***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 Construct an ethnic-specific chart and compare the prediction of adverse outcomes using this chart with the clinical ly recommended UK-WHO and customised birth weight charts using cut-offs for small-for-gestational age ( SGA : birth weight < 10th centile ) and large-for-gestational age ( LGA : birth weight > 90th centile ) . Design Prospect i ve cohort study . Setting Born in Bradford ( BiB ) study , UK . Participants 3980 White British and 4448 Pakistani infants with complete data for gestational age , birth weight , ethnicity , maternal height , weight and parity . Main outcome measures Prevalence of SGA and LGA , using the three charts and indicators of diagnostic utility ( sensitivity , specificity and area under the receiver operating characteristic ( AUROC ) ) of these chart-specific cut-offs to predict delivery and neonatal outcomes and a composite outcome . Results In White British and Pakistani infants , the prevalence of SGA and LGA differed depending on the chart used . Increased risk of SGA was observed when using the UK-WHO and customised charts as opposed to the ethnic-specific chart , while the opposite was apparent when classifying LGA infants . However , the predictive utility of all three charts to identify adverse clinical outcomes was poor , with only the prediction of shoulder dystocia achieving an AUROC>0.62 on all three charts . Conclusions Despite being recommended in national clinical guidelines , the UK-WHO and customised birth weight charts perform poorly at identifying infants at risk of adverse neonatal outcomes . Being small or large may increase the risk of an adverse outcome ; however , size alone is not sensitive or specific enough with current detection to be useful . However , a significant amount of missing data for some of the outcomes may have limited the power needed to determine true associations OBJECTIVE : To demonstrate that individualized optimal fetal growth norms , accounting for physiologic and pathologic determinants of fetal growth , better identify normal and abnormal outcomes of pregnancy than existing methods . METHODS : In a prospect i ve cohort of 38,033 singleton pregnancies , we identified 9,818 women with a completely normal outcome of pregnancy and characterized the physiologic factors affecting birth weight using multivariable regression . We used those physiologic factors to individually predict optimal growth trajectory and its variation , growth potential , for each fetus in the entire cohort . By comparing actual birth weight with growth potential , population , ultrasound , and customized norms , we calculated for each fetus achieved percentiles , by each norm . We then compared proportions of pregnancies classified as normally grown , between 10th and 90th percentile , or aberrantly grown , outside this interval , by growth potential and traditional norms , in 14,229 complicated pregnancies , 1,518 pregnancies with diabetes or hypertensive disorders , and 1,347 pregnancies with neonatal complications . RESULTS : Nineteen physiologic factors , associated with maternal characteristics and early placental function , were identified . Growth potential norms correctly classified significantly more pregnancies than population , ultrasound , or customized norms in complicated pregnancies ( 26.4 % compared with 18.3 % , 18.7 % , 22.8 % , respectively , all P<.05 ) , pregnancies with diabetes or hypertensive disorders ( 37.3 % compared with 23.0 % , 28.0 % , 34.0 % , respectively , all P<.05 ) and neonatal complications ( 33.3 % compared with 19.7 % , 24.9 % , 29.8 % , respectively , all P<.05 ) . CONCLUSION : Growth potential norms based on the physiologic determinants of birth weight are a better discriminator of aberrations of fetal growth than traditional norms . LEVEL OF EVIDENCE : BACKGROUND In 2006 , WHO produced international growth st and ards for infants and children up to age 5 years on the basis of recommendations from a WHO expert committee . Using the same methods and conceptual approach , the Fetal Growth Longitudinal Study ( FGLS ) , part of the INTERGROWTH-21(st ) Project , aim ed to develop international growth and size st and ards for fetuses . METHODS The multicentre , population -based FGLS assessed fetal growth in geographically defined urban population s in eight countries , in which most of the health and nutritional needs of mothers were met and adequate antenatal care was provided . We used ultrasound to take fetal anthropometric measurements prospect ively from 14 weeks and 0 days of gestation until birth in a cohort of women with adequate health and nutritional status who were at low risk of intrauterine growth restriction . All women had a reliable estimate of gestational age confirmed by ultrasound measurement of fetal crown-rump length in the first trimester . The five primary ultrasound measures of fetal growth -- head circumference , biparietal diameter , occipitofrontal diameter , abdominal circumference , and femur length -- were obtained every 5 weeks ( within 1 week either side ) from 14 weeks to 42 weeks of gestation . The best fitting curves for the five measures were selected using second-degree fractional polynomials and further modelled in a multilevel framework to account for the longitudinal design of the study . FINDINGS We screened 13,108 women commencing antenatal care at less than 14 weeks and 0 days of gestation , of whom 4607 ( 35 % ) were eligible . 4321 ( 94 % ) eligible women had pregnancies without major complications and delivered live singletons without congenital malformations ( the analysis population ) . We documented very low maternal and perinatal mortality and morbidity , confirming that the participants were at low risk of adverse outcomes . For each of the five fetal growth measures , the mean differences between the observed and smoothed centiles for the 3rd , 50th , and 97th centiles , respectively , were small : 2·25 mm ( SD 3·0 ) , 0·02 mm ( 3·0 ) , and -2·69 mm ( 3·2 ) for head circumference ; 0·83 mm ( 0·9 ) , -0·05 mm ( 0·8 ) , and -0·84 mm ( 1·0 ) for biparietal diameter ; 0·63 mm ( 1·2 ) , 0·04 mm ( 1·1 ) , and -1·05 mm ( 1·3 ) for occipitofrontal diameter ; 2·99 mm ( 3·1 ) , 0·25 mm ( 3·2 ) , and -4·22 mm ( 3·7 ) for abdominal circumference ; and 0·62 mm ( 0·8 ) , 0·03 mm ( 0·8 ) , and -0·65 mm ( 0·8 ) for femur length . We calculated the 3rd , 5th 10th , 50th , 90th , 95th and 97th centile curves according to gestational age for these ultrasound measures , representing the international st and ards for fetal growth . INTERPRETATION We recommend these international fetal growth st and ards for the clinical interpretation of routinely taken ultrasound measurements and for comparisons across population s. FUNDING Bill & Melinda Gates Foundation Objective : Compare customized versus population -based growth curves for identification of  small-for-gestational-age ( SGA ) and body fat percent ( BF% ) among preterm infants . Methods : Prospect i ve cohort study of 204 preterm infants classified as SGA or appropriate-for-gestational-age ( AGA ) by population -based and customized growth curves . BF% was determined by air-displacement plethysmography . Differences between groups were compared using bivariable and multivariable linear and logistic regression analyses . Results : Customized curves reclassified 30 % of the preterm infants as SGA . SGA infants identified by customized method only had significantly lower BF% ( 13.8 ± 6.0 ) than the AGA ( 16.2 ± 6.3 , p = 0.02 ) infants and similar to the SGA infants classified by both methods ( 14.6 ± 6.7 , p = 0.51 ) . Customized growth curves were a significant predictor of BF% ( p = 0.02 ) , whereas population -based growth curves were not a significant independent predictor of BF% ( p = 0.50 ) at term corrected gestational age . Conclusion : Customized growth potential improves the differentiation of SGA infants and low BF% compared with a st and ard population -based growth curve among a cohort of preterm infants OBJECTIVES Fetal growth restriction is a strong risk factor for stillbirth . We compared the performance of three fetal growth curves - customized , ultrasound ( Hadlock ) and population - in identifying abnormally grown fetuses at risk of stillbirth . METHODS We performed a case-control study of singleton stillbirths ( delivered between 2000 and 2010 ) at one center . Four liveborn controls were r and omly identified for each stillbirth . Ultrasound-estimated fetal weight within 1 month prior to delivery was used to calculate growth percentiles for each fetus using three fetal growth norms . Sensitivities and odds ratios for stillbirth , as well as odds of abnormal growth according to formula , were calculated . RESULTS There were 49 stillbirths and 197 live births . Using the customized norms , growth of the fetuses destined to be stillborn was bimodal , with both more small-for-gestational-age ( SGA ; < 10(th ) percentile ) and large-for-gestational-age ( LGA ; ≥ 90(th ) percentile ) fetuses . Odds of being abnormally grown were significantly higher using ultrasound compared with population norms ( P = 0.02 ) but were not statistically different using ultrasound and customized norms ( P = 0.21 ) . Sensitivity for identification of SGA on ultrasound as a predictor of stillbirth was higher using customized ( 39 % ; 95 % CI , 24 - 54 % ) or ultrasound ( 33 % ; 95 % CI , 19 - 47 % ) , rather than population ( 14 % ; 95 % CI , 4 - 25 % ) , norms . CONCLUSIONS Among fetuses destined to be stillborn , customized and ultrasound norms identified a greater proportion of both SGA and LGA estimated fetal weights . The customized norms performed best in identifying death among SGA fetuses . These results should be interpreted within the limitations of the study design Accurate assessment of fetal growth status requires the definition of an optimal st and ard , which represents the growth potential of the baby . Against this st and ard , individually ' customized ' percentiles can be calculated . They improve the distinction between normal and abnormal , and help in our underst and ing and diagnosis of pathological fetal growth . This method can be used as a tool for epidemiological analysis as well as for prospect i ve clinical monitoring BACKGROUND The recently published INTERGROWTH-21st Project international population st and ard for newborn size is intended for global use , but its ability to identify small infants at risk of adverse outcomes in a general obstetric population has not been reported . OBJECTIVE The objective of the study was to compare adverse neonatal outcomes among small-for-gestational-age ( SGA ) infants between the INTERGROWTH-21st st and ard  and a customized birthweight st and ard ( accounting for maternal characteristics of height , weight , parity , and ethnicity ) . We hypothesized that in a multiethnic general obstetric population in Auckl and , New Zeal and , a customized birthweight st and ard would better identify SGA infants at-risk of neonatal morbidity/mortality and stillbirth than the INTERGROWTH-21st st and ard . STUDY DESIGN Using prospect ively gathered maternity data from a general obstetric population in Auckl and , New Zeal and , from 2006 to 2013 ( n = 53,484 births at ≥ 33 weeks ) , infants were classified as SGA ( birthweight < 10th centile ) by INTERGROWTH-21st and customized st and ards . Infants were further categorized as SGA by both criteria , INTERGROWTH-21st only , customized only , or not SGA ( met neither criteria ) . Composite adverse neonatal outcome was defined as neonatal death , neonatal intensive care admission > 48 hours , or ventilation > 4 hours or 5-minute Apgar score < 7 . Relative risks for primary outcomes were estimated using modified Poisson regression , with the non-SGA group as the referent . RESULTS Incidence of SGA was 4.5 % by INTERGROWTH-21st and 11.6 % by customized st and ard . Compared with those not SGA , infants identified as small for gestational age by both criteria had the highest risk of adverse neonatal outcome ( relative risk [ RR ] , 4.1 , 95 % confidence interval [ CI ] , 3.7 - 4.6 ) and stillbirth ( RR , 8.3 , 95 % CI , 5.1 - 13.4 ) . Infants SGA by customized st and ard only ( n = 4015 ) had an increased risk of adverse neonatal outcome ( RR , 2.0 , 95 % CI , 1.8 - 2.2 ) and stillbirth ( RR , 3.0 , 95 % CI , 1.7 - 5.3 ) . Few infants were identified as SGA by INTERGROWTH-21st only ( n = 172 ) , and risks of adverse neonatal outcome and stillbirth were not increased . Findings were unchanged when analyses were 
    Output:
    
Both customized and population -based growth charts can identify SGA neonates at risk for adverse outcomes .