***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 examine any associations between routine ultrasonography in utero and subsequent brain development as indicated by non-right h and edness at primary school age and neurological development during childhood . DESIGN --Follow up of 8 and 9 year old children of women who took part in two r and omised , controlled trials of routine ultrasonography during pregnancy . SETTING --Clinics of 60 general practitioners in Norway during 1979 - 81 . Maternal and child health centres . SUBJECTS--2161 ( 89 % ) of 2428 eligible singletons were followed up , partly through a question naire to their parents and partly through information from health centres . MAIN OUTCOME MEASURES --The dominant h and of the child was assessed by 10 questions . Deficits in attention , motor control , and perception were evaluated by five questions . Impaired neurological development during the first year of life was assessed by an abbreviated version of the Denver developmental screening test . RESULTS --The odds of non-right h and edness were higher among children who had been screened in utero than among control children ( odds ratio 1.32 ; 95 % confidence interval 1.02 to 1.71 ) . No clear differences were found between the groups with regard to deficits in attention , motor control , and perception or neurological development during the first year of life . CONCLUSION --Our data suggest a possible association between  routine ultrasonography  in utero and subsequent non-right h and edness , whereas no association with impaired neurological development was found . As the question on non-right h and edness was one of six initial hypotheses , the observed results may be due to chance . None the less , the results suggest that the hypothesis may have some merit and should be tested in future studies The objective of this study was to evaluate and characterise by study of newborn biometry a possible effect on birthweight which we observed previously in a r and omised controlled trial of multiple prenatal ultrasound examinations . A total of 2743 women with single pregnancies had been allocated at r and om to either a protocol of ultrasound imaging and continuous wave Doppler studies at 18 , 24 , 28 , 34 and 38 weeks gestation ( intensive group ) , or to a protocol of a single imaging examination at 18 weeks and further imaging scans only as clinical ly indicated ( regular group ) . When compared with those in the regular group , and adjusted for other confounding variables , normally formed babies of term gestational age in the intensive group tended to be shorter when measured at birth ( P = 0.123 ) and on day 2 - 3 of age ( P = 0.068 ) . There were statistically insignificant reductions in the circumferences of the chest , abdomen and mid-arm ; and in the skinfold thicknesses of the triceps , parascapular and subscapular regions . Principal component analysis showed a trend for a reduction for the skeletal component ( P = 0.085 ) but not for the soft tissue component ( P = 0.332 ) . Comparison of the neonatal biometry in the two groups is not conclusive , but the differential effects on the various growth parameters suggest that if multiple scans do indeed restrict fetal growth , the mechanism is more likely to be an effect on bone growth rather than a reduction in nutrient supply from the placenta Abstract Despite widespread application of ultrasound imaging and Doppler blood flow studies , the effects of their frequent and repeated use in pregnancy have not been evaluated in controlled trials . From 2834 women with single pregnancies at 16 - 20 weeks gestation , 1415 were selected at r and om to receive ultrasound imaging and continuous-wave Doppler flow studies at 18 , 24 , 28 , 34 , and 38 weeks gestation ( the intensive group ) and 1419 to receive single ultrasound imaging at 18 weeks ( the regular group ) . Outcome data was obtained from 99 % of women who entered the study . The only difference between the two groups was significantly higher intrauterine growth restriction in the intensive group , when expressed both as birthweight 342 : OBJECTIVE To evaluate the effect of introducing two biophysical ultrasound examinations in a low-risk antenatal population . METHODS Scans were performed at 30–32 weeks ' gestation and 36–37 weeks ' gestation . Scans assessed placental maturity , amniotic fluid volume , and estimated fetal weight .  One thous and nine hundred ninety-eight low-risk patients were r and omized at 30 weeks ' gestation to a control group receiving st and ard antenatal care , or to the study group who also received an ultrasound scan .  Outcome measures were frequency of small for date s ( less than 10th percentile at birth ) , intervention rates , and admissions to neonatal intensive care . RESULTS The proportion of infants assessed as small for date s at birth in the study group was 6.9 % ( 69 of 994 ) compared with 10.4 % ( 104 of 999 ) in the control group ( P = 008 ) . The rates of intervention in the study and control groups were 31.3 % ( 313 of 999 ) and 16.9 % ( 169 of 999 ) , respectively ( P < .001 ) . Twenty-eight ( 2.8 % ) neonates in the study group were admitted to the neonatal unit compared with 34 ( 3.4 % ) in the control group ( P = .532 ) . CONCLUSION Introduction of an ultrasound scan at 30–32 weeks ' and 36–37 weeks ' gestation may reduce the risk of a growth-restricted infant and increases antenatal interventions . Rates of admission to a neonatal unit are not significantly affected Summary : In this study 3 different methods of screening for  birth‐weight < 10th percentile in pregnancy were evaluated both indivually and in combination ; 1,135 women with singleton pregnancies were studied . Measurements of symphysiofundal height by tape measure , and  amniotic fluid index and fetal abdominal circumference by ultrasound imaging , were made at 18 , 24 , 28 , 34 and 38 weeks . At none of these gestational ages did amniotic fluid index perform well as a screening test for birth‐weight < 10th percentile . Combining the tests , using symphysiofundal height to select a group at high risk who then had a fetal abdominal circumference measurement , reduced the false positive rate but significantly decreased the percentage of infants diagnosed . The results of this study confirm that the most appropriate antenatal diagnostic test for birth‐weight < 10th percentile is ultrasound measurement of fetal abdominal circumference . Selecting pregnancies at risk by clinical measurement of symphysiofundal height will provide a lower false positive rate than a policy of performing ultrasound on all pregnancies during the third trimester , but will also reduce the sensitivity Most fetuses in developed countries are exposed in utero to diagnostic ultrasound examination . Many pregnant women express concern about whether the procedure harms the fetus . Since most routine ultrasound examinations are done at weeks 16 - 22 , when the fetal brain is developing rapidly , effects on neuronal migration are possible . We have sought an association between routine ultrasonography in utero and reading and writing skills among children in primary school . At the age of 8 or 9 years , children of women who had taken part in two r and omised , controlled trials of routine ultrasonography during pregnancy were followed-up . The women had attended the clinics of 60 general practitioners in central Norway during 1979 - 81 . The analysis of outcome was by intention to treat : 92 % of the " screened " group had been exposed to ultrasound screening at weeks 16 - 22 , and 95 % of controls had not been so exposed , but there was some overlap . 2428 singletons were eligible for follow-up , and the school performance of 2011 children ( 83 % ) was assessed by their teachers on a scale of 1 - 7 ; the teachers were unaware of ultrasound exposure status . A subgroup of 603 children underwent specific tests for dyslexia . There were no statistically significant differences between children screened with ultrasound and controls in the teacher-reported school performance ( scores for reading , spelling , arithmetic , or overall performance ) . Results from the dyslexia test sample showed no differences between screened children and controls in reading , spelling , and intelligence scores , or in discrepancy scores between intelligence and reading or spelling . The test results classified 21 of the 309 screened children ( 7 % [ 95 % confidence interval 3 - 10 % ] ) and 26 of the 294 controls ( 9 % [ 4 - 12 % ] ) as dyslexic . The risk of having poor skills in reading and writing was no greater for children whose mothers had been offered routine ultrasonography than for those whose mothers had not been offered the procedure BACKGROUND Despite the widespread use of prenatal ultrasound studies , there are no published data from r and omised controlled trials describing childhood outcomes that might be influenced by repeated ultrasound exposures . We previously undertook a r and omised controlled trial to assess the effects of multiple studies on pregnancy and childhood outcomes and reported that those pregnancies allocated to receive multiple examinations had an unexplained and significant increase in the proportion of growth restricted newborns . Our aim was to investigate the possible effects of multiple prenatal ultrasound scans on growth and development in childhood . Here , we provide follow-up data of the childrens ' development . METHODS Physical and developmental assessment s were done on children whose pregnant mothers had been allocated at r and om to a protocol of five studies of ultrasound imaging and umbilical artery Doppler flow velocity waveform between 18 and 38 weeks ' gestation ( intensive group n=1490 ) or a single imaging study at 18 weeks ' gestation ( regular group n=1477 ) . We used generalised logistic and linear regression models to assess the group differences in developmental and growth outcomes over time . Primary data analysis was done by intention-to-treat . FINDINGS Examinations were done at 1 , 2 , 3 , 5 , and 8 years of age on children born without congenital abnormalities and from singleton pregnancies ( intensive group n=1362 , regular group n=1352 ) . The follow-up rate at 1 year was 85 % ( 2310/2714 ) and at 8 years was 75 % ( 2042/2714 ) . By 1 year of age and thereafter , physical sizes were similar in the two groups . There were no significant differences indicating deleterious effects of multiple ultrasound studies at any age as measured by st and ard tests of childhood speech , language , behaviour , and neurological development . INTERPRETATION Exposure to multiple prenatal ultrasound examinations from 18 weeks ' gestation onwards might be associated with a small effect on fetal growth but is followed in childhood by growth and measures of developmental outcome similar to those in children who had received a single prenatal scan Summary : Poor fetal growth is an important cause of perinatal mortality and morbidity . Based on the hypothesis that early diagnosis of fetal growth problems leads to more appropriate management and therefore , improved outcome , a r and omized controlled trial of ultrasound measurement was performed on 1,528 women booked though a hospital antenatal clinic This compared a number of perinatal outcomes between the group who had a  routine 2‐stage examination ( early dating and 34‐week scan ) and a group who had only a dating scan and then additional scans as generated by their clinical situations . No significant differences could be found between the groups when these perinatal outcomes were considered . These results mirror previously published r and omized controlled trials . Selection of women for third trimester ultrasound examination for suspected fetal growth problems should be based on careful clinical assessment and should not be routine In the hope of reducing perinatal risks associated with retardation of intrauterine growth a previously described two stage ultrasound screening schedule was evaluated by a controlled trial in 877 women with low risk single pregnancies . The two stages of ultrasound examination were an assessment of gestational age during early pregnancy followed by measurement of length from crown to rump and area of trunk at between 34 and 36 weeks ' gestation . The product of crown to rump length and trunk area was calculated . The sensitivity of this schedule in identifying in advance 94 % of babies who were small for date s at birth , with 90 % specificity , and the speed and simplicity of measurement confirmed the accuracy and feasibility of two stage ultrasonography as a screening procedure . The controlled trial did not , however , show any benefit from its routine application in these low risk pregnancies OBJECTIVE The objective of this r and omized clinical trial was to test the hypothesis that ultrasonographic screening would significantly alter perinatal outcome as a result of the antenatal detection of fetal congenital malformations . STUDY DESIGN Pregnant women without a specific indication for ultrasonography  were r and omly assigned to have either two screening sonograms ( 15 to 22 weeks and 31 to 35 weeks ) or conventional obstetric care with ultrasonography used only as determined by the clinical judgment of the patient 's physician . The frequency of birth defect detection in the screened and control population s was compared , as was the impact of discovery on pregnancy outcome . RESULTS Major congenital malformations occurred in 2.3 % of the 15,281 fetuses and infants in this study . Antenatal ultrasonography detected 35 % of the anomalous fetuses in the screened group versus only 11 % in the control population ( relative detection rate 3.1 ; 95 % confidence interval 2.0 to 5.1 ) . Ultrasonography screening did not , however , significantly influence the management or outcome of pregnancies complicated by congenital malformations . Specifically , only 9 abortions were performed for anomalies 
    Output:
    
Third trimester ultrasound seems a logical solution , but systematic review of evidence from r and omised trials has shown that third trimester ultrasound does not have a significant impact on perinatal mortality but may increase interventions such as caesarean delivery .