Mapping adolescent first births within three east African countries using data from Demographic and Health Surveys: exploring geospatial methods to inform policy

Abstract

Background: Early adolescent pregnancy presents a major barrier to the health and wellbeing of young women and their children. Previous studies suggest geographic heterogeneity in adolescent births, with clear "hot spots" experiencing very high prevalence of teenage pregnancy. As the reduction of adolescent pregnancy is a priority in many countries, further detailed information of the geographical areas where they most commonly occur is of value to national and district level policy makers. The aim of this study is to develop a comprehensive assessment of the geographical distribution of adolescent first births in Uganda, Kenya and Tanzania using Demographic and Household (DHS) data using descriptive, spatial analysis and spatial modelling methods.

Methods: The most recent Demographic and Health Surveys (DHS) among women aged 20 to 29 in Tanzania, Kenya, and Uganda were utilised. Analyses were carried out on first births occurring before the age of 20 years, but were disaggregated in to three age groups: <16, 16/17 and 18/19 years. In addition to basic descriptive choropleths, prevalence maps were created from the GPS-located cluster data utilising adaptive bandwidth kernel density estimates. To map adolescent first birth at district level with estimates of uncertainty, a Bayesian hierarchical regression modelling approach was used, employing the Integrated Nested Laplace Approximation (INLA) technique.

Results: The findings show marked geographic heterogeneity among adolescent first births, particularly among those under 16 years. Disparities are greater in Kenya and Uganda than Tanzania. The INLA analysis which produces estimates from smaller areas suggest "pockets" of high prevalence of first births, with marked differences between neighbouring districts. Many of these high prevalence areas can be linked with underlying poverty.

Conclusions: There is marked geographic heterogeneity in the prevalence of adolescent first births in East Africa, particularly in the youngest age groups. Geospatial techniques can identify these inequalities and provide policy-makers with the information needed to target areas of high prevalence and focus scarce resources where they are most needed.

Keywords: Adolescent; Fertility; Inequality; Small area estimation; Spatial analysis.

Fig. 1

Weighted proportion of adolescent birth in East Africa among DHS respondents aged 20 to 29, at a less than 16 years old, b 16 to 17 years old, and c 18 to 19 years old

Fig. 2

Regional heat map of adolescent birth in East Africa estimated by adaptive bandwidth KDE approach, at a less than 16 years old, b 16 to 17 years old, and c 18 to 19 years old

Fig. 3

Predicted prevalence of adolescent birth in Kenya, Uganda and Tanzania estimated by Bayesian modelling, at a less than 16 years old, b 16 to 17 years old, and c 18 to 19 years old

Fig. 4

Weighted level of education and first birth at less than 16 years old by province, Kenya DHS 2008

Fig. 5

Displaced DHS cluster locations (N = 1254) with corresponding sample size and urban versus rural status

Fig. 6

Standard deviations of predicted INLA estimates, at a less than 16 years old, b 16 to 17 years old, and c 18 to 19 years old