***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Objective To evaluate the effectiveness of youth development in reducing  teenage pregnancy , substance use , and other outcomes . Design Prospect i ve matched comparison study . Setting 54 youth service sites in Engl and . Participants Young people ( n=2724 ) aged 13 - 15 years at baseline deemed by professionals as at risk of teenage pregnancy , substance misuse , or school exclusion or to be vulnerable .  Intervention Intensive , multicomponent youth development programme including sex and drugs education ( Young People ’s Development Programme ) versus st and ard youth provision . Main outcome measures Various , including pregnancy , weekly cannabis use , and monthly drunkenness at 18 months . Results Young women in the intervention group more commonly reported pregnancy than did those in the comparison group ( 16 % v 6 % ; adjusted odds ratio 3.55 , 95 % confidence interval 1.32 to 9.50 ) . Young women in the intervention group also more commonly reported early heterosexual experience ( 58 % v 33 % ; adjusted odds ratio 2.53 , 1.09 to 5.92 ) and expectation of teenage parenthood ( 34 % v 24 % ; 1.61 , 1.07 to 2.43 ) . Conclusions No evidence was found that the intervention was effective in delaying heterosexual experience or reducing pregnancies , drunkenness , or cannabis use . Some results suggested an adverse effect . Although method ological limitations may at least partly explain these findings , any further implementation of such interventions in the UK should be only within r and omised trials To test the effectiveness of a special health care program for adolescent mothers ( 17 years old or younger ) and their infants , 243 mother-infant pairs were r and omly assigned to one of two groups . All of the mothers were unwed , on Medicaid , and black . The control group received routine well-baby care . The experimental group received routine care and services that included rigorous follow-up , discussion s with the mother about her plans for return to school and use of family planning methods , and extra health teaching . The dropout rate in the experimental group ( 60 % ) was significantly less after 18 months than the control group ( 82 % ) . In spite of the high dropout rate , 91 % of the mothers were located for the 18 month follow-up interview . The repeat pregnancy rate in the experimental group was 12 % after 18 months , and 28 % in the control group . There was no significant difference in the percentage returning to school . After 12 months , the infants in the experimental group were more likely to be fully immunized ( 33 % ) than the infants in the control group ( 18 % ) . Mothers in the special care program who continued to attend clinic used the emergency room less than the mothers who continued to attend in the control group . These results suggest that a comprehensive health care program is one way to bring about better outcomes for both adolescent mothers and their infants OBJECTIVE To examine the long-term effects of the Seattle Social Development Project intervention in promoting positive adult functioning and preventing mental health problems , crime , and substance use ( including tobacco , alcohol , and other drugs ) at 21 years of age . DESIGN This nonr and omized controlled trial followed up participants to 21 years of age , 9 years after the intervention ended . We compared the following 3 intervention conditions : a full 6-year intervention ( grade s 1 through 6 ) ; a late 2-year intervention ( grade s 5 and 6 only ) ; and a no-treatment control condition . SETTING Eighteen public elementary schools serving diverse neighborhoods , including high-crime neighborhoods , of Seattle , Wash. PARTICIPANTS A sex-balanced , multiethnic sample of 605 participants across the 3 conditions who completed interviews at 21 years of age ( 94 % of the original sample in these conditions ) . INTERVENTIONS Teacher training in classroom instruction and management , child social and emotional skill development , and parent training . MAIN OUTCOME MEASURES Self-reports of functioning in school and work , emotional and mental health , and crime and substance use at 21 years of age and official court records . RESULTS Broad significant effects on functioning in school and work and on emotional and mental health were found . Fewer significant effects on crime and substance use were found at 21 years of age . Most outcomes had a consistent dose effect , with the strongest effects in subjects in the full-intervention group and effects in the late-intervention group between those in the full-intervention and control groups . CONCLUSIONS A theory-guided preventive intervention that strengthened teaching and parenting practice s and taught children interpersonal skills during the elementary grade s had wide-ranging beneficial effects on functioning in early adulthood CONTEXT . Rates of rapid second births among low-income black adolescent mothers range from 20 % to 50 % . Most efforts to prevent rapid second births have been unsuccessful . OBJECTIVES . There were 4 objectives : ( 1 ) to examine whether a home-based mentoring intervention was effective in preventing second births within 2 years of the adolescent mother 's first delivery ; ( 2 ) to examine whether greater intervention participation increased the likelihood of preventing a second birth ; ( 3 ) to examine whether second births were better predicted from a risk practice perspective or a family formation perspective , based on information collected at delivery ; and ( 4 ) to examine how risk practice s or family formation over the first 2 years of parenthood were related to a second birth . DESIGN . We conducted a r and omized , controlled trial of a home-based intervention curriculum , based on social cognitive theory , and focused on interpersonal negotiation skills , adolescent development , and parenting . The curriculum was delivered biweekly until the infant 's first birthday by college-educated , black , single mothers who served as mentors , presenting themselves as “ big sisters . ” The control group received usual care . Follow-up evaluations were conducted in the homes 6 , 13 , and 24 months after recruitment . METHODS . Participants were recruited from urban hospitals at delivery and were 181 first time , black adolescent mothers ( < 18 years of age ) ; 82 % ( 149 of 181 ) completed the 24-month evaluation . RESULTS . Intent-to-treat analyses revealed that control mothers were more likely than intervention mothers to have a second infant . The complier average causal effect was used to account for variability in intervention participation . Having ≥2 intervention visits increased the odds of not having a second infant more than threefold . Only 1 mother who completed ≥6 visits had a second infant . At delivery of their first infant , mothers who had a second infant were slightly older ( 16.7 vs 16.2 years ) and were more likely to have been arrested ( 30 % vs 14 % ) . There were no differences in baseline contraceptive use or other measures of risk or family formation . At 24 months , mothers who had a second infant reported high self-esteem , positive life events , and romantic involvement and residence with the first infant 's father . At 24 months , there were no differences in marital rates ( 2 % ) , risk practice s , or contraceptive use between mothers who did and did not have a second infant . Mothers who did not have a second infant were marginally more likely to report no plans for contraception in their next sexual contact compared with mothers who had a second infant ( 22 % vs 8 % , respectively ) . CONCLUSIONS . A home-based intervention founded on a mentorship model and targeted toward adolescent development , including negotiation skills , was effective in preventing rapid repeat births among low-income , black adolescent mothers . The effectiveness of the intervention could be seen after only 2 visits and increased over time . There were no second births among mothers who attended ≥8 sessions . There was no evidence that risk behavior or contraceptive use was related to rapid second births . There was some evidence that rapid second births among adolescent mothers were regarded as desirable and as part of a move toward increasing autonomy and family formation , thereby undermining intervention programs that focus on risk avoidance . Findings suggest the merits of a mentoring program for low-income , black adolescent mothers , based on a relatively brief ( 6–8 sessions ) curriculum targeted toward adolescent development and interpersonal negotiation skills OBJECTIVES To test the hypotheses that ( 1 ) a monetary incentive promotes peer-support group participation ; and ( 2 ) peer-support group participation decreases  repeat adolescent pregnancies .  DESIGN Two-year , prospect i ve , r and omized controlled trial . SETTING Denver , Colo. PARTICIPANTS A total of 286 primiparous girls younger than 18 years , whose infants were younger than 5 months . INTERVENTION Participants were r and omized to 4 interventions : monetary incentive and peer-support group , peer-support group only , monetary incentive only , or no intervention . MAIN OUTCOME MEASURES Consistency of participation in planned intervention and repeat pregnancy . RESULTS Participation in interventions was generally low . Hypothesis 1 was supported : 58 % of those offered a monetary incentive participated in the peer-support groups , compared with 9 % of those who were not offered the incentive . Hypothesis 2 was rejected : the peer-support group experience failed to prevent repeat pregnancies . The incidence of second pregnancies at 6 months ( 9 % , 22/248 ) , at 12 months ( 20 % , 49/248 ) , at 18 months ( 29 % , 72/248 ) , and at 24 months ( 39 % , 97/248 ) following delivery did not vary significantly in relation to intervention strategy . Background sociodemographic characteristics significantly affected the timing of subsequent conceptions but not intervention participation . CONCLUSION A monetary incentive draws adolescent mothers to sites where they can discuss the costs and benefits of contraception and conception with knowledgeable adults and supportive peers . These discussion s do not prevent repeat pregnancies . Further studies are needed to determine if an intervention that produces substantive changes in the daily living environment will eliminate the sexual practice s that are responsible for the high rate of repeat pregnancy in this population Parent training was provided for 80 low-income , black teenage mothers during their infants ' first six months . Half of the mothers were visited biweekly in their homes to be instructed in caregiving and in sensorimotor and interaction exercises , and half were trained as CETA ( Comprehensive Employment Training ACT)-paid , teacher 's aides in a medical school infant nursery that provided care for their infants and infants of medical faculty . Growth and development during the first two years were superior for the infants whose mothers received training , particularly those who received paid parent training as teacher 's aides in the infant nursery . Repeat pregnancy rates were lower and return to work/school rates were higher for the infant nursery mothers , most of whom subsequently pursued nurse 's aide training 
    Output:
    
The results of some systematic review s show no significant overall effect on repeat pregnancy , whereas others show an overall significant reduction .
Youth development programmes are shown in some cases to lower pregnancy rates but in other cases to have no effect or even to increase them .