Contraceptive methods efficacy, effectiveness and

During the last two decades, there have been significant advances in the develop-ment of contraceptive technologies, including transitions from high-dose to low-dose combined hormonal contraceptives; from synthetic oestrogen to natural oestrogen; development of new progestogens and delivery methods of hormones (hormone-releasing intrauterine system, skin patch, vaginal ring, implants); less invasive methods for sterilization and new emergency contraceptive agents have been introduced. Since an ideal contraceptive method is missing, no single contraceptive method serves the needs of everybody. A variety of methods is overwhelmingly important to meet different needs and all, often unequal,

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opportunities. Contraceptive use overall is greater when more methods are available [84].

In family planning programmes contraceptive methods are usually divided as modern (clinic and supply methods) and traditional (non-supply) methods [10].

Modern methods include female and male sterilization, copper-releasing in-trauterine device (IUD), hormone-releasing inin-trauterine system (IUS), hormonal methods (pill, patch and ring, injectable, implant), condom and vaginal barrier methods (diaphragm, cervical cap and spermicidal agents); traditional methods include rhythm method, withdrawal, abstinence and lactational amenorrhoea [10]. Although, some traditional methods, like breastfeeding, could be reliable [85], and modern methods, like spermicides, unreliable; original concept of modern contraceptive methods is coming from the most important feature of contraceptive method – its efficacy.

Contraceptive efficacy is assessed by the rate of unintended pregnancies dur-ing a specified time of exposure. Recently published systematic review about published clinical trials presents the hierarchy in descending order of ceptive efficacy as follows: female sterilisation/long-acting hormonal contra-ceptives; Cu-IUDs/short-acting hormonal contracontra-ceptives; and barrier methods/

natural methods [86]. Translating efficacy (how well the product works in a clinical trial) results into practice (how well the product works in actual practice), “perfect use” and “typical use” efficacy rates are often presented.

Effectiveness of contraceptive methods – their use under typical conditions – is categorized into three tiers ranging from the most effective (implants, IUDs, sterilisation) to the least effective methods (traditional methods and barrier methods, including male/female condoms) [87]. Effectiveness of every method is dependent on its correct and consistent use and the frequency of intercourse [88] – half of all unintended pregnancies in US occur among contraceptive users;

only one in ten result from method failure and nine in ten from inconsistent or incorrect method use [89].

Among all the reasons why women choose particular contraceptives, method effectiveness ranks one of the most important. [90]. However, from user per-spective there could be other qualities which have at least the same importance as effectiveness. The main concerns are side-effects or health concerns – in some countries, 30–50% of women discontinue use of hormonal methods within the first year of use because of side-effects or health concerns [91]. Other players in decision-making process might be partner-indipendency, user-indipendency, coitus-indipendency, quick fertility reversibility. According to Marcia Meldrum, Christopher Tietze wrote already in the 1950s that “…any contraceptive approach succeeds only if it is “use-effective” – one which individual women (and men) find appropriate for use within their own lives”[92]. In addition to effectiveness in preventing pregnancy, some contraceptives also have sub-stantial non-contraceptive health benefits. Condoms prevent STI/HIV. Hormonal methods exert a beneficial effect on many aspects of menstrual bleeding, re-ducing the risk of iron deficiency anaemia; preventing ovarian, endometrial and

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colorectal cancer, functional ovarian cysts, pelvic inflammatory disease (PID), ectopic pregnancy, benign breast disease and; these are effective to alleviate symptoms caused by endometriosis and fibromyoma. Combined hormonal methods have the potential to reduce symptoms related to excess of androgens [93]. More than half of pill users, 58% rely on the method at least in part for purposes other than pregnancy prevention; 14% of pill users rely on the method for only non-contraceptive purposes [94].

Contraceptive methods for men are limited to male condoms and steri-lization (vasectomy).

Contraceptive prevalence rate (CPR) and the unmet need for contraception (or the unmet need for family planning) are two key indicators for measuring improvements in SH. Contraceptive prevalence means the proportion of women in reproductive age (15–49) currently using a contraceptive method divided by number of women of reproductive age at risk of pregnancy (sexually active, not infecund, not pregnant, not amenorrhoeic) at the same point in time [10]. The unmet need for contraception concerns women who are at risk of pregnancy but do not use contraception. Broder definition of the unmet need for contraception includes women who use contraceptive methods with limited efficacy; women with unwanted pregnancies; and women with related reproductive health prob-lems like infertility caused by STI/HIV [95,96]. It is even argued that if a woman is using a method that she does not like, it should be considered as having an unmet need [74]. The definition itself is not necessarily a problem until the data are misinterpreted. In countries, like Estonia, where traditional contraceptive methods are still widely used, the difference between levels of unmet need calculated using the conventional or expanded formulation may be considerable.

Data from contraceptive prevalence could be obtained from several sources.

However, a population-based sample surveys provide the most comprehensive data on contraceptive behaviour [10]. Differences in design and questions of survey can affect the comparability of the data. Since there is no consistent defi-nition across data sources of what is meant by “currently using” a method of contraception, for measuring CPR, it should be taken into consideration what time period was concerned. Most surveys ask about use “now” or within the past month, although some specify other time periods. As there are usually diffi-culties to obtain data on how correctly and consistently the methods are used, one option is to chose the contraceptive method used during the last intercourse as an outcome measure. The limitation is that measures of contraceptive use at one point in time do not take into account its changing nature. The precentage of contraceptive methods is usually higher than 100% as some people use more than one method concurrently. The list of indicators about contraception was recently expanded – indicators measuring different aspects of access to and satisfaction with contraceptive services has been added [76].