Determinants of adolescent pregnancy in sub-Saharan Africa: a systematic review

Background Adolescent pregnancy has been persistently high in sub-Saharan Africa. The objective of this review is to identify factors influencing adolescent pregnancies in sub-Saharan Africa in order to design appropriate intervention program. Methods A search in MEDLINE, Scopus, Web of science, and Google Scholar databases with the following keywords: determinants, factors, reasons, sociocultural factors, adolescent pregnancy, unintended pregnancies, and sub- Saharan Africa. Qualitative and cross-sectional studies intended to assess factors influencing adolescent pregnancies as the primary outcome variable in sub- Saharan Africa were included. Our search was limited to, articles published from the year 2000 to 2017 in English. Twenty-four (24) original articles met the inclusion criteria. Results The study identified Sociocultural, environmental and Economic factors (Peer influence, unwanted sexual advances from adult males, coercive sexual relations, unequal gender power relations, poverty, religion, early marriage, lack of parental counseling and guidance, parental neglect, absence of affordable or free education, lack of comprehensive sexuality education, non-use of contraceptives, male’s responsibility to buy condoms, early sexual debut and inappropriate forms of recreation). Individual factors (excessive use of alcohol, substance abuse, educational status, low self-esteem, and inability to resist sexual temptation, curiosity, and cell phone usage). Health service-related factors (cost of contraceptives, Inadequate and unskilled health workers, long waiting time and lack of privacy at clinics, lack of comprehensive sexuality education, misconceptions about contraceptives, and non-friendly adolescent reproductive services,) as influencing adolescent pregnancies in Sub-Saharan Africa Conclusion High levels of adolescent pregnancies in Sub-Saharan Africa is attributable to multiple factors. Our study, however, categorized these factors into three major themes; sociocultural and economic, individual, and health service related factors as influencing adolescent pregnancies. Community sensitization, comprehensive sexuality education and ensuring girls enroll and stay in schools could reduce adolescent pregnancy rates. Also, provision of adolescent-friendly health services in schools and healthcare centers and initiating adolescent empowerment programs could have a positive impact.


Plain English summary
Adolescent pregnancies have been persistently high in sub-Saharan Africa. This study seeks to identify factors influencing adolescent pregnancies in sub-Saharan Africa through a systematic review of published scientific articles.
A total of two hundred and twenty nine (229) original articles published between 2000 and 2017 were first identified from various data bases. Finally, twenty-four (24) original articles met the inclusion criteria and were included in the study. All articles were studies conducted in sub-Saharan Africa.
The study identified Sociocultural, environmental and Economic factors (Peer influence, unwanted sexual advances from adult males, coercive sexual relations, unequal gender power relations, poverty, religion, early marriage, lack of parental counseling and guidance, parental neglect, absence of affordable or free education, lack of comprehensive sexuality education, non-use of contraceptives, male's responsibility to buy condoms, early sexual debut and inappropriate forms of recreation). Individual factors (excessive use of alcohol, substance abuse, educational status, low self-esteem, and inability to resist sexual temptation, curiosity, and cell phone usage). Health service-related factors (cost of contraceptives, Inadequate and unskilled health workers, long waiting time and lack of privacy at clinics, lack of comprehensive sexuality education, misconceptions about contraceptives, and non-friendly adolescent reproductive services,) as influencing adolescent pregnancies in Sub-Saharan Africa.
We believe that Community sensitization, sex education and ensuring girls enrol and stay in schools could reduce adolescent pregnancy rates. Also, provision of adolescent friendly health services at schools and initiating adolescent empowerment programs could have positive impact.

Background
The long-lived belief in the African society where females were not prioritized for education is fading out. With this, it expected that female education will increase in sub-Saharan Africa [1]. Unfortunately, adolescent pregnancy contributes to denying brilliant students education and has potential to retard their growth and development including that of their children.
According to WHO about 17 million adolescent girls give birth every year and most of these births occur in low-and middle-income countries [2]. Adolescent health and development are of global concern. The need to prevent early pregnancy among adolescent girls in Sub-Saharan Africa has been recognized increasingly over recent years [3]. African countries lead the world in teen pregnancies: With Niger on the top list of 203.604 births per 100,000 teenage women. Mali follows with 175.4438, Angola (166.6028), Mozambique (142.5334), Guinea (141.6722), Chad (137.173), Malawi (136.972), and Cote d'Ivoire (135.464) [4].
Adolescent girls continue to experience the disproportionately high burden of sexual and reproductive ill health, particularly in Sub-Saharan Africa [3]. High adolescent pregnancies with adverse health and social consequences are urgent problems facing low-and middle-income countries [2]. Adolescents are likely to have complications of pregnancy including unsafe abortion and more likely to become young mothers a second time [2,5,6]. Their infants are also more likely to be born premature and to die in the perinatal period [7]. Babies born to adolescent mothers face a substantially higher risk of dying than those born to women aged 20 to 24 [2,5,8]. They are at risk of malnutrition, low mental and physical development, inappropriate social connection with parents and poor education [5,9].
Adolescents develop psychological problems from social stigma, suffer physical and domestic violence in their attempt to meet the demands of pregnancy and childbearing [9,10]. Also, they most likely would drop out and may not get the chance to return to school [11]. The inadequate resources of low and middle-income countries would have to be channeled to cater for the health needs of pregnant and teen mothers including their children [5]. Economic opportunities are limited to adolescents who could not complete school because of unintended pregnancies. This could be the beginning of a poverty cycle in families, however, some are able to face the challenge and become productive later in life.
Factors associated with unintended pregnancies amongst adolescents are early marriages, culture, religion, gender [12], poor social and economic support [13,14]. Curiosity and peer pressure [15,16], lack of comprehensive sexuality education [17][18][19], poor reproductive health services provision [19,20], poor attitude of health workers to providing contraceptive services for adolescents [15,21]. Also, unmet need for contraceptives by adolescents [22] and fear of contraceptive side effects [16]. Barriers to contraceptive use among adolescents include inadequate sexual knowledge and risk perceptions. Also, lack of skills and power to negotiate safer sex options, ambivalence towards sex, and negative social norms around premarital sexual activity and pregnancy [23].
Policy makers in Sub-Saharan Africa need to understand the determinants of adolescent pregnancy in their context in order to design pragmatic interventional programs to reduce unintended pregnancies amongst adolescents. Since there has not been any review of literature on the determinants of adolescent pregnancy in Sub-Saharan Africa, this study aims to identify the determinants of high adolescent pregnancy in Sub-Saharan Africa.

Search strategy
MEDLINE, Scopus, web of science and Google Scholar databases were searched in July 2017 with the following keywords: determinants, factors, reasons, sociocultural factors, adolescent pregnancy, unintended pregnancies, and sub-Saharan Africa. Qualitative and cross-sectional studies intended to assess the factors influencing adolescent pregnancies either intended or unintended as the primary outcome variable in sub-Saharan Africa was included. Our search was limited to articles published in English from 2000 to 2017.

Inclusion and exclusion criteria
Qualitative and cross-sectional studies that assessed the factors associated with adolescent pregnancy, conducted in sub-Saharan Africa, whether the pregnancy was intended or not, from the year 2000 to 2017 were included. Studies that addressed factors associated with adolescent pregnancy, yet conducted outside Sub-Saharan Africa were excluded from the study.

Identification of reviews
A search framework was constructed and implemented through a broad scope and exhaustive search using Tehran University of Medical Sciences electronic library to identify applicable studies published in English. The search identified a total of 229 articles, which composed of 244 original research articles and 5 review articles. After the screening of titles and abstracts, 54 articles were excluded because they did not address adolescent pregnancy. Articles that addressed adolescent pregnancy were 170 and 5 reviews. All the review articles were excluded because 3 were conducted outside the study setting, and the other 2 did not assess the determinants of adolescent pregnancy. With the rest of the articles, 40 did not assess determinants of adolescent pregnancy, 16 were conducted before the year 2000, 56 were not full text and 34 were duplicated. Therefore, 24 research articles were sieved and included in the study. Figure 1 demonstrates articles selection criterion.

Variables assessed
The main variables assessed were age, lack of money, lack of family support, the culture of not talking about sex at home, peer influence, broken homes, early marriages, and religion. Service-related factors such as lack of adolescent-friendly services, inadequate comprehensive sexuality education, non-availability and cost of contraceptives, inadequate health personnel, judgmental attitude of service providers and inadequate counseling. Personal behavioral factors such as alcohol and tobacco use, fear of stigma and being judged by the service provider, low self-efficacy, low self-esteem, vulnerability and rape, curiosity, inadequate education and knowledge about contraceptives.

Articles appraisal
The Joanna Briggs appraisal tool [24] was used independently by the authors to appraise and certify for inclusion or exclusion of articles. Both authors, before inclusion, reached consensus. The tool consists of a checklist of ten questions for qualitative studies, eight for cross-sectional studies and 11 for systematic reviews and research syntheses.

Strengths of the study
The study has revealed, through a comprehensive search the determinants of adolescent pregnancy in Sub-Saharan Africa. The results of the study are similar to global reports [25]. In addition, the study revealed a gap in research regarding literature on determinants of adolescent pregnancy in the five sub-Saharan Africa countries with the highest rates [4].

Weaknesses of the study
Diverse disciplines deal with adolescents and adolescent pregnancies; this makes it possible to miss some articles during the search process since their findings may not be published in scientific based journals which were our main source of data. Secondly, grey literature, reports, and unpublished studies were not included in this review. In addition, some articles reported findings from small sample sizes.

Operational definition of concepts Adolescent reproductive services
Healthcare services offered to assist adolescents access sexual and reproductive health information.

Comprehensive sexuality education
Teaching abstinence as the best method for avoiding unintended pregnancy, but also teaching about condoms and contraception to reduce the risk of unintended pregnancy. It also involves empowering adolescents to resist sexual temptations and peer pressure.

Curiosity
A strong desire to discover new things, especially about sex and relationships.

Early marriage
Union between two people in which one or both parties are younger than 18 years of age:

Early sexual debut
Having had first sexual intercourse at or before age 14.

Excessive use of alcohol
Uncontrolled and widespread alcohol usage.

Family dysfunction
Unhealthy interactions, conflict, misbehaviour, and child neglect of parents.

Gender power relations
The culturally determined social status of men and women in relationships.

Inability to resist sexual temptation
Inability to avoid or say no to sexual desires and pressure from both internal and external sources, and acting on it.

Inappropriate recreation
Recreational activities, which creates a risky sexual environment e.g. disco dances, clubbing etc.

Low self-esteem
Lacking self-confidence to turn down sexual advances from men.

Peer influence
Social pressure by members of one's peer group to take a certain action, adopt certain values, or otherwise conform in order to be accepted.

Positive attitude towards early sexual relationships
Having a good feeling or emotion towards early sexual relationships.

Religion
A system of faith and worship.

Sexual advances
Purposeful visual, verbal or physical conduct of a sexual nature.

Substance abuse
Excessive and uncontrolled use of illicit and addictive substances such as tobacco, marijuana.
Participants in this study were mostly adolescents. The study settings were both rural and urban, with an approximated total population of 11,651 participants. Participants per study varied from 10 as the least to 3122 as the highest. Refer to Table 2 for a detailed description of participant's characteristics.
At least 12 key informants composed of parents, school teachers, health providers, and adolescent mothers/fathers were involved in some of the included studies. They provided information regarding some of the determinants of adolescent pregnancy.
It is interesting to note that there is no published data within this review years from the top five sub-Saharan African countries with adolescent pregnancy above 140 births per 100,000 adolescents [47].
The study revealed three major themes influencing adolescent pregnancy in sub-Saharan Africa: Sociocultural, environmental and Economic, Individual, and Health-Related Factors.

Discussion
Sociocultural, economic, individual and health service factors were identified as the main determinants of adolescent pregnancy. These factors were found to influence high rates of adolescent pregnancy in sub-Saharan Africa, similar to the developed world [25]. A study by Fearon et al. reported peers to be influential in romantic and sexual behaviors of adolescents [48]. Their finding is consistent with the findings of this review. Studies from Ghana, Nigeria, Swaziland, Kenya, Tanzania, and South Africa reported the influence of peers in adolescent pregnancy. Particularly mentioned in a study from Nigeria [41], peers encourage their friends to get boyfriends.
Low socioeconomic status of parents makes adolescents vulnerable to unintended pregnancies since the means to afford basic needs, and sometimes contraceptives is a challenge. Some adults take advantage of this situation to provide basic needs to unsuspecting adolescents and engage in sexual relationships with them. This creates a power difference between adolescents and their adult partners making them powerless to negotiate for  G r e a t e rG i y a n iM u n i c i p a l i t y / South Africa   [23], South Africa [31] and Tanzania [29] demonstrate how poverty leads adolescents to engage in sexual relations with elderly men in order to meet their basic needs. Lambani [36], reported that adolescents intentionally get pregnant to receive government support intended for teenage mothers to improve their economic condition not considering the consequence of their action. Lack of parental counseling and guidance, severe family dysfunction with parental neglect were found as risk factors for adolescent pregnancies [26,33,35,40,45]. Parental counseling and guidance improves communication between parents and adolescents and enables parents to address challenges of adolescents. Improved family communication and parent involvement in adolescents pregnancy prevention programs could delay adolescent sexual activity and pregnancy [49].
Inadequate knowledge, misconceptions and non-use of contraceptives [15,19,23,26,29,31,32,34,36,37,41,45,46] were identified as determinants of adolescent pregnancy. As indicated by Wood and Hendricks [31], health practitioners don't relate health education to sociocultural context of adolescents but rather on biomedical facts and warn of negative consequences. They do not as well explore their fears regarding contraception; therefore, adolescents do not feel the impact of comprehensive sexuality education. Uninformed adolescents perceive contraceptives as a reserve for married couples [29].
Inappropriate modes of recreation in the form of unmonitored nightclubs or mixed-sex partying. These expose adolescents to early sex since they socialize easily with men [45].
We found the positive attitude towards early sexual relationship and early sexual debut as factors contributing to adolescent pregnancy, consistent with findings from some developed countries [50][51][52]. The participants mostly lived in a social environment where adolescents had free will to choose sexual partners at an early age without much criticism from parents, caregivers, and peers [23]. In other reports, adolescents intentionally became pregnant as proof of love and commitment to their sexual partners [30].
Religion and early marriages were also found to contribute to high reports of adolescent pregnancies, which is consistent with a study by Parsons et al. [53]. Adolescents affected by early marriages are deprived of economic empowerment and self-efficacy and are at risk of early pregnancies [3]. They are also prone to maternal morbidity and mortality [54]. WHO's guidelines on prevention of unintended pregnancy stressed on policies to reduce early marriage [6]. Rape, coerced sex, sexual advances from adult men and unequal gender power in relationships identified in this review, undermines adolescents' decision-making ability to either reject sex or negotiate the use of contraceptives [55].
Individual factors that influence adolescent pregnancies include excessive use of alcohol and substance abuse. This behavior makes adolescent girls vulnerable, and an easy target for sexual exploits. This is consistent with previous findings which reported an association between high-risk sexual behavior, adolescent pregnancy and substance abuse [56]. Cell phone usage promotes easy communication among peers and their partners and also gives them easy access to the internet which they use without regulation, to surf explicit content motivating early sex [34].
Health service-related factors include the cost of contraceptives [19], healthcare centers lacking the adequate and skilled staff to attend to adolescents who need reproductive health services [19,27,43]. Long waiting time and lack of privacy at clinics discourage adolescents from visiting the facilities for services [27]. Also, inadequate comprehensive sexuality education and misconceptions about contraceptives [15,19,23,27,29,30,34,35,38,40,45,46] were identified. Similarly, lack of friendly adolescent reproductive services and negative attitude of health workers towards providing reproductive health services for adolescents [15,19,27,29,43,44] were all associated with adolescent pregnancy.

Conclusion
High levels of adolescent pregnancies in Sub-Saharan Africa is attributable to multiple factors. Our study, however, categorized these factors into three major themes; Sociocultural, environmental and Economic factors (Peer influence, unwanted sexual advances from adult males, coercive sexual relations, unequal gender power relations, poverty, religion, early marriage. In addition, lack of parental counseling and guidance, parental neglect, the absence of affordable or free education, lack of comprehensive sexuality education, misconceptions, and non-use of contraceptives, male's responsibility to buy condoms, positive attitude towards early sexual relationships, early sexual debut and inappropriate forms of recreation). Individual factors (excessive use of alcohol, substance abuse, educational status, low self-esteem, and inability to resist sexual temptation, curiosity, and cell phone usage). Health service-related factors (cost of contraceptives, Inadequate and unskilled health workers, long waiting time and lack of privacy at clinics, lack of comprehensive sexuality education, misconceptions about contraceptives, non-friendly adolescent reproductive services, and negative attitude of health workers towards providing reproductive health services for adolescents) as influencing adolescent pregnancies.
Seemingly unique to sub-Saharan Africa, our study found determinants of adolescent pregnancy to be associated with religious factors, early marriages, low level of education, and poverty. Also, cost of contraceptives, lack of adolescent-friendly health service provision, inadequate and unskilled health workers, and lack of comprehensive sexuality education.
Policymakers and opinion leaders should focus on community sensitization, comprehensive sexuality education and ensure girls enroll and stay in schools. Also, peers and significant others should be involved in designing interventional programs for adolescent pregnancy prevention. This could reduce adolescent pregnancy rates. Moreover, provision of adolescent-friendly health services at schools and healthcare centers, and initiating adolescent empowerment programs could have a positive impact on reducing adolescent pregnancy.
Further research is required on the determinants of adolescent pregnancy in the top five sub-Saharan African countries-Niger, Mali, Angola, Mozambique, and Guinea-with rates of adolescent pregnancy above 140 births per 100,000 adolescent women.