***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: In a study of 2000 unselected pregnant women the development of a mature placental appearance ( grade 3 ) on ultrasonography by 34 - 36 weeks ' gestation , observed in 15 % of cases , was associated with maternal smoking , low parity , low maternal age , and being white . These women had an increased risk of problems during labour and their babies had an increased risk of low birth weight , poor condition at birth , and perinatal death . The women were r and omly allocated to two groups : in one group the result of the placental grading was reported to the clinician responsible for care ; in the second the result was noted but not reported . There was a significant decrease in the risk of perinatal death in the group where the grading was known . This reduction was responsible for a difference in the principal outcome index , a heterogeneous group of measures of mortality and morbidity , but this difference was not significant . This study alone does not justify routine late scanning , and further , larger trials are required . Nevertheless , the results do provide a basis for the reporting of placental grading when ultrasound examination is performed during the third trimester Background In high-re source setting s , obstetric ultrasound is a st and ard component of prenatal care used to identify pregnancy complications and to establish an accurate gestational age in order to improve obstetric care . Whether or not ultrasound use will improve care and ultimately pregnancy outcomes in low-re source setting s is unknown . Methods / Design This multi-country cluster r and omized trial will assess the impact of antenatal ultrasound screening performed by health care staff on a composite outcome consisting of maternal mortality and maternal near-miss , stillbirth and neonatal mortality in low-re source community setting s. The trial will utilize an existing research infrastructure , the Global Network for Women ’s and Children ’s Health Research with sites in Pakistan , Kenya , Zambia , Democratic Republic of Congo and Guatemala . A maternal and newborn health registry in defined geographic areas which documents all pregnancies and their outcomes to 6 weeks post-delivery will provide population -based rates of maternal mortality and morbidity , stillbirth , neonatal mortality and morbidity , and health care utilization for study clusters . A total of 58 study clusters each with a health center and about 500 births per year will be r and omized ( 29 intervention and 29 control ) . The intervention includes training of health workers ( e.g. , nurses , midwives , clinical officers ) to perform ultrasound examinations during antenatal care , generally at 18–22 and at 32–36 weeks for each subject . Women who are identified as having a complication of pregnancy will be referred to a hospital for appropriate care . Finally , the intervention includes community sensitization activities to inform women and their families of the availability of ultrasound at the antenatal care clinic and training in emergency obstetric and neonatal care at referral facilities . Discussion In summary , our trial will evaluate whether introduction of ultrasound during antenatal care improves pregnancy outcomes in rural , low-re source setting s. The intervention includes training for ultrasound-naïve providers in basic obstetric ultrasonography and then enabling these trainees to use ultrasound to screen for pregnancy complications in primary antenatal care clinics and to refer appropriately . Trial registration Clinical trials.gov ( NCT # 01990625 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 The study was performed to investigate any associations between routine ultrasonography during pregnancy and subsequent reduced vision and /or hearing among children .  A follow-up was carried out of primary school children born to women who took part in two r and omized , controlled trials of routine ultrasonography during pregnancy . Of 2428 eligible singletons , 2161 ( 89 % ) were followed up with a parental question naire and with information from maternal and child health centers . Parents assessed vision and hearing in their children and reported their observations in question naires . At the age of 7 years , the children were also screened with bilateral visual acuity tests and pure tone audiometry  at public maternal and child health centers . No significant differences between ultrasound-screened children and their controls were found in the parental assessment of vision or hearing . The objective tests did not show any significant differences between children in the two groups with regard to visual acuity or hearing . The risk of reduced vision or hearing was no greater for children of mothers who had been offered routine ultrasonography during pregnancy than for those whose mothers had not received that offer 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 : To compare detection rates of small‐for‐gestational‐age fetuses , large‐for‐gestational‐age fetuses , congenital anomalies and adverse perinatal outcomes in pregnancies r and omized to third‐trimester routine ultrasound or ultrasound on clinical indication Objective To compare the effects of four methods of analysis on the results of r and omised controlled trials that recruit women with multiple pregnancies and measure outcomes on their babies OBJECTIVES This r and omized clinical trial of 15,530 women was design ed to test the hypothesis that screening ultrasonography in low-risk pregnancies would improve perinatal outcome . A secondary hypothesis addressed in this article was that screening ultrasonography would have a favorable impact on maternal management or outcome . STUDY DESIGN Pregnant women without a specific indication for ultrasonographic examination in early pregnancy were r and omly assigned to have either two screening sonograms or conventional obstetric care . Pregnancy interventions and maternal outcomes were compared in the two groups . RESULTS No significant differences were found in maternal outcomes . Use of ultrasonography  was markedly higher in the screened group . The rates of induced abortion , amniocentesis , tests of fetal well-being , external version , induction , and cesarean section and the distribution of total hospital days were similar in the two groups . Use of tocolytics and the rate of post date pregnancy were both slightly lower in the screened group . CONCLUSION Screening ultrasonography result ed in no clinical ly significant benefit A total of 745 Caucacian women were allocated at r and om between two groups , A and B , at the first antenatal visit . At the completion of the study , 341 patients in group A underwent a single ultrasonic measurement of fetal chest area  between 32 and 36 weeks of gestation . The medical staff was not informed of these results . Three hundred and sixty‐four patients in group B acted as controls 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 " screen 
    Output:
    
There was no difference in antenatal , obstetric and neonatal outcome or morbidity in screened versus control groups .
Routine late pregnancy ultrasound was not associated with improvements in overall perinatal mortality .
There is little information on long-term substantive outcomes such as neurodevelopment .
There is a lack of data on maternal psychological effects .
Based on existing evidence , routine late pregnancy ultrasound in low-risk or unselected population s does not confer benefit on mother or baby .
There was no difference in the primary outcomes of perinatal mortality , preterm birth less than 37 weeks , caesarean section rates , and induction of labour rates if ultrasound in late pregnancy was performed routinely versus not performed routinely .