***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: OBJECTIVES To determine lower genital tract carriage rates of C. trachomatis , N. gonorrhoeae and bacterial vaginosis among women seeking termination of pregnancy . To compare two clinical management strategies for minimising the risks of infective morbidity after induced abortion . DESIGN Prevalence of infections was assessed by screening women undergoing abortion . Clinical management strategies were compared by a r and omised trial . SETTING The gynaecology departments of four hospitals in Scotl and . PARTICIPANTS 1672 women undergoing induced abortion . INTERVENTIONS Women r and omised to prophylaxis received metronidazole 1 g rectally before abortion plus doxycycline 100 mg twice daily for seven days . Women r and omised to screen- and -treat received appropriate antibiotics only if screening proved positive for one or more infection . MAIN OUTCOME MEASURES Prevalences of infections ; morbidity in the eight weeks following abortion as assessed by reported symptoms , general practitioner consultation and prescription rates and hospital re-attendances ; costs to the NHS of alternative managements . RESULTS Prevalence rates : C. trachomatis 5.6 % ; N gonorrhoeae 0.19 % ; bacterial vaginosis 17.5 % . Overall , women allocated to receive prophylaxis had lower rates of measures of short term infective morbidity than those allocated to screen- and -treat . These differences only reached statistical significance for women who were reported negative on screening . The direct costs to the NHS of prophylaxis and screen- and -treat were calculated to be 8.17 and 18.34 per woman , respectively . CONCLUSIONS Prevalences of lower genital tract infections which have been implicated in increased rates of infective morbidity after abortion are similar to those reported elsewhere . Universal antibiotic prophylaxis is at least as effective as a policy of screen- and -treat in minimising the risk of short term infective morbidity and is far more cost efficient In a prospect i ve study , 288 women were tested for Chlamydia trachomatis ( CT ) in the cervix prior to legal abortion . In the control group ( n = 259 ) , CT culturing was carried out only when postoperative infection was suspected . CT was isolated in 14.2 % of asymptomatic women . These patients were treated preoperatively with Doxycyc‐line . In this group , no cases of postoperative infection were detected . Among those cases where CT was not detected , 4.9 % contracted the infection , while in the control group the rate of infection was 9.7 % . In the control group all the infections due to CT gave late symptoms after the operation ( 1–4 weeks ) BACKGROUND Opportunistic screening for genital chlamydia infection is being introduced in Engl and , but evidence for the effectiveness of this approach is lacking . There are insufficient data about young peoples ' use of primary care services to determine the potential coverage of  opportunistic screening  in comparison with a systematic population -based approach . AIM To estimate use of primary care services by young men and women ; to compare potential coverage of opportunistic chlamydia screening with a systematic postal approach . DESIGN OF STUDY Population based cross-sectional study . SETTING Twenty-seven general practice s around Bristol and Birmingham . METHOD A r and om sample of patients aged 16 - 24 years were posted a chlamydia screening pack .  We collected details of face-to-face consultations from general practice records . Survival and person-time methods were used to estimate the cumulative probability of attending general practice in 1 year and the coverage achieved by opportunistic and systematic postal chlamydia screening . RESULTS Of 12 973 eligible patients , an estimated 60.4 % ( 95 % confidence interval [ CI ] = 58.3 to 62.5 % ) of men and 75.3 % ( 73.7 to 76.9 % ) of women aged 16 - 24 years attended their practice at least once in a 1-year period . During this period , an estimated 21.3 % of patients would not attend their general practice but would be reached by postal screening  , 9.2 % would not receive a postal invitation but would attend their practice , and 11.8 % would be missed by both methods . CONCLUSIONS Opportunistic and population -based approaches to chlamydia screening would both fail to contact a substantial minority of the target group , if used alone . A pragmatic approach combining both strategies might achieve higher coverage Background : In Engl and , screening for genital chlamydial infection has begun ; however , screening frequency for women is not yet determined . Aim : To measure chlamydia incidence and reinfection rates among young women to suggest screening intervals . Methods : An 18-month prospect i ve cohort study of women aged 16–24 years recruited from general practice s , family planning clinics and genitourinary medicine ( GUM ) clinics : baseline-negative women followed for incidence and baseline-positive women for reinfection ; urine tested every 6 months via nucleic acid amplification ; and behavioural data collected . Extra test and question naire completed 3 months after initial positive test . Factors associated with infection and reinfection investigated using Cox regression stratified by healthcare setting of recruitment . Results : Chlamydia incidence was mean ( 95 % CI ) 4.9 ( 2.7 to 8.8 ) per 100 person-years ( py ) among women recruited from general practice s , 6.4 ( 4.2 to 9.8 ) from family planning clinics and 10.6 ( 7.4 to 15.2 ) from GUM clinics . Incidence was associated with young age , history of chlamydial infection and acquisition of new sexual partners . If recently acquiring new partners , condom use at last sexual intercourse was independently associated with lower incidence . Chlamydia reinfection was mean ( 95 % CI ) 29.9 ( 19.7 to 45.4 ) per 100/person-year from general practice s , 22.3 ( 15.6 to 31.8 ) from family planning clinics and 21.1 ( 14.3 to 30.9 ) from GUM clinics . Factors independently associated with higher reinfection rates were acquisition of new partners and failure to treat all partners . Conclusions : Sexual behaviours determined incidence and reinfection , regardless of healthcare setting . Our results suggest annual screening of women aged 16–24 years who are chlamydia negative , or sooner if partner change occurs . Rescreening chlamydia-positive women within 6 months of baseline infection may be sensible , especially if partner change occurs or all partners are not treated We compared the efficacy of a screening program for urogenital Chlamydia trachomatis infections based on home sampling with that of a screening program based on conventional swab sampling performed at a physician 's office . Female subjects , comprising students at 17 high schools in the county of Aarhus , Denmark , were divided into a study group ( tested by home sampling ) and a control group ( tested in a physician 's office ) . We assessed the number of new infections and the number of subjects who reported being treated for pelvic inflammatory disease ( PID ) at 1 year of follow-up ; 443 ( 51.1 % ) of 867 women in the intervention group and 487 ( 58.5 % ) of 833 women in the control group were available for follow-up . Thirteen ( 2.9 % ) and 32 ( 6.6 % ) new infections were identified in the intervention group and the control group , respectively ( Wilcoxon exact value , P=.026 ) . Nine ( 2.1 % ) women in the intervention group and 20 ( 4.2 % ) in the control group reported being treated for PID ( P=.045 ) , indicating that a screening strategy involving home sampling is associated with a lower prevalence of C. trachomatis and a lower proportion of reported cases of PID 
    Output:
    
There is an absence of evidence supporting opportunistic chlamydia screening in the general population younger than 25 years , the most commonly recommended approach .