What is the impact of contraceptive methods and mixes of contraceptive methods on contraceptive prevalence, unmet need for family planning, and unwanted and unintended pregnancies?

Background - In many low-and middle-income countries, there is high maternal, infant and child mortality due in part to low contraceptive use and high unmet need for family planning. The aim of this overview of systematic reviews is to synthesise the findings of systematic reviews conducted in this area to assess the impact of various contraceptive methods and mixes of contraceptive methods on contraceptive prevalence, unwanted and unintended pregnancies, and unmet need (a desire to limit the number of children but not currently using any contraception) for family planning in developing countries/regions.Methods - Eight databases (Bioline international, The Cochrane Library, Latin American and Caribbean Health Sciences Literature - LILACS, Popline, PubMed, Turning Research Into Practice, World Health Organisation Reproductive Health Library and Zetoc) were searched from 28 October 2010 to 08 December 2010. Cochrane and non-Cochrane systematic reviews were included. Eligible reviews included studies whose participants were sexually active women or men from countries classified as ‘developing’, ‘low-income’ or ‘middle-income’. Systematic reviews of any intervention (or combination of interventions) designed to increase contraceptive prevalence, reduce fertility or both were eligible. Data were extracted and synthesised narratively. A Measurement Tool to Assess Systematic Reviews, AMSTAR, was used to evaluate the quality of the included systematic reviews, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to evaluate the quality of the body of evidence for each comparison. To aid the interpretation of the findings for a variety of settings, relevant contextual information was presented where possible.Results - There were 22 systematic reviews included in this overview of reviews. The overview examined a range of contraceptive methods, including modern (terminal and spacing) and traditional methods (such as withdrawal and periodic abstinence which do not require contraceptive substances or devices and also do not require clinical procedures). However, the systematic reviews included did not address all the objectives of the overview.The results of the review are summarised below according to the objectives.Objective 1: To assess the impact of various contraceptive methods and mixes ofcontraceptive methods on contraceptive prevalence in developing countries/regions. There was no systematic review that met this objective.Objective 2: To assess the impact of various contraceptive methods and mixes ofcontraceptive methods on unwanted and unintended pregnancies in developingcountries/regions.The body of evidence for the relative efficacy or effectiveness of a variety ofcontraceptive methods to prevent pregnancy in developing countries was generally rated as of low or moderate quality. There was, however, a number of comparisons (between different derivatives of the same contraceptive methods) for which the evidence was rated as of high or moderate quality. Evidence from systematic reviews is lacking on the acceptability of contraceptive methods and their impact on prevalence and on unmet needs for family planning. The evidence for the relative effectiveness of a variety of contraceptive methods to prevent pregnancy in developing countries is generally of low quality. There is some high-quality evidence comparing different derivatives of the same contraceptive methods, although this is more often evidence of efficacy than evidence of effectiveness.Objective 3: To assess the impact of various contraceptive methods and mixes ofcontraceptive methods on unmet need for family planning in developing countries/regions.There was no systematic review that met this objective.