To our knowledge, this is the first comprehensive analysis of the NDHS from 2003 through 2018 that focuses specifically on the influence of both individual and contextual-level factors on pregnancy termination among young women-a demographic group that is often overlooked in terms of research and public health interventions. Our key findings reveal a declining trend in pregnancy termination between 2003 and 2013, with a reversal in trend in 2018. Additionally, whilst the overall trend in pregnancy termination between 2003 and 2018 showed a decline, amongst some groups of young women there were disparities in the trends particularly for measures of socioeconomic status: young women with no education/primary education, and those from the poorest/poorer households showed no decline in pregnancy termination as opposed to those who were educated or were from wealthier households. The observed trend in pregnancy termination mirrored the trends in contraceptive use, and age at sexual debut, which were found to be significant factors associated with pregnancy termination in the multivariable model. The declining trend in pregnancy termination persisted especially from 2003 to 2013 after individual and contextual factors were controlled for.
One potential explanation for these observed declining trends in termination could be due to the impact of the nationwide introduction of the school-based Family Life and HIV Education (FLHE) curriculum. However, it is noteworthy that implementation of the FLHE in Nigeria was fraught with setbacks in some states with allowance for states to modify the content of the curriculum coupled with the minimal acceptance of sexuality education particularly in regions with highly conservative religious and cultural values [39–40]. However, recent evidence shows that in states where the FLHE were effectively implemented, an improvement in sexual behaviour and life skills performances of youth is found. Overall, implementation of this programme has dwindled in recent years [41], which could be a potential explanation for the increase in early sexual initiation and pregnancy termination we observed in the data from 2013 to 2018 [32]. The declining trend between 2003 and 2013 we found, albeit with lower percentages, is similar to another study using DHS data for Nigeria but limited to married women of wider age range (15–49 years) [13].
Surprisingly, we found that a significant decline in contraceptive use from 2003 to 2018 for young women aged 15–24, in contrast with another study which reported an increase in contraceptive use among all women aged 15–49 in Nigeria [32]. This important finding has not been evident in previous studies that aggregated data for a wider age range of women, perhaps due to an ecological fallacy [13, 14; 16; 17]. This calls into question whether the current National Reproductive Health Policy and Strategy to achieve Quality Reproductive Health and Sexual Health for All Nigerians including the provision of free family planning services in public facilities [42] has benefited young women in Nigeria. Our findings indicate that young women are still being left behind on reproductive health matters despite increasing attention to prioritising their health globally.
Another interesting finding was the influence of contextual level factors on pregnancy termination. Although most variations were at the individual level, significant variations in pregnancy termination exist between young women across communities and states. While some community and state-level variables were not significantly associated with pregnancy termination, contraceptive prevalence’ at community level, which we derived from the individual-level variable ‘contraceptive use’ and then used as a proxy for reproductive health service accessibility within a community, was strongly positively associated with pregnancy termination. This suggests that communities with higher levels of reproductive health services, indicated by higher prevalence of contraceptive use, are linked to higher prevalence of pregnancy termination. This may indicate that despite availability of reproductive health services and contraceptives, factors such as pressure to have children and stigma surrounding non-marital sexual activity may hinder accessing them [45]. Interventions to discourage early marriage and dispel misconceptions and stigmatising attitudes towards contraceptive use such as scientifically accurate Comprehensive Sexuality Education (CSE) could help overcome these barriers and should be encouraged [18, 45]. However, these results contradict the findings of a previous study in Nigeria which found that residing in a community with contraceptive use at levels above the median for the community was associated with a lower likelihood of terminating pregnancy [20]. The disparity in the findings could be attributable to the fact that the previous study [20] focused on a wider age range of women (15–49 years). The integration of both young and older women in the study may have influenced the results as evidence has shown that older women have more contraceptive utilisation rate compared to younger women [12, 46].
Furthermore, at the individual level, we found that pregnancy termination was higher among older women aged 20–24 than younger counterparts aged 15–19 controlling for confounding factors. This is not surprising as the NDHS report in 2018 revealed that the median age at first sexual intercourse is 17.2 years for women of reproductive age in Nigeria [32]; meaning that older women are more likely to be sexually active or exposed than their younger counterparts, which predisposes them to unwanted pregnancy, leading to abortions in many cases [47–48]. The higher risk of pregnancy termination among older women persisted, even after the age of sexual debut was controlled for. It is possible that younger women are less likely to report or seek abortion services due to cultural, socio-economic and institutional barriers [45, 47]. Several other studies have reported similar findings [13, 15, 33].
Marital status was found to be a strong predictor of pregnancy termination. Currently married young women, those living with a partner or previously married and not living with a partner were more likely to terminate pregnancy than never-married women. This could be linked to social desirability bias as never-married young women may be reluctant to report pregnancy termination due to social stigma surrounding non-marital sexual activity or use of contraceptive [44]. However, this is inconsistent with the findings of previous school-based studies in Nigeria [16, 18] and facility-based studies among older women in Ethiopia [23], Burkina Faso [49] and Ghana [22], which found that unmarried youth are more likely to terminate a pregnancy than the married counterparts. The conflicting findings could be due to the difference how pregnancy termination was defined. In this study it was defined as any pregnancy that resulted in a miscarriage, abortion or stillbirth, which may not accurately reflect the main outcome of interest (induced abortion) [50]. While the school-based and facility-based studies measured only abortion. Although evidence from the DHS methodological report shows that only 2–5% of women who reported their pregnancy ending in miscarriage during a face-to-face interview changed their responses to induced abortion in a self-administered questionnaire [51].
Also, the results of this study revealed that young women from both Igbo and Yoruba ethnic groups (predominantly in the South) have a lower tendency for pregnancy termination than those from Hausa ethnic group (predominantly in the North). The states with the highest risk of pregnancy termination are predominantly in the North rather than the South. This could conceivably be attributable to the disparity in the level of education, rates of early marriage, and cultural norms/beliefs across different ethnic groups in Nigeria [52]. For example, the average age at marriage for most girls in Northern Nigeria is 15 years compared with a median age of 24 years in the Southern regions of the country, Girls in the Southern regions are more likely to access formal education, while in the Northern regions, girls are less likely to access formal education and, consequently, experience sexual initiation at earlier ages [53–55]. It is also worth stressing that maternal mortality and under-five mortality rates in Nigeria vary considerably with some Northern states reporting nearly 50% more deaths for both indicators than the national average [31, 56]. Furthermore, the North-South disparity in education supports our findings that young women educated to primary level and above are less likely to terminate a pregnancy than their uneducated counterparts. Young women who are educated are more likely to have access to information and available services and possibly, delay childbearing and marry later than those with no education. These findings are consistent with the findings of other studies [8, 15, 22, 24]. Also, in Ethiopia, evidence has shown that women with higher education were less likely to have induced abortion [57]. Lack of education and early sexual initiation/exposure, without doubt, expose young women to unintended pregnancy; leading to pregnancy termination [16].
Strengths and limitations
This study has key strengths due to utilising nationally-representative datasets (from 2003–2018), a large sample size and controlling for both individual and contextual (community and state) level factors. The analysis of variance indicated that around 24% of the variation in pregnancy termination among young women was due to the contextual level factors; supporting the value of including these in multivariable analyses. However, it, is not void of limitations that could have potential implications for the findings. One of the shortcomings is due to the cross-sectional study design which does not enable us to infer causal relationships between predictors and the outcome variable [13, 58]. Another is that the NDHS depends on self-reported data collection, which can be subject to bias especially in a setting like Nigeria where abortion is legally restrictive; making pregnancy termination more likely to be under-reported. This could be averted by the use of indirect questioning techniques in elucidating responses to the question on pregnancy termination [20]. Furthermore, a terminated pregnancy could mean any type of pregnancy other than one resulting in a live birth-including stillbirths, miscarriages and abortions which could lead to overestimation of terminated pregnancy. Finally, this study did not control for facility-level factors which previous studies have posited that influence pregnancy termination [25, 59]. However, our analysis indicated that residual confounding due to unobserved contextual level factors is only 12%. Therefore, the impact of this may be small.