Around 8.6% of Filipino women aged 15–19 have been or is currently pregnant. Coverage of contraception information vary widely according to media type, ranging from 5% via short messaging service to 55% via television. After adjusting for confounding variables, there is evidence of a positive association between increasing age and having just primary education with teenage pregnancy. On the other hand, belonging to higher socio-economic strata, having frequent internet access, and being of the Protestant or Muslim faith lower the odds of teenage pregnancy.
In analyses of previous NDHS in the Philippines, better socio-economic status and higher educational attainment was found to protect against teenage pregnancy (15). Similar trends can be observed for the current analysis, although the evidence of association for the protective effect of education is borderline significant. Such minor differences may be explained by secular changes which may have transpired in the four years between the data collection of the previous NDHS and the NDHS used for this analyses (10, 12), which would include greater internet coverage and the full implementation of the country’s K-to-12 education policy. Moreover, significant reproductive health policy developments such as greater implementation of the country’s reproductive health law, which was still recently passed as of the previous NDHS, and the implementation of Executive Order No. 12 which aims to improve the provision of family planning methods regardless of background (26, 30), might have also affected how these variables are associated with teenage pregnancy. Another possible difference might be attributable to differences in study methodology: the previous analyses included respondents aged 20–24 years old with the justification that this population group are no longer at risk of having adolescent pregnancies, and would thus give a clear picture of the overall risk of developing adolescent pregnancies as compared to studying respondents aged 15–19, as was done in this analysis (15). Another difference is in how the covariates were selected in the studies’ respective modelling strategies. The previous analyses only assessed for the effect of relatively few socio-demographic covariates and used stepwise regression methods, which could mean that the effect of other variables known to affect the outcome may not have been sufficiently adjusted for in the multivariate model. This analysis considered a greater number of possible exposure variables and controlled for as many known determinants of the outcome as possible. Such variable selection strategies leads to better control of confounding at the expense of parsimony (31).
The strong evidence of positive association between finishing just primary education and teenage pregnancy highlights the need to further strengthen reproductive health education even at the primary level. The country’s Reproductive Health Law contains specific provisions on comprehensive reproductive health education throughout the K-12 education curriculum (30, 32, 33). However, there may be a need to invest in the re-training of teachers as there are some teachers who have negative attitudes on reproductive health education, which could lead to poorer outcomes for students who did not receive it properly. Current initiatives led by the private sector to improve provision of reproductive health education by engaging both teachers and local chief executives is a step in the right direction (34), but it needs to be scaled-up and institutionalized by the national government considering that teenage pregnancy is prevalent nationwide (11, 14, 25). A Cochrane review of interventions to prevent unintended pregnancies among adolescents posits that educational interventions, on its own, were unlikely to significantly delay the initiation of sexual intercourse; together with contraceptive-promoting interventions, however, it appears to reduce unintended pregnancy among adolescents (35). Thus, reproductive health education might just be insufficient in preventing teenage pregnancy but should also be coupled with contraceptive-promoting interventions, such as contraception education and provision of free, unlimited contraception. Such interventions are necessary to ensure that young women have adequate knowledge about sexual and reproductive health to prevent them from having unwanted pregnancies.
Two things from the univariate analyses remain to be causes of concern: (1) the low proportion of women aged 15–19 using modern forms of contraception, (2) the positive associations of using both traditional and modern contraceptive methods with teenage pregnancy. The positive associations between contraceptive use and teenage pregnancy are counter intuitive. Previous studies have noted similar counter intuitive results as well, and have attributed such to reverse causality, considering that women who previously had an unwanted pregnancy might opt to use contraceptive methods to prevent further pregnancies. Alternatively, this could mean that these women have been using ineffective contraception methods, as in the case for traditional methods, or have been using these contraceptions incorrectly (15, 42–44). In any case, these findings highlight the need to educate adolescents on modern contraception methods and their proper use considering that the benefits of modern contraception, especially consistent condom use, prevent unwanted pregnancies and transmission of STIs, including HIV (45, 46). This is especially important in tailoring contraception-promotion interventions to accompany comprehensive reproductive health education interventions.
Age was found to be positively associated with teenage pregnancy, which has been consistent with previous research conducted in the Philippines and elsewhere (15–23). This study also finds that certain religions lower the odds of teenage pregnancy; specifically, adhering to Islam and Protestantism lower the odds of teenage pregnancy as compared to adherents of Roman Catholicism. While previous studies document that religion is associated with teenage pregnancy (3, 24, 36), the specific mechanisms as to how different religious beliefs affect teenage pregnancy is not clear. Most religious belief systems in the Philippines consider premarital sex to be taboo and on one hand, there is evidence that increased religiosity delays sexual debut (37). On the other hand, evidence from the United States show that increased religiosity is associated with teenage pregnancy as more religious teens may be less likely to use contraception (36). One possible mechanism explaining this association is the respective belief systems’ stand on contraceptive use. Roman Catholicism explicitly prohibits all forms of artificial contraception. On the contrary, Muslims are encouraged to use contraception but only within marriage as premarital sex is taboo in Islam. Protestant denominations adjust guidelines according to the circumstances of the woman and use of contraception is encouraged to prevent teenage pregnancy (37). The more encouraging stance of the latter religions might explain why their adherents have lower odds of teenage pregnancy.
The negative association between frequency of internet access and teenage pregnancy is not well-documented in published literature (38). Among studies in teenage pregnancy in the Philippines, this is the first time this association is demonstrated. One mechanism of action for this negative association is that more frequent internet access would expose people to information on effective contraception technologies and costs and difficulties of raising children. Another mechanism of action is that more frequent internet access would supplant face-to-face social interaction, reducing frequency of sexual intercourse, and therefore, birth rate. Analyses show that the rapid increase of internet coverage account for at least 13% of the decline in birth rates between 1999–2007 in the United States (38). Thus, increasing internet coverage can be considered as an intervention to reduce teenage pregnancies. Recent government and private sector investments in increasing internet access throughout the country (39, 40) may hopefully help decrease teenage pregnancies; however, such investments are only starting to be felt by the time the survey was conducted for it to have any meaningful effect in decreasing teenage pregnancy. Future research studying these associations should be conducted.
The tests for interaction are known for having low statistical power (41), which may explain the lack of joint effect between frequency of internet access and accessing contraceptive information via the internet. We were also unable to adjust for the effects of civil status and contraceptive use and intention, two known confounders in other studies (15–24), due to issues in separation and/or autocorrelation. Including such variables in the model might control for their possible confounding effect, but would affect the overall stability of the model by having unrealistic effect estimates and wide confidence intervals (47). For this reason, we excluded these two variables in multivariate analyses. In addition, this analysis has several other weaknesses. As compared to the analysis of the previous NDHS in the Philippines (15), this analysis included respondents aged 15–19, which means that the respondents are still at risk of developing the outcome, which may give an incomplete picture of the risk factors of teenage pregnancy. On the other hand, it may be argued that studying current teenagers minimizes issues on recall bias. Another possible weakness is residual confounding, especially that we were unable to control for many known confounders due to substantial missing data for these variables. Our prevalence of teenage pregnancy may also be an underestimate as we only had questions on currently pregnant and number of children, which means that those who had an abortion were not counted. Lastly, as the study used self-report data, the validity of its findings is as good as the information provided by the respondents.