***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 
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    Input: Summary Background Many countries now offer support to teenage mothers to help them to achieve long-term socioeconomic stability and to give a successful start to their children . The Family Nurse Partnership ( FNP ) is a licensed intensive home-visiting intervention developed in the USA and introduced into practice in Engl and that involves up to 64 structured home visits from early pregnancy until the child 's second birthday by specially recruited and trained family nurses . We aim ed to assess the effectiveness of giving the programme to teenage first-time mothers on infant and maternal outcomes up to 24 months after birth . Methods We did a pragmatic , non-blinded , r and omised controlled , parallel-group trial in community midwifery setting s at 18 partnerships between local authorities and primary and secondary care organisations in Engl and . Eligible participants were nulliparous and aged 19 years or younger , and were recruited at less than 25 weeks ' gestation . Field-based research ers r and omly allocated mothers ( 1:1 ) via remote r and omisation ( telephone and web ) to FNP plus usual care ( publicly funded health and social care ) or to usual care alone . Allocation was stratified by site and minimised by gestation ( < 16 weeks vs ≥16 weeks ) , smoking status ( yes vs no ) , and preferred language of data collection ( English vs non-English ) . Mothers and assessors ( local research ers at baseline and 24 months ' follow-up ) were not masked to group allocation , but telephone interviewers were blinded . Primary endpoints were biomarker-calibrated self-reported tobacco use by the mother at late pregnancy , birthweight of the baby , the proportion of women with a second pregnancy within 24 months post-partum , and emergency attendances and hospital admissions for the child within 24 months post-partum . Analyses were by intention to treat . This trial is registered with IS RCT N , number IS RCT N23019866 . Findings Between June 16 , 2009 , and July 28 , 2010 , we screened 3251 women . After enrolment , 823 women were r and omly assigned to receive FNP and 822 to usual care . All follow-up data were retrieved by April 25 , 2014 . 304 ( 56 % ) of 547 women assigned to FNP and 306 ( 56 % ) of 545 assigned to usual care smoked at late pregnancy ( adjusted odds ratio [ AOR ] 0·90 , 97·5 % CI 0·64–1·28 ) . Mean birthweight of 742 babies with mothers assigned to FNP was 3217·4 g ( SD 618·0 ) , whereas birthweight of 768 babies assigned to usual care was 3197·5 g ( SD 581·5 ; adjusted mean difference 20·75 g , 97·5 % CI −47·73 to 89·23 . 587 ( 81 % ) of 725 assessed children with mothers assigned to FNP and 577 ( 77 % ) of 753 assessed children assigned to usual care attended an emergency department or were admitted to hospital at least once before their second birthday ( AOR 1·32 , 97·5 % CI 0·99–1·76 ) . 426 ( 66 % ) of 643 assessed women assigned to FNP and 427 ( 66 % ) 646 assigned to usual care had a second pregnancy within 2 years ( AOR 1·01 , 0·77–1·33 ) . At least one serious adverse event ( mainly clinical events associated with pregnancy and infancy period ) was reported for 310 ( 38 % ) of 808 participants ( mother – child ) in the usual care group and 357 ( 44 % ) of 810 in the FNP group , none of which were considered related to the intervention . Interpretation Adding FNP to the usually provided health and social care provided no additional short-term benefit to our primary outcomes . Programme continuation is not justified on the basis of available evidence , but could be reconsidered should supportive longer-term evidence emerge . Funding Department of Health Policy Research Programme A home visit intervention program for adolescents throughout their pregnancy and during the early stages of motherhood was evaluated . The participants ( N = 90 ) were part of a larger group of adolescents treated in two health centers in a poor neighborhood in Santiago , Chile . The program was carried out by volunteer community health monitors and evaluated through an experimental , r and omized , controlled clinical trial . Cost-effectiveness was examined in comparison with st and ard health care . Results show higher scores for the intervention group on the mothers ’ mental health and nutritional state , as well as on the children ’s levels of linguistic development PURPOSE The purpose of this study was to determine whether teenage girls who had been pregnant were more likely to engage in other risk or problem behaviors than girls who had had sexual intercourse without becoming pregnant . METHODS The 1993 Ohio Youth Risk Behavior Survey was administered to a r and om sample of 2461 high school students . A subset of 592 girls ( mean age 16.1 + /- 1.1 years , 69.2 % Caucasian , 24.1 % African-American , 2.4 % Hispanic , 4.3 % other ) reported  sexual activity ( SA ) on the anonymous survey .  Demographic factors plus risk and problem behaviors were compared between 98 girls who had been pregnant and 494 girls who had never been pregnant using Chi-square analysis . Risk and problem behaviors were classified into four distinct groups : recent risk behaviors , age of onset of behavior , lifetime behavior , and general behavior . Variables which were univariately significant at p < 0.15 were considered in one of four stepwise multiple logistic regression models based on behavior type , with demographic factors considered in all four models . The final logistic regression model was developed using variables which were significant at p < 0.01 . Variables which were significantly associated with pregnancy were summarized as odds ratios ( OR ) and 99 % confidence intervals ( CI ) ; these ORs were adjusted for the effects of the other variables in the model . RESULTS Pregnancy was more common in girls of color than in Caucasian girls ( OR 99 % and CI , 2.09 , 1.06 - 4.11 ) and in older girls than in younger girls ( 1.52 , 1.12 - 2.08 ) . Among SA girls , weapon carrying in the past 30 days ( 4.06 , 1.75 - 9.42 ) was significantly associated with pregnancy , whereas alcohol use in the past 30 days ( 0.37 , 0.18 - 0.76 ) was less likely to be associated with pregnancy . The risk of pregnancy increased 1.75 times ( 1.26 - 2.43 ) for each additional sexual partner . Girls who had tried cocaine were 4.88 times ( 1.40 - 16.95 ) more likely to have been pregnant , and the risk of having been pregnant increased 1.43 times ( 1.14 - 1.80 ) for each additional year of SA . Past history of sexually transmitted disease ( 3.50 , 1.28 - 9.55 ) was associated with increased pregnancy risk . CONCLUSIONS Girls who had been pregnant also had engaged in other risk behaviors , including recent weapon carrying and cocaine use . A history of previous sexually transmitted diseases plus increasing numbers of partners add to the risk of pregnancy . Counseling and educational efforts should continue to identify teens at risk both to prevent pregnancy and to decrease associated risks R and omized controlled clinical trials are conducted to determine whether differences of clinical importance exist between selected treatment regimens . When statistical analysis of the study data finds a P value greater than 5 % , it is convention to deem the assessed difference nonsignificant . Just because convention dictates that such study findings be termed nonsignificant , or negative , however , it does not necessarily follow that the study found nothing of clinical importance . Subject sample s used in controlled trials tend to be too small . The studies therefore lack the necessary power to detect real , and clinical ly worthwhile , differences in treatment . Freiman et al. found that only 30 % of a sample of 71 trials published in the New Engl and Journal of Medicine in 1978 - 79 with a P value greater than 10 % were large enough to have a 90 % chance of detecting even a 50 % difference in the effectiveness of the treatments being compared , and they found no improvement in a similar sample of trials published in 1988 . It is therefore wrong and unwise to interpret so many negative trials as providing evidence of the ineffectiveness of new treatments . One must instead seriously question whether the absence of evidence is a valid justification for inaction . Efforts must be made to look for quantification of an association rather than just a P value , especially when the risks under investigation are small . The authors cite a recent trial comparing octreotide and sclerotherapy in patients with variceal bleeding  , as well as the overview of clinical trials evaluating fibrinolytic treatment for preventing reinfa rct ion after acute myocardial infa rct ion as examples Background Although the experiences of unintended pregnancies and poor birth outcomes among adolescents aged 15–19 years in the general population are well documented , there is limited underst and ing of the same among those who are living with HIV . This paper examines the factors associated with experiencing unintended pregnancies , poor birth outcomes , and post-partum contraceptive use among HIV-positive female adolescents in Kenya . Methods Data are from a cross-sectional study that captured information on pregnancy histories of HIV-positive female adolescents in four regions of Kenya : Coast , Nairobi , Nyanza and Rift Valley provinces . Study participants were identified through HIV and AIDS programs in the four regions . Out of a total of 797 female participants , 394 had ever been pregnant with 24 % of them experiencing multiple pregnancies . Analysis entails the estimation of r and om-effects logit models . Results Higher order pregnancies were just as likely to be unintended as lower order ones ( odds ratios [ OR ] : 1.2 ; 95 % confidence interval [ CI ] : 0.8–2.0 ) while pregnancies occurring within marital unions were significantly less likely to be unintended compared to those occurring outside such unions ( OR : 0.1 ; 95 % CI : 0.1–0.2 ) . Higher order pregnancies were significantly more likely to result in poor outcomes compared to lower order ones ( OR : 2.5 ; 95 % CI : 1.6–4.0 ) . In addition , pregnancies occurring within marital unions were significantly less likely to result in poor outcomes compared to those occurring outside such unions ( OR : 0.3 ; 95 % CI : 0.1–0.9 ) . However , experiencing unintended pregnancy was not significantly associated with adverse birth outcomes ( OR : 1.3 ; 95 % CI : 0.5–3.3 ) . There was also no significant difference in the likelihood of post-partum contraceptive use by whether the pregnancy was unintended ( OR : 0.9 ; 95 % CI : 0.5–1.5 ) . Conclusions The experience of repeat unintended pregnancies among HIV-positive female adolescents in the sample is partly due to inconsistent use of contraception to prevent recurrence while poor birth outcomes among higher order pregnancies are partly due to abortion . This underscores the need for HIV and AIDS programs to provide appropriate sexual and reproductive health information and services to HIV-positive adolescent clients in order to reduce the risk of undesired reproductive health outcomes STUDY OBJECTIVE To evaluate the outpatient initiation of  postpartum long-acting reversible contraception ( LARC ) . DESIGN Prospect i ve cohort study of pregnant adolescents ' prenatal contraceptive intentions and successful postpartum initiation of LARC . SETTING Urban , university hospital-affiliated , adolescent outpatient clinic . PARTICIPANTS Adolescents attending an integrated prenatal and postpartum maternity clinic . INTERVENTIONS Data were collected via the electronic medical record and telephone interview . MAIN OUTCOME MEASURES Contraceptive intentions during the third trimester , contraceptive methods used postpartum , timing of LARC initiation , timing of resumption of intercourse . RESULTS 116 patients were enrolled ; 75 % intended LARC use postpartum . Of 38 implant-intenders , 14 received it within 14 days postpartum . All reported abstinence pre-placement . Mean time to insertion was 18±13 days . Of 37 IUD-intenders , only two received one by 8 weeks postpartum . By 14 weeks postpartum , 43 % received one . Over half reported intercourse prior to insertion ; the only method of contraception used was condoms . Mean time to insertion was 70±11 days . Resumption of intercourse prior to initiation of the intended LARC method was significantly higher in IUD recipients compared to those who intended and received the implant ( RR 8.8 ; CI 1.3 - 57.5 ) . CONCLUSION In postpartum teens attending a clinic that prioritizes contraceptive use , the implant is far more likely to be received prior to resumption of sexual activity than the IUD . This may be due to more and earlier opportunities for placement , or waning commitment with time since delivery . Post-placental IUDs may be needed to equal the success of the implant in this patient population . Short-acting , reliable contraceptive methods should be implemented for postpartum adolescents preferring to wait for IUD insertion OBJECT 
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Service user feedback suggested that there were specific motivations for many repeat conceptions , for example to replace loss or to please a partner .
Realist synthesis highlighted that context , motivation , planning for the future and letting young women take control with connectedness and tailoring provide a conceptual framework for future research .
LIMITATIONS Included studies rarely characterised adolescent pregnancy as intended or unintended , that is interventions to reduce repeat conceptions rarely addressed whether or not pregnancies were intended .
Nearly all of the studies were conducted in the USA and focused largely on African American or Hispanic and Latina American population s. CONCLUSIONS We found no evidence to indicate that existing interventions to reduce repeat teenage pregnancy  were effective ; however , subsequent births were reduced by home-based interventions .
Qualitative and realist evidence helped to explain gaps in intervention design that should be addressed .