title: Interventions for preventing unintended pregnancies among adolescents.
abstract: BACKGROUND
  Unintended pregnancy among adolescents represents an important public health challenge in high-income countries, as well as middle- and low-income countries. Numerous prevention strategies such as health education, skills-building and improving accessibility to contraceptives have been employed by countries across the world, in an effort to address this problem. However, there is uncertainty regarding the effects of these interventions, hence the need to review the evidence-base.
  
  
  OBJECTIVE
  To assess the effects of primary prevention interventions (school-based, community/home-based, clinic-based, and faith-based) on unintended pregnancies among adolescents.
  
  
  METHODS
  We searched all relevant studies regardless of language or publication status up to November 2015. We searched the Cochrane Fertility Regulation Group Specialised trial register, The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2015 Issue 11), MEDLINE, EMBASE, LILACS, Social Science Citation Index and Science Citation Index, Dissertations Abstracts Online, The Gray Literature Network, HealthStar, PsycINFO, CINAHL and POPLINE and the reference lists of articles.
  
  
  METHODS
  We included both individual and cluster randomised controlled trials (RCTs) evaluating any interventions that aimed to increase knowledge and attitudes relating to risk of unintended pregnancies, promote delay in the initiation of sexual intercourse and encourage consistent use of birth control methods to reduce unintended pregnancies in adolescents aged 10 years to 19 years.
  
  
  METHODS
  Two authors independently assessed trial eligibility and risk of bias, and extracted data. Where appropriate, binary outcomes were pooled using a random-effects model with a 95% confidence interval (Cl). Where appropriate, we combined data in meta-analyses and assessed the quality of the evidence using the GRADE approach.
  
  
  RESULTS
  We included 53 RCTs that enrolled 105,368 adolescents. Participants were ethnically diverse. Eighteen studies randomised individuals, 32 randomised clusters (schools (20), classrooms (6), and communities/neighbourhoods (6). Three studies were mixed (individually and cluster randomised). The length of follow up varied from three months to seven years with more than 12 months being the most common duration. Four trials were conducted in low- and middle- income countries, and all others were conducted in high-income countries. Multiple interventionsResults showed that multiple interventions (combination of educational and contraceptive-promoting interventions) lowered the risk of unintended pregnancy among adolescents significantly (RR 0.66, 95% CI 0.50 to 0.87; 4 individual RCTs, 1905 participants, moderate quality evidence. However, this reduction was not statistically significant from cluster RCTs. Evidence on the possible effects of interventions on secondary outcomes (initiation of sexual intercourse, use of birth control methods, abortion, childbirth, sexually transmitted diseases) was not conclusive.Methodological strengths included a relatively large sample size and statistical control for baseline differences, while limitations included lack of biological outcomes, possible self-report bias, analysis neglecting clustered randomisation and the use of different statistical tests in reporting outcomes. Educational interventionsEducational interventions were unlikely to significantly delay the initiation of sexual intercourse among adolescents compared to controls (RR 0.95, 95% CI 0.71 to 1.27; 2 studies, 672 participants, low quality evidence).Educational interventions significantly increased reported condom use at last sex in adolescents compared to controls who did not receive the intervention (RR 1.18, 95% CI 1.06 to 1.32; 2 studies, 1431 participants, moderate quality evidence).However, it is not clear if the educational interventions had any effect on unintended pregnancy as this was not reported by any of the included studies. Contraceptive-promoting interventionsFor adolescents who received contraceptive-promoting interventions, there was little or no difference in the risk of unintended first pregnancy compared to controls (RR 1.01, 95% CI 0.81 to 1.26; 2 studies, 3,440 participants, moderate quality evidence).The use of hormonal contraceptives was significantly higher in adolescents in the intervention group compared to those in the control group (RR 2.22, 95% CI 1.07 to 4.62; 2 studies, 3,091 participants, high quality evidence)
  
  
  CONCLUSIONS
  A combination of educational and contraceptive-promoting interventions appears to reduce unintended pregnancy among adolescents.  Evidence for programme effects on biological measures is limited. The variability in study populations, interventions and outcomes of included trials, and the paucity of studies directly comparing different interventions preclude a definitive conclusion regarding which type of intervention is most effective.
authors.affiliation: GIDP Entomology and Insect Science, University of Tucson, Tucson, Arizona, USA, 85721.
authors.forename: Chioma
authors.initials: C
authors.lastname: Oringanje
authors.forename: Martin M
authors.initials: MM
authors.lastname: Meremikwu
authors.forename: Hokehe
authors.initials: H
authors.lastname: Eko
authors.forename: Ekpereonne
authors.initials: E
authors.lastname: Esu
authors.forename: Anne
authors.initials: A
authors.lastname: Meremikwu
authors.forename: John E
authors.initials: JE
authors.lastname: Ehiri
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D011247:Pregnancy; D011253:Pregnancy in Adolescence / Q000517:prevention & control*; D049168:Pregnancy, Unplanned; D016032:Randomized Controlled Trials as Topic; D055815:Young Adult
references.citation: J Adolesc Health. 2014 Jul;55(1):85-92
references.pmid: 24518532
references.citation: J Health Commun. 2001 Jan-Mar;6(1):45-60
references.pmid: 11317423
references.citation: Nurs Res. 2005 Mar-Apr;54(2):108-18
references.pmid: 15778652
references.citation: Am J Obstet Gynecol. 2008 Nov;199(5):517.e1-7
references.pmid: 18468575
references.citation: Arch Pediatr Adolesc Med. 2006 Nov;160(11):1101-7
references.pmid: 17088511
references.citation: Harefuah. 2003 Feb;142(2):131-6, 158, 157
references.pmid: 12653047
references.citation: Perspect Sex Reprod Health. 2007 Mar;39(1):21-8
references.pmid: 17355378
references.citation: Fam Plann Perspect. 1986 Sep-Oct;18(5):221-6
references.pmid: 3542558
references.citation: Fam Plann Perspect. 1997 Nov-Dec;29(6):248-55, 295
references.pmid: 9429869
references.citation: Fam Plann Perspect. 2001 Mar-Apr;33(2):52-61
references.pmid: 11330851
references.citation: J Sch Health. 2002 May;72(5):178-83
references.pmid: 12109172
references.citation: Trop Med Int Health. 2006 Jan;11(1):3-16
references.pmid: 16398750
references.citation: Fam Plann Perspect. 1990 Jan-Feb;22(1):21-6
references.pmid: 2323402
references.citation: Int J Infect Dis. 2003 Mar;7(1):61-73
references.pmid: 12718812
references.citation: Am J Health Behav. 2002 Nov-Dec;26(6):473-85
references.pmid: 12437022
references.citation: J Adolesc Health. 2003 Aug;33(2):98-107
references.pmid: 12890601
references.citation: J Adolesc Health. 2007 Jan;40(1):22-8
references.pmid: 17185202
references.citation: Pediatrics. 2006 Oct;118(4):e1087-99
references.pmid: 17015500
references.citation: BMJ. 2006 May 20;332(7551):1189-94
references.pmid: 16682420
references.citation: Rev Saude Publica. 2002 Aug;36(4 Suppl):88-95
references.pmid: 12364905
references.citation: J Community Health. 2011 Jun;36(3):375-80
references.pmid: 20924781
references.citation: Contraception. 2011 Nov;84(5):478-85
references.pmid: 22018121
references.citation: Soc Sci Med. 2004 Oct;59(8):1561-72
references.pmid: 15279915
references.citation: Obstet Gynecol. 2002 Sep;100(3):481-6
references.pmid: 12220767
references.citation: Int J Epidemiol. 2002 Jun;31(3):555-6
references.pmid: 12055153
references.citation: Perspect Sex Reprod Health. 2002 Sep-Oct;34(5):244-51
references.pmid: 12392217
references.citation: Adolescence. 1991 Fall;26(103):631-41
references.pmid: 1962546
references.citation: J Gen Intern Med. 2008 Jun;23(6):794-9
references.pmid: 18398664
references.citation: J Epidemiol Community Health. 2007 Mar;61(3):221-5
references.pmid: 17325399
references.citation: Fam Pract. 2004 Oct;21(5):537-44
references.pmid: 15367476
references.citation: J Pediatr. 1996 Feb;128(2):288-95
references.pmid: 8636834
references.citation: Sex Transm Dis. 2005 Feb;32(2):123-9
references.pmid: 15668620
references.citation: Obstet Gynecol. 2006 Nov;108(5):1098-106
references.pmid: 17077230
references.citation: Lancet. 2004 Jul 24-30;364(9431):338-46
references.pmid: 15276393
references.citation: WMJ. 1997 Sep;96(9):38-43
references.pmid: 9368461
references.citation: Health Promot Int. 2005 Jun;20(2):157-65
references.pmid: 15764686
references.citation: Fam Plann Perspect. 1986 Mar-Apr;18(2):61-6
references.pmid: 3792524
references.citation: Obstet Gynecol. 2012 Dec;120(6):1291-7
references.pmid: 23168752
references.citation: Obstet Gynecol. 2014 Apr;123(4):771-6
references.pmid: 24785603
references.citation: JAMA. 2004 Jul 14;292(2):171-9
references.pmid: 15249566
references.citation: Nurs Res. 2006 Jan-Feb;55(1):43-51
references.pmid: 16439928
references.citation: J Pediatr. 2001 Sep;139(3):407-12
references.pmid: 11562621
references.citation: Perspect Sex Reprod Health. 2004 Jul-Aug;36(4):162-9
references.pmid: 15321783
references.citation: Fam Plann Perspect. 1990 Nov-Dec;22(6):261-71
references.pmid: 2289544
references.citation: Trop Med Int Health. 2002 Dec;7(12):1053-63
references.pmid: 12460397
references.citation: Pediatrics. 1989 Mar;83(3):375-9
references.pmid: 2645566
references.citation: Fam Plann Perspect. 2000 Sep-Oct;32(5):237-45
references.pmid: 11030261
references.citation: Fam Plann Perspect. 2000 Sep-Oct;32(5):227-35
references.pmid: 11030260
references.citation: J Adolesc Health. 2005 Jun;36(6):534-6
references.pmid: 15901520
references.citation: Health Educ Res. 2002 Aug;17(4):471-81
references.pmid: 12197592
references.citation: BMJ. 2009 Jul 07;339:b2534
references.pmid: 19584408
references.citation: Trop Med Int Health. 2008 Oct;13(10):1235-44
references.pmid: 18778329
references.citation: Indian Pediatr. 2004 Feb;41(2):137-45
references.pmid: 15004299
references.citation: Sex Transm Dis. 2005 Nov;32(11):665-71
references.pmid: 16254540
references.citation: J Health Educ. 1994 Jan-Feb;25(1):24-9
references.pmid: 12287798
references.citation: Biometrics. 1992 Jun;48(2):577-85
references.pmid: 1637980
references.citation: PLoS One. 2019 Jan 23;14(1):e0209064
references.pmid: 30673710
references.citation: Am J Public Health. 2007 Jun;97(6):1084-9
references.pmid: 17463382
references.citation: Arch Pediatr Adolesc Med. 2005 May;159(5):440-9
references.pmid: 15867118
references.citation: JAMA Pediatr. 2013 Apr;167(4):333-40
references.pmid: 23440337
references.citation: Health Educ Res. 2014 Apr;29(2):319-29
references.pmid: 24488649
references.citation: Prev Med. 2005 Apr;40(4):420-31
references.pmid: 15530594
references.citation: Contraception. 2011 Sep;84(3):252-8
references.pmid: 21843690
references.citation: Health Educ Behav. 1997 Jun;24(3):300-12
references.pmid: 9158975
references.citation: BMJ. 2007 Jan 20;334(7585):133
references.pmid: 17118950
references.citation: Health Econ. 2010 Sep;19 Suppl:55-68
references.pmid: 19946887
references.citation: J Adolesc Health. 2011 Feb;48(2):159-63
references.pmid: 21257114
references.citation: Int J Adolesc Med Health. 2002 Apr-Jun;14(2):91-6
references.pmid: 12467178
references.citation: Scand J Public Health. 2002;30(4):300-5
references.pmid: 12680507
references.citation: Obstet Gynecol. 2006 Jan;107(1):121-7
references.pmid: 16394049
references.citation: J Sch Health. 2006 Oct;76(8):414-22
references.pmid: 16978165
references.citation: Fam Plann Perspect. 1997 May-Jun;29(3):109-14
references.pmid: 9179579
references.citation: AIDS Educ Prev. 2006 Jun;18(3):187-203
references.pmid: 16774462
references.citation: Health Educ Res. 1999 Oct;14(5):675-83
references.pmid: 10510075
references.citation: J Adv Nurs. 2008 May;62(4):457-69
references.pmid: 18476946
references.citation: J Community Health Nurs. 2004 Spring;21(1):39-47
references.pmid: 14979845
references.citation: Matern Child Health J. 2011 Dec;15 Suppl 1:S42-53
references.pmid: 21809218
references.citation: J Clin Epidemiol. 2004 Aug;57(8):785-94
references.pmid: 15485730
references.citation: Psychol Rep. 2002 Dec;91(3 Pt 2):1129-32
references.pmid: 12585524
references.citation: Curr Opin Pediatr. 2003 Aug;15(4):362-9
references.pmid: 12891047
references.citation: Obstet Gynecol. 2000 Jul;96(1):1-7
references.pmid: 10862832
references.citation: BMJ. 2002 Jun 15;324(7351):1426
references.pmid: 12065267
references.citation: Arch Pediatr Adolesc Med. 2001 Jan;155(1):73-9
references.pmid: 11177066
references.citation: Pediatrics. 1984 Feb;73(2):126-31
references.pmid: 6694867
references.citation: J Adolesc Health. 2012 Mar;50(3):279-88
references.pmid: 22325134
references.citation: JAMA. 1990 Mar 9;263(10):1385-9
references.pmid: 2406472
references.citation: Fam Plann Perspect. 1997 May-Jun;29(3):100-8
references.pmid: 9179578
references.citation: Eur J Contracept Reprod Health Care. 2015 Apr;20(2):88-100
references.pmid: 25327958
references.citation: Lancet. 2007 Jul 21;370(9583):251-261
references.pmid: 17631387
references.citation: J Sex Res. 2002 Feb;39(1):27-33
references.pmid: 12476253
references.citation: J Adolesc Health. 2005 Jun;36(6):508-16
references.pmid: 15901516
references.citation: Fam Plann Perspect. 1990 May-Jun;22(3):115-21
references.pmid: 2379568
references.citation: J Adolesc Health. 2013 Mar;52(3):314-21
references.pmid: 23299011
references.citation: Public Health Rep. 2001;116 Suppl 1:82-93
references.pmid: 11889277
references.citation: AIDS Patient Care STDS. 2010 Jun;24(6):381-7
references.pmid: 20565322
references.citation: Int J Epidemiol. 2003 Feb;32(1):131-6
references.pmid: 12690024
references.citation: Salud Publica Mex. 2008 Jan-Feb;50(1):59-66
references.pmid: 18297183
references.citation: J Sch Health. 2004 Oct;74(8):329-34
references.pmid: 15554119
references.citation: Arch Pediatr Adolesc Med. 2006 Aug;160(8):772-7
references.pmid: 16894074
references.citation: JAMA. 1998 May 20;279(19):1529-36
references.pmid: 9605896
references.citation: J Adolesc Health. 2005 Jan;36(1):64-9
references.pmid: 15661598
references.citation: Health Promot Pract. 2012 Jul;13(4):462-71
references.pmid: 21606323
references.citation: PLoS Med. 2008 Nov 25;5(11):e224; discussion e224
references.pmid: 19067478
references.citation: Fam Plann Perspect. 1986 May-Jun;18(3):119-26
references.pmid: 3803552
references.citation: Perspect Sex Reprod Health. 2003 Mar-Apr;35(2):62-70
references.pmid: 12729135
references.citation: Perspect Sex Reprod Health. 2011 Dec;43(4):247-54
references.pmid: 22151512
references.citation: J Adolesc Health. 2004 Dec;35(6):442-52
references.pmid: 15581523
references.citation: Qual Health Care. 1997 Jun;6(2):102-8
references.pmid: 10173252
references.citation: BMJ. 2002 Jun 15;324(7351):1430
references.pmid: 12065268
references.citation: J Adolesc Health. 2006 Dec;39(6):900-7
references.pmid: 17116522
references.citation: J Adolesc Health. 2000 Oct;27(4):236-47
references.pmid: 11008086
references.citation: Perspect Sex Reprod Health. 2005 Dec;37(4):166-73
references.pmid: 16380361
references.citation: Health Educ Behav. 2001 Apr;28(2):166-85
references.pmid: 11265827
references.citation: J Adolesc Health. 2005 Oct;37(4):337
references.pmid: 16182145
references.citation: AIDS Educ Prev. 1998 Apr;10(2):128-48
references.pmid: 9573435
references.citation: J Sex Res. 2002 Feb;39(1):51-7
references.pmid: 12476257
references.citation: Adv Adolesc Mental Health. 1990;4:265-80
references.pmid: 12317629
references.citation: Ann N Y Acad Sci. 1993 Dec 31;703:125-33; discussion 133-4
references.pmid: 8192290
references.citation: Trials. 2010 Oct 21;11:100
references.pmid: 20964860
references.citation: Contraception. 2010 May;81(5):435-40
references.pmid: 20399951
references.citation: Fam Plann Perspect. 2000 Nov-Dec;32(6):272-80
references.pmid: 11138863
references.citation: J Am Coll Health. 2012;60(8):574-82
references.pmid: 23157199
references.citation: J Child Adolesc Psychiatr Nurs. 2004 Apr-Jun;17(2):66-77
references.pmid: 15366313
references.citation: J Adolesc Health. 2015 May;56(5):515-21
references.pmid: 25739520
references.citation: BMJ. 2002 May 18;324(7347):1179
references.pmid: 12016180
references.citation: Am J Public Health. 2002 Jan;92(1):109-15
references.pmid: 11772772
references.citation: Fam Plann Perspect. 1988 Jul-Aug;20(4):188-92
references.pmid: 3149589
references.citation: Am J Obstet Gynecol. 2008 Jun;198(6):630.e1-8
references.pmid: 18395692
references.citation: J Obstet Gynaecol. 2007 Jul;27(5):513-7
references.pmid: 17701804
references.citation: Am J Public Health. 2003 Jun;93(6):933-8
references.pmid: 12773358
references.citation: J Adv Nurs. 2008 Jan;61(1):81-91
references.pmid: 18173736
references.citation: Ann Fam Med. 2009 Sep-Oct;7(5):436-45
references.pmid: 19752472
references.citation: J Perinat Neonatal Nurs. 2001 Sep;15(2):1-17
references.pmid: 12095025
references.citation: Psychol Health Med. 2011 Mar;16(2):141-55
references.pmid: 21328143
references.citation: Pediatr Clin North Am. 2003 Aug;50(4):781-800, viii
references.pmid: 12964694
references.citation: Health Educ Behav. 2000 Aug;27(4):454-70
references.pmid: 10929753
references.citation: J Epidemiol Community Health. 2005 Mar;59(3):223-30
references.pmid: 15709083
references.citation: J Health Care Poor Underserved. 1998 Aug;9(3):322-40
references.pmid: 10073212
references.citation: J Adolesc Health. 2004 Jan;34(1):3-26
references.pmid: 14706401
references.citation: J Adolesc Health. 2004 Jul;35(1):62-4
references.pmid: 15193576
references.citation: AIDS Educ Prev. 2005 Jun;17(3):185-99
references.pmid: 16006206
references.citation: JAMA. 2005 Jan 5;293(1):54-62
references.pmid: 15632336
references.citation: J Adolesc Health. 2005 Apr;36(4):289-304
references.pmid: 15780784
references.citation: AIDS Educ Prev. 1997 Feb;9(1 Suppl):44-61
references.pmid: 9083598
references.citation: Contraception. 2012 Oct;86(4):383-90
references.pmid: 22402258
references.citation: Am J Public Health. 2003 Jun;93(6):963-9
references.pmid: 12773363
references.citation: Perspect Sex Reprod Health. 2006 Sep;38(3):139-47
references.pmid: 16963387
references.citation: Health Educ Res. 1999 Jun;14(3):411-9
references.pmid: 10539231
references.citation: Health Educ Q. 1985 Summer;12(2):185-210
references.pmid: 3997538
references.citation: J Adolesc Health. 2002 Jul;31(1):93-100
references.pmid: 12090970
references.citation: Am J Public Health. 1999 Feb;89(2):176-81
references.pmid: 9949745
references.citation: BMJ. 1999 Sep 11;319(7211):670-4
references.pmid: 10480822
references.citation: J Res Adolesc. 1993;3(4):393-422
references.pmid: 12319701
references.citation: AIDS Educ Prev. 2002 Aug;14(4):269-81
references.pmid: 12212714
references.citation: Am J Public Health. 2010 Apr;100(4):720-6
references.pmid: 20167903
references.citation: JAMA. 1993 Jun 2;269(21):2749-53
references.pmid: 8492400
references.citation: JAMA. 1992 Jul 8;268(2):240-8
references.pmid: 1535110
references.citation: Arch Pediatr Adolesc Med. 2010 Apr;164(4):370-6
references.pmid: 20368491
references.citation: J Womens Health (Larchmt). 2014 Apr;23(4):358-64
references.pmid: 24707900
references.citation: Am J Public Health. 2004 May;94(5):843-51
references.pmid: 15117710
references.citation: J Adolesc Health. 2000 Jan;26(1):5-17
references.pmid: 10638713
references.citation: J Natl Black Nurses Assoc. 1990 Fall-Winter;4(1):28-34
references.pmid: 2198329
references.citation: BMC Womens Health. 2014 Feb 13;14:27
references.pmid: 24521075
references.citation: Perspect Sex Reprod Health. 2008 Mar;40(1):42-51
references.pmid: 18318871
references.citation: J Adolesc. 2013 Oct;36(5):859-70
references.pmid: 24011102
references.citation: J Adolesc Health. 2012 Aug;51(2):164-70
references.pmid: 22824447
references.citation: J Adolesc Health. 2011 Aug;49(2):172-9
references.pmid: 21783050