We report a high proportion of adolescents that had ever given birth in the last five years than expected and a further look at the observation shows that being in a lower-income household alone was associated with increased chances of giving birth, while higher educational attainment reduced these chances when other factors were adjusted. These findings also consistently show these patterns of associations for both rural and urban areas suggesting a strong link between socio-economic status and fertility in general, further indicating the presence of differential inequities that may be at play in the study population. Other studies have indicated similar observations among adolescent boys and girls [4, 7, 24-26].
Higher wealth status increased protection against ever giving both among the adolescents, particularly for those in urban areas. Remarkably, we observed that urban adolescents with a lower wealth status were more likely to give birth compared to rural adolescents. Others found that advantageous socioeconomic status increased the likelihood of postponement of childbearing among adolescents and young adults . The link between low wealth status and ever giving birth could be an indication of reduced accessibility to contraception information and services among adolescents with a lower wealth status. A study observed that despite the high potential for coverage of social services and family planning, in this case, the urban with a lower wealth status still have inaccessible or low-quality services and a low response to the marginalizing effects of their socioeconomic status .
Higher educational attainment was strongly linked to reduced odds of ever giving birth. In addition to reduced fertility, literature also suggests that higher educational attainment is linked to higher wealth status , suggesting that these are essential drivers of adolescent fertility that need to be looked into further. Keeping in mind the empowerment factors that are important for understanding fertility preferences among women- higher education, increased skills development, increased decision-making power, and more control over household resources, a case for keeping girls in school to reduce their fertility can be made, with a specific focus on rural and urban-poor adolescents who face reduced empowerment and severe income inequalities .
Marital status was another significant determinant of adolescent fertility in this study; married adolescents were more likely to give birth compared to the unmarried. There is an indication that marriage continues to contribute to early childbearing, especially with 70% of the married adolescents already giving birth at least once. These findings were consistent with evidence from 24 African countries [31, 32]. Marriage increases childbearing expectations of the adolescents by their communities as is the case in many African cultures  and marriage is viewed as a form of security for the young daughters from rape, premarital sexual activity, unintended pregnancy outside marriage and infections . Furthermore, rural married adolescents were more likely to give birth compared to urban married adolescents and this was consistent with studies done elsewhere .
While marriage was linked to increased odds of ever giving birth, these odds were also linked to contraception use, indicating that ever giving birth increased access to SRH services for adolescents and the health systems responds more married adolescents and those who had ever given birth compared to those that had not. Also, studies have found that married adolescents are less likely to face stigma for early pregnancy, accessing contraceptives and sexual and reproductive health services due to their marital status . This observation could explain why contraception use was much higher among the adolescents who had given birth before or were married, compared to adolescents who were not. Besides, family planning interventions in Zambia have gradually been shifting towards providing postpartum contraception information and services to women and girls as they go for antenatal services to increase child spacing and reduce fertility . Despite this intervention, this finding indicates that unmarried adolescents, who had never given birth before remained unreached and at risk of unwanted pregnancy and unsafe abortions [10, 36, 37] and their situation is compounded by lower socioeconomic status and lower educational attainment.
The ZDHS reports indicate that knowledge of contraception is ‘universal', and our observation too was that there was a significant relationship between knowledge of contraception and ever giving birth, especially in rural areas. Paradoxically, it has been noted in other studies that adolescents have inadequate information about conception, contraception and abortion [13, 38, 39] and they remain making fertility control-related decisions based on incomplete or inadequate information about contraception [10, 36, 40]. Knowledge among rural adolescents was significantly linked to reduced odds of ever giving birth while all the urban adolescents knew at least one contraceptive method. Rural/ urban differences in knowledge indicate the need for different approaches for these adolescents and their unique SRH needs.
Zambian health system’s response through postpartum contraception  has been effective to an extent, but also too late for those who have not given birth before as they continue to face barriers to information and services while adolescents who have given birth before are in a better position to learn about contraception, although postpartum. Alternatively, the link between increased odds of giving birth and contraceptive knowledge and use could also be an indication of other socio-cultural factors that could affect the uptake of contraception among young people who have never given birth before such as the fear of infertility and fear of side effects of contraception, or alternative sources of contraception such as traditional healers . There need to probe further on the knowledge of contraception and use of among adolescents.
Interestingly, abortion had a significant relationship with reduced fertility for rural adolescents although they were expected to have had limited access to safe abortion services, and this could be an indicator of unsafe abortion among rural adolescents. A study in rural India reported that abortions were the preferred method for fertility control . The findings from this study could be indicative of abortion as an option for those who had given birth before, even though only 1.6% of the adolescents in the survey had ever terminated a pregnancy. However, abortion information is usually underreported [43-45]. Literature suggests that abortion rates are higher than this for adolescents but the incidence in Zambia is still unknown, and it is mostly estimated from facility-based post-abortion care information, or from selected facilities that have support for the provision of abortion care services .
While some interventions are on occasion inclusive of the rural adolescents from lower-income households, urban adolescents from lower-income households also need specific interventions that respond to their unique structural position. Additionally, an increase in age was significantly associated with giving birth, particularly for rural adolescents and this was consistent with a study in Ethiopia . This study suggests that rural older adolescents are more likely to experience childbearing, compared to the younger ones. Differences in the chance of giving birth by age indicate a need to age-appropriate messages and interventions for the varying age-related SRH needs rather than grouping them into one homogeneous group . others stressed the need to focus on different categories of adolescents in the various interventions as they have varying sexual and reproductive health information and needs . Also, addressing urban poverty and access to services in these communities then becomes a significant factor in controlling fertility .
In the 2013/14 ZDHS, the ‘births’ variable has three levels, reporting those who have had up to 3 births. In this analysis, the variable was binary to ensure an adequate number of observations for the analysis. This analysis was based on a cross-sectional survey that included questions that were answered retrospectively. As such, causality could not be established, and there was uncertainty on the exact estimates as respondents were asked to recall past events. Besides, some of the data may have been under-reported due to the discomfort of discussing sensitive topics such as abortion among adolescents. This may have led to an underestimation of some variables such as abortion. However, abortion could be evaluated further to see its relationship with adolescent fertility. Despite these limitations, the study results remain valid and are useful for informing policy and practice, as well as a basis for more research on adolescent fertility. The results from this analysis are based on a sample with national representation; therefore, are generalizable to all locations in Zambia.