human
***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: PURPOSE Recent studies have question ed the relationship between low birthweight and hypertension in pregnancy , especially in term pregnancies . We aim ed to analyse the influence of chronic hypertension , preeclampsia , gestational hypertension and superimposed preeclampsia on birth weight in singleton pregnancies at different gestational ages . METHODS Between January 1 , 2001 and December 31 , 2002 data on hypertension ( subdivided in chronic hypertension , preeclampsia , gestational hypertension , superimposed preeclampsia and eclampsia ) were collected prospect ively for all deliveries in the region of Fl and ers , Belgium . Multiple pregnancies and patients with diabetes were excluded from analysis . Multiple linear regression was performed to construct a model for the prediction of birthweight and to determine the contribution of hypertension . RESULTS Hypertension was diagnosed in 5,284 of 111,007 ( 4.8 % ) singleton pregnancies , and of these 647 had chronic hypertension ( 0.6 % of the total group ) , 2,253 ( 2 % ) gestational hypertension , 2,244 ( 2 % ) preeclampsia and 140 ( 0.1 % ) superimposed preeclampsia . Birthweight less than 2,500 g was most frequent in the preeclamptic group and less frequent in case of gestational hypertension , but in all hypertensive groups it was statistically more frequent compared to the normotensive pregnancies . Before 26 weeks ' gestational age the presence of any kind of hypertension did not influence birthweight . From 26 weeks on preeclampsia contributed to a lower birthweight . Gestational hypertension result ed in a lower birthweight between 28 and 34 weeks , but not before or after this period . Superimposed preeclampsia only had an effect between 32 and 34 weeks and chronic hypertension only marginally contributed to birthweight . A relation with both a high birthweight ( > 4000 g ) and birthweight < 2500 g was found in term gestational hypertension and preeclampsia . CONCLUSION At an early gestational age ( less then 26 weeks ) hypertension is not a significant factor influencing birthweight . Uncomplicated chronic hypertension is not an important factor determining birthweight but preeclampsia is . Gestational hypertension influences birthweight in a limited period between 28 and 34 weeks of gestational age . When hypertensive pregnancies reach term they tend to result both in more babies weighing < 2,500 g and > 4,000 OBJECTIVE We sought to compare the rates of superimposed preeclampsia and adverse outcomes in women with chronic hypertension with or without prior preeclampsia . STUDY DESIGN We conducted secondary analysis of 369 women with chronic hypertension ( 104 with prior preeclampsia ) enrolled at 12 - 19 weeks as part of a multisite trial of antioxidants  to prevent preeclampsia ( no reduction was found ) . Outcome measures were rates of superimposed preeclampsia and other adverse perinatal outcomes . RESULTS Prepregnancy body mass index , blood pressure , and smoking status at enrollment were similar between groups . The rates of superimposed preeclampsia ( 17.3 % vs 17.7 % ) , abruptio placentae ( 1.0 % vs 3.1 % ) , perinatal death ( 6.7 % vs 8.7 % ) , and small for gestational age ( 18.4 % vs 14.3 % ) were similar between groups , but preterm delivery < 37 weeks was higher in the prior preeclampsia group ( 36.9 % vs 27.1 % ; adjusted risk ratio , 1.46 ; 95 % confidence interval , 1.05 - 2.03 ; P = .032 ) . CONCLUSION In women with chronic hypertension , a history of preeclampsia does not increase the rate of superimposed preeclampsia , but is associated with an increased rate of delivery at < 37 weeks The present study was design ed to ( 1 ) outline , in a prospect i ve manner , vascular responsiveness to angiotensin II ( A-II ) in gravidas with essential hypertension and ( 2 ) ascertain if increased sensitivity to infused A-II could be detected before worsening of hypertension developed in those women who were destined to develop superimposed pregnancy-induced hypertension ( PIH ) . Sixty-three women with chronic essential hypertension were studied sequentially throughout pregnancy and two groups of patients were defined on the basis of clinical outcome and serial measurements of vascular reactivity to exogeneously administered A-II . The first group consisted of 29 gravidas with chronic hypertension alone and the second group was composed of 34 patients with chronic hypertension who were destined to develop superimposed PIH .  Vascular resistance to infused A-II  ( more than 7 ng . per kilograms per minute required to increase diastolic blood pressure 20 mm . Hg ) was observed from weeks 21 to 27 of gestation in both groups of patients . In the gravidas with essential hypertension alone , resistance to A-II persisted throughout the remainder of pregnancy . However , in those women destined to develop PIH , an increased sensitivity to A-II developed after week 27 of gestation and the differences in mean values between the two groups of patients became highly significant after week 30 of gestation ( P less than 0.025 ) . although individual determinations obtained in both groups of patients between weeks 28 and 32 of preganncy suggested that pressor responsiveness to A-II might be used as a screening technique to identify those women destined to develop PIH , additional studies conducted between weeks 28 and 32 of gestation will be required before the efficacy of such a screening technique is clearly established BACKGROUND The offspring of women with hypertension during pregnancy are at increased risk of low birthweight , preterm birth , diseases of prematurity and death . The risk of developing these outcomes among women with either preeclampsia or chronic hypertension , relative to those with gestational hypertension , is not known . STUDY DESIGN Prospect i ve cohort study . PARTICIPANTS A total of 1948 singleton women seen at a large tertiary care obstetrical center , whose blood pressure was greater than 140/90 mm Hg during pregnancy . The four types of hypertension were strictly defined : 864 women ( 44.4 % ) had gestational hypertension , 459 ( 23.6 % ) isolated chronic hypertension , 501 ( 25.7 % ) isolated preeclampsia , and 124 ( 6.4 % ) chronic hypertension with superimposed preeclampsia . OUTCOME MEASURES The primary outcome of the study was a composite of the diseases of prematurity , need for assisted ventilation for greater than 1 day , or perinatal death . The secondary outcomes were each of those included in the primary endpoint , as well as admission to the neonatal ICU , small for gestational age ( SGA ) birthweight and preterm birth . We controlled for the effects of other maternal risk factors , such as age , parity , history of preterm delivery , cigarette smoking , pre-pregnancy weight , diabetes mellitus ( DM ) , renal dysfunction , and current use of an antihypertensive agent or prednisone . RESULTS For the primary composite outcome , compared to the offspring of women with gestational hypertension , the adjusted odds ratio was 1.9 ( 95 % confidence interval 1.2 to 3.0 ) in the preeclamptic group and 2.0 ( 95 % confidence interval 1.0 to 4.0 ) for those with chronic hypertension plus superimposed preeclampsia . Those with preeclampsia were at increased risk for small for gestational age birthweight ( odds ratio 2.2 , 95 % confidence interval 1.5 to 3.1 ) , as were the offspring of mothers who had chronic hypertension with superimposed preeclampsia ( odds ratio 2.1 , 95 % confidence interval 1.2 to 3.8 ) . Similarly , the rate of preterm birth before 32 weeks was highest among the infants of both preeclamptic mothers ( 28.5 % ; odds ratio 4.7 , 95 % confidence interval 2.9 to 7.6 ) and those with chronic hypertension and preeclampsia ( 30.5 % ; odds ratio 3.5 , 95 % confidence interval 1.8 to 6.7 ) . The perinatal mortality rate was highest in the group of women with chronic hypertension plus preeclampsia ( 9.2 % ; odds ratio 3.2 , 95 % confidence interval 1.2 to 9.1 ) . Other significant risk factors for the primary composite outcome included previous preterm delivery ( odds ratio 2.7 , 95 % confidence interval 1.4 to 5.2 ) , smoking ( odds ratio 1.8 , 95 % confidence interval 1.1 to 3.0 ) and use of an antihypertensive agent during pregnancy ( odds ratio 1.8 , 95 % confidence interval 1.2 to 2.7 ) . Prednisone use was strongly associated with risk for perinatal death ( odds ratio 4.9 , 95 % confidence interval 1.4 to 17.1 ) . CONCLUSIONS Relative to women with isolated gestational hypertension , those who develop preeclampsia , either with or without underlying chronic hypertension , experience worse perinatal outcomes . A history of previous preterm delivery and maternal smoking increase the rate preterm birth and major perinatal disease .  Antihypertensive and prednisone therapy may be important risk factors for adverse perinatal events , but further research is needed to confirm these findings Objective . To evaluate l-arginine ( l-Arg ) supplementation in pregnant women with chronic hypertension and its effects on blood pressure ( BP ) and maternal and neonatal complications . Methods . We enrolled 80 women affected by mild chronic hypertension referred to the High Risk Clinic of the Mother – Infant Department of the University of Modena and Reggio Emilia . Each woman after obtaining oral consent was r and omized to receive oral l-Arg versus placebo and thereafter su bmi tted to 24-h ambulatory BP monitoring . The primary outcome was BP change after 10–12 weeks of treatment . Secondary outcomes were as follows : percentage of women on antihypertensive treatment at delivery , maternal , and fetal outcome . Results . The BP changes after 10–12 weeks of treatment did not differ between groups . A lower percentage of women received antihypertensive drugs in the l-Arg group than the placebo group . The incidence of superimposed preeclampsia indicated delivery before the 34th weeks and certain neonatal complications tended to be higher in the placebo group . Conclusions . l-Arg supplementation in pregnant women with mild chronic hypertension does not significantly affect overall BP but is associated with less need for antihypertensive medications and a trend toward fewer maternal and neonatal complications . The results of the study were limited by the small sample size and by the exclusion of women with severe chronic hypertension . In our policy , these patients needed many hypertensive drugs and were normally managed by the cardiologist . Nevertheless , considering the promising results on maternal and fetal outcome , we believe that further studies should be performed to confirm such data and to clarify the role of l-Arg as a protective supplement in high-risk pregnancy OBJECTIVE To evaluate the role of uterine artery Doppler investigation in predicting perinatal outcome of patients with chronic hypertension . STUDY DESIGN Uterine artery velocimetry was investigated at 24 weeks gestation in 78 chronic hypertensive pregnant women by means of color Doppler . The resistance index ( RI ) and the presence of a diastolic notch were recorded and related to the development of superimposed preeclampsia ( SPE ) , pregnancy aggravated hypertension ( PAH ) . and intrauterine growth retardation ( IUGR ) . RESULTS There were more pregnancy complications in the 25 patients with abnormal RI , compared with the 53 women with normal RI ( SPE 12 % vs. 0 % , PAH 36 % vs. 7 % and IUGR 52 % vs. 2 % ; P<0.01 ) , and more in women with a bilateral diastolic notch compared with those without ( SPE 23 % vs. 0 , PAH 54 % vs. 4 % , IUGR 85 % vs. 2 % ; P<0.0001 ) , while no differences were detected in those with only a unilateral notch , except for PAH ( 27 % vs. 4 % ; P<0.01 ) . CONCLUSION Uterine artery Doppler velocimetry identifies a subgroup of chronic hypertensive patients with a high frequency of pregnancy complications BACKGROUND Hypertension is associated with increased maternal and fetal mortality and morbidity . While there is consensus that severe hypertension should be treated , antihypertensive treatment for mild chronic hypertension during pregnancy remains controversial . OBJECTIVE To evaluate clinical course , and maternal and perinatal outcomes of pregnant women with mild chronic hypertension without other disease , under strict control of maternal hypertension ( target dBP of 85 - 89 mmHg ) . PATIENTS AND METHODS We conducted a prospect i ve cohort study of 110 pregnant women with mild chronic hypertension without other disease ; clinical course was classified in three groups : stable condition , exacerbation of hypertension and superimposed preeclampsia . We compare maternal and perinatal outcomes ; statistical comparisons were performed by ANOVA test . Relative risk ( RR 
    Output:
    
agent
***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: PURPOSE Recent studies have question ed the relationship between low birthweight and hypertension in pregnancy , especially in term pregnancies . We aim ed to analyse the influence of chronic hypertension , preeclampsia , gestational hypertension and superimposed preeclampsia on birth weight in singleton pregnancies at different gestational ages . METHODS Between January 1 , 2001 and December 31 , 2002 data on hypertension ( subdivided in chronic hypertension , preeclampsia , gestational hypertension , superimposed preeclampsia and eclampsia ) were collected prospect ively for all deliveries in the region of Fl and ers , Belgium . Multiple pregnancies and patients with diabetes were excluded from analysis . Multiple linear regression was performed to construct a model for the prediction of birthweight and to determine the contribution of hypertension . RESULTS Hypertension was diagnosed in 5,284 of 111,007 ( 4.8 % ) singleton pregnancies , and of these 647 had chronic hypertension ( 0.6 % of the total group ) , 2,253 ( 2 % ) gestational hypertension , 2,244 ( 2 % ) preeclampsia and 140 ( 0.1 % ) superimposed preeclampsia . Birthweight less than 2,500 g was most frequent in the preeclamptic group and less frequent in case of gestational hypertension , but in all hypertensive groups it was statistically more frequent compared to the normotensive pregnancies . Before 26 weeks ' gestational age the presence of any kind of hypertension did not influence birthweight . From 26 weeks on preeclampsia contributed to a lower birthweight . Gestational hypertension result ed in a lower birthweight between 28 and 34 weeks , but not before or after this period . Superimposed preeclampsia only had an effect between 32 and 34 weeks and chronic hypertension only marginally contributed to birthweight . A relation with both a high birthweight ( > 4000 g ) and birthweight < 2500 g was found in term gestational hypertension and preeclampsia . CONCLUSION At an early gestational age ( less then 26 weeks ) hypertension is not a significant factor influencing birthweight . Uncomplicated chronic hypertension is not an important factor determining birthweight but preeclampsia is . Gestational hypertension influences birthweight in a limited period between 28 and 34 weeks of gestational age . When hypertensive pregnancies reach term they tend to result both in more babies weighing < 2,500 g and > 4,000 OBJECTIVE We sought to compare the rates of superimposed preeclampsia and adverse outcomes in women with chronic hypertension with or without prior preeclampsia . STUDY DESIGN We conducted secondary analysis of 369 women with chronic hypertension ( 104 with prior preeclampsia ) enrolled at 12 - 19 weeks as part of a multisite trial of antioxidants  to prevent preeclampsia ( no reduction was found ) . Outcome measures were rates of superimposed preeclampsia and other adverse perinatal outcomes . RESULTS Prepregnancy body mass index , blood pressure , and smoking status at enrollment were similar between groups . The rates of superimposed preeclampsia ( 17.3 % vs 17.7 % ) , abruptio placentae ( 1.0 % vs 3.1 % ) , perinatal death ( 6.7 % vs 8.7 % ) , and small for gestational age ( 18.4 % vs 14.3 % ) were similar between groups , but preterm delivery < 37 weeks was higher in the prior preeclampsia group ( 36.9 % vs 27.1 % ; adjusted risk ratio , 1.46 ; 95 % confidence interval , 1.05 - 2.03 ; P = .032 ) . CONCLUSION In women with chronic hypertension , a history of preeclampsia does not increase the rate of superimposed preeclampsia , but is associated with an increased rate of delivery at < 37 weeks The present study was design ed to ( 1 ) outline , in a prospect i ve manner , vascular responsiveness to angiotensin II ( A-II ) in gravidas with essential hypertension and ( 2 ) ascertain if increased sensitivity to infused A-II could be detected before worsening of hypertension developed in those women who were destined to develop superimposed pregnancy-induced hypertension ( PIH ) . Sixty-three women with chronic essential hypertension were studied sequentially throughout pregnancy and two groups of patients were defined on the basis of clinical outcome and serial measurements of vascular reactivity to exogeneously administered A-II . The first group consisted of 29 gravidas with chronic hypertension alone and the second group was composed of 34 patients with chronic hypertension who were destined to develop superimposed PIH .  Vascular resistance to infused A-II  ( more than 7 ng . per kilograms per minute required to increase diastolic blood pressure 20 mm . Hg ) was observed from weeks 21 to 27 of gestation in both groups of patients . In the gravidas with essential hypertension alone , resistance to A-II persisted throughout the remainder of pregnancy . However , in those women destined to develop PIH , an increased sensitivity to A-II developed after week 27 of gestation and the differences in mean values between the two groups of patients became highly significant after week 30 of gestation ( P less than 0.025 ) . although individual determinations obtained in both groups of patients between weeks 28 and 32 of preganncy suggested that pressor responsiveness to A-II might be used as a screening technique to identify those women destined to develop PIH , additional studies conducted between weeks 28 and 32 of gestation will be required before the efficacy of such a screening technique is clearly established BACKGROUND The offspring of women with hypertension during pregnancy are at increased risk of low birthweight , preterm birth , diseases of prematurity and death . The risk of developing these outcomes among women with either preeclampsia or chronic hypertension , relative to those with gestational hypertension , is not known . STUDY DESIGN Prospect i ve cohort study . PARTICIPANTS A total of 1948 singleton women seen at a large tertiary care obstetrical center , whose blood pressure was greater than 140/90 mm Hg during pregnancy . The four types of hypertension were strictly defined : 864 women ( 44.4 % ) had gestational hypertension , 459 ( 23.6 % ) isolated chronic hypertension , 501 ( 25.7 % ) isolated preeclampsia , and 124 ( 6.4 % ) chronic hypertension with superimposed preeclampsia . OUTCOME MEASURES The primary outcome of the study was a composite of the diseases of prematurity , need for assisted ventilation for greater than 1 day , or perinatal death . The secondary outcomes were each of those included in the primary endpoint , as well as admission to the neonatal ICU , small for gestational age ( SGA ) birthweight and preterm birth . We controlled for the effects of other maternal risk factors , such as age , parity , history of preterm delivery , cigarette smoking , pre-pregnancy weight , diabetes mellitus ( DM ) , renal dysfunction , and current use of an antihypertensive agent or prednisone . RESULTS For the primary composite outcome , compared to the offspring of women with gestational hypertension , the adjusted odds ratio was 1.9 ( 95 % confidence interval 1.2 to 3.0 ) in the preeclamptic group and 2.0 ( 95 % confidence interval 1.0 to 4.0 ) for those with chronic hypertension plus superimposed preeclampsia . Those with preeclampsia were at increased risk for small for gestational age birthweight ( odds ratio 2.2 , 95 % confidence interval 1.5 to 3.1 ) , as were the offspring of mothers who had chronic hypertension with superimposed preeclampsia ( odds ratio 2.1 , 95 % confidence interval 1.2 to 3.8 ) . Similarly , the rate of preterm birth before 32 weeks was highest among the infants of both preeclamptic mothers ( 28.5 % ; odds ratio 4.7 , 95 % confidence interval 2.9 to 7.6 ) and those with chronic hypertension and preeclampsia ( 30.5 % ; odds ratio 3.5 , 95 % confidence interval 1.8 to 6.7 ) . The perinatal mortality rate was highest in the group of women with chronic hypertension plus preeclampsia ( 9.2 % ; odds ratio 3.2 , 95 % confidence interval 1.2 to 9.1 ) . Other significant risk factors for the primary composite outcome included previous preterm delivery ( odds ratio 2.7 , 95 % confidence interval 1.4 to 5.2 ) , smoking ( odds ratio 1.8 , 95 % confidence interval 1.1 to 3.0 ) and use of an antihypertensive agent during pregnancy ( odds ratio 1.8 , 95 % confidence interval 1.2 to 2.7 ) . Prednisone use was strongly associated with risk for perinatal death ( odds ratio 4.9 , 95 % confidence interval 1.4 to 17.1 ) . CONCLUSIONS Relative to women with isolated gestational hypertension , those who develop preeclampsia , either with or without underlying chronic hypertension , experience worse perinatal outcomes . A history of previous preterm delivery and maternal smoking increase the rate preterm birth and major perinatal disease .  Antihypertensive and prednisone therapy may be important risk factors for adverse perinatal events , but further research is needed to confirm these findings Objective . To evaluate l-arginine ( l-Arg ) supplementation in pregnant women with chronic hypertension and its effects on blood pressure ( BP ) and maternal and neonatal complications . Methods . We enrolled 80 women affected by mild chronic hypertension referred to the High Risk Clinic of the Mother – Infant Department of the University of Modena and Reggio Emilia . Each woman after obtaining oral consent was r and omized to receive oral l-Arg versus placebo and thereafter su bmi tted to 24-h ambulatory BP monitoring . The primary outcome was BP change after 10–12 weeks of treatment . Secondary outcomes were as follows : percentage of women on antihypertensive treatment at delivery , maternal , and fetal outcome . Results . The BP changes after 10–12 weeks of treatment did not differ between groups . A lower percentage of women received antihypertensive drugs in the l-Arg group than the placebo group . The incidence of superimposed preeclampsia indicated delivery before the 34th weeks and certain neonatal complications tended to be higher in the placebo group . Conclusions . l-Arg supplementation in pregnant women with mild chronic hypertension does not significantly affect overall BP but is associated with less need for antihypertensive medications and a trend toward fewer maternal and neonatal complications . The results of the study were limited by the small sample size and by the exclusion of women with severe chronic hypertension . In our policy , these patients needed many hypertensive drugs and were normally managed by the cardiologist . Nevertheless , considering the promising results on maternal and fetal outcome , we believe that further studies should be performed to confirm such data and to clarify the role of l-Arg as a protective supplement in high-risk pregnancy OBJECTIVE To evaluate the role of uterine artery Doppler investigation in predicting perinatal outcome of patients with chronic hypertension . STUDY DESIGN Uterine artery velocimetry was investigated at 24 weeks gestation in 78 chronic hypertensive pregnant women by means of color Doppler . The resistance index ( RI ) and the presence of a diastolic notch were recorded and related to the development of superimposed preeclampsia ( SPE ) , pregnancy aggravated hypertension ( PAH ) . and intrauterine growth retardation ( IUGR ) . RESULTS There were more pregnancy complications in the 25 patients with abnormal RI , compared with the 53 women with normal RI ( SPE 12 % vs. 0 % , PAH 36 % vs. 7 % and IUGR 52 % vs. 2 % ; P<0.01 ) , and more in women with a bilateral diastolic notch compared with those without ( SPE 23 % vs. 0 , PAH 54 % vs. 4 % , IUGR 85 % vs. 2 % ; P<0.0001 ) , while no differences were detected in those with only a unilateral notch , except for PAH ( 27 % vs. 4 % ; P<0.01 ) . CONCLUSION Uterine artery Doppler velocimetry identifies a subgroup of chronic hypertensive patients with a high frequency of pregnancy complications BACKGROUND Hypertension is associated with increased maternal and fetal mortality and morbidity . While there is consensus that severe hypertension should be treated , antihypertensive treatment for mild chronic hypertension during pregnancy remains controversial . OBJECTIVE To evaluate clinical course , and maternal and perinatal outcomes of pregnant women with mild chronic hypertension without other disease , under strict control of maternal hypertension ( target dBP of 85 - 89 mmHg ) . PATIENTS AND METHODS We conducted a prospect i ve cohort study of 110 pregnant women with mild chronic hypertension without other disease ; clinical course was classified in three groups : stable condition , exacerbation of hypertension and superimposed preeclampsia . We compare maternal and perinatal outcomes ; statistical comparisons were performed by ANOVA test . Relative risk ( RR 
    Output:
    