Abstracts

Introduction

Family planning has several health benefits such as preventing unintended pregnancies, spacing births, reducing maternal and child morbidity and mortality, empowering women, offering protection against sexually transmitted diseases, and decreasing unsafe abortion cases ¹1. Nonvignon J, Novignon J. Trend and determinants of contraceptive use among women of reproductive age in Ghana. African Population Studies 2014; 28:956-67.^,22. World Health Organization. Family planning/contraception. https://www.who.int/news-room/fact-sheets/detail/family-planning-contraception (accessed on Sep/2020).
https://www.who.int/news-room/fact-sheet... .

One of the milestones of the United Nations Sustainable Development Goals (SDGs) is the universal access to sexual and reproductive health ³3. Marmot M, Bell R. The Sustainable Development Goals and health equity. Epidemiology 2018; 29:5-7.. Adolescents are the priority in achieving this goal, since teenage pregnancy is associated with a range of adverse health and social outcomes ⁴4. World Health Organization. Adolescent pregnancy. https://www.who.int/news-room/fact-sheets/detail/adolescent-pregnancy (accessed on Sep/2020).
https://www.who.int/news-room/fact-sheet... ^,55. Darroch JE, Woog V, Bankole A. Adding it up: costs and benefits of meeting the contraceptive needs of adolescents. New York: Guttmacher Institute; 2016.. Projections indicate that the number of unintended births, abortions, and maternal deaths would annually decrease by 6 million, 3.2 million, and 5,600, respectively, if all unmet needs for modern contraception in adolescents were satisfied ⁴4. World Health Organization. Adolescent pregnancy. https://www.who.int/news-room/fact-sheets/detail/adolescent-pregnancy (accessed on Sep/2020).
https://www.who.int/news-room/fact-sheet... . Among the available contraceptive methods, modern methods - those which involve medical or technological resources ⁶6. Hubacher D, Trussell J. A definition of modern contraceptive methods. Contraception 2015; 92:420-1. - are usually prioritized since they are the only methods which offer protection from sexually transmitted infections and are recognized as having the lowest failure rates ⁷7. Bradley SEK, Polis CB, Bankole A, Croft T. Global contraceptive failure rates: who is most at risk? Stud Fam Plann 2019; 50:3-24.^,88. Polis CB, Bradley SEK, Bankole A, Onda T, Croft T, Singh S. Typical-use contraceptive failure rates in 43 countries with Demographic and Health Survey data: summary of a detailed report. Contraception 2016; 94:11-7..

Modern contraceptive methods have many advantages, such as giving couples safety and more reliability to follow their family planning choices. However, it is estimated that 60% of adolescents from low- and middle-income countries who would like to avoid pregnancies fail to use modern contraceptive methods ⁵5. Darroch JE, Woog V, Bankole A. Adding it up: costs and benefits of meeting the contraceptive needs of adolescents. New York: Guttmacher Institute; 2016.. Some adolescents and young adults opt to use traditional methods, such as coitus interruptus, whereas others use no contraceptive method, which is even more concerning ⁷7. Bradley SEK, Polis CB, Bankole A, Croft T. Global contraceptive failure rates: who is most at risk? Stud Fam Plann 2019; 50:3-24.^,99. Department of Reproductive Health and Research, World Health Organization; Center for Communication Programs Knowledge for Health Project, Johns Hopkins Bloomberg School of Public Health. Family planning: a global handbook for providers (2018 update). https://apps.who.int/iris/bitstream/handle/10665/260156/9780999203705-eng.pdf?sequence=1 (accessed on Jan/2021).
https://apps.who.int/iris/bitstream/hand... . There is evidence that the failure rates of traditional contraceptive methods - considerably higher than modern contraceptives - are higher among adolescents and young adults ⁷7. Bradley SEK, Polis CB, Bankole A, Croft T. Global contraceptive failure rates: who is most at risk? Stud Fam Plann 2019; 50:3-24.^,88. Polis CB, Bradley SEK, Bankole A, Onda T, Croft T, Singh S. Typical-use contraceptive failure rates in 43 countries with Demographic and Health Survey data: summary of a detailed report. Contraception 2016; 94:11-7.. For example, the 12-month failure rate for coitus interruptus was 17.3 (95%CI: 15.9; 18.7). Nevertheless, for modern contraceptive methods such as the pill, condoms, and intrauterine devices (IUDs), the respective values were 6.3 (95%CI: 5.9; 6.8), 8.6 (95%CI: 7.6; 9.6), and 1.2 (95%CI: 0.9; 1.5) ⁷7. Bradley SEK, Polis CB, Bankole A, Croft T. Global contraceptive failure rates: who is most at risk? Stud Fam Plann 2019; 50:3-24..

Although there is evidence of progressive increases in contraceptive use, the literature shows inequalities in their use ¹⁰10. Alkema L, Kantorova V, Menozzi C, Biddlecom A. National, regional, and global rates and trends in contraceptive prevalence and unmet need for family planning between 1990 and 2015: a systematic and comprehensive analysis. Lancet 2013; 381:1642-52.. In several low- and middle-income countries, poorer and less educated women showed a lower prevalence of contraceptive use ¹¹11. Ewerling F, Victora CG, Raj A, Coll CVN, Hellwig F, Barros AJD. Demand for family planning satisfied with modern methods among sexually active women in low- and middle-income countries: who is lagging behind? Reprod Health 2018; 15:42.. Moreover, parity and marital status were also associated with this use. A study using surveys from 73 low- and middle-income countries identified that married women and those without children showed the lowest median of modern contraceptive prevalence worldwide, ranging from 2.9% in West and Central Africa to 29% in Latin America and the Caribbean ¹²12. Coll CVN, Ewerling F, Hellwig F, Barros AJD. Contraception in adolescence: the influence of parity and marital status on contraceptive use in 73 low-and middle-income countries. Reprod Health 2019; 16:21..

In Brazil, data from the 2013 National Health Survey indicates that 79.4% of women in reproductive age were using some modern contraceptive method with similar levels of prevalence among all groups of wealth ¹³13. Ponce de Leon RG, Ewerling F, Serruya SJ, Silveira MF, Sanhueza A, Moazzam A, et al. Contraceptive use in Latin America and the Caribbean with a focus on long-acting reversible contraceptives: prevalence and inequalities in 23 countries. Lancet Glob Health 2019; 7:e227-35.. Among adolescents, a national school-based study conducted in 2013 and 2014 evaluating boys and girls aged 12 to 17 years observed that around 80% used some contraceptive method in their last sexual intercourse ¹⁴14. Borges ALV, Fujimori E, Kuschnir MCC, Chofakian CBN, Moraes AJP, Azevedo GD, et al. ERICA: sexual initiation and contraception in Brazilian adolescents. Rev Saúde Pública 2016; 50 Suppl 1:15s.. A study conducted in São Paulo, Brazil ¹⁵15. Olsen JM, Lago TDG, Kalckmann S, Alves MCGP, Escuder MML. Práticas contraceptivas de mulheres jovens: inquérito domiciliar no Município de São Paulo, Brasil. Cad Saúde Pública 2018; 34:e00019617., in 2015 with adolescent girls aged 15 to 19 years showed that condoms and oral contraceptives were the most used methods (28.2% and 23%, respectively).

Monitoring the use of contraceptive methods in different population subgroups is fundamental for a more efficient planning of public policies in the area. However, recent population-based studies with a more detailed description of the different kinds of contraceptive methods, investigating groups with less coverage are limited in Brazil and are mainly performed with schoolchildren. Despite the limitation of where information was collected - which may interfere in answers related to sexual behavior - adolescents and young people who dropped out of school were ignored in these studies. It provides a limited point of view since family planning choices and the use of contraceptive methods may differ between those who are enrolled in school and those who dropped out. One study showed the lower prevalence of contraceptive use among adolescents and young adults who dropped out of school, for example ¹⁶16. Maslyanskaya S, Coupey SM, Chhabra R, Khan UI. Predictors of early discontinuation of effective contraception by teens at high risk of pregnancy. J Pediatr Adolesc Gynecol 2016; 29:269-75.. Our study uses data from a birth cohort conducted in Brazil, allowing us to investigate modern contraceptive use in different periods and in adolescent and young women subgroups. It is also essential to identify inequalities to highlight possible pathways to achieve universal access to sexual and reproductive health care.

Therefore, this study aims our to evaluate the prevalence of contraceptive methods use (traditional, modern, hormonal and barrier), and its inequalities among adolescents and young women in the 1993 Pelotas birth cohort, Rio Grande do Sul State, Brazil.

Material and methods

Participants

In 1993, all live births from mothers who gave birth from January 1^st to December 31^st and dwelled in the urban area of Pelotas, Southern Brazil, were invited to participate in this cohort study. Among the 5,265 live births, 5,249 mothers agreed to participate. Mothers were interviewed soon after delivery (perinatal study) providing information on their demographic, socioeconomic, behavioral, and other characteristics. From birth to the 11-year follow-up, subsamples were evaluated, and all cohort members were sought when they reached the mean age of 11, 15, 18, and 22 years. Follow-up rates were 87.5%, 85.7%, 81.4%, and 76.3%, respectively. A detailed description of the cohort can be found elsewhere ¹⁷17. Gonçalves H, Wehrmeister FC, Assunção MCF, Tovo-Rodrigues L, De Oliveira IO, Murray J, et al. Cohort profile update: the 1993 Pelotas (Brazil) birth cohort follow-up at 22 years. Int J Epidemiol 2018; 47:1389-90E.^,1818. Gonçalves H, Assunção MCF, Wehrmeister FC, Oliveira IO, Barros FC, Victora CG, et al. Cohort profile update: the 1993 Pelotas (Brazil) birth cohort follow-up visits in adolescence. Int J Epidemiol 2014; 43:1082-8.^,1919. Victora CG, Hallal PC, Araújo CLP, Menezes AMB, Wells JCK, Barros FC. Cohort profile: the 1993 Pelotas (Brazil) birth cohort study. Int J Epidemiol 2008; 37:704-9..

Our study was based on data collected during the 15-, 18- and 22-year follow-ups. We included only female participants who had already started their sexual lives at the time of each follow-up and those who were not pregnant.

Outcomes

All information regarding contraception use was collected using a confidential questionnaire. At the 15-year follow-up, contraceptive use was assessed by asking the following question: “In your last sexual intercourse, did you use any of these methods to avoid pregnancy or to protect yourself?” Answer options were: condoms, oral contraceptives, coitus interruptus, none, others (which one?), whereas at the 18 and 22-year follow-ups contraceptive use was assessed as follows: “In your last sexual intercourse, what did you use to avoid pregnancy?” Answer options were the same as mentioned above plus: the calendar method, contraceptive injections, IUDs, emergency contraceptive pills, others (which one?). Moreover, some extra contraceptive method options were evaluated at the 22-year follow-up: vaginal rings, female sterilization, male sterilization, subdermal implants, diaphragms, spermicidal agents and male and female condoms. A summary of the methods assessed in each follow-up is shown in the Table 1.

Contraceptive methods were divided into modern and traditional methods. The traditional methods evaluated were: coitus interruptus and the calendar method. However, if these methods were used with any modern method, we considered only the use of the modern method. The modern methods evaluated were: condoms (male or female), oral contraceptives, emergency contraceptive pills, injectable contraceptives, IUDs, diaphragms, vaginal rings, subdermal implants, spermicidal agents, and female/male sterilization ⁶6. Hubacher D, Trussell J. A definition of modern contraceptive methods. Contraception 2015; 92:420-1..

Furthermore, we also evaluated if the modern contraceptive method was a hormonal or a barrier method. The following methods were considered hormonal: oral contraceptives, emergency contraceptive pills, injectable contraceptives, vaginal rings, and subdermal implants, whereas condoms (male or female) and diaphragms were considered barrier methods.

Covariables

Information on self-reported ethnicity was collected at the 15-year follow-up (white, black or other), whereas the following variables were assessed in all follow-ups (15-, 18- and 22-year): schooling in completed years of formal education (0-4, 5-8, 9 or more), wealth index (generated using a principal component analysis based on possession of assets and divided into quintiles, in which the first quintile was the poorest and the last, the richest), having children (no; yes), relationship status (single; having a boyfriend; living with a partner) and school backwardness (no; yes). According to Sampaio & Nespoli ²⁰20. Sampaio M, Nespoli V. Índice de adequação idade-anos de escolaridade. Revista Brasileira de Estudos Pedagógicos 2004; 85:137-42., the individual is considered school backward if there is a difference of two or more years between the current schooling of the individual and the age considered adequate for that schooling level. Thus, at ages 15, 18 and 22 women who showed, respectively, ≤ 6 years, ≤ 9 years and, ≤ 10 years of schooling (unfinished high school) were considered school backward.

Statistical analysis

Firstly, we described (in absolute and relative frequencies) the sample according to independent variables for each follow-up. Secondly, we showed the prevalence and a 95% confidence interval (95%CI) of the most used contraceptive methods according to the year of the study. We also showed the prevalence and 95%CI of the use of any contraceptive method according to type (traditional, modern, hormonal, barrier). Furthermore, the use of barrier methods combined with other modern methods, as recommended by specialists, was also evaluated ²¹21. Braverman PK, Adelman WP, Alderman EM, Breuner CC, Levine DA, Marcell AV, et al. Contraception for adolescents. Pediatrics 2014; 134:e1244-56.^,2222. Gavin L, Pazol K. Update: providing quality family planning services - recommendations from CDC and the U.S. Office of Population Affairs, 2015. MMWR Morb Mortal Wkly Rep 2016; 65:231-4.. As supplementary material, we showed an adjusted analysis. The prevalence of contraceptive use at 18 years was adjusted for the prevalence of contraceptive use at 15 years, whereas contraceptive use at 22 was adjusted for the prevalence of contraceptive use at 15 and 18 years. We used Poisson regression followed by the “margins” post estimation command to express the results as prevalence and 95%CI.

Lastly, inequalities in the use of modern methods and barrier methods along other modern methods, according to wealth index, school backwardness and ethnicity for all follow-ups were evaluated. All analyses were performed using Stata version 16.1 (https://www.stata.com).

Ethics

Ethical approval was obtained from the Ethics Research Committee of the School of Medicine of the Federal University of Pelotas for all stages of the study. A written Informed Consent Form was signed by participants’ mothers or tutors in every follow-up, and verbal consent was given by the adolescents in the 15-year follow-up. At the 18-year follow-up, the cohort members signed the informed consent form. The 18- and 22-year follow-ups have protocol numbers 05/11 and 1,250,366, respectively.

Results

At the 15-, 18- and 22-year follow-ups, we included 335, 1,458, and 1,711 women, respectively, who reported having started their sexual lives and were not pregnant at the moment of the study. In all follow-ups, white women made up about 60% of the sample. At the 15- and 18-year follow-ups, more than half of the girls were school backward (50.4% and 53.7%, respectively), whereas at the 22-year, this occurrence was lower (34.6%). At the 22-year follow-up, 45% of participants reported living with a partner and 35.8% had children (Table 2).

Table 3 shows the prevalence of contraceptive use according to the follow-ups. At age 15, the most used method were condoms (85.4%, 95%CI: 80.9; 89.0), whereas at 18 and 22 years, oral contraceptives (57.5%, 95%CI: 54.9; 60.1) and (59.8%, 95%CI: 57.3; 62.0), respectively. The use of at least one modern contraceptive method was lower at 22 years (83.8%, 95%CI: 81.9; 85.4). The use of barrier methods decreased as age increased, from 85.4% (95%CI: 80.9; 89.0) at 15 to 36.3% (95%CI: 34.0; 38.6) at 22 years. The use of barrier methods with other modern methods was lower than 50% in all follow-ups and decreased as age increased. At 15 years, its prevalence was 47.7% (95%CI: 41.0; 54.4), whereas at 22, 19.9% (95%CI: 18.1; 21.9). On the other hand, the prevalence of at least one hormonal method remained constant according to age. We observed few significant changes after adjusting for contraceptive use prevalence in previous follow-ups. Table 4 shows the prevalence of coitus interruptus (not accompanied by modern contraceptive methods) at 22 years; the use of hormonal methods at 18 and 22 years increased, whereas the prevalence of condoms or any barrier method at 18 and 22 years decreased even more.

Table 5 shows the prevalence of at least one modern contraceptive method according to stratifiers. The two upper quintiles showed slightly higher coverage than the lower quintiles, specially at the 22-year follow-up (79.9% vs. 87.9% in the poorest and richest quintiles, respectively). Furthermore, at 18- and 22-year follow-ups show significantly lower prevalence of modern contraceptive use among school backward women and this difference was more pronounced at 22 years (77% vs. 87.3%). Regarding ethnicity, we observed no significant differences.

Table 5 shows the use of barrier contraceptive methods concomitantly with other modern methods, at 15-, 18- and 22-year sollow-ups according to stratifiers. We observed no differences among wealth indices at the 15-year follow-up, whereas in the other two, those in the richest quintile showed the highest prevalence. This difference was more pronounced at 18 years, in which those in the poorest and in the richest quintile showed a prevalence of 24.9% and 46.7%, respectively. The prevalence of the use of barrier methods concomitantly with other modern methods was lower among women who were school backward at 18 and 22 years. Regarding ethnicity, significant differences were observed at the 22-year follow-up, in which black women showed lower prevalence of coverage than white women (12.2% vs. 21.6, respectively).

Discussion

Using a simple approach, we estimated the prevalence of contraceptive use and inequalities in modern contraceptive use among women at 15-, 18-, and 22-year follow-ups. Condoms were the most used method at the 15-year follow-up, whereas oral contraceptives, the most used at the 18- and 22-year ones. Modern contraceptive use decreased with age, mainly due to the decrease in barrier method use. Less than half of the participants reported using barrier methods concomitantly with other modern methods in their last sexual intercourse and the lowest prevalence was observed at the 22-year follow-up (19.9%). Moreover, we observed some inequalities in its use.

The prevalence of modern contraceptive use in adolescents has increased globally and appears to be the primary proximal determinant of the decline in adolescent pregnancy and birth rates ²³23. Liang M, Simelane S, Fortuny Fillo G, Chalasani S, Weny K, Salazar Canelos P, et al. The state of adolescent sexual and reproductive health. J Adolesc Health 2019; 65(6 Suppl):S3-15.^,2424. Lindberg L, Santelli J, Desai S. Understanding the decline in adolescent fertility in the United States, 2007-2012. J Adolesc Health 2016; 59:577-83.. However, countries show important differences in the prevalence of contraceptive use. In the United States, a study with data from 2014 showed that 88% of girls aged 15 to 19 years reported using contraceptive methods, 27% reported using the pill and 55%, condoms in their last sexual intercourse ²⁵25. Lindberg LD, Santelli JS, Desai S. Changing patterns of contraceptive use and the decline in rates of pregnancy and birth among U.S. adolescents, 2007-2014. J Adolesc Health 2018; 63:253-6.. On the other hand, another study shows lower prevalence in data from 46 low- and middle-income countries, in which 32.4% of girls aged 15 to 19 years reported current use of contraception methods and 24.6%, modern short-term methods ²⁶26. Kalamar AM, Tunçalp Ö, Hindin MJ. Developing strategies to address contraceptive needs of adolescents: exploring patterns of use among sexually active adolescents in 46 low- and middle-income countries. Contraception 2018; 98:36-40..

In Brazil, studies have showed high prevalence in the use of at least one contraceptive method. Population-based studies conducted in 2009, 2013-2014 and 2015 showed that 75%, 85.2% and 81%, respectively, of young women used contraceptive methods ¹⁴14. Borges ALV, Fujimori E, Kuschnir MCC, Chofakian CBN, Moraes AJP, Azevedo GD, et al. ERICA: sexual initiation and contraception in Brazilian adolescents. Rev Saúde Pública 2016; 50 Suppl 1:15s.^,1515. Olsen JM, Lago TDG, Kalckmann S, Alves MCGP, Escuder MML. Práticas contraceptivas de mulheres jovens: inquérito domiciliar no Município de São Paulo, Brasil. Cad Saúde Pública 2018; 34:e00019617.^,2727. Farias MR, Leite SN, Tavares NUL, Oliveira MA, Arrais PSD, Bertoldi AD, et al. Use of and access to oral and injectable contraceptives in Brazil. Rev Saúde Pública 2016; 50 Suppl 2:14s., a prevalence similar to our findings (higher than 85% in all follow-ups). In our study, as well as in other national and international studies, oral contraceptives and condoms were the most used methods ¹⁵15. Olsen JM, Lago TDG, Kalckmann S, Alves MCGP, Escuder MML. Práticas contraceptivas de mulheres jovens: inquérito domiciliar no Município de São Paulo, Brasil. Cad Saúde Pública 2018; 34:e00019617.^,2525. Lindberg LD, Santelli JS, Desai S. Changing patterns of contraceptive use and the decline in rates of pregnancy and birth among U.S. adolescents, 2007-2014. J Adolesc Health 2018; 63:253-6.. The strong dominance of the pill may be in part due to cultural and individual choices, but it also relates to health programs and professional preferences. Fundamental aspects of family planning services include providing counselling on all contraceptive methods without any form of coercion and providing a wide range of contraceptive methods, allowing women and couples to choose the best one for their needs and circumstances. Furthermore, as in a Finnish study, we observed a decrease in the use of modern contraceptives with age, due to a substantial reduction in the use of barrier methods ²⁸28. Apten D. Contraception options aspects unique to adolescent and young adult. Best Pract Res Clin Obstet Gynaecol 2018; 48:115-27..

When we compare women from different age groups, we should consider differences regarding attitudes and experiences. In our study, the prevalence of living with a partner increased considerably between ages 18 and 22 (from 22.8% to 45%, respectively). This could explain the substantial decrease in the use of barrier methods. With increasing age and in a more stable relationship, women tend to switch to hormonal methods ²⁸28. Apten D. Contraception options aspects unique to adolescent and young adult. Best Pract Res Clin Obstet Gynaecol 2018; 48:115-27.. A decrease in the use of condoms is expected with an increase in age. However, the importance of condoms should not be underestimated since they prevent not only unintended pregnancies but also decrease the risks of STIs, including HIV ²⁹29. Faculty of Sexual and Reproductive Healthcare. Barrier methods for contraception and STI prevention 2015. http://www.fsrh.org/documents/ceuguidancebarriermethodscontraceptionsdi/ (accessed on Jan/2021).
http://www.fsrh.org/documents/ceuguidanc... . The main barrier for condom use in a stable relationship is the implied lack of trust in the partner ³⁰30. Do Nascimento Chofakian CB, Moreau C, Borges ALV, Dos Santos OA. Contraceptive discontinuation: frequency and associated factors among undergraduate women in Brazil. Reprod Health 2019; 16:131.. However, infidelity may occur even after marriage ³¹31. Cleland J. Use of the male condom within marriage. IPPF Medical Bulletin 2005; 39:1-2.. There is evidence that in severe, generalised HIV epidemics, up to 20% of couples may be HIV-discordant. Despite providing information and contraceptive commodities, family planning services need to focus on men’s attitude and women’s empowerment regarding contraceptive choices.

To prevent pregnancies, the perfect failure rate of condoms is 2%, the typical, 15% for all age groups and may be higher among adolescents ³²32. Trussell J, Lalla AM, Doan QV, Reyes E, Pinto L, Gricar J. Cost effectiveness of contraceptives in the United States. Contraception 2009; 79:5-14.. Therefore, dual contraception is recommended for a better protection against STIs and pregnancies, such as condoms in addition to a highly effective hormonal or other long-acting methods ²¹21. Braverman PK, Adelman WP, Alderman EM, Breuner CC, Levine DA, Marcell AV, et al. Contraception for adolescents. Pediatrics 2014; 134:e1244-56.^,2222. Gavin L, Pazol K. Update: providing quality family planning services - recommendations from CDC and the U.S. Office of Population Affairs, 2015. MMWR Morb Mortal Wkly Rep 2016; 65:231-4.. Despite this recommendation, studies have shown that this double contraception is largely unused. In a Finnish study with data from 2009 and 2010, only 7% of secondary school students used condoms combined with oral contraceptives in their last sexual intercourse ²⁸28. Apten D. Contraception options aspects unique to adolescent and young adult. Best Pract Res Clin Obstet Gynaecol 2018; 48:115-27.. In the United States, this prevalence was slightly higher (9.1%) among High School students in 2019 ³³33. Szucs LE, Lowry R, Fasula AM, Pampati S, Copen CE, Hussaini KS, et al. Condom and contraceptive use among sexually active high school students - Youth Risk Behavior Survey, United States, 2019. MMWR Suppl 2020; 69:11-8.. A study conducted in Canada, Israel and Europe in 2013 and 2014 showed that 20.8% of girls and boys aged 14 to 16 years used this combination of methods ³⁴34. Looze M, Madkour AS, Huijts T, Moreau N, Currie C. Country-level gender equality and adolescents' contraceptive use in Europe, Canada and Israel: findings from 33 countries. Perspect Sex Reprod Health 2019; 51:43-53.. In comparison with these studies, our results showed higher prevalence at the 15- and 18-year follow-ups (47.7% and 31%, respectively), and similar prevalence to the study performed by Looze et al. ³⁴34. Looze M, Madkour AS, Huijts T, Moreau N, Currie C. Country-level gender equality and adolescents' contraceptive use in Europe, Canada and Israel: findings from 33 countries. Perspect Sex Reprod Health 2019; 51:43-53. at 22 years (19.9%). Nevertheless, this coverage needs to be improved, mainly, in some specific groups.

When we considered data dependency, adjusting the prevalence of contraceptive use for the prevalence of the previous follow-up, we observed significant changes in coitus interruptus (increased at 22 years), barrier (decreased at 18 and 22 years) and hormonal methods (increased at 18 and 22 years), and no significant changes for the other estimates. These few alterations could be explained by only 216 women participating in all 3 follow-ups, resulting in low data dependency.

Adolescents, especially those from lower socioeconomic positions, still suffer from lack of access to contraceptive methods and knowledge about contraception. In Brazil, the Unified National Health System (SUS) and other public policies, such as the Family Health Strategy, are making progress in reducing health inequalities over time ³⁵35. Ramírez GR, Bravo PE, Vivaldi MIM, Manríquez IP, Pérez TG. Acceso a anticoncepción en adolescentes: percepciones de trabajadores de la salud en Huechuraba, Chile. Rev Panam Salud Pública 2017; 41:e77.. However, our results showed a persistent pro-rich pattern of inequality in the use of barrier methods combined with hormonal methods or IUDs/implants, finding a substantially higher prevalence among the richest quintile, especially at ages 18 and 22. Furthermore, those in school backwardness and with black skin color also showed lower coverage at 18 and 22 years. Women with less schooling may show lower access to information and health services, impacting their contraceptive use ³⁶36. Faisal-cury A, Tabb KM, Niciunovas G, Menezes PR, Huang H. Lower education among low-income Brazilian adolescent females is associated with planned pregnancies. Int J Womens Health 2017; 9:43-8.. Moreover, data from a national population-based study conducted with women aged 15 to 20 years showed that those from lower economic positions and lower education levels reported more frequently the desire to leave their parents’ home, to get married and to be a mother ³⁷37. Berquó E, Garcia S, Lima L. Youth and reproduction: demographic, behavioral and reproductive profiles in the PNDS-2006. Rev Saúde Pública 2012; 46:685-93.. Furthermore, ethnicity is a marker of vulnerable social condition in Brazil, since black and brown people usually show lower wages, lower education levels, higher unemployment rates, lower access to health services, and worse health than white people ³⁸38. Instituto Brasileiro de Geografia e Estatística. IBGE mostra as cores da desigualdade. http://www.ibge.gov.br/home/presidencia/noticias/25072002pidoso.shtm (accessed on Jan/2021).
http://www.ibge.gov.br/home/presidencia/... ^,3939. Monk EP. The cost of color: skin color, discrimination, and health among African-Americans. AJS 2015; 121:396-444..

In our study, less than 1% of women reported using LARCs (long-acting reversible contraceptives), a much smaller prevalence than in high-income countries ³³33. Szucs LE, Lowry R, Fasula AM, Pampati S, Copen CE, Hussaini KS, et al. Condom and contraceptive use among sexually active high school students - Youth Risk Behavior Survey, United States, 2019. MMWR Suppl 2020; 69:11-8.. LARCs are more effective in avoiding unintended pregnancies than condoms and pills, since they do not depend on adherence and correct daily use. In Brazil, pills and male condoms are the most frequently used methods. They are, however, usually associated with high discontinuation rates and, consequently, more unintended pregnancies. The offer of LARCs in the Brazilian public health system could modify the Brazilian contraceptive profile, with positive effects in decreasing the occurrence of unintended pregnancies and induced abortions ¹⁴14. Borges ALV, Fujimori E, Kuschnir MCC, Chofakian CBN, Moraes AJP, Azevedo GD, et al. ERICA: sexual initiation and contraception in Brazilian adolescents. Rev Saúde Pública 2016; 50 Suppl 1:15s..

Our study has some limitations. The questions used to assess contraceptive use were not standardized over the follow-ups, which may have underestimated condom use at 18 and 22 years. Non-reporting may have been associated with non-use of contraceptive methods. The possible effect of this limitation on our results is especially important in the first follow-up, due to the social pressure over sexual activity among young adolescents. Nevertheless, we used confidential questionnaries to measure contraceptive methods, which probably minimized the non-reporting bias. Furthermore, we assessed contraceptive use in their last sexual intercourse, which may not necessarily represent ongoing contraceptive practices. Summarizing contraceptive behavior may be difficult sometimes, especially among adolescents. Therefore, most of the previous studies used the same information.

Conclusions

Regular monitoring of trends in the sexual health behavior of women and its inequalities are needed to guide evidence-based intervention programs and health policies. In our study, we showed that the prevalence of contraceptive use in adolescents was high and decreased with age, mainly the use of barrier methods. Moreover, there are some differences regarding method choice and socioeconomic and demographic characteristics. Improvements in the use of condoms combined with other methods, as well as the use of LARCs in young women should be considered in future sexual and reproductive health policies in Brazil, mainly for more vulnerable groups.

Acknowledgments

This study was carried out in part with the support of the Brazilian Graduate Studies Coordinating Board (CAPES, financing code 001). M.F.S. is a research fellow funded by the Brazilian National Research Council (CNPq), and the Rio Grande do Sul State Research Foundation (FAPERGS). The 22-year follow-up was financed by the Department of Science and Technology, Brazilian Ministry of Health, with resources transferred through the CNPq (grant n. 400943/2013-1).

References

Publication Dates

History