***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 
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    Input: Objective To test the hypothesis that a relative deficiency in L-arginine , the substrate for synthesis of the vasodilatory gas nitric oxide , may be associated with the development of pre-eclampsia in a population at high risk . Design R and omised , blinded , placebo controlled clinical trial . Setting Tertiary public hospital in Mexico City . Participants Pregnant women with a history of a previous pregnancy complicated by pre-eclampsia , or pre-eclampsia in a first degree relative , and deemed to be at increased risk of recurrence of the disease were studied from week 14 - 32 of gestation and followed until delivery . Interventions Supplementation with a medical food — bars containing L-arginine plus antioxidant vitamins , antioxidant vitamins alone , or placebo — during pregnancy . Main outcome measure Development of pre-eclampsia/eclampsia . Results 222 women were allocated to the placebo group , 228 received L-arginine plus antioxidant vitamins , and 222 received antioxidant vitamins alone . Women had 4 - 8 prenatal visits while receiving the bars . The incidence of pre-eclampsia was reduced significantly ( χ2=19.41 ; P<0.001 ) in women r and omised to L-arginine plus antioxidant vitamins compared with placebo ( absolute risk reduction 0.17 ( 95 % confidence interval 0.12 to 0.21 ) . Antioxidant vitamins alone showed an observed benefit , but this effect was not statistically significant compared with placebo ( χ2=3.76 ; P=0.052 ; absolute risk reduction 0.07 , 0.005 to 0.15 ) . L-arginine plus antioxidant vitamins compared with antioxidant vitamins alone result ed in a significant effect ( P=0.004 ; absolute risk reduction 0.09 , 0.05 to 0.14 ) . Conclusions Supplementation during pregnancy with a medical food containing L-arginine and antioxidant vitamins reduced the incidence of pre-eclampsia in a population at high risk of the condition . Antioxidant vitamins alone did not have a protective effect for prevention of pre-eclampsia . Supplementation with L-arginine plus antioxidant vitamins needs to be evaluated in a low risk population to determine the generalisability of the protective effect , and the relative contributions of L-arginine and antioxidant vitamins to the observed effects of the combined treatment need to be determined . Trial registration Clinical trials NCT00469846 Background . To investigate the effect of dietary intake of the NO‐donor l‐arginine on the diastolic blood pressure in women with pre‐eclampsia OBJECTIVE : To assess the benefit of l-arginine , the precursor to nitric oxide , on blood pressure and recovery of the glomerular lesion in preeclampsia . METHODS : Forty-five women with preeclampsia were r and omized to receive either l-arginine or placebo until day 10 postpartum . Primary outcome measures including mean arterial pressure , glomerular filtration rate , and proteinuria were assessed on the third and 10th days postpartum by inulin clearance and albumin-to-creatinine ratio .  Nitric oxide , cyclic guanosine 3′5′ monophosphate , endothelin-1 , and asymmetric-dimethyl-arginine and arginine levels were assayed before delivery and on the third and 10th days postpartum . Healthy gravid women provided control values . Assuming a st and ard deviation of 10 mm Hg , the study was powered to detect a 10-mm Hg difference in mean arterial pressure ( α .05 , β .20 ) between the study groups . RESULTS : No significant differences existed between the groups with preeclampsia before r and omization . Compared with the gravid control group , women with preeclampsia exhibited significantly increased serum levels of endothelin-1 , cyclic guanosine 3′5′ monophosphate , and asymmetric-dimethyl-arginine before delivery . Despite a significant increase in postpartum serum arginine levels due to treatment , no differences were found in the corresponding levels of nitric oxide , endothelin-1 , cyclic guanosine 3′5′ monophosphate , or asymmetric-dimethyl-arginine between the two groups with preeclampsia . Further , there were no significant differences in any of the primary outcome measures with both groups demonstrating similar levels in glomerular filtration rate and equivalent improvements in both blood pressure and proteinuria . CONCLUSION : Blood pressure and kidney function improve markedly in preeclampsia by the 10th day postpartum . Supplementation with l-arginine does not hasten this recovery . LEVEL OF EVIDENCE : Pre-eclampsia is a hypertensive disorder of pregnancy in which enzymatic antioxidant defenses fail and tissues are injured . This prospect i ve case-control study evaluated whether pre-eclamptic women and their newborns show higher degrees of oxidative stress than normal pregnancies and sought to determine if this stress is related to clinical severity . Forty-four pre-eclamptic and thirty healthy pregnant women attending two hospitals in Valparaíso , Chile , were studied . The following plasmatic variables of antioxidant capacity were evaluated : glutathione peroxidase activity ( GPx ) , total antioxidant capacity measured by oxidation of ABTS substrate ( 2,2'-azino-bis ( 3-ethylbenzthiazoline-6-sulfonic acid ) , and superoxide dismutase activity ( SOD ) . malondialdehide ( MDA ) was measured to evaluate lipoperoxidation . The evaluation was performed at diagnosis of pre-eclampsia , delivery , 30 days and 120 days post delivery . Newborns were studied at delivery through umbilical cord blood sample s. Our analysis shows that antioxidant enzyme activity ( SOD , GPx , ABTS ) was significantly decreased , while lipoperoxidation ( MDA ) was increased in both pre-eclamptic groups compared to normal pregnant women ( p<0.01 ) . Statistically significant difference was found between mild and severe pre-eclamptic groups ( p<0.01 ) , for all biochemical markers studied . Therefore , the clinical severity of this pathology is closely related to the degree of oxidative stress Estimation of the influence of oral supplementation with low dose of L-arginine on biophysical profile , foeto-placental circulation and neonatal outcome in preeclampsia . R and omized , placebo-controlled , double-blind , clinical trial . Oral therapy with 3 g of L-arginine daily or placebo as a supplement to st and ard therapy . Eighty-three preeclamptic women , r and omly assigned to the  L-arginine  ( n=42 ) or  placebo ( n=41 ) groups ; [ n=30 ( L-arginine ) and n=31 ( placebo ) ended the study , respectively ] . Foetal gain chances due to ultrasound biometry , biophysical profile , Doppler velocimetry of pulsatility indices of umbilical and middle cerebral arteries , cerebro-placental ratio , as well as differences in duration of pregnancy and clinical data of newborn .  L-arginine treatment transitory accelerated foetal gain and improved biophysical profile . Starting from 3rd week of therapy , the umbilical artery pulsatility indices values were significantly lower in L-arginine than in placebo group . Moreover , treatment with L-arginine caused significant increase of middle cerebral artery pulsatility indices and cerebro-placental ratio values . Latency was longer in L-arginine group . Neonates delivered in the L-arginine group revealed higher Apgar score . Supplementary treatment with oral L-arginine seems to be promising in improving foetal well-being and neonatal outcome as well as in prolonging pregnancy complicated with preeclampsia . However , these benefits require confirmation in more-powered , larger studies BACKGROUND Previous trials have suggested that calcium supplementation during pregnancy may reduce the risk of preeclampsia . However , differences in study design and a low dietary calcium intake in the population s studied limit acceptance of the data . METHODS We r and omly assigned 4589 healthy nulliparous women who were 13 to 21 weeks pregnant to receive daily treatment with either 2 g of elemental calcium or placebo for the remainder of their pregnancies . Surveillance for preeclampsia was conducted by personnel unaware of treatment-group assignments , using st and ardized measurements of blood pressure and urinary protein excretion at uniformly scheduled prenatal visits , protocol s for monitoring these measurements during the hospitalization for delivery , and review s of medical records of unscheduled outpatient visits and all hospitalizations . RESULTS Calcium supplementation did not significantly reduce the incidence or severity of preeclampsia or delay its onset . Preeclampsia occurred in 158 of the 2295 women in the calcium group ( 6.9 percent ) and 168 of the 2294 women in the placebo group ( 7.3 percent ) ( relative risk , 0.94 ; 95 percent confidence interval , 0.76 to 1.16 ) . There were no significant differences between the two groups in the prevalence of pregnancy-associated hypertension without preeclampsia ( 15.3 percent vs. 17.3 percent ) or of all hypertensive disorders ( 22.2 percent vs. 24.6 percent ) . The mean systolic and diastolic blood pressures during pregnancy were similar in both groups . Calcium did not reduce the numbers of preterm deliveries , small-for-gestational-age births , or fetal and neonatal deaths ; nor did it increase urolithiasis during pregnancy . CONCLUSIONS Calcium supplementation during pregnancy did not prevent preeclampsia , pregnancy-associated hypertension , or adverse perinatal outcomes in healthy nulliparous women The objective of the present study is to compare the effectiveness of transdermal glyceryl-trinitrate versus oral nifedipine in lowering blood pressure in patients affected by pregnancy-induced hypertension ( PIH ) . Thirty-six consecutive pregnant women have been evaluated at different gestational ages after the diagnosis of PIH or preeclampsia ( PE ) . After a 24-h ambulatory blood pressure monitoring , patients were allocated to three groups : those receiving oral nifedipine and those receiving transdermal glyceryl-trinitrate in a continuous ( 24 h/day ) or intermittent ( 16 h/day ) administration . A second blood pressure monitoring was performed after 2 weeks of treatment . Systolic and diastolic blood pressure were compared by using the Cosinor method looking at mesor , amplitude , and acrophase . Baseline systolic and diastolic blood pressure was similar among the three groups . Neither the transdermal glyceryl-trinitrate administered for 24 or 16 h nor oral nifedipine affected systolic and diastolic blood pressure . Analysis of variance showed that the posttreatment values were similar among the groups . Further studies are needed to verify the possible use of transdermal glyceryl-trinitrate as an antihypertensive drug during pregnancy Background Several lines of evidence point to the dysfunction of the endothelial l‐arginine – NO system in preeclampsia . We investigated the influence of dietary supplementation with l‐arginine on blood pressure and biochemical measures of NO production in women with preeclampsia in prospect i ve , r and omized , placebo‐controlled study Objective : The present report evaluates the effect of acute L-arginine administration on fetal heart variables by a computerized non-stress test ( NST ) analysis . Methods : Fifteen pregnant women at 30–34 weeks of gestational age affected by mild to moderate gestational hypertension were enrolled in the study . The study was performed in the second and third days of hospitalization . Each woman received both active ( Arg ) or placebo treatment ( Placebo ) , in a double-blind , r and omized , cross-over design . Women received saline infusion for 40 min , then they were infused with either placebo ( saline infusion prepared by Damor Pharmaceutics and labeled as Arg-B ) or Arg ( L-Arg 20 g/500 ml labeled as Arg-A ) . Results : Multiple analysis of variance ( MANOVA ) indicated that both placebo and Arg infusion were unable to affect cardiac variables and fetal movements . As far as maternal blood pressure changes were concerned , MANOVA indicated that active treatment showed an acute hypotensive effect on both systolic ( F = 8.98 , p < 0.001 ) and diastolic values ( F = 15.78 , p > 0.001 ) . Conversely , placebo infusion does not seems to have induced any change . Considering each time of infusion we observed that Arg treatment was able to lower systolic and diastolic blood pressure after the 40 min of infusion , with this effect persisting for 20 min . Conclusions : These data indicate that the acute , intravenous administration of high-dose L-arginine does not induce significant changes in fetal heart rate ( FHR ) , whereas it lowers maternal blood pressure . Such conclusions are reinforced by the observation that saline administration in the same pregnant women was neutral for both FHR and maternal blood pressure values . According to previous studies , it seems conceivable that maternal L-arginine treatment enters the fetal circulation by crossing the placenta . The lack of changes in FHR , however , suggests that no significant hemodynamic changes were induced by the treatment . Contrary to what happens in the mother , this may possibly be due to a low , if any , conversion of L-arginine to nitric oxide in the fetus BACKG 
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Conclusion : This study demonstrates L-arginine supplementation is superior to placebo  in lowering diastolic pressure and prolonging pregnancy  in patients with gestational hypertension with or without proteinuria , but the effect on lowering systolic pressure and increasing neonatal weight was not statistically significant