Title: Trends and Determinants of Adolescent Pregnancy: Results from Kenya Demographic
Health Surveys 2003–2014
Version: 2 Date: 04 Feb 2022
Reviewer's report:
Thank you for the opportunity to review this manuscript describing the prevalence of late
adolescent pregnancy across multiple demographic health surveys conducted in Kenya, and
the associated modelling exercise looking at the factors  that underlie adolescent pregnancy.
It has potentially important implications for factors to focus on in further reducing adolescent
pregnancies in Kenya. There are some spots where further explanation could strengthen the
manuscript, as outlined below.
General comment:
- As the authors were interested in pregnancies between 15-19 years, they might consider
stating "late adolescent pregnancies" throughout the article and title, as opposed to adolescent
pregnancies  generally, which would include those to adolescents <15 years.
Methods:
- The authors give rationale as to why only data from those 20-24 was used to assess adolescent
pregnancy (i.e., among those reproductive-age females 15-19 the adolescent period was not
over). However, did they consider comparing the demographic characteristics among those
20-24 and 15-19? This could be included in an appendix. The SES and other characteristics of
interest included in the analysis may have been different at the actual time of pregnancy (when
participants were 15-19 years) compared to the timing of the survey (when participants are
20-24 years). For example, reporting being divorced at the time of the DHS conduction doesn't
necessarily reflect one's status at the time of their pregnancy given the time offset in data being
used in the analysis. This should also be acknowledged as a limitation.
- Furthermore,  did the authors consider conducting a subgroup analysis to see how the inclusion
of the younger group might change the analysis and conclusions? This could also be included
in an appendix, as readers will likely ask this question.
Results:
- There was a large difference in the rural/urban distribution for participants between the two
earlier DHS cycles and the 2014 cycle. Do the authors know why this is? Is it possible there
was a different sampling strategy used for 2014? Urban/rural sampling differences could also
account for the change in schooling proportions seen in the 2014 DHS cycle.
- What method was used to derive wealth quintile? Or were these pre-assigned within the
accessed DHS data? This was not described in the Methods. Notably, there was an increase in
representation across the wealth quintiles.
- At the end of the paragraph titled 'Adolescent pregnancy among women aged 20–24 years',
the 4 on 2014 was accidentally omitted.
- Perhaps I missed it, but in Table 4 and 5, what was adjusted for when generating the adjusted
odds ratios? It would be good to note this in the text and as a footnote in each respective table.
- Out of curiosity, is there a reason why occupation wasn't investigated?
Discussion:
- For the sentence, "PMA 2020 data show that adolescent pregnancy in 2018 was 25.6% among
women aged 14–18 (18)." can the authors explain a bit more about what PMA is and how their
data was collected/the sampling strategy? It would be helpful to the reader to understand the
characteristics of the data collection and design of PMA, to contextualize how this compares
to the DHS.
Limitations to this research:
- As outlined above, further acknowledgment of the time-related limitations of this research
should be considered.