Prevalence, predictors and adverse outcomes of adolescent pregnancy in sub-Saharan Africa: a protocol of a systematic review
Sama et al. Systematic Reviews
Prevalence, predictors and adverse outcomes of adolescent pregnancy in sub-Saharan Africa: a protocol of a systematic review
Carlson-Babila Sama 0 1
Stewart Ndutard Ngasa 0 2 6
Bonaventure Suiru Dzekem 0 4 5
Simeon-Pierre Choukem 3 7
0 Galactic Corps Research Group (GCRG) , Buea , Cameroon
1 School of Life and Medical Sciences, Faculty of Population Health Sciences, Institute for Global Health, University College London, WC1E 6BT , London , UK
2 Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine , London , UK
3 Health and Human Development (2HD) Research Group , Douala , Cameroon
4 Clinical Research Education , Networking and Consultancy (CRENC), Douala , Cameroon
5 Health Services Partner Cameroon , Kumba , Cameroon
6 Sporedata Research Inc , Durham, NC , USA
7 Department of Internal Medicine, Douala General Hospital , P.O. Box 4856, Douala , Cameroon
Background: Several studies have reported on factors influencing adolescent pregnancies and the associated outcomes, but evidence from a systematic review is limited, especially in sub-Saharan Africa where the greater burden lies. Establishment of accurate epidemiological data on the rates of adolescent pregnancy, its predictors, and adverse outcomes (maternal and neonatal) may have important implications towards attainment of the Sustainable Development Goals. Methods: This will be a systematic review of studies reporting predictors of adolescent pregnancy and adverse outcomes in sub-Saharan Africa published between January 2000 and December 2017. The following databases will be searched: PubMed/MEDLINE, Excerpta Medica Database (EMBASE), SCOPUS, Popline, Africa Wide Information, African Index Medicus, Google scholar and the Cochrane library. Three authors will independently screen all potential articles for eligibility as guided by the selection criteria. The Stata statistical software will be used in analysing the data. Appropriate metaanalytic techniques will be used to pool prevalence estimates from studies with similar features, overall and by major subgroups as warranted. Heterogeneity of studies will be evaluated by the χ2 test on Cochrane's Q statistic. Publication bias will be sorted for using funnel plot analysis and Egger's test. Qualitative synthesis will be used where data are insufficient to produce a quantitative synthesis. This protocol is reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) 2015 guidelines. Discussion: This systematic review and meta-analysis is expected to serve as a template for designing adolescentfriendly preventive and control programmes to help curb the ever-growing burden of adolescent pregnancies, and as a guide for future research. Systematic review registration: PROSPERO CRD42017070773
Adolescent; Pregnancy; Prevalence; Outcome; Africa; Systematic review
Adolescence is defined as all persons aged 10 to 19 years,
and it is further subdivided into younger adolescents (10
to 14 years) and older adolescents (15 to 19 years) [
In developed and developing nations alike, adolescent
pregnancy is of growing public health importance with
approximately 11% of global births occurring in girls
aged 15 to 19 years, and about 95% of these births occur
in low and middle countries (LMICs) [
]. The regional
burden in LMICs is more in sub-Saharan Africa (SSA),
where it is estimated that about half of the women gave
birth before the age of 20 years, with a resultant high
pregnancy-related morbidity and mortality [
In Africa, a quarter of the estimated 6 million unsafe
abortions and 22,000 abortion-related deaths annually
occur among women aged 15–19 years [
that adolescent pregnancy is often not the result of a
deliberate choice. In these settings, adolescent pregnancy
is a multifaceted problem and, among others, exposes
these young girls to a variety of medical, socio-cultural
and economic risks. Factors such as marital status,
poverty, culture, inadequate knowledge on sexual education/
contraceptive use, gender-based violence/inequalities
and substance abuse have been implicated as some
predictors of adolescent pregnancy [
]. These young
mothers face a higher risk of dropping out of school and
social exclusion from family members, teachers and
peers which may have a long-lasting negative impact on
their physical and mental health [
]. Also, increased
risk of adverse pregnancy outcomes including stillbirth,
preterm birth, low birthweight, perinatal death,
obstructed labour, perineal tears, obstetric fistulae,
postpartum haemorrhage and maternal deaths have been
noted to occur among adolescent girls [
Furthermore, it has been observed that babies born to
adolescent mothers have a significantly increased risk of
living in poverty, poor school performance and being
unemployed later in life . All these have substantial
costs to society and contribute to the vicious cycle of
ill-health, neglect and poverty worldwide [
2, 15, 19
Thus, giving the considerable variability and somewhat
controversial views on predisposing factors (predictors) and
outcomes of adolescent pregnancy [
16, 17, 20, 21
], there is
a consequent need for a large and high-quality study,
especially from LMICs where most of the adverse outcomes are
documented to occur. Along these lines, a systematic
review is therefore necessary to critically appraise existing
literature so as to provide an insightful and comprehensive
up-to-date evidence on factors influencing adolescent
pregnancy as well as the associated adverse outcomes.
The overall aim of the study will be to estimate the
prevalence of pregnancy, its predictors and outcomes
among adolescent girls in sub-Saharan Africa via a
systematic review and meta-analysis.
This 17-year review is expected to answer the following
1. What is the prevalence of adolescent pregnancy in
2. What are the predictors of adolescent pregnancy in
3. What are the adverse maternal outcomes associated
with adolescent pregnancy in sub-Saharan Africa?
4. What are the adverse neonatal outcomes associated
with adolescent pregnancy in sub-Saharan Africa?
This review protocol is registered in the PROSPERO
International Prospective Register of systematic reviews
(Registration Number: CRD42017070773) and is written
and reported in accordance with the Preferred Reporting
Items for Systematic Reviews and Meta-Analysis
Protocols (PRISMA-P) 2015 Guidelines [
]. The items of this
checklist as fulfilled by this protocol are shown in
Additional file 1.
Eligibility criteria for considering studies for the review
Study designs and participants: observational studies
(cross-sectional, case-control and cohort studies) on
either the prevalence of pregnancy, its predictors
and/or outcomes among adolescent girls (10 years ≤
age < 20 years) residing in one of the countries in
Study setting: Health facility or community-based
studies conducted in rural or urban settings within
Time period: Studies published between January 1,
2000 and December 31, 2017 in the selected
Language: No language restriction will be applied.
For studies with duplicate results of the same study,
only the most comprehensive and up-to-date version
will be considered.
Studies lacking prevalence rates, predictors and/or
outcomes of adolescent pregnancy with absence of
data to compute the relevant effect sizes will be
excluded from quantitative analysis if the necessary
information is still not accessible even after multiple
requests from the authors.
Unpublished manuscripts and conference abstracts
as well as editorials, commentaries, reviews, letters
to editors and any publication without primary data.
Search strategy and identification of studies
Main database search
With the appropriate Boolean operators, we will use
Medical Subject Headings (MeSH) and combining
relevant text words with names of countries in
subSaharan Africa to search PubMed/MEDLINE for eligible
studies. If a country has changed its name over time,
both names will be included in the search. This main
search strategy (Table 1) will be adapted to fit with other
databases we intend searching including Excerpta
Medica Database (EMBASE), SCOPUS, Popline, Africa
Wide Information, African Index Medicus and the
Cochrane library. Articles returned by the search will be
saved to the Zotero V.126.96.36.199 software which will be
used to remove duplicates. The titles and abstracts of
the articles remaining after exclusion of duplicates will
be reviewed against eligibility criteria, and the full
articles will then be accessed via PubMed, HINARI or the
corresponding journal’s site. Authors whose full articles
will not be accessible after numerous internet-based
searches will be directly contacted to provide them.
The reference lists of all eligible research articles will
also be scrutinised for additional potentially relevant
Other general and less precise search engines such as
Google Scholar will be searched for relevant material.
The authors of studies that will be selected for critical
appraisal will be contacted by email for the existence of
any unpublished literature, research in progress or
unpublished data if warranted. In the event of no response
after repeated attempts to contact authors, the said
study shall be excluded.
After de-duplication of records by Zotero V.188.8.131.52
software, retained data will be uploaded to the Rayyan
software to facilitate online collaboration between
investigators during the selection of eligible articles. A
standardised pretested questionnaire containing inclusion
and exclusion criteria will be drafted by the investigators
to orient the screening of titles and abstracts.
The full text of all potentially eligible studies will be
rigorously reviewed by three independent reviewers
(CBS, SNN, and BSD) using the pretested questionnaire.
In case of unsettled disagreements between these
reviewers, the problem will be solved by a fourth
reviewer (SPC). A PRISMA flowchart will be produced
to reflect the entire review process and also detailing
potentially eligible studies which will be excluded with
reasons for their exclusion.
Data extraction and items
A data extraction sheet will be produced on IBM-SPSS
statistical software v.20 for Windows (SPSS Inc.,
Chicago, IL) and pretested by two investigators (CBS
and BSD) prior to data collection. Data from the
different studies to be included in the final analysis will then
be extracted by two independent investigators (CBS and
SNN), and any inconsistency will be reconciled through
Adolescent[MeSH terms] OR adolescent[tw] OR adolescents[tw] OR teen*[tw] OR youth*[tw] OR young[tw]
Pregnancy[MeSH terms] OR pregnancy[tw] OR pregnant[tw] OR gravid*[tw] OR parity[tw] OR deliver*[tw]
#1 AND #2
Africa[MeSH terms] or Africa[tw] OR “Africa South of the Sahara”[MeSH terms] OR “sub Saharan Africa”[tw] OR “sub Saharan African”[tw] OR
“subSaharan Africa”[tw] OR “subSaharan African”[tw] OR Angola[tw] OR Benin[tw] OR Botswana[tw] OR “Burkina Faso”[tw] OR Burundi[tw]
OR Cameroon[tw] OR “Cape Verde”[tw] OR “Central African Republic”[tw] OR Chad[tw] OR Comoros[tw] OR Congo[tw] OR “Democratic
Republic of Congo”[tw] OR Djibouti[tw] OR “Equatorial Guinea”[tw] OR Eritrea[tw] OR Ethiopia[tw] OR Gabon[tw] OR Gambia[tw] OR
Ghana[tw] OR Guinea[tw] OR “Guinea Bissau”[tw] OR “Ivory Coast”[tw] OR “Cote d’Ivoire”[tw] OR Kenya[tw] OR Lesotho[tw] OR Liberia[tw]
OR Madagascar[tw] OR Malawi[tw] OR Mali[tw] OR Mauritania[tw] OR Mauritius[tw] OR Mozambique[tw] OR Namibia[tw] OR Niger [tw] OR
Nigeria[tw] OR Principe[tw] OR Reunion[tw] OR Rwanda[tw] OR “Sao Tome”[tw] OR Senegal[tw] OR Seychelles[tw] OR “Sierra Leone”[tw] OR
Somalia[tw] OR “South Africa”[tw] OR Sudan[tw] OR Swaziland[tw] OR Tanzania[tw] OR Togo[tw] OR Uganda[tw] OR “Western Sahara”[tw]
OR Zambia[tw] OR Zimbabwe[tw] OR “Central Africa”[tw] OR “Central African”[tw] OR “West Africa”[tw] OR “West African”[tw] OR “Western
Africa”[tw] OR “Western African”[tw] OR “East Africa”[tw] OR “East African”[tw] OR “Eastern Africa”[tw] OR “Eastern African”[tw] OR “South
African”[tw] OR “Southern Africa”[tw] OR “Southern African”[tw]
consensus or arbitration with a third investigator (SPC).
The following items will be extracted from the selected
studies: authors, year of study, year of publication and
journal, country where study was conducted,
geographical region, language of publication, study design and
setting, duration of study, sample size, objectives, mean/
median age, age range, gravidity, parity, gestational age,
antenatal records and proportion of adolescent
pregnancy, as well as its measures of association (χ2, ORs,
RR, CIs and p values) when available.
Assessment of methodological quality and risk of bias
The quality of included studies will be independently
scored by two reviewers (CBS and SNN). The STROBE
] for observational studies will be used to
evaluate the quality of reporting in each paper. The Risk
of Bias Tool for Prevalence Studies developed by Hoy
and collaborators [
] (Table 2) and the
ACROBATNRSI tool provided by the Cochrane handbook will be
used to assess the risk of bias for each study, and results
will be presented in a table, accompanied by narrative
Data synthesis, analysis and assessment of heterogeneity
The information on the data extraction sheet will be
exported to the Stata software (Stata Corp V.14, Texas,
USA), and analysis will be done. If extracted data are
insufficient for quantitative synthesis, we will proceed
only with qualitative synthesis; otherwise, after
stabilising the variance of individual studies using the
FreemanTukey double arc-sine transformation [
heterogeneity will be assessed using the χ2 test on Cochrane’s Q
statistic, as well as the I2 [
] and the tau-squared (τ2)
statistics. With low heterogeneity, we will proceed with
meta-analysis with pooled effect sizes and the
corresponding forests plots will also be generated. The
random effects meta-analysis models will be
preferentially reported over fixed-effects models to obtain an
overall pooled summary estimate of prevalence rates
A meta-analysis will be performed to assess the
association between predisposing factors/outcomes and
adolescent pregnancy. Univariate proportion effect size
metric will be used to address objective 1 while odds
ratio/risk ratio metrics or correlations will be used to
address objectives 2, 3 and 4 as warranted. Where
substantial heterogeneity will be detected, meta-regressions
and subgroup stratified analyses will be done to detect
its possible sources according to important study
characteristics such as study quality, study setting, study
design, sample size, adjusting for confounders or not
and any other relevant parameters identified during the
extraction. Any subgroup differences identified will be
described and interpreted accordingly. Cohen’s κ
coefficient will be used to assess inter-rater agreement
for study inclusion [
]. Funnel plots, as well as Egger’s
weighted regression methods, will be used to assess for
possible publication bias [
]. A p value < 0.1 will be
considered indicative of statistically significant
Confidence in cumulative evidence
The Grading of Recommendations Assessment,
Development and Evaluation (GRADE) approach will be used
to assess for quality of evidence provided by the
included studies taking into account the study limitations,
indirectness, inconsistencies, imprecision and
publication bias. Overall quality of evidence following
assessment will be graded as follows:
High: if further research is unlikely to change the
Moderate: if further research is likely to have a
considerable impact on effect estimates
Low: if further research is capable of changing effect
Very low: those in which there is uncertainty in
Reporting and potential amendments to protocol
We intend to publish this review according to the
PRISMA-P guidelines [
] for the reporting of systematic
reviews and meta-analysis protocols and the PRISMA
checklist will be published alongside the completed report.
In a bid to avoid any possibility of reporting bias, no
further amendments will be made to this protocol. However,
if amendments become inevitable, then it will be clearly
documented, justified and reported transparently.
Adolescent pregnancy remains a significant public health
challenge and a developmental setback, especially in
sub-Saharan Africa where very high rates have been
reported with a resultant significant morbidity and
mortality. All these are happening within the backdrop of
high rates sexually transmitted diseases (STDs). Our
results will help to guide and formulate the content of
future adolescent-friendly preventive and control
programmes. Such an inclusive programme, in-part, will
motivate a more pragmatic response to adolescent
pregnancies, help monitor progress towards reducing its
incidence and possibly, help curb the high rates of STDs
including HIV/AIDS in sub-Saharan Africa.
Consequently, these will facilitate the overall attainment of the
Sustainable Development Goals (goals 1, 2, 3 and 4)
]. The findings will be published in a peer-reviewed
journal. Furthermore, we will submit it to appropriate
health and policy authorities and also present it at
various conferences. Future updates to the review are
envisaged as more recent studies become available in order to
guide health service and inform policy solutions.
Possible limitations of this study would include:
Predominance of poor quality studies on the subject
Significant heterogeneity of eligible studies which
may preclude further analysis
Predominance of cross-sectional studies would
possibly make it difficult to reliably obtain or
ascertain predictors and outcomes of adolescent
The exclusion of unpublished studies, as well as
interventional studies may lead to loss of potential
substantial data if pre-test results were reported.
Additional file 1: PRISMA-P 2015 checklist for a systematic review and
meta-analysis protocol on determinants and outcomes of adolescent
pregnancy in sub–Saharan Africa. (DOCX 19 kb)
AIDS: Acquired immune deficiency syndrome; HIV: Human immune-deficiency
virus; LMICs: Low and middle countries; MeSH: Medical Subject Headings;
PRISMA-P: Preferred Reporting Items for Systematic Reviews and Meta-Analysis
Protocols; SSA: Sub-Saharan Africa; STDs: Sexually transmitted diseases
We thank the entire members of the Galactic Corps Research Group and
Professor Fru F. Angwafo III for their substantial input.
Availability of data and materials
The datasets that will be generated during and/or analysed during the current
study will be available from the corresponding author on reasonable request.
CBS and SNN conceived and designed the protocol. CBS produced the
manuscript which was critically reviewed for methodological and intellectual
content by SNN, BSD and SPC. CBS is the guarantor of this review. All the
authors read and approved the final version of the manuscript.
Ethics approval and consent to participate
Given that this study is based on already published data, a formal ethical
approval will not be required.
Consent for publication
The authors declare that they have no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in
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