAM), periodic abstinence, withdrawal, and other methods.

In DHS VI surveys, other modern method and other traditional methods were added to the list. Pill was moved after implants in the methods hierarchy. In DHS-7 surveys, emergency contraception and standard days method (SDM) are listed as separate methods; diaphragm and foam or jelly are included in “other modern method”.

References

Ali, M.M., J. Cleland, and I.H. Shah. 2012. Causes and Consequences of Contraceptive Discontinuation: Evidence from 60 Demographic and Health Surveys. Geneva: World Health Organization. https://apps.who.int/iris/handle/10665/75429

Bradley, S.E.K., H.M. Schwandt, and S. Khan. 2009. Levels, Trends, and Reasons for Contraceptive Discontinuation. DHS Analytical Studies No. 20. Calverton, MD: ICF Macro. https://dhsprogram.com/publications/publication-AS20-Analytical-Studies.cfm

Curtis, S.L. and A. Blanc. 1997. Determinants of Contraceptive Failure, Switching, and Discontinuation: An Analysis of DHS Contraceptive Histories. DHS Analytical Reports No. 6. Calverton, MD: Macro International Inc. https://dhsprogram.com/publications/publication-AR6-Analytical-Studies.cfm

Curtis, S.L. and C.R. Hammerslough. 1995. Model further analysis plan: Contraceptive use dynamics. DHS Further Analysis Reports No. 59. Calverton, Maryland, USA: Macro International. https://dhsprogram.com/publications/publication-fa59-further-analysis.cfm

Staveteig, S., L. Mallick, and R. Winter. 2015. Uptake and discontinuation of long-acting reversible contraceptives (LARCs) in low-income countries. DHS Analytical Studies No. 54. Rockville, Maryland, USA: ICF International. https://dhsprogram.com/publications/publication-as54-analytical-studies.cfm

Polis, C.B., S.E.K. Bradley, A. Bankole, T. Onda, T. Croft, S. Singh. 2016. “Typical-use contraceptive failure rates in 43 countries with Demographic and Health Survey data: Summary of a detailed report.” Contraception, Volume 94, Issue 1, 11-17. https://www.contraceptionjournal.org/article/S0010-7824(16)00103-7/abstract

Polis, C.B., S.E.K. Bradley, A. Bankole, T. Onda, T. Croft, S. Singh. 2016. Contraceptive Failure Rates in the Developing World: An Analysis of Demographic and Health Survey Data in 43 Countries. New York: Guttmacher Institute. https://www.guttmacher.org/report/contraceptive-failure-rates-in-developing-world

Resources

DHS-8 Tabulation plan: Table 7.13

API Indicator IDs:

FP_DISR_W_PRG, FP_DISR_W_DES, FP_DISR_W_FRT, FP_DISR_W_SID, FP_DISR_W_WME, FP_DISR_W_MET, FP_DISR_W_OTH, FP_DISR_W_ANY, FP_DISR_W_SWH

(API link, STATcompiler link)

DHS Contraceptive Calendar Tutorial: https://www.dhsprogram.com/data/Calendar-Tutorial/index.cfm

DHS Contraceptive Calendar Tutorial Video Part 1: Completing the Contraceptive Calendar https://www.youtube.com/watch?v=_7V6S5ljnZc

DHS Contraceptive Calendar Tutorial Video Part 2: Data Structure of the Contraceptive Calendar https://www.youtube.com/watch?v=T2pS8IM0jyU

Measure Evaluation. Online Course: Multiple-Decrement Life Tables.

https://www.measureevaluation.org/resources/training/online-courses-and-resources/non-certificate-courses-and-mini-tutorials/multiple-decrement-life-tables

FP2020 Core Indicator 18a: Contraceptive Discontinuation Rate

FP2020 Core Indicator 18b: Contraceptive Method Switching

Percent distribution of discontinued episodes of contraceptive use in the 5 years preceding the survey by reason for discontinuation

Definition

Percent distribution of discontinued episodes of contraceptive use in the 5 years preceding the survey, by reason for discontinuation, according to specific method.

Coverage:

Population base: Episodes of contraceptive use that were discontinued among all interviewed women who used a contraceptive method in the five years preceding the survey (IR file)

Time period: Episode of use that occurred 3–62 months before the interview

Numerator: Number of episodes of use that were discontinued, by reason for discontinuation, according to contraceptive method and for all methods together

Denominator: Total number of episodes of use that were discontinued, according to contraceptive method and for all methods

Variables: IR file.

Calculation

In the DHS standard recode file, the data for contraceptive discontinuation rates come from the reproductive calendar. The reproductive calendar in the questionnaire consists of two or more columns of boxes where each box represents a specific calendar month. The reproductive calendar usually begins with the first month of the fifth calendar year before the date of the start of fieldwork. For example, if the fieldwork began in July 2018, the calendar would start in January 2013. In the first column, episodes of use of contraception are indicated by placing a method code in the boxes that correspond to the calendar months when used. Pregnancies, births, and non-live birth terminations are also represented in this column by placing the corresponding codes in the appropriate months. Months with no codes are those in which the woman did not use contraception, was not pregnant, did not give birth or did not have a fetal loss or stillbirth. In the second column, the reason for contraceptive discontinuation is noted in the box that corresponds to the month of discontinuation.

In the standard recode file, the reproductive calendar is represented by character strings of fixed length. Each position within the character string represents a calendar month with the first position in the string representing the most recent point in time, and the last representing the beginning of the calendar (e.g. January 2013. Thus, the third position from the end may represent March 2013, while the fifth position from the end represents May 2013. Each position is examined in chronological order for a contraceptive code starting in the 59 month before the interview (position = v018 + 59) and moving towards the beginning. The first code following a month without that code indicates the start of a new episode of use. Subsequent positions are examined until a different code is found. An episode of use ends if the following month does not have the same contraceptive code (a discontinuation). The episodes are then tabulated by reason for discontinuation for each type of contraceptive method and for all methods combined. The reason for discontinuation is noted in the second column of the reproductive calendar in the box that corresponds to the month of discontinuation.

See the Contraceptive Calendar Tutorial at https://www.dhsprogram.com/data/Calendar-Tutorial/index.cfm for a description of the calendar, how the data are stored and how to analyze the calendar data, and particularly Example 5 - Reasons for discontinuation in the last five years by method at https://www.dhsprogram.com/data/Calendar-Tutorial/index.cfm#example5.

Handling of Missing Values

Use of contraception is generally not allowed to be missing in any month in the calendar. In the few surveys where it is missing, these are treated as months of non-use of contraception. Missing and unknown reasons for discontinuation are treated as “Other” reasons.

Notes and Considerations

The distributions, by reason for discontinuation, are based on episodes of use of particular methods. An individual woman may contribute more than one episode to the calculation.

The distribution of reasons for discontinuation is a little different than that obtained in the calculation of discontinuation rates. In the distribution, all discontinuations in the five years preceding the survey are included, whereas in the calculation of the discontinuation rates, only those that ended within the first 12 months of use are included. Also, censored episodes are not included in the rate calculations.

Methods that have less than 25 discontinued episodes (unweighted) are not shown because of large sampling variance.

Changes over Time

The list of specific methods and their categorization has changed.

In DHS I and II surveys, modern methods included pill, IUD, injection, vaginal methods, condom, female sterilization, and male sterilization. The vaginal methods included in a single group diaphragm, foam, and jelly. Traditional methods included periodic abstinence (of any kind), withdrawal, and all respondent- mentioned other methods.

In DHS III surveys, modern methods included pill, IUD, injection, vaginal methods, condom, female sterilization, male sterilization, and implants. Traditional methods included periodic abstinence (of any kind), withdrawal, and lactational amenorrhea. Folk methods included respondent-mentioned other methods and were categorized separately from traditional methods.

In DHS IV surveys, emergency contraception was added to the list of contraceptive methods but is not included as a separate method for current use (i.e., included in “other”). The questionnaire allowed for more than one method to be currently used but restricted the calendar to only one code (method) in each box according to the following hierarchy: female sterilization, male sterilization, contraceptive pill, intrauterine contraceptive device (IUD), contraceptive injection, contraceptive implants (Norplant), condoms, diaphragm, form or jelly, lactational amenorrhea method (LAM), periodic abstinence, withdrawal, and other methods.

In DHS VI surveys, other modern method and other traditional methods were added to the list. Pill was moved after implants in the methods hierarchy. In DHS-7 surveys, emergency contraception and standard days method (SDM) are listed as separate methods; diaphragm and foam or jelly are included in “other modern method”.  

References

DHS Contraceptive Calendar Tutorial. Example 5 - Reasons for discontinuation in the last five years by method. https://www.dhsprogram.com/data/Calendar-Tutorial/index.cfm#example5

Resources

DHS-8 Tabulation plan: Table 7.14

API Indicator IDs:

FP_RDIS_W_PRG, FP_RDIS_W_DES, FP_RDIS_W_DIS, FP_RDIS_W_WME, FP_RDIS_W_SID, FP_RDIS_W_ACC, FP_RDIS_W_CST, FP_RDIS_W_INC, FP_RDIS_W_FAT, FP_RDIS_W_DIF, FP_RDIS_W_INF, FP_RDIS_W_SEP, FP_RDIS_W_OTH, FP_RDIS_W_DKN, FP_RDIS_W_MIS

(API link, STATcompiler link)

DHS Contraceptive Calendar Tutorial: https://www.dhsprogram.com/data/Calendar-Tutorial/index.cfm

DHS Contraceptive Calendar Tutorial Video Part 1: Completing the Contraceptive Calendar https://www.youtube.com/watch?v=_7V6S5ljnZc

DHS Contraceptive Calendar Tutorial Video Part 2: Data Structure of the Contraceptive Calendarhttps://www.youtube.com/watch?v=T2pS8IM0jyU