***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: OBJECTIVES To establish the relationship of cervical length at 23 weeks of gestation to the risk of  spontaneous delivery before 33 weeks and to determine the possible additional risk if funneling is present . METHODS During a 36-month period , 6819 women with singleton pregnancies underwent transvaginal sonographic cervical assessment at 22 - 24 weeks as a screening test for preterm delivery . The distribution of cervical length and the prevalence of funneling , defined as dilatation of the internal os of > or = 5 mm in width , were established . Women who underwent cervical cerclage , iatrogenic preterm delivery or were lost to follow-up were excluded from further analysis . In the remaining 6334 pregnancies , logistic regression was used to examine the contribution of  cervical length and funneling to the risk of spontaneous preterm delivery before 33 weeks . RESULTS The median cervical length was 36 mm and in 1.6 % of cases the length was < or = 15 mm . There was a significant inverse association between cervical length and percentage rate of spontaneous delivery before 33 weeks . Funneling of the internal os was present in about 4 % of pregnancies and the prevalence decreased with increasing cervical length from 98 % when the length was < or = 15 mm to about 25 % for lengths of 16 - 30 mm and less than 1 % at lengths of > 30 mm . The rate of preterm delivery was 6.9 % in those with funneling compared to 0.7 % in those without funneling ( chi2 = 86.7 ; P < 0.0001 ) . However , logistic regression analysis demonstrated that funneling did not provide a significant additional contribution to cervical length in the prediction of spontaneous delivery before 33 weeks ( odds ratio for short cervix = 24.9 , Z = 4.43 , P < 0.0001 ; odds ratio for funneling = 1.8 , Z = 0.84 , P = 0.40 ) . CONCLUSION In the prediction of preterm delivery , funneling does not provide any significant contribution in addition to cervical length OBJECTIVE This study was undertaken to determine whether progestational agents can prevent inflammation-induced preterm parturition and fetal demise . STUDY DESIGN The activation of contractile and inflammatory pathways in response to localized intrauterine inflammation was investigated by using quantitative polymerase chain reaction ( PCR ) . Serum progesterone ( P4 ) levels and alterations in progesterone receptor-B ( PR-B ) were determined with radioimmunoassay and quantitative PCR , respectively . With our in vivo model of intrauterine inflammation , animals were r and omly assigned to pretreatment with P4 or medroxyprogesterone acetate ( MPA ) before intrauterine lipopolysaccharide ( LPS ) . Animals were observed for preterm delivery . The number of live pups 48 hours after intrauterine LPS was recorded for each treatment group . The ability of MPA to alter signal transduction pathways leading to preterm parturition were investigated by quantitative PCR and histochemical studies . RESULTS Intrauterine inflammation is associated with decreased serum progesterone levels and decreased transcription of PR-B. Preterm delivery rates were 100 % for LPS alone , 63 % for LPS+P4 , and 0 % for LPS+MPA . No live pups remained at 48 hours in the LPS or LPS+P4 groups . Pretreatment with MPA significantly preserved fetal viability .  MPA suppressed activation of contraction-associated genes and inflammatory mediators and prevented cervical ripening in response to intrauterine inflammation . CONCLUSION MPA , with its progestational and anti-inflammatory properties , prevented inflammation-induced preterm parturition and significantly preserved fetal viability 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 On the basis of the recent Maternal Fetal Medicine Unit Networks clinical trial , the American College of Obstetricians and Gynecologists supports the administration of 17-alpha hydroxyprogesterone caproate to high-risk patients . Because inflammation/infection is believed to be a contributing factor in many cases of preterm birth , it is imperative to underst and the effect of 17-alpha hydroxyprogesterone caproate treatment in this clinical situation . STUDY DESIGN Using a mouse model of localized intrauterine inflammation , we investigated the ability of progestational agents to prevent preterm birth .  On gestational day 15 ( E15 ) , dams were assigned r and omly to treatment with 17-alpha hydroxyprogesterone caproate , medroxyprogesterone acetate , or vehicle before intrauterine infusion of lipopolysaccharide . All dams were monitored for morbidity and preterm birth . Three separate sets of experiments were performed to assess different outcomes at 6 , 24 , and 96 hours . At 6 and 24 hours , C-reactive protein , interleukin-6 , and interleukin-10 levels were measured in maternal serum by enzyme-linked immunosorbent assay . RESULTS Pretreatment with 17-alpha hydroxyprogesterone caproate or medroxyprogesterone acetate before intrauterine lipopolysaccharide treatment significantly decreased the preterm birth rate , compared with lipopolysaccharide treatment alone . Medroxyprogesterone acetate treatment was more effective than 17-alpha hydroxyprogesterone caproate treatment in the prevention of preterm birth and result ed in live pups at term . Treatment with 17-alpha hydroxyprogesterone caproate was associated with significant maternal morbidity . CONCLUSION In the setting of intrauterine inflammation , progestational agents decrease the preterm birth rate but can result in maternal morbidity . 17-Alpha hydroxyprogesterone caproate should not be used in patients who are suspected of having sub clinical infection and /or acute preterm labor . The mechanisms by which progestational agents inhibit preterm birth warrants further investigations so that the use of this drug to appropriate population s could be pursued without undue fetal or maternal harm Objective To compare the effects of 50 mg or 200 mg of oral mifepristone with placebo on cervical ripening and induction of labor in primigravid women at term with unfavorable cervices . Methods This was a double-blind study in which 80 primigravidae at term with a modified Bishop score of 4 or less were r and omly assigned to one of three treatment groups . They were assessed at 24-hour intervals for 72 hours , after which labor was induced if it had not occurred spon-taneously . Results Two hundred milligrams of mifepristone result ed in a favorable cervix ( with a Bishop score greater than 6 or in spontaneous labor ) in significantly more women than placebo ( P = .01 ) . An improvement in cervical ripening was seen in the group given 50 mg of mifepristone , but this was not statistically significant . There were more cesarean deliveries performed for fetal distress in the group treated with 200 mg of mifepristone than placebo , but this was not statistically significant and was not associated with any differences between groups in terms of neonatal outcome . Conclusion Mifepristone , a progesterone antagonist , is known to cause softening and dilation of the human early pregnant cervix and an increase in uterine activity . It is theoretically attractive for use as an adjunct in cervical priming and labor induction . In this study , 200 mg of mifepristone was significantly more likely to result in a favorable cervix than placebo 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 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 OBJECTIVE To investigate the efficacy of vaginal progesterone to prevent early preterm birth in women with sonographic evidence of a short cervical length in the midtrimester . METHODS This was a planned , but modified , secondary analysis of our multinational , multicenter , r and omized , placebo-controlled trial , in which women were r and omized between 18 + 0 and 22 + 6 weeks of gestation to receive daily treatment with 90 mg of vaginal progesterone gel or placebo .  Cervical length was measured with transvaginal ultrasound at enrollment and at 28 weeks of gestation . Treatment continued until either delivery , 37 weeks of gestation or development of preterm rupture of membranes . Maternal and neonatal outcomes were evaluated for the subset of all r and omized women with cervical length < 28 mm at enrollment . The primary outcome was preterm birth at < /= 32 weeks . RESULTS A cervical length < 28 mm was identified in 46 r and omized women : 19 of 313 who received progesterone and 27 of 307 who received the placebo .  Baseline characteristics of the two groups were similar . In women with a cervical length < 28 mm , the rate of preterm birth at < /= 32 weeks was significantly lower for those receiving progesterone than it was for those receiving the placebo ( 0 % vs. 29.6 % , P = 0.014 ) . With progesterone , there were fewer admissions into the neonatal intensive 
    Output:
    
There were no significant differences between the vaginal progesterone and placebo groups in the rate of adverse maternal events or congenital anomalies .
CONCLUSION Vaginal progesterone administration to asymptomatic women with a sonographic short cervix  reduces the risk of preterm birth and neonatal morbidity and mortality