***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: We did a prospect i ve study of women with singleton viable pregnancies at 10 - 13 weeks ' gestation who requested first-trimester fetal karyotyping because of advanced maternal age , parental anxiety , or family history of chromosomal abnormality . Women were counselled as to the available options of non-invasive screening or invasive testing by mid-trimester amniocentesis , early amniocentesis ( EA ) , or chorionic villus sampling ( CVS ) , or r and omisation to EA or CVS at 10 - 13 weeks . EA was done in 731 patients ( 493 by choice and 238 by r and omisation ) and CVS in 570 ( 320 by choice and 250 by r and omisation ) . Both procedures were done by transabdominal ultrasound-guided insertion of a 20-gauge needle . The rate of successful sampling was the same for both procedures ( 97.5 % ) . Spontaneous loss ( intrauterine or neonatal death ) was significantly higher after EA ( total group mean = 5.3 % , 95 % CI 3.8 - 7.2 ; r and omised subgroup mean = 5.9 % , 3.3 - 9.7 ) than after CVS ( total group : mean = 2.3 % , 1.2 - 3.9 ; r and omised subgroup : mean = 1.2 % , 0.3 - 3.5 ) . The gestation at delivery and birthweight of the infants after EA and CVS were similar . In the EA group the incidence of talipes equinovarus ( 1.63 % ) , was higher than in the CVS group ( 0.56 % ) , but this difference was not significant BACKGROUND Midtrimester amniocentesis to investigate fetal karyotype carries a small risk of fetal loss . AIM To test the hypothesis that progesterone prophylaxis may reduce this . STUDY DESIGN A r and omised controlled trial comparing a short prophylactic treatment with progesterone after amniocentesis with untreated controls . RESULTS There were no differences in frequency of miscarriage , preterm delivery or neonatal outcome . CONCLUSION Prophylactic progesterone treatment after amniocentesis does not improve obstetric outcome OBJECTIVES The primary purpose of this pilot study was to determine whether the safety of early amniocentesis ( EA ; 11 weeks to 12 weeks and 6 days ) is similar to midtrimester amniocentesis ( MA ; 15 weeks to 16 weeks and 6 days ) . The secondary objectives were to determine the cytogenetic success and accuracy of EA compared with MA . METHODS This prospect i ve , r and omized clinical trial compared continuous ultrasound-guided EA and MA ( 22-gauge needle ) in patients at a late maternal age ( > or = 35 years ) . The procedures were compared for safety , success and accuracy . RESULTS Among the 683 women r and omized and followed to pregnancy completion , there was a total of 27/344 ( 7.8 % ) and 25/339 ( 7.4 % ) fetal losses ( spontaneous and induced abortions ) in the EA and MA groups , respectively ( difference 0.4 % ; CI -3.6 to 4.4 % ) . The rate of postprocedure spontaneous fetal loss was 2.4 % ( 8/330 ) in the EA group and 3.3 % ( 10/299 ) in the MA group ( NS ) . The procedure success rate at the first attempt was 97.6 % in the EA group and 99.7 % in the MA group . There were no diagnostic errors , and all but 2 EA cultures were successful ( both repeated successfully ) . The perinatal outcome was similar in both groups . CONCLUSIONS EA appears to be as safe and accurate as MA . A large multicentered , r and omized trial is currently underway to verify these results This was a prospect i ve study in 1,492 women with singleton viable pregnancies undergoing chorion villus sampling ( CVS ) or early amniocentesis ( EA ) at 10 - 13 weeks of gestation because of advanced maternal age , parental anxiety or family history of chromosomal abnormality in the absence of parental chromosomal rearrangement . They were offered the option of having CVS or EA , or to be r and omised into one of the two tests . CVS was performed in 652 cases ( 375 by choice and 277 by r and omisation ) and EA was performed in 840 cases ( 562 by choice and 278 by r and omisation ) . Both procedures were carried out by transabdominal ultrasound-guided insertion of a needle ( 20 gauge ) using a free-h and technique . The two techniques were similar in providing a sample ( CVS 99.3 % , EA 100 % ) and in giving a non-mosaic cytogenetic result ( CVS 97.5 % , EA 97.9 % ) . Spontaneous loss ( intrauterine or neonatal death ) after EA ( total group 4.9 % , r and omised subgroup 5.8 % ) was significantly higher than after CVS ( total group 2.1 % , r and omised subgroup 1.8 % ; difference 2.8 % , 95 % CI 1.3 - 4.3 % , and difference 4 % , 95 % CI 1.3 - 6.7 % ) . The gestation at delivery and birth weight of the infants after EA and CVS were similar . In the EA group the incidence of talipes equinovarus ( 1.66 % ) was higher than in the CVS group ( 0.48 % ) , but this difference was not significant This study compares anxiety levels in women undergoing prenatal testing by means of chorionic villus sampling versus genetic amniocentesis . Chorionic villus sampling can be performed earlier in a pregnancy ( 8 to 12 weeks ' gestation ) but has a higher risk of miscarriage . R and omized to undergo chorionic villus sampling or genetic amniocentesis as part of a trial examining the safety and accuracy of these procedures , the women were studied at four time periods : time 1 , before prenatal testing ( 9 to 12 weeks ' gestation ) ; time 2 , after the chorionic villus sampling results were received ( 13 weeks ) ; time 3 , before the genetic amniocentesis results were known ( 18 weeks ) , and time 4 , after all results were known ( 22 weeks ) . Although they were still at risk for miscarriage , members of the chorionic villus sampling group showed a sharp drop in anxiety levels immediately after receiving their results . The genetic amniocentesis group remained anxious until the last test time . In summary , prenatal testing by means of chorionic villus sampling result ed in earlier and sustained anxiety reduction Midtrimester  amniocentesis  for antenatal genetic diagnostic purpose s is a relatively new procedure . The assumption that placental localization before amniocentesis will reduce the numbers of abortions , bloody taps , and missed taps has result ed in the routine use of diagnostic ultrasound for placental localization . This study consists of two groups undergoing midtrimester amniocentesis .  The groups were distinguished by the use and absence of the use of ultrasound data prior to amniocentesis . Comparisons between the groups failed to support the contention that the routine use of ultrasound reduces the complications of midtrimester amniocentesis . Our findings support other published data concluding that the routine use of ultrasound does not help to reduce the number of midtrimester amniocentesis complications In April 1985 , having completed a study of the short‐term complications of chorionic villus sampling ( CVS ) , we began a r and omized comparison of CVS versus amniocentesis . Our study continued over a 15‐month period , and during that time we had difficulty recruiting patients , with only 10.6 % of 1254 women referred for prenatal diagnosis fully participating in this study . However , 30.2 % of those eligible by date s and indication chose to enter the study . CVS was available in our province only through this study , and the two most common reasons for such a low rate of recruitment were reporting too late in pregnancy and the concern about the potential risks of CVS . Patients continued to seek counselling too late for CVS despite direct and continuous contact with regional physicians . Our patients ' concern about risk might well vary with the attitude of their physicians towards CVS , and with the information provided at the time of pre‐test counselling A total of 800 patients were r and omized at the 9th to 11th week of pregnancy either for transcervical chorionic villus sampling ( CVS ) on the day of trial entry or for amniocentesis ( AC ) at the 16th week . The indication for fetal karyotyping was maternal age in 94 per cent of the cases ; the mean maternal age was 39.2 years . An adequate sample was obtained in 98.3 per cent of the cases in the CVS group and in all cases in the AC group . Retesting was indicated in 3.3 per cent of the CVS cases . An abnormal karyotype was found in 6.1 per cent of the CV sample s and in 4.5 per cent of the amniotic fluid sample s. There was one false-positive chromosome result in both groups . Twelve ( 3.1 per cent ) miscarriages occurred by the 22nd week of pregnancy in the CVS group in pregnancies intended to continue . No difference was seen between the groups for total fetal loss rates . The number of surviving infants in the CVS group was 92.2 per cent and in the AC group 91.7 per cent ( rate difference 0.5 per cent ( 95 per cent confidence interval -3.3 to 4.3 ) ) . In our study , both the diagnostic accuracy and the risk of fetal loss were equal in the CVS and AC groups OBJECTIVES To evaluate whether local anesthesia decreases patients ' pain experience during mid-trimester amniocentesis . METHODS In a r and omized trial , one group did not receive local anesthesia while , in another group , lignocaine 1 % was injected subcutaneously prior to amniocentesis . Five different scoring systems were used to evaluate patients ' pain experience . RESULTS Two hundred and twenty women entered the study : 114 received local anesthesia , while 106 did not . The mean ( SD ) Visual Analog Scale was 1.4 ( 1.5 ) on a 0 - 10 scale ( range 0 - 7.6 ) . Some 97 % of patients described the procedure as not painful or bearable , 79 % had expected the procedure to be more painful and 59 % reported the amniocentesis to have a comparable discomfort as venous blood sampling ; 98 % of women declared they would undergo an amniocentesis again if indicated . There were no statistical differences between both r and omization groups . CONCLUSIONS Mid-trimester amniocentesis is not a painful procedure . Local anesthesia does not affect pain experience during amniocentesis OBJECTIVES The  Amniocentesis  Results : Investigation of Anxiety ( ARIA ) trial tested two hypotheses : first , that giving amniocentesis results out on a fixed date alters maternal anxiety during the waiting period , compared with a policy of telling parents that the result will be issued ' when available ' ( i.e. a variable date ) , and secondly , that issuing early results from a rapid molecular test alters maternal anxiety during the waiting period , compared with not receiving any results prior to the karyotype . The effects of the two interventions on anxiety 1 month after receiving karyotype results were also examined . DESIGN A multi-centre , r and omised , controlled , open fixed sample , 2 x 2 factorial design trial , with equal r and omisation . SETTING Twelve hospitals in Engl and offering amniocentesis as a diagnostic test for Down 's syndrome . PARTICIPANTS A total of 226 women who had had an amniocentesis were r and omised between June 2002 and July 2004 . Eight women with abnormal results or test failure were excluded post-r and omisation . INTERVENTIONS Issuing karyotype results on a prespecified fixed date , rather than issuing them as soon as they became available and issuing karyotype results alone , or subsequent to issuing results from a rapid molecular test for the most common chromosomal abnormalities . MAIN OUTCOME MEASURES Average anxiety during the waiting period , calculated using daily scores from the short version of the Spielberger State-Trait Anxiety Inventory ( STAI ) . Recalled anxiety , measured 1 month after receiving karyotype results , using a rating scale . Anxiety at the 1-month follow-up , measured using the short-form STAI . RESULTS There was no evidence that giving out karyotype results on a fixed or on a variable date altered maternal anxiety during the waiting period . However , the analysis only had sufficient power to detect a moderate to large effect . Issuing early results from a partial , but rapid , test reduced maternal anxiety during the waiting period , compared with receiving only the full karyotype results . This was a moderate to large effect . In addition , group differences in recalled anxiety reflected fairly closely the differences in anxiety women had experienced while waiting for results . One month after receiving normal karyotype results , anxiety was low in all groups , but women who had been given rapid test results were more anxious than those who had not . This was a small to moderate effect . CONCLUSIONS Since there are no clear advantages in anxiety terms of issuing karyotype results as soon as they become available , or on a fixed date , women could be given a choice between them . Rapid testing was a beneficial addition to karyotyping , at least in the short term . This does not necessarily imply that early results would be preferred to comprehensive ones if women had to choose between them . There should be further research , including more qualitative studies , into the causes , characteristics and consequences of anxiety associated with pr 
    Output:
    
CVS methods ; 5 .
Transcervical CVS may be more technically dem and ing than transabdominal CVS , with more failures to obtain sample ( 2.0 % versus 1.1 % ; average RR 1.79 , 95 % CI 1.13 to 2.82 , moderate- quality evidence ) .Overall , we found low- quality evidence for outcomes when early amniocentesis was compared to transabdominal CVS .
Early amniocentesis was not as safe as second trimester amniocentesis , illustrated by increased pregnancy loss and congenital anomalies ( talipes ) .
Transcervical chorionic villus sampling compared with second trimester amniocentesis may be associated with a higher risk of pregnancy loss , but results were quite heterogeneous .