***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 assess the measurement of inactive urinary kallikrein ( IUK ) to creatinine ( Cr ) ratio ( IUK : Cr ) on an untimed urine sample , collected between 16 and 20 weeks of pregnancy , as a predictive test for the development of both proteinuric and nonproteinuric pre‐eclampsia Objective : To compare uterine artery resistance index values in twin and singleton pregnancies , to examine eventual modifications of these values in twin pregnancies complicated by gestational hypertension and preeclampsia , and to determine whether resistance index values in twin pregnancies could predict the development of gestational hypertension and preeclampsia . Methods : In a cross-sectional study , reference limits for gestation were constructed for the uterine artery resistance index ( higher , lower , and mean values ) in 96 uncomplicated twin pregnancies and compared to the reference limits constructed from 315 normal singleton pregnancies . Uterine artery resistance indexes obtained in 53 twin pregnancies complicated by either gestational hypertension or preeclampsia were compared with the newly established nomograms . The clinical efficacy of the  uterine artery resistance index  to predict hypertensive complications was evaluated prospect ively in 64 twin pregnancies studied at 20 - 24 weeks ' gestation . Results : In both singleton and twin pregnancies , uterine artery resistance indexes decreased linearly with advancing gestation . However , twin pregnancies showed significantly different slopes and constant values , result ing in lower resistance indexes at all gestational ages examined . No significant differences were found when comparing resistance indexes in all patients with gestational hypertension or preeclampsia to the reference limits . Statistically significant differences were obtained for the higher ( P ≤ .05 ) and mean ( P ≤ .01 ) resistance indexes when the comparison was restricted to preeclamptic patients . In the twin pregnancies studied at 20 - 24 weeks ' gestation , the diagnostic efficacy of the uterine artery resistance index for predicting the development of gestational hypertension and /or preeclampsia was disappointingly low ( k<0.10 ) . Conclusions : Resistance index values in the uterine artery are lower in twin pregnancies than in singleton pregnancies . Gestational hypertension and preeclampsia may occur in twin pregnancies despite normal uterine artery velocity waveforms , suggesting a limited role of this measurement in the management and prediction of hypertensive complications in twin pregnancies OBJECTIVE To evaluate the prevalence in normal pregnancies of anti-32 glycoprotein I ( anti-beta2GPI ) antibodies , and their association with obstetrical complications . STUDY DESIGN Prospect i ve study of anti-beta2GPI and anticardiolipin ( CL ) antibodies in 510 healthy pregnant women at 15 - 18 weeks . According to the results , women were categorized into three groups : group I , negative for both antibodies ; group II , positive for anti-beta2GPI antibodies ; group III , positive for aCL only . The rates of fetal loss , abruptio placentae , preeclampsia-eclampsia , and fetal growth retardation were compared in the three groups . RESULTS  Anti-beta2GPI antibodies  were found in 20 women ( 3.9 % ) and aCL in 8 patients ( 1.6 % ) . Obstetrical complications were more frequent , even if not significantly different , in group II , 15 % , than in group I , 4.1 % ( difference 10.9 % ; 95 % confidence interval ( CI ) : 1.6 - 20.2 % ; p=0.0575 ) , while no complications were seen in group III . Preeclampsia-eclampsia were significantly more frequent in group II ( 10 % ) than in group I ( 0.8 % ; difference 9.2 % ; 95 % CI : 4.4 - 14 % ; p=0.021 ) . The prevalence of fetal growth retardation was not significantly different in the two groups ( 5 % vs. 2 % , respectively ) . COMMENT Our findings indicate that anti-beta2GPI antibodies are associated with some obstetrical complications , mainly preeclampsia-eclampsia , even if more conventional antiphospholipid antibodies are not present . This observation suggests that these antibodies should be investigated in such cases , in order to improve the outcome of subsequent pregnancies , as well as in women with a history of early and /or recurrent severe preeclampsia in order to start a prophylactic treatment ( i.e. low-dose aspirin or heparin ) In a prospect i ve study of  maternal serum alpha-fetoprotein screening for both high and low values , we assessed the overall predictive value , sensitivity , specificity and relative risks for  congenital defects and complications of pregnancy .  Among 13,486 women with singleton pregnancies interviewed at the time of screening ( 15 to 20 weeks of gestation ) , 3.9 % had high and 3.4 % had low values . A high maternal serum alpha-fetoprotein value was associated with the following adverse outcomes : neural tube defects ( relative risk = 224 ) , other major congenital defects ( relative risk = 4.7 ) , fetal deaths ( relative risk = 8.1 ) , neonatal death ( relative risk = 4.7 ) , low birth weight ( relative risk = 4.0 ) , newborn complications ( relative risk = 3.6 ) , oligohydramnios ( relative risk = 3.4 ) , abruptio placentae ( relative risk = 3.0 ) and preeclamptic toxemia ( relative risk = 2.3 ) . A low maternal serum alpha-fetoprotein value was associated with chromosomal defects ( relative risk = 11.6 ) for fetal death ( relative risk = 3.3 ) . Either high or low maternal serum alpha-fetoprotein values were associated with 34.2 % of all major congenital defects , 19.1 % of all stillbirths and fetal-neonatal deaths , 11.0 % of major pregnancy complications , and 15.9 % of serious newborn complications .  Maternal serum alpha-fetoprotein screening provides an important adjunctive tool for the identification of high-risk pregnancy and adverse neonatal outcome OBJECTIVE To assess the value of uterine artery Doppler ultrasound screening , when performed in a clinical setting , to predict complications of impaired uteroplacental blood flow in high-risk women . DESIGN A prospect i ve audit . SUBJECTS A total of 116 pregnancies in 114 women at high risk of pre-eclampsia and /or small-for-gestational-age ( SGA ) babies attending a maternal-fetal medicine clinic at National Women 's Hospital , a tertiary referral hospital , Auckl and , New Zeal and . METHODS Uterine artery Doppler screening was performed as part of clinical practice between 22 and 24 weeks ' gestation . A resistance index ( RI ) was calculated from each uterine artery and the presence or absence of a notch was determined . An RI of > 0.58 was defined as abnormal and an RI of > or = 0.7 was defined as very abnormal . The main outcome measures were : pre-eclampsia , SGA baby ( birth weight < 10th centile ) , placental abruption , intrauterine death , ' all ' and ' severe ' outcomes . RESULTS Thirty-two ( 27.5 % ) women developed pre-eclampsia , 31 ( 26.7 % ) had SGA babies , 23 ( 20 % ) were delivered at < 34 weeks because of pregnancy complications , and there were three ( 2.6 % ) placental abruptions and three ( 2.6 % ) perinatal deaths . The sensitivity of any RI of > 0.58 for pre-eclampsia , SGA , ' all ' outcomes and ' severe ' outcome was 91 % , 84 % , 83 % and 90 % , respectively . The specificity of any RI of > 0.58 for these outcomes was 42 % , 39 % , 47 % and 38 % , respectively . The positive predictive value of any RI of > 0.58 for the same outcomes was 37 % , 33 % , 58 % and 24 % , respectively . Among women with both RI values of > or = 0.7 , 58 % , 67 % , 85 % and 58 % developed pre-eclampsia , SGA , ' all ' and ' severe ' outcomes , respectively . In women with bilateral notches , 47 % , 53 % , 76 % and 65 % developed the respective outcomes . Women with both RI values of > or = 0.7 and women with bilateral notches had relative risks of 11.1 ( 95 % CI 2.6 - 46.4 ) and 12.7 ( 95 % CI 4.0 - 40.4 ) for developing severe outcome , respectively . Only 5 % of women with both RI values of < 0.58 developed a severe outcome . CONCLUSION In high-risk women , uterine artery Doppler waveform analysis performed best in the prediction of severe adverse outcome and was better than clinical risk assessment in the prediction of pre-eclampsia and SGA babies . Further studies are necessary to determine how information from uterine artery Doppler studies should modify current practice in high-risk women OBJECTIVE The purpose of this study was to characterize gestational profiles of biochemical markers that are associated with preeclampsia in the blood of pregnant women in whom preeclampsia developed later and to compare these markers with the markers of women who were delivered of small-for-gestational-age infants without preeclampsia and with women who were at low risk for the development of preeclampsia . STUDY DESIGN This was a prospect i ve case control study . The subjects were women at risk of preeclampsia who were enrolled in the placebo arm of a clinical trial .  Indices of antioxidant status , oxidative stress , placental and endothelial function , and serum lipid concentrations were evaluated from 20 weeks of gestation until delivery in 21 women in whom preeclampsia developed later , in 17 women without preeclampsia who were delivered of small-for-gestational-age infants , and in 27 women who were at low risk for the development of preeclampsia . RESULTS  Ascorbic acid was reduced early in preeclampsia and small-for-gestational-age pregnancies . Leptin , placenta growth factor , the plasminogen activator inhibitor (PAI-1)/PAI-2 ratio , and uric acid were predictive of the development of preeclampsia . CONCLUSION Gestational profiles of several markers were abnormal in the group with preeclampsia , and some of the markers that may prove useful in the selective prediction of preeclampsia were identified BACKGROUND To prospect ively assess maternal serum free beta human chorionic gonadotrophin ( beta hCG ) estimation between 15 and 18 weeks gestation , as a screening test for pre-eclampsia in primigravid women . METHODS A prospect i ve longitudinal study in a University Teaching Hospital . The study population was 430 primigravid women , who had maternal serum free beta hCG levels measured as part of antenatal serum screening for Down 's Syndrome in the second trimester , who booked consecutively within the unit and went on to deliver on the unit 's labor ward . These women were followed during their subsequent pregnancy and categorized into those who remained normotensive and those who developed pre-eclampsia on both clinical and biochemical grounds . The beta hCG levels were used to construct a receiver operator characteristics curve ( ROC ) to assess the screening potential for pre-eclampsia . RESULTS Nineteen ( 4.4 % ) women in the study group developed pre-eclampsia . The median second trimester free beta hCG multiples of the median ( MOM ) was significantly elevated compared to that of the control group ( 1.52 vs 1.10 , p=0.03 ) . The ROC curve shows that for a sensitivity of 79 % , the specificity was only 54 % . CONCLUSIONS Maternal serum free beta hCG alone measured in the second trimester is not clinical ly useful as a screening test for pre-eclampsia in primigravid women . It has , however , some predictive value Objective To investigate the association of anticardiolipin antibody with the genesis of spontaneous abortion , fetal growth restriction ( FGR ) , and preeclampsia . Methods Eight hundred sixty pregnant women constituted the study population .  Anticardiolipin antibody was screened by enzyme-linked immunosorbent assay during the first trimester of pregnancy . The outcome of pregnancy in these women was analyzed prospect ively , and the rate of occurrence of spontaneous abortion , preeclampsia , and FGR was compared in the anticardiolipin antibody-positive and -negative groups . Results  Anticardiolipin antibody  was positive in 60 of the 860 women ( 7.0 % ) and negative in 800 ( 93.0 % ) . The rate of spontaneous abortions in the anticardiolipin antibody-positive group , 25.0 % , was significantly higher than that in the anticardiolipin antibody-negative group , at 9.8 % ( P < .001 ; relative risk [ RR ] 2.56 , 95 % confidence interval ( CI ) 1.37–4.81 ) . The rates of preeclampsia ( 11. 
    Output:
    
Moderate predictive accuracy of anticardiolipin antibodies , the presence of bilateral diastolic notches during Doppler ultrasonography , and urinary kallikrein were found in women at low risk of developing preeclampsia .
Nevertheless , because the pretest probability of preeclampsia with a positive result was but minimally increased , the clinical use of these tests is limited .
Other ultrasonography characteristics and the measurement of fetal and placental peptides showed low predictive accuracy .
In population s that were deemed at high risk for preeclampsia , the use of Doppler ultrasonography had low predictive accuracy .
: As of 2004 , there is no clinical ly useful screening test to predict the development of preeclampsia .