***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: 11 mg natural progesterone ( P ) was administered to 20 healthy menopausal women by means of a nasal spray or intramuscular injection .  Circulating P levels were calculated at various times after administration . The spray formulation yielded a CMax of 3.75 ng/ml at TMax = 60 min , the area under the curve (AUC)0 - 720 being 1,481.6 + /- 343 . Intramuscular administration yielded a mean CMax of 4.137 ng/ml at TMax = 240 min , the AUC0 - 720 being 2,491.2 + /- 540 . P absorption was faster through the nasal than through the intramuscular route , but intramuscular administration led to high serum levels for a much longer period Progesterone was administered to postmenopausal women in a form of vaginal suppositories containing 100 and 200 mg active substance in Butyrum cacao ( BC ) and Massa estarinum ( ME ) , a base with emulsifying properties . In the case of single doses , blood sample s were taken at 2 , 4 , 6 , 24 , 48 and 72 h. Another group of patients received vaginal suppositories ( 100 mg progesterone ) once a day for a 6 day period , with blood sample s taken 12 h after each administration . The plasma levels of progesterone were evaluated by  radioimmunoassay .  The time of maximum concentration ( tmax ) was 4 h in most cases , and 6 h in the others . The plasma levels were not dose-proportional . Peak plasma concentrations were in the range of 10 - 15 ng/ml with a mean of 10.5 ng/ml for the 100 mg and 12 ng/ml for the 200 mg doses . The ratio of the mean area under the curve ( AUC ) for 200 mg and the mean AUC for the 100 mg dose was found to be 1.37 . Replacing BC with ME result ed in the lowering of cmax and AUC , and an increase in tmax following a reducing in the rate and extent of adsorption . In the case of ME suppositories , the variability in AUC , cmax and tmax was greater compared to that observed with the BC suppositories . Elimination half-time was in the range of 9 - 10 h for BC and 14 h for ME suppositories . In vitro assessment of the release kinetics from a hydrophobic and an emulsion type base confirmed previous findings : the latter base assured better pharmaceutical availability . The repeated doses did not seem to produce an accumulation of progesterone in the plasma . On the contrary , a small decrease in plasma levels over time appeared during the 6 day period . Numerical analysis revealed an excellent goodness of fit for the in vivo experimental data via biexponential curves , i.e. a pseudomonocompartmental model 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 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 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 BACKGROUND The aim was to study whether prolongation of luteal support during early pregnancy influences the delivery rate after IVF . METHODS Dual centre study including 303 women who achieved pregnancy after IVF or ICSI was used . All were treated with the long protocol using GnRH agonists and given luteal support with 200 mg vaginal progesterone three times daily during 14 days from the day of transfer until the day of a positive HCG test . The study group ( n = 150 ) withdrew vaginal progesterone from the day of positive HCG . The control group ( n = 153 ) continued administration of vaginal progesterone during the next 3 weeks of pregnancy . RESULTS The number of miscarriages prior to and after week 7 of gestation was seven ( 4.6 % ) and 15 ( 10.0 % ) in the study group and five ( 3.3 % ) and 13 ( 8.5 % ) in the control group respectively . The number of deliveries was 118 ( 78.7 % ) in the study group and 126 ( 82.4 % ) in the control group . The differences were not significant . CONCLUSIONS Prolongation of progesterone supplementation in early pregnancy has no influence on the miscarriage rate , and thus no effect on the delivery rate .  Progesterone supplementation can safely be withdrawn at the time of a positive HCG test 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 The use of luteal phase support has been demonstrated in patients undergoing an IVF/ET procedure . This study was design ed to compare the absorption and the efficacy of two different luteal supports : 17-alpha-hydroxyprogesterone caproate ( Lentogest , AMSA , Italy ) and natural Progesterone ( Prontogest , AMSA , Italy ) . A total of 80 patients received luteal supplementation with 50 mg of natural P/day intramuscularly , until beta-hCG evaluation . Then , in case of positive beta-hCG , patients were r and omly divided into two groups ( A and B ) in order to compare two different protocol s : Group A , 17-OHPc ( 341 mg once a week ) and Group B , natural P ( 50 mg/day ) both intramuscularly and extended for 10 - 12 weeks . Our study showed that the treatment with 17-OHPc results in a higher percentage of pregnancy rate compared to natural P , but the differences are not statistically significant . Thus , we emphasize that 17-OHPc preparation for better acceptance appears to be the most suitable and comfortable method for luteal phase support OBJECTIVE To analyse hospital readmissions to 1 year in infants < 33 weeks ' gestation . STUDY DESIGN Cohort of very preterm infants born in Western Australia . METHODS Parental social class , history of asthma , race , gestational age , birthweight , sex , severity of 
    Output:
    
For progesterone supplementation to be advocated for women at the risk of preterm birth , the prolongation of gestation demonstrated in this meta- analysis must translate into improved infant outcomes , including a reduction in mortality .
There is currently insufficient information to allow recommendations regarding the optimal dose , route , and timing of administration of progesterone supplementation