Modern contraception, defined as the set of reversible methods (hormonal, mechanical, and chemical) that allow the prevention of unwanted pregnancies, is a pillar of family planning [1][2]. It represents a major public health challenge and plays a key role in reducing maternal mortality, which remains a concerning issue in low-income countries: 346 deaths per 100,000 births, compared to only 10 in developed countries [2].

Adolescence is a critical transition phase marked by significant physical, psychological, and social changes [3]. This period is often associated with early sexual activity, with a median age of first sexual intercourse at 14 years [4]. In 2019, 21 million young girls (aged 15 - 19) became pregnant; 50% of these pregnancies were unwanted and often led to dangerous clandestine abortions [5]. This phenomenon is driven by ignorance and low utilization of modern contraceptive methods [6][7]. In Congo, the situation is alarming: the rate of early pregnancies increases from 19.8% at age 16 to 25.9% at age 17 [8]. Despite the risks of complications and the repressive legal framework surrounding abortion, data remain poorly documented. It is in this context that we aimed to analyze the knowledge, attitudes, and practices of female high school adolescents in Brazzaville regarding modern contraceptive methods in 2024.

This was an analytical KAP (Knowledge, Attitudes, and Practices) study conducted from February 1 to July 25, 2024 (6 months) in two public general education high schools in the city of Brazzaville, listed under the Departmental Directorate of Preschool, Primary, Secondary Education, and Literacy, namely: Nganga Édouard High School and the Revolution High School. The selection of the two high schools was motivated by their central location in the city of Brazzaville—a determining criterion, as the positioning of these two educational establishments allows them to attract students from all districts of the city, thereby ensuring a certain representativeness of adolescent girls from the entire city and not just from specific areas.

The target population consisted of female adolescents enrolled and regularly attending the aforementioned high schools during the 2023-2024 school year. Excluded were female high school adolescents with medical or psychological conditions that would make participation in the study difficult or inappropriate, as well as those who had participated in a similar study in the six months prior.

The 400 students were selected using simple random sampling. The sample size was calculated using the SCHWARTZ formula, with the modern contraceptive prevalence among adolescents estimated at 39% according to the Demographic and Health Survey EDSC2/2011-2012 in the Republic of Congo [9], increased by 10%.

The variables studied were:

Sociodemographic, sexual, and reproductive characteristics: age, nationality, place of residence, level of education, marital status, religion, age at first sexual intercourse, parity, induced abortion; Knowledge: overall and partial knowledge; Attitudes: perceptions, beliefs, and misconceptions regarding modern contraceptive methods;Practices: modern contraceptives previously used, mode of use, source of supply, current use of modern contraceptives, and recourse to a health agent.

To ensure the effective implementation of the survey, a pre-test was conducted to assess the female high school adolescents’ understanding of the questionnaire. This pre-test was carried out with 5 female high school students from each grade level, randomly selected from a public high school not included in the study. This phase allowed for the adjustment of certain questions and the adaptation of the questionnaire to the comprehension level of this population.

Data analyses were performed using SPSS version 25 software.

The questionnaire was adapted from CAP (Knowledge, Attitudes, and Practices) tools published in previous studies on contraception in sub-Saharan Africa [10]-[12]. It consisted of 30 items, including 12 on knowledge, 10 on attitudes, and 8 on practices. Scoring rules and classification thresholds were defined for each domain.

The knowledge level was judged as “sufficient” when the score of correct answers was >7/14 and “insufficient” when the score of correct answers was ≤7/14.

Attitudes were judged as “appropriate” when the score of correct answers was >25/50 and “inappropriate” when the score of correct answers was ≤25/50.

Practices, for their part, were judged as “good” when the score of correct answers was >5/10 and “poor” when the score of correct answers was ≤5/10.

An analysis of the certainty level of responses was also conducted using the response quality spectrum for Instruction 1 by Dieudonné Leclercq [13]. This method categorizes knowledge questions into a spectrum where the investigator marks the given response and circles the degree of certainty or probability percentage among the following six options: 0%, 20%, 40%, 60%, 80%, 100%. If the respondent had no knowledge of the question, the investigator was required to indicate a certainty level of 0%.

Attitudes were evaluated using a Likert scale, with a predefined scale featuring the following response options: totally agree, agree, disagree, totally disagree. Practices were considered good if they met the usage norms for the various methods, and poor if they did not comply with these norms.

Pearson’s Chi-square test was used to compare percentages. Subsequently, the Odds Ratio (OR) and its 95% confidence interval (CI) were calculated; these measures were used to assess the correlation between two qualitative variables, with a p-value less than 5%.

The study received approval from the Ethics Committee of the Faculty of Health Sciences at Marien Ngouabi University. For minor participants, double consent was obtained (written assent from the adolescents and consent from the parent/legal guardian).

Our study was conducted only in two public general education high schools, selected through reasoned choice. Consequently, although the results are relevant, they cannot be generalized to all female high school adolescents in the city of Brazzaville, nor to those in other departments.

The female high school adolescents were aged 14 to 19 years, with a mean age of 17.1 ± 1.4 years. Dramé et al. in Guinea Conakry in 2023 [14] reported similar findings, where the mean age was 17.3 years.

More than half of the participants were sexually active. Oko et al. in Congo Brazzaville had already reported in 2024 a high prevalence of early sexual intercourse at 72.7% [15]. We attribute this proportional difference to the heterogeneity (boys and girls) of the population selected by the authors.

Although Congolese society is pro-natalist, this does not apply to adolescents, as seen in our study. The majority of those who had previously been pregnant had already undergone at least one clandestine abortion, thereby exposing them to the risk of serious complications [16][17].

These facts highlight, on the one hand, the undesirability of early pregnancies [18]-[21]; and on the other hand, a lack of knowledge about modern contraceptive methods [20].

In order to adopt good contraceptive practices, the female high school adolescents in Brazzaville need to acquire knowledge on the subject. The overall analysis of their knowledge revealed that 78.3% of the adolescents had an insufficient knowledge level regarding modern contraceptive methods. Nearly identical conclusions, with 86% of cases, were drawn by Mbou Essié et al. in 2018 [22], whose population consisted of postpartum women in the same region. The absence of teaching modules on sexual and reproductive health in secondary schools, as well as sociocultural barriers to the use of contraceptive methods, are the causes [8]. These observations contrast sharply with those reported by Debuo et al. in 2023 in Ghana, where 78.5% of high school girls had an adequate knowledge level regarding modern contraceptive methods, explained by the existence of several sensitization campaigns on modern contraceptives that had a significant influence on the entire population, particularly students [23].

In our study, the distribution of RI (Incorrect Responses) takes the form of a steep J-shaped curve to the left; this is concerning, as 8.7% of the 15.3% incorrect responses from the female high school adolescents were given with maximum certainty (100%), and it is noted that 12.7% of the misconceptions are harmful. These harmful misconceptions, spanning all the questions, suggest the need for educational reinforcement by integrating a structured sexual and reproductive health education program into the school curriculum starting from secondary level, with interactive sessions including educational games, debates, and simulations to strengthen learning.

However, we noted that the Imprudence index, or the average certainty accompanying incorrect responses, at 3.1% here, was reassuring because it is low.

Regarding correct responses, it would be desirable for their distribution on the graphical spectrum to have its peak as far to the right as possible (also a J-shaped curve). This is the case in our study, where the curve takes a steep J-shape to the right, which is satisfactory. It is observed that 58.4% of the knowledge is usable, including 29.9% perfect responses (correct with 100% certainty), 18.9% doubtful responses (correct with 20% and 40% certainty), and 7.4% admitted ignorance. The Confidence index, or the average certainty accompanying correct responses, is 14.1%, which is very low.

The Confidence and Imprudence indices are impact indicators that will serve as references in evaluating knowledge after the educational reinforcement of the school curriculum with the structured sexual and reproductive health education program.

In our context, the overall attitudes were predominantly maladapted. This result reflects the existence of erroneous beliefs, misconceptions, or reluctance to use modern contraceptive methods. Our results are comparable to those of Ramathuba et al. in South Africa [20], who reported that 63% of adolescents exhibited a negative attitude toward modern contraceptives. These authors justify these results by the presence of prejudices related to religion and morality, which consider the use of contraceptives as reprehensible and conducive to premarital sexual relations.

The female high school adolescents mostly had poor contraceptive practices. Dramé et al. [14] found a proportion of 99% of female students with a poor level of contraceptive practices, underscoring the importance of persistent barriers to the effective use of modern contraceptive methods in African contexts.

The influence of insufficient knowledge on attitudes and practices aligns with the conclusions of Ramathuba et al. [24], according to which the information deficit remains one of the major determinants of risky contraceptive behaviors in sub-Saharan Africa.

Female high school adolescents are predominantly nulligravid and sexually active. They exhibit insufficient knowledge, maladaptive attitudes, and poor contraceptive practices. This finding underscores the major influence of the knowledge level on attitudes and behaviors, calling for reinforcement of reproductive health education, as well as facilitated access to services adapted to their needs.