Contraceptive use and needs among adolescent women aged 15-19: Regional and global estimates and projections from 1990 to 2030 from a Bayesian hierarchical modelling study

Abstract

Expanding access to contraception and ensuring that need for family planning is satisfied are essential for achieving universal access to reproductive healthcare services, as called for in the 2030 Agenda for Sustainable Development. To quantify the gaps that remain in meeting needs among adolescents, this study provides a harmonised data set and global estimates and projections of family planning indicators for adolescents aged 15-19 years. We compiled a comprehensive dataset of family-planning indicators among women aged 15-19 from 754 nationally representative surveys. We used a Bayesian hierarchical model with country-specific annual trends to estimate contraceptive prevalence and unmet need for family planning, with 95% uncertainty intervals (UIs), for 185 countries, taking into account changes in proportions married or in a union and differences in sexual activity among unmarried women across countries. Among 300 million women aged 15-19 years in 2019, 29.8 million (95% UI 24.6-41.7) use any contraception, and 15.0 million (95% UI 12.1-29.2) have unmet need for family planning. Population growth and the postponement of marriage influence trends in the absolute number of adolescents using contraception or experiencing unmet need. Large gaps remain in meeting family-planning needs among adolescents. The proportion of the need satisfied by modern methods, Sustainable Development Goals (SDG) indicator 3.7.1, was 59.2% (95% UI 44.8-67.2) globally among adolescents, lower compared to 75.7% (95% UI 73.2%-78.0%) among all women age 15-49 years. It was less than one half of adolescents in need in Western Asia and Northern Africa (38.7%, 95%UI = 20.9-56.5), Central and Southern Asia (43.5%, 95%UI = 36.6-52.3), and sub-Saharan Africa (45.6%, 95%UI = 42.2-49.0). The main limitations of the study are: (i) the uncertainty surrounding estimates for countries with limited or biased data is large; and (ii) underreporting of contraceptive use and needs is likely, especially among unmarried adolescents.

Fig 1. Proportion of women aged 15–19 years who are married or in a union, for the world and SDG level 1 regions, 1990–2030.

Fig 2. Estimates and projections of contraceptive prevalence (any method) (left panels) and unmet need for family planning (right panels), and source data, among married (top panels) and unmarried (bottom panels) women aged 15–19 years in Colombia, 1970–2030.

Note: Estimates and projections are indicated by the solid line (posterior medians), dashed lines (lower and upper limits of 80% uncertainty/prediction interval), and grey ribbon (extent of 95% uncertainty/prediction interval). The source data are indicated by the red (DHS), green (other international surveys) and orange (national surveys) circles.

Fig 3. Family planning indicators as categories of a composition (top panel) and illustration of family planning compositions plotted on a ternary diagram (bottom panel).

Note: The bars represent compositions; vectors of components that sum to 100%. The points inside the triangle plot the values for specific hypothetical countries. The right edge is the axis for contraceptive prevalence, the left edge for unmet need, and the bottom edge is the axis for no need. All axes range from 0 to 100%. The arrows adjacent to the triangle’s edges indicate the direction of increasing values; they point to the vertex at which that component is 100%. The open circle marks the centre of the triangle; at this point all components are equal at 33¹/₃%.

Fig 4. Estimates and projections of the proportion of adolescent women (15–19 years) using contraception (any method and modern methods) and having unmet need for family planning, by marital status and regions, 1990–2030.

Given are the posterior medians (solid lines) posterior 95% uncertainty intervals (ribbons).

Fig 5. Proportion of need for family planning satisfied by modern methods among adolescent women (ages 15–19 years) in 2019, by region.

Note: Ribbons indicate the extent of posterior 95% uncertainty intervals, solid lines indicate posterior medians. To facilitate comparisons, regions in are plotted, left to right, in order of increasing value among all adolescent women.

Fig 6. Proportion of need for family planning satisfied by modern methods among women of reproductive age (15–49 years) and adolescent girls and women (15–19 years) in 2019, by country.

Note: The colours indicate regions.

Fig 7. Ternary colour scheme map for married adolescent women aged 15–19, showing posterior median estimates of contraceptive use (any method), unmet need for family planning, and no need for family planning in 2019.

The base map was obtained from Natural Earth (https://naturalearthdata.com). The boundaries and names shown and the designations used on this map do not imply official endorsement or acceptance by the United Nations. Note: The arrows point in the direction of increasing values.

Fig 8. Ternary colour scheme map for unmarried adolescent women aged 15–19 years in 2019, showing posterior median estimates of contraceptive use (any method), unmet need for family planning, and no need for family planning (percentages).

The base map was obtained from Natural Earth (https://naturalearthdata.com). The boundaries and names shown and the designations used on this map do not imply official endorsement or acceptance by the United Nations. Note: The arrows point in the direction of increasing values.

Fig 9. Ternary colour scheme map for all adolescent women aged 15–19, showing posterior median estimates of contraceptive use (any method), unmet need for family planning, and no need for family planning in 2019.

The base map was obtained from Natural Earth (https://naturalearthdata.com). The boundaries and names shown and the designations used on this map do not imply official endorsement or acceptance by the United Nations. Note: The arrows point in the direction of increasing values.

Fig 10. Estimates and projections the number of users (millions) of contraception (any method and modern methods), number experiencing unmet need for family planning, and number in need of family among women aged 15–19, by marital status, 2019, for the world and sub-Saharan Africa.

Given are the posterior medians (solid lines) posterior 95% uncertainty intervals (ribbons).