Topics and study designs

Most studies addressed hormonal contraceptives such as oral contraceptive pills, the vaginal ring, implants, injectables, and hormone-releasing intrauterine devices (IUDs) and patches. The studies examined various aspects of contraceptives and their usage such as: efficacy and failure rates, adherence, compliance, acceptability, satisfaction, safety, (dis)advantages, side effects, cycle control, bleeding characteristics and reasons for (dis)continuation. Some studies compared specific pairs of contraceptive methods such as the ring and the patch or the ring and the pill. Only a few papers compared a wide variety of contraceptive methods, including copper IUDs, spermicides, condoms, cervical barriers, withdrawal and fertility awareness methods. Other studies investigated different regimens or bleeding patterns. Study designs and methods were well documented. Sixty-one experimental studies, 60 observational studies and two qualitative studies were found. The 61 experimental studies included 32 randomised trials. Many of the papers included a specific study description such as ‘multicentre clinical study’ or ‘multicentre, open label, single arm, clinical study’. The observational studies included prospective and retrospective cohort studies, cross-sectional studies and chart reviews. One of the two qualitative studies used a focus group approach and the other collected data through one-on-one interviews.

Categories of discontinuation reasons

Thirty-one parent nodes were categorised from a total of 789 nodes (see online Supplementary Material Appendix 3). Of these, the node termed Bleeding (n=88) was the most reported reason for discontinuation followed by Pregnancy (n=62), Other (n=51), Pain (n=47), Compliance issues (n=43), Adverse events (n=42), Side effects (n=35) and Participant-related issues (i.e. ‘became menopausal’, ‘individual patient's decision’, ‘subject's request’, ‘not willing to cooperate’, and so on) (n=38). The numbers in parentheses refer to the number of papers that included each stated reason for discontinuation.

The parent node Participant-related issues contains categories stating this fact but authors did not often explain the reasons. For example, the category ‘individual patient's decision’ (to discontinue the method) states what happened but does not shed light on the participant's reason for discontinuation. When adverse events were reported together with detailed information in brackets (n=7), such as ‘adverse events’ (bleeding, increased weight, etc.), all the reasons in the brackets were recoded into relevant nodes. When a category called ‘Other’ detailed the information that constituted it, all the reasons in the brackets were recoded into relevant nodes.

Some studies reported percentages of those in the discontinuation subsample while others calculated them based on the entire sample included in the data analysis. For example, the percentage of women whose reasons for discontinuation fell into the category of ‘other’ ranged from 0.4% to 78% in the studies reviewed. Only one paper clearly addressed what the percentages referred to, stating that 4% of all users discontinued their participation in the study for ‘other reasons’.6

The top two reasons: bleeding and pregnancy

‘Bleeding’ included changes in bleeding patterns, the amount of bleeding (e.g. excessive or heavy bleeding), nature of bleeding (e.g. spotting and irregular bleeding) and frequency of bleeding. Some papers used medical terminology (e.g. amenorrhoea, dysmenorrhoea and menorrhagia). Bleeding was referred to as both ‘periods’ and ‘menstruation’. Some studies included specific information such as ‘vaginal bleeding’ and ‘withdrawal bleeding’. Only a few studies tried to grasp women's subjective experiences of bleeding, using terms such as ‘unacceptable bleeding’, ‘nuisance bleeding’ and ‘intolerance to the symptom of amenorrhoea’. It was often unclear whether these terms were used by the women themselves or determined by the researchers. Not all of the studies included a clear definition of bleeding but some papers adopted the bleeding profiles defined by the World Health Organization (WHO) to differentiate amongst bleeding, spotting, bleeding day, spotting day, bleeding-free day, bleeding/spotting episode, bleeding episode and amenorrhoea.7

There were discrepancies between women's and investigators’ perceptions of bleeding. Archer et al.8 reported that subjects who requested withdrawal from the study comprised 15.7% (n=335) of those sampled and included those who cited reasons related to uterine bleeding events (9.8% of all subjects). However, they did not have clinically important uterine bleeding in the opinion of the investigator and were not reported by the investigator as ‘uterine bleeding as an adverse event causing withdrawal’ from the study.8 Anderson and Hait9 reported that unacceptable bleeding was sometimes cited as an adverse event but at other times cited as simply the reason given by an individual for her decision to withdraw from the study.

Some women discontinued using contraceptives because they wished to conceive whereas others encountered an unintended pregnancy. Terms such as ‘desired pregnancy’ or ‘planned conception’ were used in some papers but others simply gave ‘became pregnant’ or ‘pregnancy’ as reasons and so it was unclear whether or not this indicated a planned pregnancy.

‘Other’ as reasons for discontinuation of contraceptives

The category ‘other’ was variously defined by researchers. It sometimes consisted of unknown reasons but not always. Small studies and those reporting a small number of discontinuations provided detailed information about what constituted this category. Studies focused on specific conditions such as weight gain and bleeding often specified how many women discontinued and for what reasons. In contrast, large studies including different contraceptive methods10 and/or data collected from multiple sites11 tended to categorise reasons for discontinuation broadly into ‘other’ without explanation. Some researchers12 even put pregnancy into the category ‘other’ whereas other researchers13 considered that pregnancy was due to user failure and categorised it as non-compliance.

One-third (41/123) of the papers included the term ‘other’ alone or in combination with other words [‘other reasons’, ‘other personal’, ‘another reason’, ‘unknown/other’, and ‘(an)other method’] as a reason for method discontinuation. A further 27 papers included the terms ‘non-medical’, ‘unknown’, ‘personal’, ‘personal reasons’, ‘unspecified reasons’, ‘unwilling to continue’, ‘subject request’, ‘any termination’, ‘user-related’, ‘patient's own decision’, ‘patient's choice’, ‘switch to another contraceptive’ or ‘no reasons elicited’. There were only 12 papers in which the category ‘other’ was expanded by detailed information outlining what constituted the other reasons.

Eight papers did not include any category such as ‘other’ or ‘unknown’ but included categories that attributed discontinuation to the participant, such as ‘premature discontinuation of study medication’, ‘early termination’, ‘did not complete survey’, ‘early withdrawal’, ‘dissatisfied with contraceptive method’, ‘used other contraceptive method’ and ‘did not really want it’. Some papers used both ‘other’ and also ‘non-medical reasons’, and thus the above-listed reasons overlapped in some studies. As a result, nearly two-thirds of the 123 papers used at least one of the above-mentioned ambiguously addressed categories as reasons for discontinuation.

In one paper14 the authors reported two specific reasons for discontinuation of either condoms or OCs (‘not having sex’ and ‘trying to get pregnant’), and remaining reasons were all gathered into the category ‘other’. The women were given the opportunity to elaborate in more detail on their reasons. In the case of condoms, they referred to issues such as a desire to switch to an easier or more reliable method, a monogamous relationship, the perception that condoms were uncomfortable and interfered with their sex life, vaginal irritation and latex allergies. In the case of OCs they mentioned issues such as yeast infections, nausea, episodes of depression, headaches, the development of hypertension and breakthrough bleeding.

Other authors clearly addressed how they categorised the category ‘other’. Harvey et al.15 noted that when women reported single reasons for discontinuation, such as low libido, pelvic pain, headaches, mastalgia, arm pain, dislike of hormones or light menstrual flow, these were combined under the category ‘other’. This is understandable because the researchers were specifically interested in rates of and reasons for removal of the implant. Nevertheless, it is possible that many of the reasons for discontinuation were overlooked. The participants were using one of 13 contraceptive methods, so their reasons for discontinuation would have been varied and method-specific.

Some studies regarded switching to another method as discontinuation, but other studies did not, or were unclear. One example was a retrospective study on IUDs in which the category ‘other’ included ‘subject using another birth control method’ but this was not fully explored.16 ‘Other’ reasons presented by another study included ‘fear of hormone/cancer’,17 which is an example of women's subjective claims being gathered into the category ‘other’.

One study on the IUD provided detailed information about each category, including what constituted the category ‘other’.18 Only two subjects belonged to the category ‘other’ in this study and only one of them gave her reason for the removal of the IUD. Another one of the categories was ‘pelvic inflammatory disease’, and seven women were reported to have been treated for this condition, which required the removal of the IUD. Their own opinion of the IUD was not recorded in the paper.

Pain

A variety of expressions describing pain were found, such as ‘headache’, ‘migraine’, ‘breast pain’, ‘mastalgia’, ‘pelvic pain’, ‘abdominal pain’, ‘arm pain’, ‘cramping’ and ‘general pain’, but some of the papers merely stated ‘pain’ without explaining the location or type of pain.

Compliance

The category ‘(non)compliance’ was generally more explicit, with reasons given such as difficulty remembering, loss of health insurance, lack of transport, logistical reasons, lack of time, and difficulty keeping track of the ring.

No longer in need of contraception

Ten studies used the terms ‘end of relationship’, ‘no longer in a relationship’, ‘no longer sexually active’ or ‘no longer in need of contraceptives’. These expressions have slightly different nuances but are not explored in any depth in the studies. As noted above, pregnancy during method use and discontinuation to become pregnant were sometimes recorded as reasons for no longer needing contraception.

Adverse effects and side effects

The terms ‘adverse events’ and ‘side effects’ were used to describe medically undesired signs or symptoms associated with a method, but were used inconsistently. Only Winkler et al.19 listed all of the adverse events recognised by the WHO in a table and reported the number of women who experienced each. The most frequently addressed adverse event was bleeding but, as noted above, the degree and nature of bleeding was not always clear.

Loss to follow-up and withdrawal of consent

Eighty-eight of the 123 (72%) studies reviewed were either clinical trials or cohort studies and approximately one-third of the studies (36) provided the number of participants who were lost to follow-up. Generally, the ‘lost to follow-up’ group was reported separately from the reasons for discontinuation (n=19), but many studies (n=17) that included the category ‘lost to follow-up’ referred to this as a reason for discontinuation. For example, one paper reported that ‘the most common reasons for premature discontinuation were adverse events, lost [sic] to follow-up, and individual patient decision.’9 Clearly, however, it is not possible to know whether these participants continued using the given contraceptive method or not, since the investigators were unable to follow them up. The percentage of those lost to follow-up was occasionally as high as 50% of the subjects reported as having discontinued a method.12 Some studies reported ‘withdrawal of consent’ as a separate issue from reasons for discontinuation; however, two studies included ‘withdrawal of consent’ as a reason for discontinuation of the study. For example, a Phase 3, open-label, non-comparator, multinational, multicentre 1-year study grouped reasons for discontinuation into four categories: ‘adverse events’, ‘withdrawal of consent’, ‘loss to follow-up’ and ‘protocol violation’.20

Apart from adverse events, it is unclear why some women withdrew their consent or failed to attend follow-up sessions. Another ambiguous categorisation was found in a study that included not only ‘withdrawal of consent’ as one of the reasons for discontinuation of the study but also a category called ‘premature discontinuation of the study medication’.21 In this case, ‘withdrawal of consent’ could possibly be interpreted as withdrawal of consent with no reasons elicited and ‘premature discontinuation of the study medication’ might be interpreted as withdrawal from the study due to dissatisfaction with the study medication. All of these categorisations such as ‘withdrawal of consent’, ‘loss to follow-up’, ‘protocol violation’ and ‘premature discontinuation of the study medication’ are expressed from the researchers’ point of view, merely reporting the fact that some women discontinued participating in the study, without exploring or citing the reasons given by the women themselves. Some women may have chosen to withdraw their consent or no longer participate in the study (and were therefore lost to follow-up) without explanation. Others may have given an explanation that was not recorded.

Diverse categorisation of reasons for discontinuation

Overall, the categorisations reflected a lack of definition and agreement as well as great diversity about what constituted discontinuation. Many reported from the most common to the least common reasons.15 A few studies reported only the most commonly addressed reasons.22–25 For example, Brucker et al.'s26 study reported only the main reason cited by women for their discontinuation. As the most commonly reported reason was side effects (35%), reasons given by the other 65% of the women were not reported in the paper. This tendency was more apparent when the scope of the study was very narrow, for example a study27 ,28 that focused on adverse mood effects, and therefore reported only two categories explaining discontinuation, ‘adverse mood effects’ and ‘other than adverse mood effects’. It was evident that some researchers were unable to obtain reasons: one study29 failed to obtain reasons for discontinuation from nearly 40% of women who discontinued IUDs.

Do studies reflect the voices of women or researchers?

Some studies strove to obtain detailed information about women's reasons for discontinuation by asking open-ended questions3 ,30 and/or allowing for multiple reasons to be noted by participants. It was generally unclear whether women had been given the option to provide multiple responses. Exceptions were Rai et al.31 who noted how many implant removals had multiple indications, and Moreau et al.4 who allowed up to 14 reasons for women to address. Considering the broad scope of the latter study, which focused retrospectively on contraceptive discontinuation over women's lives due to dissatisfaction, allowing women to address up to 14 reasons is reasonable. It is unrealistic to expect that women will have used a single contraceptive throughout their life unless they are still at the early stage of contraceptive use. In fact, Moreau et al. reported that “the proportion of women who had ever discontinued a method due to dissatisfaction increased with the number of different methods ever used. While a quarter of women who used fewer than three different methods had discontinued at least one of them due to dissatisfaction, 80% of those who used five or more different methods had discontinued for this reason”.4 Even in this study, the category ‘other reason’ accounted for between 8% and 16% of reasons for discontinuation (8% for depot medroxyprogesterone injections, 10% for implants, 11% for the pill and 16% for condoms). However, more importantly, the two reasons ‘experienced side effects’ and ‘worried about side effects’ together constituted one-fifth of the reasons for discontinuation of condoms and over three-quarters for hormonal contraceptives such as the pill (80%), implants (75%) and depot injections (77%).

Except for the studies offering an open-ended questionnaire3 ,30 that allowed participants to address issues in their own words, the majority of the studies did not report how the reasons for discontinuation were obtained. If women were asked to choose their reasons for discontinuation of contraceptives from a list of fixed (medical) reasons, they could have chosen the category ‘other’ either passively because they could not articulate a reason, or deliberately because their own reason was not listed.

Dissociation between contraceptives and sex

Some studies used the category ‘other’ to describe reasons such as ‘no longer having a sexual relationship’ and ‘relationship ended’, whereas other studies did not gather those reasons into the category of ‘other’. Regardless of how these reasons are categorised, it is an inevitable argument that the use of contraceptives is directly linked to having sexual intercourse, with the possible exception of some contraceptive pills used as treatment for acne or for cycle control. Side effects such as bleeding, spotting, mood change, headaches, nausea and weight gain are not directly related to sexual intercourse, but they may directly and/or indirectly affect sexual life.

Five studies reported decreased (or low or loss of) libido as one of the reasons for discontinuation of contraceptive methods. Four of them created a separate category describing changes in libido (e.g. ‘decreased libido’ and ‘asthenia’),32–36 but one gathered low libido into the category ‘other’ together with other reasons such as pelvic pain, headaches, mastalgia, arm pain, dislike of hormones and light menstrual flow.10 It is unclear whether ‘libido’ is a term actually used by women or whether researchers use this term to describe what the women reported. As it is predominantly a medical and not a colloquial term, it is unlikely that it has a shared meaning between health care professionals and women themselves.

Other possible sex-related reasons for method discontinuation such as physical discomfort (e.g. from a diaphragm or vaginal ring, or from an IUD during deep penetration) or partner discomfort (e.g. from an IUD string) were notably absent from the study reports. This could be due to women's unwillingness to talk explicitly about sex in the clinical context, as this is not something people do in their everyday life. Women may not be confident that they have the appropriate language to describe their experiences.37 ,38 Women may take advantage of the availability of medical terms instead of revealing personal information using everyday language. Alternatively they may offer no response if confronted with a word or term they do not understand.39 Settling for apparently objective categories such as ‘adverse events’, ‘side effects’ and even ‘bleeding’ allows researchers to avoid asking women to address sexual issues directly.