Social transmission and the spread of modern contraception in rural Ethiopia

Abstract

Socio-economic development has proven to be insufficient to explain the time and pace of the human demographic transition. Shifts to low fertility norms have thus been thought to result from social diffusion, yet to date, micro-level studies are limited and are often unable to disentangle the effect of social transmission from that of extrinsic factors. We used data which included the first ever use of modern contraception among a population of over 900 women in four villages in rural Ethiopia, where contraceptive prevalence is still low (<20%). We investigated whether the time of adoption of modern contraception is predicted by (i) the proportion of ever-users/non ever-users within both women and their husbands' friendships networks and (ii) the geographic distance to contraceptive ever-users. Using a model comparison approach, we found that individual socio-demographic characteristics (e.g. parity, education) and a religious norm are the most likely explanatory factors of temporal and spatial patterns of contraceptive uptake, while the role of person-to-person contact through either friendship or spatial networks remains marginal. Our study has broad implications for understanding the processes that initiate transitions to low fertility and the uptake of birth control technologies in the developing world.

Figure 1. Thresholds for contraceptive uptake in women's networks at the time of adoption.

A threshold corresponds to the proportion of adopters in an individual's network at the time of adoption of an innovation. Among women who have ever used contraception (N = 176), 86.3% are innovative relative to their network members, while 89.0% are innovative relative to their husband's networks.

Figure 2. Temporal and spatial patterns of contraceptive uptake.

Contraceptive prevalence varies from less than 1% before 1998 to reach a level of 18.8% in 2008 among women of reproductive age (i.e. 15-45 years, N = 936). Adoption of modern contraception also shows spatial variation (i.e. village A = 22.3%, village B = 15.4%, village C = 22.5%, village D = 22.8%).

Figure 3. Risk of contraceptive uptake across time: main predictors.

(a) Parity (number of living children). (b) Religious group. The risk of contraceptive uptake increases by 40% with each additional child. As compared to Muslims, Orthodox Christians show a 80% decrease in the risk of contraceptive uptake. The relationships are controlled for age, age², social status, cohort, education and marital status.

Figure 4. Averaged estimates (red squares) and 95% confidence intervals (black lines) for the effects of individual factors, social environment, and social interactions on the risk of first contraceptive use.

Data cover a period of 14 years and involve >900 women (see Methods). Wnt: women's network; Hnt: husband's network; formal education is compared to the level “no education”; villages are compared to the first level “Village A”; Being polygynously married is compared to being “monogamously married”. “x” indicates an interaction.