Examining internal migration effects on short versus long interbirth intervals in Cotonou, Benin Republic

Abstract

BackgroundThe literature on migration-fertility relationship uses various measures of fertility, such as fertility rates, actual fertility and family size preferences. This study introduces a different measure—interbirth intervals over women’s reproductive years—to examine how internal migration is associated with short interbirth intervals (less than 24 months) and long interbirth intervals (greater than 60 months) in Cotonou, the largest city of Benin Republic.MethodsThe paper uses primary data on 2852 live births to 1659 women aged 15–49 years from the 2018 Fertility and Migration Survey in Cotonou. Competing-risks models were fitted for the analysis.ResultsNineteen percent of live births were of short interbirth intervals and 16% were of long interbirth intervals. The prevalence of short interbirth intervals was higher among migrants who spent less than 5 years in Cotonou (29%) than among non-migrants (19%) and earlier migrants (18%). Non-migrants had the highest proportion of long interbirth intervals (19%). Within the first 5 years following the migration to Cotonou, migrants had higher subhazard ratio (SHR) of short interbirth intervals (SHR: 1.71, 95% CI: 1.33–2.21) and lower SHR of long interbirth intervals (SHR: 0.64, 95% CI: 0.47–0.87) than non-migrants. This association holds after controlling for socioeconomic characteristics—but with a slightly reduced gap between migrants who spent less than 5 years in Cotonou and non-migrants. Afterwards and irrespective of women’s socioeconomic backgrounds, migrants who spent 5 or more years in Cotonou and non-migrants had similar risks of short and long interbirth intervals. Finally, from 5 years of stay in Cotonou, migrants for reasons other than school or job were less likely to experience short interbirth intervals (SHR: 0.65, 95% CI: 0.46–0.98 for migrants who spent 5–10 years in Cotonou, and SHR: 0.74, 95% CI: 0.54–1.02 for migrants who spent more than 10 years in Cotonou) than non-migrants.ConclusionFamily planning programmes should mainly target migrants in the early years after their arrival in Cotonou. Moreover, non-migrants need to be sensitised on the adverse health outcomes of long interbirth intervals.

Rural–Urban Migration and Fertility Ideation in Senegal: Comparing Returned, Current, and Future Migrants to Dakar to Rural Nonmigrants

“…These suggest a high degree of contextual variability in support for either the socialization or adaptation mechanisms and for the influence of migration on the levels of fertility in the destinations (Adserà and Ferrer 2015;Kulu et al 2019;Kulu and González-Ferrer 2014). Despite relatively limited data, the bulk of evidence from LMIC settings points to support for adaptation and selection mechanisms in explaining migrant fertility, particularly in the association between lower fertility and duration of migration spells (Anglewicz, Corker, and Kayembe 2017;Banougnin et al 2018;Banougnin 2019;Chattopadhyay, White, and Debpuur 2006;Rokicki, Montana, and Fink 2014). In research comparing internal migrants to nonmigrants in their origin populations, such differences have been interpreted as evidence against strong socialization effects.…”

“…At the same time, comparing migrants from various places of origin to the same destination, childhood place of residence seems to have a lasting impact on fertility, suggesting at least some enduring effects of socialization (Erman and Behrman 2021;Farid et al 2013;Gabrielli, Paterno, and White 2007). Both disruption/interrelation and selection effects have also been seen as potentially important in such comparisons, though adequately identifying these has often been challenging (Banougnin 2019;Chattopadhyay, White, and Debpuur 2006;Eryurt and Koç 2012;Lindstrom 2003).…”

“…Despite relatively limited data, the bulk of evidence from LMIC settings points to support for adaptation and selection mechanisms in explaining migrant fertility, particularly in the association between lower fertility and duration of migration spells (Anglewicz, Corker, and Kayembe 2017; Banougnin et al. 2018; Banougnin 2019; Chattopadhyay, White, and Debpuur 2006; Rokicki, Montana, and Fink 2014). In research comparing internal migrants to nonmigrants in their origin populations, such differences have been interpreted as evidence against strong socialization effects.…”

“…2013; Gabrielli, Paterno, and White 2007). Both disruption/interrelation and selection effects have also been seen as potentially important in such comparisons, though adequately identifying these has often been challenging (Banougnin 2019; Chattopadhyay, White, and Debpuur 2006; Eryurt and Koç 2012; Lindstrom 2003).…”

Migration and interbirth transition rate using Benin Demographic and Health Survey data: Does episode-splitting matter?

“…A number of studies [4][5][6] have examined the determinants of fertility and several interventions aimed at reducing the number of births per woman have been put in place [7,8]. The role of internal migration on fertility has also been studied and the results have been mixed [9,10], leaving questions of the effect of migration on fertility-related behaviours. Notably, the issue of temporal precedence between migration and fertility has been far less investigated, and even less so with cross-sectional data, which continues to muddy understanding of the linkages.…”