Study design, area and period
Community based unmatched case-control study was conducted in Oromia regional state, West Arsi zone, Shashamane district from April 12 to May 18, 2021. It is located at 250 km south to main city of Ethiopia, Addis Ababa. Shashamane district has 281,247 populations, 58,593 households and 61,874 women of reproductive age group residing in 37 rural kebeles. There are 7 health centers and 38 Health posts that provide health service for the community by 91 health extension workers and 144 health workers. In addition, there were 11 private clinics. All health centers and health posts provide implanon insertion and removal service. The prevalence of long-acting family planning utilization according to annual report in 2019/2020 was 17.4% and 26.8% in West Arsi Zone and Shashamane District respectively. Similarly, according to this report among women who have utilized long acting family planning in 2019/20; 23% of them in West Arsi Zone and 31% of them in Shashamane district have discontinued service before intended time(27).
Source population
All women of child bearing age group (15-49) who ever used implanon in Shashamane district were the source population for this study.
Study population
Cases: Were all women of child bearing age group in the selected kebeles who have discontinued their implanon before 3 years of insertion.
Controls: Were all women of child bearing age group who used implanon for the complete 3 years in the selected kebeles.
Inclusion and exclusion criteria
Women of child bearing age group, who are eligible for cases and controls and residing in the study district were included as study participants. Women of reproductive age group, who had discontinued the implanon due to life threatening medical complications, method failure and who were critically ill at the time of the interview were excluded from the study.
Sample size determination and sampling procedure
The sample size was calculated using two population proportions for unmatched case control study by STATCALC Epi info version 7.2.2. Discussion with partner, side effects and previous history of abortion were the strongest determinant factors of Implanon discontinuation in the previous studies conducted in Bahir Dar town, Mekelle City and Wolaita Zone(20–22). Sample size was computed for each factors and previous history of abortion was chosen as main exposure variable to calculate optimal sample size. Hence, With the assumption of level of significance 5%, power 80%, case to control ratio of one to two (1:2), odd ratio 2.3 and percent of controls with previous history of abortion 28.6 (the main exposure variable of the study that gave optimum sample size) and finally considering 10% no-response rate the final sample size was 264 (88 cases and176 controls).
There are 37 kebeles in Shashamane district, lowest administrative unit in Ethiopia, and one third of the district kebeles (thirteen kebeles) were selected by lottery method. To select the samples, lists of women were obtained from implanon removal registration book of health posts and health centers from selected kebeles. First, the sampling frame was prepared based on the client's serial number recorded on implanon removal registration book of health posts and health centers for cases and controls respectively. After preparing the sampling frame the total sample sizes of the cases and controls were allocated for each kebeles proportionally. Finally, cases and controls selected by systematic random sampling method to select study participants [Figure 1].
Variables of Study
The dependent variable of the study was Implanon discontinuation. The independent variables were socio-economic and demographic variables ( age, educational level, income, occupation, religion, marital status, ethnicity, husband support, husband opposition, family planning service accessibility), obstetric factors ( previous abortion, number of deliveries (parity), desire for pregnancy, number of living children) ,counselling related factors( pre-insertion counselling, follow-up, discussion with their partners, place of insertion, satisfaction to service, informed choice, decision making and exposure to family planning messages), method related factors (side effects, health concern, method failure, past contraceptive utilization, method shift, and inconvenience to use)
Operational Definitions
Implanon discontinuation: It is discontinuation of the use of Implanon before completion of three years(28).
Cases- All women of reproductive age group who were discontinued their implanon before 3 years of its expiring date(21,22).
Controls- All women of reproductive age group who had removed their implanon after using three completed years(21,22).
Counselling: includes making the women aware of its long protection, effectiveness, and side effects due to insertion and removal.
Side Effects: It is the development of at least one of the following conditions: menstrual disruption, headache, weight gains, insertion arm pain, insertion site infection, back pain and expulsion.
Health Concerns: Known medical condition which may result fear of the use of Implanon contraceptive methods.
Data Collection procedure (instruments, personnel)
The study used quantitative method to collect pertinent information to attain its objectives by structured questionnaires, which was adapted from different studies (18,21,22,29). Data collection was carried out home to home in selected kebeles of Shashamane district by five diploma nurses as data collectors and two-degree holder nurses as supervisors. The data were collected from women of child bearing age group by face to face interview. The questionnaire has five parts: The first part addresses socio-economic and demographic characteristics of mothers, the second part of the questionnaire is Obstetric history, the third part covers past knowledge and utilization of contraceptive methods, the fourth part contains counselling related factors and fifth part is reasons for removal of Implanon .
Data Quality Assurance
The research questionnaire was prepared in English version and translated into local language (Afan Oromo). Before data collection, one day training was given for data collectors and supervisors by the principal investigator about the purpose of the study and how to interview the subjects. The questionnaire was pre tested on 5% (4 cases and 8 controls) of the calculated sample size in nearby kebele (Abaro Kebele) which is preceding the actual data collection period in order to test and clarity tools and estimation of interview time. The result of this pre-test study was used to correct any necessary amendments before carrying out the remainder of the study.
The collected data were checked by the supervisors daily for completeness, inconsistencies, and cleanness and finally the principal investigator monitored the overall quality of data collection and handling. The fieldwork was supervised; and re- interview of randomly selected study participants was done and was compared against the questionnaires filled by the data collectors to ensure validity of the data. Participants were requested kindly to give honest responses during the interview. Any error found during the process was corrected immediately.
Data Processing and Analysis
The data were checked for completeness, consistency, cleaned, coded, entered into Epi info version 7.2.2 and exported to statistical package for social science (SPSS) version 25.0 for analysis. Descriptive statistics including frequency and percentage was computed to describe the data. Bi-variate and multivariable logistic regression analysis was performed to see the association between outcome and explanatory variables. Variables that were found to be less than 0.2 P-value in the bivariate analysis was entered in to multivariable logistic regression model. Finally, multivariable logistic regression analysis was done to identify factors associated with implanon discontinuation. During multivariable analysis, model fitness was checked using the Hosmer and Lemeshow`s goodness of fitness test (p = .412). Adjusted odds ratio along with, 95% Confidence Interval (CI) was used to assess the association between explanatory variables and implanon discontinuation. Level of statistical significance was declared at p-value less than 0.05.