***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 evaluate the screening accuracy of pregnancy hypertensive disorders by maternal serum biomarkers and uterine artery Doppler in the first trimester . STUDY DESIGN Prospect ively enrolled nulliparous women had uterine artery Doppler and serum measured at 11 - 13 weeks .  Maternal characteristics , uterine artery Doppler , and serum placental biomarkers ( pregnancy-associated plasma protein-A , Inhibin-A , placental protein 13 , A disintegrin and metalloprotease 12 , free β-hCG , placental growth factor ) were recorded . RESULTS Among 893 women , 20 ( 2.2 % ) had gestational hypertension developed and 40 ( 4.5 % ) had preeclampsia developed , including 9 ( 1.0 % ) early-onset preeclampsia and 16 ( 1.8 % ) severe preeclampsia . A combined screening model with clinical characteristics , pregnancy-associated plasma protein-A , Inhibin-A , and placental growth factor could detect 75 % of early-onset preeclampsia at a 10 % false-positive rate . After adjustment for clinical variables , uterine artery Doppler , placental protein 13 , and A disintegrin and metalloprotease 12 did not improve the diagnostic accuracy . CONCLUSION A combination of clinical characteristics and first-trimester maternal serum biomarkers ( pregnancy-associated plasma protein-A , Inhibin-A , and placental growth factor ) provides an accurate screening for early-onset preeclampsia in nulliparous women Angiogenic factors like placental growth factor and its antiangiogenic antagonist soluble fms-like tyrosine kinase 1 ( sFlt1 ) are closely related to the pathogenesis of preeclampsia and intrauterine growth restriction . Because it is known that altered maternal sFlt1 and placental growth factor levels are detectable weeks before the onset of these pregnancy complications , it was the aim of the study to investigate the predictive value of these markers in high-risk second trimester pregnancies characterized by abnormal uterine perfusion . This prospect i ve study includes 63 second trimester pregnant women with abnormal uterine perfusion . Twenty five of them developed a later complication ( 12 with preeclampsia , 11 with intrauterine growth restriction , and 2 with intrauterine death ) , whereas 38 had a normal course of pregnancy . Pregnancies with adverse pregnancy outcome showed in the second trimester significantly higher sFlt1 ( 1403.6±555 versus 451.8±42 pg/mL ; P<0.05 ) and lower placental growth factor ( 139.6±24 versus 184.1±21 pg/mL ) levels compared with those with normal outcome . These alterations were more pronounced in pregnancies with subsequent preeclampsia compared with intrauterine growth restriction and early onset diseases ( delivery < 34 weeks ) compared with late-onset diseases . The combination of Doppler and sFlt1  increases the sensitivity of Doppler alone for iatrogenic preterm delivery from 64 % up to 79 % and the specificity from 63 % up to 80 % . Using both factors , sFlt1 and placental growth factor , early onset preeclampsia can be predicted with 83 % sensitivity and 95 % specificity . We conclude that the concurrent measurement of uterine perfusion and angiogenic factors allows an efficient prediction of early onset pregnancy complications , particularly preeclampsia OBJECTIVES To examine the performance of screening for hypertensive disorders in pregnancy at 11 - 13 weeks by a combination of the maternal history , uterine artery Doppler imaging and blood pressure . METHODS This was a prospect i ve screening study for pre-eclampsia ( PE ) requiring delivery before 34 weeks ( early PE ) , late PE and gestational hypertension ( GH ) in women attending for their routine first hospital visit in pregnancy at 11 + 0 to 13 + 6 weeks of gestation . Maternal history was recorded , color flow Doppler imaging was used to identify the uterine artery with the lowest pulsatility index ( L-PI ) and automated devices were used to measure the mean arterial pressure ( MAP ) . The performance of screening for PE and GH by a combination of the maternal factor-derived a-priori risk , the uterine artery L-PI and MAP was determined . RESULTS There were 8061 ( 96.4 % ) cases unaffected by PE or GH , 165 ( 2.0 % ) that developed PE including 37 that required delivery before 34 weeks ( early PE ) and 128 with late PE , and 140 ( 1.7 % ) that developed GH . The MAP was higher in early PE , late PE and GH than in the unaffected group ( P < 0.0001 ) , and in early PE than in GH ( P = 0.002 ) . The uterine artery L-PI was significantly higher in early PE and late PE than in the unaffected group ( P < 0.0001 ) , in early PE than late PE or GH ( P < 0.0001 ) , and in GH than in the unaffected group ( P = 0.014 ) . In screening by a combination of the maternal factor-derived a-priori risk , uterine artery L-PI and MAP , the estimated detection rate at a 10 % false-positive rate was 89.2 % ( 95 % CI , 74.6 - 96.9 % ) for early PE , 57.0 % ( 95 % CI , 48.0 - 65.7 % ) for late PE and 50.0 % ( 95 % CI , 41.4 - 58.6 % ) for GH . CONCLUSIONS Effective screening for hypertensive disorders in pregnancy is provided by a combination of maternal history , uterine artery Doppler imaging and blood pressure at 11 - 13 weeks Objective . To examine the value of one-step uterine artery Doppler at 20 weeks of gestation in the prediction  pre-eclampsia ( PE ) and /or intrauterine growth restriction ( IUGR ) .  Methods . A prospect i ve multicentre study that included all women with singleton pregnancies at 19–22 weeks of gestation ( w ) . The mean pulsatility index ( mPI ) of both uterine arteries was calculated . Receiver-operating characteristics curves ( ROC ) were drawn to compare uterine artery Doppler and maternal risk factors for the prediction of early-onset PE and /or IUGR ( before 32 w ) and late-onset PE and /or IUGR . Results . 6,586 women were included in the study . Complete outcome data was recorded for 6,035 of these women ( 91.6 % ) . PE developed in 75 ( 1.2 % ) and IUGR in 69 ( 1.1 % ) cases . Uterine Doppler mPI was 0.99 and the 90th centile was 1.40 . For 10 % false-positive rate , uterine Doppler mPI identified 70.6 % of pregnancies that subsequently developed early-onset PE and 73.3 % of pregnancies that developed early-onset IUGR . The test had a lower detection rate for the late-onset forms of the disease ( 23.5 % for PE and 30 % for IUGR ) . Maternal history has a low sensitivity in the detection of early-onset cases , although it is better at detecting late-onset PE . Conclusion . Uterine artery Doppler and maternal risk factors seem to select two different population s - early and late-onset PE which might suggest a different pathogenesis OBJECTIVES To calculate the risk of developing pre-eclampsia ( PET ) in a consecutive series of low-risk women at 18 - 24 weeks ' gestation , using recently published logistic regression models . METHODS This was a prospect i ve study , with complete follow-up , in a consecutive series of unselected low-risk singleton pregnancies . Uterine artery pulsatility index as well as a combination of maternal factors were recorded at 18 - 24 weeks ' gestation . The distribution of the estimated risks for the 16 PET patients was compared with that obtained for 136 women who had a normal pregnancy , as assessed by routine testing . A receiver-operating characteristics ( ROC ) curve was plotted to evaluate the detection rate at fixed false-positive rates ( FPRs ) of 5 % , 10 % and 20 % and the corresponding odds cut-offs . RESULTS Just 1/16 ( 6.2 % ) women with PET developed the disease before the 34(th ) week of gestation . Using the ' All PET ' logistic regression model , for 16 PET cases the overall median odds was 1 : 1454 , higher compared with that of 1 : 41635 estimated for controls . Using the ' PET > or= 34 weeks ' model , the median odds of the 15 women who developed PET late was 1 : 3405 , compared with 1 : 40785 for controls . In the case of PET before 34 weeks , the risk was 1 : 426373 vs. 1 : 4159823126 estimated for controls ( ' PET < 34 weeks ' model ) . Detection rates for the All PET model were 18 % , 50 % and 62 % at a FPR of 5 % , 10 % and 20 % , respectively . For the PET > or= 34 weeks model these detection rates were 6 % , 46 % and 60 % , respectively . CONCLUSION Even though the individual odds estimation is too low to represent the real risk of PET , the recently published logistic regression models detected more than 60 % of PET at a FPR of 20 % for both All PET and PET > or= 34 weeks models . Using these models in clinical practice does not seem to give any significant improvement over Doppler alone in the prediction of PET , but the use of a PET-specific odds instead of an actual Doppler value alone seems to be useful for clinical management OBJECTIVE The purpose of this study was to evaluate possible relationships between placental markers and endothelial dysfunction in preeclampsia and intrauterine growth restriction . STUDY DESIGN A prospect i ve study was conducted in 76 patients with preeclampsia and 37 patients with intrauterine growth restriction that were classified as early onset ( < 34 weeks of gestational age ) or late onset , and 40 control subjects .  Plasma levels of placental growth factor , soluble fms-like tyrosine kinase-1 , vascular cell adhesion molecule-1 , and uterine artery Doppler indices  were measured . RESULTS In early-onset preeclampsia and intrauterine growth restriction , placental growth factor was lower and soluble fms-like tyrosine kinase-1 and vascular cell adhesion molecule-1 higher than in control subjects , although all changes were more pronounced in preeclampsia . In late-onset preeclampsia , those patients with abnormal uterine artery Doppler indices had higher soluble fms-like tyrosine kinase-1 and vascular cell adhesion molecule-1 levels . CONCLUSION Biochemical changes in early-onset preeclampsia and intrauterine growth restriction point to a common placental disorder and a state of endothelial dysfunction , which may require interaction with other factors to explain the maternal disease in preeclampsia . Data in late-onset preeclampsia suggest that a proportion of them may occur with minimal placental involvement OBJECTIVES To examine the performance of screening for hypertensive disorders in pregnancy by a combination of the maternal factor-derived a-priori risk with the uterine artery ( UtA ) pulsatility index ( PI ) and to determine whether it is best in such screening to use the mean PI of the two arteries , the highest PI or the lowest PI . METHODS This was a prospect i ve screening study for pre-eclampsia ( PE ) requiring delivery before 34 weeks ( early PE ) , late PE and gestational hypertension ( GH ) in women attending their routine first hospital visit in pregnancy at 11 + 0 to 13 + 6 weeks of gestation . Maternal history was recorded and color flow Doppler imaging was used to measure the left and right UtA-PI . The performance of screening for PE and GH by a combination of the maternal factor-derived a-priori risks determined in a previous study and the UtA-PI was assessed . RESULTS There were 8061 ( 96.4 % ) cases unaffected by PE or GH , 37 ( 0.4 % ) that developed early PE , 128 ( 1.5 % ) with late PE and 140 ( 1.7 % ) with GH . The lowest , mean and highest UtA-PI were significantly higher in early PE and late PE than in the controls ( P < 0.0001 ) and in early PE than late PE ( P < 0.0001 ) . The lowest UtA-PI was higher in GH than in controls ( P = 0.014 ) . The best performance in screening was provided by the lowest PI . The detection rate of early PE at a 10 % false-positive rate increased from 47 % in screening by maternal factors alone to 81 % in screening by maternal factors and the lowest UtA-PI . The respective 
    Output:
    
Results : Several tests provided moderate or convincing prediction of early PE , but screening for late PE was poor .
Although UAD is more accurate in the second trimester , we found encouraging results for first-trimester screening when it was combined with other markers .
Performance of screening was consistently lower in population s with risk factors for PE in the maternal history .
Conclusions : We present encouraging results for the prediction of early PE , even in the first trimester of pregnancy .
The different performance of tests in screening for early vs. late PE , and of low- vs. high-risk population s , supports the concept that PE is a heterogeneous disease