***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: BACKGROUND Midtrimester amniocentesis to investigate fetal karyotype carries a small risk of fetal loss . AIM To test the hypothesis that progesterone prophylaxis may reduce this . STUDY DESIGN A r and omised controlled trial comparing a short prophylactic treatment with progesterone after amniocentesis with untreated controls . RESULTS There were no differences in frequency of miscarriage , preterm delivery or neonatal outcome . CONCLUSION Prophylactic progesterone treatment after amniocentesis does not improve obstetric outcome Whilst only about a third of all cerebral palsy occurs in children who had been of low birthweight , recent increases in the survival of low and very low birthweight infants have coincided with significant increases in the numbers of cerebral palsy children amongst them . This paper analyses data from the Western Australian Cerebral Palsy Register and from the Maternal and Child Health Research Data Base for stillbirths , neonatal deaths and survivors to address the issues of increased survival , cerebral palsy and timing of brain damage . The analysis is inconclusive but suggestive that both antenatal and postnatal complications are important in the increases in cerebral palsy in low birthweight infants . The good news is that this means that a certain proportion of postnatally damaged low birthweight survivors could possibly be prevented by better neonatal care . The bad news is that the remaining proportion have probably received their damage well before delivery and the possibilities for prevention are still remote . Further studies of low birthweight infants with cerebral palsy are urgently required . They should include antenatal factors , investigating the various aetiological pathways to preterm birth , r and omised controlled trials of neonatal interventions and search ing for better neonatal predictors of brain damage OBJECTIVE Our purpose was to determine gestational age-specific outcomes of infants born in a period of surfactant use . STUDY DESIGN All 465 consecutive births between 23 and 28 weeks ' gestation in a tertiary center from 1987 to 1992 were analyzed prospect ively . At 18 months ' corrected age , 217 of 254 ( 85 % ) survivors were evaluated . RESULTS From 1987 and 1988 to 1991 and 1992 there was an increase in survival for infants born at 24 weeks ( from 0 % to 33 % p = 0.17 ) , 25 to 26 weeks ( 38 % to 71 % , p < 0.005 ) , and 27 to 28 weeks ( 66 % to 84 % , p < 0.05 ) . At each weekly interval from 24 to 28 weeks of gestation the respective incidence of normality was 44 % , 71 % , 57 % , 76 % and 72 % ( not significant ) and the respective mean developmental quotient was 91 + /- 17 , 89 + /- 25 , 90 + /- 24 , 96 + /- 15 and 96 + /- 14 ( not significant ) . CONCLUSIONS Gestational age was strongly associated with outcome in terms of survival . Overall , 70 % of children followed up were developing within the normal range A prior report suggested that active-duty pregnant women are at increased risk for low-birth weight infants and a higher perinatal mortality rate . The present double-blind investigation was design ed to prospect ively evaluate that risk and to test the efficacy of 17 alpha-hydroxyprogesterone caproate to prevent reported complications . Three groups of active-duty women were studied , beginning between 16 and 20 weeks ' gestation . They were similar for parity , previous abortion , race , cigarette smoking , and marital status . Of these , 80 were given 17 alpha-hydroxyprogesterone caproate , 88 received placebo , and 78 declined to participate in the protocol . There was no significant differences in the three groups when comparisons were made for low-birth weight infants and for perinatal mortality . However , when comparison was made to a military dependent population , they had a significantly worse outcome with regard to both perinatal mortality ( p = 0.001 ) and infants with a birth weight less than 2,500 gm ( p = 0.01 ) . We concluded that pregnant military personnel were at increased risk for adverse pregnancy outcome , but that this risk was not altered by therapy with 17 alpha-hydroxyprogesterone caproate OBJECTIVE The purpose of this study was to evaluate whether 17-alpha-hydroxyprogesterone caproate ( 17P ) treatment affect changes in cervical length . STUDY DESIGN Women with singleton pregnancy , between 25 and 33 + 6 weeks of gestation , who were hospitalized for preterm labor were included . Patients with rupture of membranes and /or signs of chorioamnionitis were excluded . Sixty undelivered patients were allocated r and omly to either observation or to receive 341 mg of 17P intramuscularly , twice each week until gestational week 36 . Cervical length was measured by transvaginal  ultrasound scanning at discharge and at day 7 and 21 after discharge . Statistical comparisons were done with analysis of variance and chi-square test . RESULTS Shortening of the cervix in the observation group ( 30 cases ) was higher than in the 17P group ( 30 cases ) both at day 7 ( 2.37 + /- 2.0 mm vs 0.83 + /- 1.74 mm ; P = .002 ) and day 21 ( 4.60 + /- 2.73 mm vs 2.40 + /- 2.46 mm ; P = .002 ) . Treatment with 17P was associated with both a reduction in the risk of cervical shortening of > or = 4 mm ( odds ratio , 0.18 ; 95 % CI , 0.04 - 0.66 ) and in the risk of preterm delivery ( odds ratio , 0.15 ; 95 % CI , 0.04 - 0.58 ) . CONCLUSION Undelivered patients after preterm labor undergo progressive shortening of the cervix , which is attenuated by 17P treatment BACKGROUND Previous r and omized trials have shown that progesterone administration in women who previously delivered prematurely reduces the risk of recurrent premature delivery . Asymptomatic women found at midgestation to have a short cervix are at greatly increased risk for spontaneous early preterm delivery , and it is unknown whether progesterone reduces this risk in such women . METHODS Cervical length was measured by transvaginal ultrasonography at a median of 22 weeks of gestation ( range , 20 to 25 ) in 24,620 pregnant women seen for routine prenatal care .  Cervical length was 15 mm or less in 413 of the women ( 1.7 % ) , and 250 ( 60.5 % ) of these 413 women were r and omly assigned to receive vaginal progesterone ( 200 mg each night ) or placebo from 24 to 34 weeks of gestation . The primary outcome was spontaneous delivery before 34 weeks . RESULTS Spontaneous delivery before 34 weeks of gestation was less frequent in the progesterone group than in the placebo group ( 19.2 % vs. 34.4 % ; relative risk , 0.56 ; 95 % confidence interval [ CI ] , 0.36 to 0.86 ) . Progesterone was associated with a nonsignificant reduction in neonatal morbidity ( 8.1 % vs. 13.8 % ; relative risk , 0.59 ; 95 % CI , 0.26 to 1.25 ; P=0.17 ) . There were no serious adverse events associated with the use of progesterone . CONCLUSIONS In women with a short cervix , treatment with progesterone reduces the rate of spontaneous early preterm delivery . ( Clinical Trials.gov number , NCT00422526 [ Clinical Trials.gov ] . ) OBJECTIVE The purpose of this study was to evaluate the effect of prophylactic vaginal progesterone in decreasing preterm birth rate in a high-risk population . STUDY DESIGN A r and omized , double-blind , placebo-controlled study included 142 high-risk singleton pregnancies .  Progesterone ( 100 mg ) or placebo was administered daily by vaginal suppository and all patients underwent uterine contraction monitoring with an external tocodynamometer once a week for 60 minutes , between 24 and 34 weeks of gestation . Progesterone ( n = 72 ) and placebo ( n = 70 ) groups were compared for epidemiologic characteristics , uterine contraction frequency , and incidence of preterm birth . Data were compared by chi(2 ) analysis and Fisher exact test . RESULTS The preterm birth rate was 21.1 % ( 30/142 ) . Differences in uterine activity were found between the progesterone and placebo groups ( 23.6 % vs 54.3 % , respectively ; P < .05 ) and in preterm birth between progesterone and placebo ( 13.8 % vs 28.5 % , respectively ; P < .05 ) . More women were delivered before 34 weeks in the placebo group ( 18.5 % ) than in the progesterone group ( 2.7 % ) ( P < .05 ) . CONCLUSION Prophylactic vaginal progesterone reduced the frequency of uterine contractions and the rate of preterm delivery in women at high risk for prematurity Eighty pregnant women at high risk of giving birth prematurely were divided r and omly into two groups . Treatment with either 17 alpha-hydroxyprogesterone caproate , 250 mg by intramuscular injection once a week , or a placebo was given in a double-blind fashion . Imminent premature labor occurred in 29.0 % of the treated group and in 59.4 % of the control group ( p less than 0.025 ) . The rate of premature deliveries was also significantly lower in the treated group ( 16.1 % ) than in the control group ( 37.82 % ) ( p less than 0.05 ) . There were no cases of perinatal death or fetal malformations in either group . The mean birth weight of all infants of the treated group was significantly higher than in those of the control group ( 3111.9 + /- 905 gm versus 2680 + /- 813.4 gm , p less than 0.05 ) . The results support treatment with progesterone caproate for the prevention of premature labor We conducted a double-blind study to determine the efficacy of 17alpha-hydroxyprogesterone caproate in preventing premature delivery in 43 high-risk patients .  Premature delivery did not occur in 18 patients receiving the progestational agent , whereas 41 per cent of the 22 receiving the palcebo had premature delivery ( P less than 0.01 ) . The mean duration of pregnancy and the mean birth weight in the former group ( 38.6 weeks + /- 1.6 S.D. , and 2836 g + /- 412 S.D. ) were both significantly greater ( P less than 0.025 ) than that in the latter ( 35.2 weeks + /- 6.7 S.D. ; 2361 g + /- 1085 S.D. ) . The perinatal mortality rate in the group given the progestational agent ( O per cent ) was significantly less than that observed in the placebo group ( 27 per cent ) ( P less than 0.05 ) . Although there were no complications attributable to the progestational drug , the study population was too small for assessment of immediate or long term safety . However , the results indicate a possible obstetric use for this drug BACKGROUND In singleton gestations , 17 alpha-hydroxyprogesterone caproate ( 17P ) has been shown to reduce the rate of recurrent preterm birth . This study was undertaken to evaluate whether 17P would reduce the rate of preterm birth in twin gestations . METHODS We performed a r and omized , double-blind , placebo-controlled trial in 14 centers . Healthy women with twin gestations were assigned to weekly intramuscular injections of 250 mg of 17P or matching placebo , starting at 16 to 20 weeks of gestation and ending at 35 weeks . The primary study outcome was delivery or fetal death before 35 weeks of gestation . RESULTS Six hundred sixty-one women were r and omly assigned to treatment . Baseline demographic data were similar in the two study groups . Six women were lost to follow-up ; data from 655 were analyzed ( 325 in the 17P group and 330 in the placebo group ) .  Delivery or fetal death before 35 weeks occurred in 41.5 % of pregnancies in the 17P group and 37.3 % of those in the placebo group ( relative risk , 1.1 ; 95 % confidence interval [ CI ] , 0.9 to 1.3 ) . The rate of the prespecified composite outcome of serious adverse fetal or neonatal events was 20.2 % in the 17P group and 18.0 % in the placebo group ( relative risk , 1.1 ; 95 % CI , 0.9 to 1.5 ) . Side effects of the injections were frequent in both groups , occurring in 65.9 % and 64.4 % of subjects , respectively ( P=0.69 ) , but were generally mild and limited to the injection site . CON 
    Output:
    
: Progesterone is associated with some beneficial effects in pregnancy outcome for some women at increased risk of preterm birth