Background Child marriage has long been a public health concern around the world, because it has the potential to deprive adolescent girls of their sexual reproductive health rights and limits their ability to reach their full potential in life. The prevalence of child marriage has been consistently higher in sub-Saharan Africa than elsewhere. However, fewer studies have explored the influence of both individual and community-level influences on early marriage in sub-Saharan Africa. This study, therefore, examined individual and community-level factors associated with child marriages in Zambia. Methods Data came from the Zambia Demographic and Health Surveys (ZDHS) conducted in 2007, 2013–14 and 2018. A pooled weighted sample of 9990 women aged 20–29 years was used in the analysis. Stata software version 17 was used to perform statistical analysis, taking into account complex survey design. The association between individual- and community- level factors and early marital behavior was assessed using multilevel logistic regression models. Results The prevalence of child marriage among women aged 20–29 was 44.4 percent (95% CI: 42.1, 46.7) in 2018, declining from 51.5 percent (95% CI: 48.9, 54.0) in 2007. Women with secondary or higher level of education [aOR = 0.36, 95% CI = 0.26–0.49] and [aOR = 0.07, 95% CI = 0.03–0.18] and those whose age at first birth was (15–19 year) or (20–29 years) were associated with less likelihood of experiencing child marriage. Communities with a high percentage of women who gave birth at a young age [aOR = 1.36, 95% CI = 1.15–1.62] were more likely to experience child marriage. Individual and community-level characteristics accounted for 35% of the overall variations in communities' likelihood of experiencing early marriage. Even after controlling for both individual and community-level influences, the intra-class correlation revealed that around 4.5 percent of the overall variations remained unexplained. Conclusion Prevalence of child marriage has reduced over the years but is still high in Zambia. Both individual and community- level factors influenced child marriage in Zambia. There is a need to strengthen strategies that keep girls in school to delay their exposure to early sexual debut and child marriage. Designing of reproductive health interventions in the country should consider integration of community factors such as economic insecurity and access to reproductive health information.

In many developing countries, population expansion and high fertility rates have been of concern to individuals, society, and governments. Zambia is one of the countries in sub-Saharan Africa, which has been experiencing high fertility for more than four decades since it attained independence. Understanding of factors associated with desired family size, especially amongst young women, is important because their future reproductive behaviour has the potential to influence the country’s course of fertility. Therefore, this study was conducted to examine the determinants of family size choice among young women in Zambia. The study analysed data extracted from repeated cross-sectional surveys conducted in 2007, 2013 and 2018. The analysis was done on a pooled weighted sample of 15,528 young women aged 15–24 years. Multivariate logistic regression was used to examine factors associated with the desired family size of young women. All analyses were conducted using Stata software version 17 and considered complex survey design. The prevalence of young women who had the desire of at least 4 children has been considerably high in Zambia, at 63.2%. Young women in the age group 20–24 were found to have higher odds (AOR = 1.31; 95% CI: 1.03, 1.66) of desiring at least 4 children compared to those aged 15–19. Women living in the rural areas were (AOR = 1.41; 95% CI: 1.10, 1.79) more likely to desire at least 4 children compared to their counterparts living in urban areas. Age of a young woman, place of residence, level of education, household wealth status, number of living children, and exposure to mass-media family planning messages were significantly associated with desire of at least 4 children. The desire for a large family size remains a social concern for reducing fertility in Zambia. This is because the proportion of young women who desire a large family size has been consistently high. Increasing access to education and sexual reproductive health information to young women especially to those in rural areas is key to changing their reproductive behaviour.