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PubMed1996

The preterm prediction study: maternal stress is associated with spontaneous preterm birth at less than thirty-five weeks' gestation. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.

OBJECTIVE: Our purpose was to determine whether various measures of poor psychosocial status in pregnancy are associated with spontaneous preterm birth, fetal growth restriction, or low birth weight. STUDY DESIGN: Anxiety, stress, self-esteem, mastery, and depression were assessed at 25 to 29 weeks in 2593 gravid women by use of a 28-item Likert scale. Scores for each psychosocial subscale were determined, and an overall psychosocial score was calculated. Scores were divided into quartiles, and the lowest quartile scores were used to define poor psychosocial status. The percent spontaneous preterm birth, low birth weight, and fetal growth restriction in women with low and high psychosocial scores were compared. Logistic regression analyses provided the odds ratios and 95% confidence intervals. RESULTS: Analyses revealed that stress was significantly associated with spontaneous preterm birth and with low birth weight with odds ratios of 1.16, p = 0.003, and 1.08, p = 0.02, respectively, for each point on the scale. A low score on the combined scale or on any subscale other than stress did not predict spontaneous preterm birth, fetal growth restriction, or low birth weight. After multivariate adjustment was performed for psychosocial status, substance use, and demographic traits, black race was the only variable significantly associated with spontaneous preterm birth, fetal growth restriction, and low birth weight; stress and low education were associated with spontaneous preterm birth and low birth weight. CONCLUSION: Stress was associated with spontaneous preterm birth and low birth weight even after adjustment for maternal demographic and behavioral characteristics. Black race continues to be a significant predictor of spontaneous preterm birth, fetal growth restriction, and low birth weight even after adjustment for stress, substance use, and other demographic factors.

Adult↗

PubMed2001

Uterine electrical activity as predictor of preterm birth in women with preterm contractions.

OBJECTIVE: To estimate the risk of preterm birth in women admitted to the tertiary maternity hospital for preterm contractions by measuring electrical uterine activity. STUDY DESIGN: The study included 47 patients with contractions between the 25th and 35th week of gestation and additional risk factors for preterm delivery. Uterine electrical activity was recorded using bipolar electrodes placed on the abdominal surface. A logistic model with the electromyographic and obstetric data was built, preterm delivery before 37th week of gestation being the outcome measure. RESULTS: Seventeen patients (36%) delivered before term. Logistic regression model suggested only the intensity of electrical uterine activity and woman's body weight to be significant predictors of preterm delivery, with high values related to preterm birth. They predict preterm delivery with the sensitivity of 47% and specificity of 90%. CONCLUSION: We propose uterine EMG as a simple, non-invasive means to estimate the risk of preterm birth in a high-risk population with multiple risk factors present.

Electromyography↗

PubMed2002

The role of bacterial vaginosis in preterm labor and preterm birth: a case-control study.

OBJECTIVE: To study the association between preterm labor and bacterial vaginosis; in women with preterm labor, to determine whether vaginosis modifies the risk of preterm delivery. STUDY DESIGN: Case-control study. We used Amsel's clinical criteria to test 102 patients hospitalized for preterm labor and 102 control patients for bacterial vaginosis. RESULTS: Patients with preterm labor were diagnosed with bacterial vaginosis significantly more often (13.8%, 95% confidence interval (CI) (7.7-22.0) than control patients (0.0%, 95% CI (0.0-3.6)) (P<0.001). Among the former, the time elapsed to delivery was identical regardless of the patient's bacterial vaginosis status (elapsed time: 35.9 versus 37.1 days, rate of spontaneous preterm birth 42.9 versus 43.2%, not significant). CONCLUSION: Bacterial vaginosis is associated with preterm labor. Nonetheless, it does not appear to predict preterm birth among these patients.

Adult↗

PubMed1997

Pathogenesis of preterm labor and preterm premature rupture of membranes associated with intraamniotic infection.

We have proposed a model in which the initiation of human parturition in the presence of infection is controlled by the host. Systemic maternal infections such as pyelonephritis or localized infections such as deciduitis can trigger parturition by the activation of the monocyte and macrophage system in peripheral blood and human decidua. Preterm labor and preterm PROM can, according to this, be considered events that occur when the intrauterine or maternal environment is hostile and threaten the survival of the fetal-maternal pair. From this point of view, the initiation of preterm labor may have survival value. Why does intrauterine infection result in preterm labor in some cases and PROM in others? It is possible that regulation of different components of the host response has an important role to play in determining clinical presentation. Thus, if preferential activation of the host response leads to the secretion of uterotonic agents (i.e., prostaglandins), preterm labor will result. On the other hand, if the activation of the host response results predominantly in the production of proteases (i.e., leukocyte elastase and MMPs), patients are more likely to experience PROM. Preterm labor and preterm PROM can be considered expressions of the same basic phenomenon: activation of the host-defense macrophage system. Although we have provided evidence that infection is an important factor in the pathogenesis of these conditions, preterm parturition should be considered as a syndrome with multiple causes.

Amnion↗

PubMed1998

Tocolysis of preterm contractions does not improve preterm delivery rate or perinatal outcomes.

To determine whether hospital admission and parenteral tocolysis of patients with threatened preterm labor results in a decreased preterm delivery rate and improved perinatal outcome, we performed a prospective cohort study comparing tocolytic treatment versus no tocolytic treatment. Women between 20 and 37 weeks' gestation who presented with at least eight uterine contractions per hour and a cervical examination <2 cm dilated, <80% effaced, and no cervical change over a 2-hr period were entered into the study. Exclusion criteria included cervical change, multiple gestation, chorioamnionitis, rupture of membranes, placenta previa or abruption, undiagnosed vaginal bleeding, and prior tocolytic therapy in the current pregnancy. Seventy-five patients were admitted to the hospital for tocolysis (tocolysis cohort) and 81 were observed and discharged to home (observation cohort). There was no significant difference in mean gestational age at delivery, mean birth weight, or in preterm delivery rate between the two cohorts. Four of the eight women in the observation cohort who delivered preterm had a history of preterm delivery. We conclude that discharging women with preterm contractions without objective evidence of labor does not result in an increase in preterm births. More importantly, tocolysis did not decrease the preterm delivery rate in this cohort.

Adult↗

PubMed2000

The Preterm Prediction Study: sequential cervical length and fetal fibronectin testing for the prediction of spontaneous preterm birth. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.

OBJECTIVES: This study was undertaken to further elucidate the pathogenesis of preterm birth by means of traditional risk factors and new markers for preterm birth derived from the Preterm Prediction Study. STUDY DESIGN: A total of 3076 women (2929 with singleton gestations and 147 with twin pregnancies) were categorized according to the presence of risk factors including black race, low body mass index, the presence of bacterial vaginosis, and previous preterm birth. At 24 and 28 weeks' gestation cervical length was measured and categorized as short (</=25 mm) or normal (>25 mm). Vaginal and cervical fetal fibronectin concentrations were measured at 24, 26, 28, and 30 weeks' gestation and results were categorized as positive (>/=50 ng/mL) or negative (<50 ng/mL). RESULTS: At 24 to 26 weeks' gestation women with each of the risk factors were more likely to have positive fibronectin test results or to have a short cervix. Among women with negative fetal fibronectin results at 24 to 26 weeks' gestation those with a short cervix were more likely to have positive fetal fibronectin results at 28 to 30 weeks' gestation, and among those with normal cervical length those women who had positive fetal fibronectin results were more likely to have a short cervix at later evaluation. Most women who had positive fetal fibronectin results at 24 to 26 weeks' gestation had negative results at 28 to 30 weeks' gestation, whereas most but not all women who had a short cervix at 24 to 26 weeks' gestation still had a short cervix at 28 to 30 weeks' gestation. In each period women with both a positive fetal fibronectin result and a short cervix were at substantially increased risk of spontaneous preterm birth; women with either marker alone had intermediate and approximately equal risks of spontaneous preterm birth, and women without either marker had a low risk of spontaneous preterm birth. CONCLUSION: Regardless of other risk factors, a short cervix predicts a subsequent positive fetal fibronectin result, and a positive fetal fibronectin result predicts subsequent cervical shortening. These data do not support a single sequence of events leading to spontaneous preterm birth.

Biomarkers↗

PubMed2001

The Preterm Prediction Study: association between cervical interleukin 6 concentration and spontaneous preterm birth. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.

OBJECTIVE: The aim of this study was to determine the interrelationship between cervical concentration of interleukin 6 and detection of fetal fibronectin and other risk factors for spontaneous preterm birth. STUDY DESIGN: All patients with spontaneous preterm birth at <35 weeks' gestation (case patients; n = 125) and subjects matched for race, parity, and center delivered at > or = 37 weeks' gestation (n = 125; control subjects) were selected from women enrolled in the National Institute of Child Health and Human Development's Preterm Prediction Study. Interleukin 6 concentrations were determined by enzyme-linked immunosorbent assay in cervical swabs obtained at 22 weeks' to 24 weeks 6 days' gestation. Cutoffs to define an elevated interleukin 6 concentration included the 90th and 95th percentiles for control subjects (>305 and >538 pg/mL, respectively). RESULTS: The mean (+/-SD) interleukin 6 concentration was significantly higher in case patients than in control subjects (212 +/- 339 vs 111 +/- 186 pg/mL; P = .008). With either cutoff value elevated interleukin 6 concentration was significantly associated with spontaneous preterm birth (90th percentile, 20% vs 9.6%; P = .02; 95th percentile, 12% vs 4.8%; P = .04). Cervical interleukin 6 levels were highest within 4 weeks of delivery, and the trend continued until term. Elevated interleukin 6 concentration was not significantly associated with bacterial vaginosis, maternal body mass index <19.8 kg/m2, or a short cervix (< or = 25 mm), but it was significantly associated with a positive cervicovaginal fetal fibronectin test result (90th percentile, odds ratio, 5.5; 95% confidence interval, 2.6-11.9; 95th percentile, odds ratio, 5.3, 95% confidence interval, 2.1-12.9). The mean interleukin 6 concentration among women with a positive fibronectin test result was 373 +/- 406 pg/mL; that among women with a negative fetal fibronectin test result was 130 +/- 239 pg/mL (P = .001). In a regression analysis that adjusted for risk factors significantly associated with spontaneous preterm birth in this population (positive fetal fibronectin test result, body mass index <19.8 kg/m2, vaginal bleeding in the first or second trimester, previous spontaneous preterm birth, and short cervix) elevated cervical interleukin 6 concentration was not independently associated with spontaneous preterm birth (odds ratio, 1.8; 95% confidence interval, 0.8-4.3). CONCLUSIONS: At 24 weeks' gestation cervical interleukin 6 concentration in women who subsequently had a spontaneous preterm birth at <35 weeks' gestation was significantly elevated relative to those who were delivered at term. The association was particularly strong within 4 weeks of testing. A positive fetal fibronectin test result was strongly associated with elevated cervical interleukin 6 concentration, but bacterial vaginosis was not.

Case-Control Studies↗

PubMed2004

Bone mineralization and growth are enhanced in preterm infants fed an isocaloric, nutrient-enriched preterm formula through term.

BACKGROUND: Because recent data on the effects of mineral concentrations in preterm infant formula on bone mineralization are lacking, recommendations for the mineral content of preterm infant formula differ greatly between committees. OBJECTIVE: The goal of the study was to assess the effects of an isocaloric, nutrient-enriched preterm formula, which was fed from the age when full enteral feedings were tolerated through expected term, on bone mineralization in preterm infants. DESIGN: We conducted a prospective, randomized, double-blind study in healthy, preterm infants (gestational age of 28-32 wk) who were fed either a control preterm formula (n=20) or an isocaloric, nutrient-enriched preterm formula (n=21) until 3 mo of age (ie, approximate expected term). Serum calcium indexes were taken throughout the study, and bone mass was determined by using dual-energy X-ray absorptiometry at hospital discharge and expected term. RESULTS: A total of 37 infants (experimental formula, n=19; control formula, n=18) completed the study. Compared with control subjects, infants fed the experimental formula had 25% and 40% higher intakes of calcium and phosphorus, respectively. Serum calcium, phosphorus, osteocalcin, and alkaline phosphatase concentrations and urinary collagen type I cross-linked N-telopetide concentrations were not significantly different between the groups at any time point. The bone mineral content of infants fed the experimental formula was 23% (P=0.039) and 35% (P=0.002) higher at hospital discharge and expected term, respectively. CONCLUSIONS: Bone mineralization at hospital discharge and expected term was significantly higher in preterm infants fed the isocaloric, nutrient-enriched formula than in those fed control formula. Continuation of the experimental formula beyond hospital discharge, through expected term, further improved bone mineralization.

Absorptiometry, Photon↗

PubMed1986

Ethnic differences in preterm and very preterm delivery.

Ethnic differences in preterm (less than 37 weeks) and very preterm (less than 33 weeks) delivery were evaluated in a prospective cohort of 28,330 women. Blacks had the highest rate of preterm and very preterm delivery, followed by Mexican-Americans, Asians, and Whites. Adjustment for maternal age, education, marital status, employment, parity, number of previous spontaneous or induced abortions, smoking and drinking during pregnancy, infant sex, and gestational age at initiation of prenatal care resulted in the following odds ratios for preterm delivery: 1.79 (1.55-2.08) for Blacks, 1.40 (1.19-1.63) for Mexican-Americans, 1.40 (1.16-1.69) for Asians, and 1.00 for Whites. The corresponding odds ratios for very preterm delivery were 2.35 (1.72-3.22) for Blacks, 1.31 (0.88-1.94) for Mexican-Americans, 1.10 (0.67-1.83) for Asians, and 1.00 for Whites. Exclusion of cases of premature rupture of membranes, placenta previa, and abruptio placenta did not explain the large ethnic differences. Although Whites and Mexican-Americans had similar birthweight distributions, Mexican-Americans had an increased risk for preterm delivery. Fifty-five per cent of low birthweight babies in Kaiser were preterm and this fraction did not vary substantially by ethnic group.

Adult↗

PubMed2004

Extensively and partially hydrolysed preterm formulas in the prevention of allergic diseases in preterm infants: a randomized, double-blind trial.

AIM: A randomized, double-blind study was conducted to evaluate whether use of protein hydrolysate-based preterm formulas in infants with an atopic predisposition helps prevent the development of allergic diseases. METHODS: Preterm infants (n = 122) with at least one first-degree relative (parent or sibling) with allergic disease were randomly assigned to receive an extensively or partially hydrolysed preterm formula (intervention groups) or a standard preterm formula until 4 to 5 mo of age. Infants whose parents preferred that they be breastfed received their mothers' fortified breast milk. RESULTS: Intention-to-treat analysis showed that the overall incidence of allergic diseases did not significantly differ between groups at both 4-5 and 12 mo of age. However, by 12 mo, use of the extensively hydrolysed versus the standard preterm formula had significantly reduced the risk of atopic dermatitis. At 4-5 and 12 mo, there was a significantly increased risk of non-acceptance of the extensively hydrolysed formula compared with the other formulas. CONCLUSIONS: This study failed to show that extensively or partially hydrolysed preterm formulas in comparison with a standard preterm formula reduced the overall incidence of allergic diseases in infants at high risk for atopic disease. However, use of the extensively hydrolysed compared with a standard preterm formula significantly reduced the incidence of atopic dermatitis observed at 12 mo. Infants who received extensively hydrolysed formulas were at increased risk for intervention discontinuation for any reason, particularly non-acceptance of the formula. Because of the small number of patients eligible for this analysis, these results should be interpreted with caution.

Caseins↗

PubMed2000

Doxapram versus methylxanthine for apnea in preterm infants.

BACKGROUND: Recurrent apnea is common in preterm infants, particularly at very early gestational ages. These episodes of loss of effective breathing can lead to hypoxemia and bradycardia which may be severe enough to require resuscitation including use of positive pressure ventilation. Doxapram and methylxanthine drugs have been used to stimulate breathing and so prevent apnea and its consequences. OBJECTIVES: In preterm infants with recurrent apnea, how does treatment with doxapram compare with treatment with theophylline in leading to a clinically important reduction in apnea and use of mechanical ventilation, without clinically important side effects. SEARCH STRATEGY: The standard search strategy of the Neonatal Review Group, as outlined in the Cochrane Library, was used. SELECTION CRITERIA: All trials utilising random or quasi-random patient allocation, in which doxapram was compared with methylxanthine (e.g. theophylline) for the treatment of apnea, were eligible. There must have been an effort to exclude specific causes of apnea. DATA COLLECTION AND ANALYSIS: The standard methods of the Cochrane Collaboration and its Neonatal Review Group were used to select trials, assess quality and to extract and synthesize data. The methodological quality of each trial was reviewed by the second author blinded to trial authors and institution(s). Additional information was requested from authors to clarify methodology. Each author extracted the data separately, then they were compared and differences resolved. Meta-analysis was carried out with use of relative risk and risk difference. MAIN RESULTS: In these trials involving a relatively small number of preterm infants with apnea of prematurity, there is no apparent difference between the effect of intravenous treatment with doxapram or methylxanthine on the incidence of apnea within 48 hours. There were no infants reported to have been given mechanical ventilation on either treatment. No adverse effects were reported. REVIEWER'S CONCLUSIONS: Implications for practice. The overall results of these small trials suggest that intravenous doxapram and intravenous methylxanthine are not different in their effectiveness in the short term in the treatment of apnea of prematurity. Caution is warranted as the number of patients in these trials is too small to exclude an important difference between these two treatments or to exclude the possibility of less common side effects. Longer term outcome of infants treated in these trials has not been reported. Implications for research. Further studies would require a large number of infants, stratified by gestation, to clarify which infants are likely to benefit and whether there might be differences in responses or side effects with these two drugs at different ages. It would be valuable to include important clinical outcomes such as use of mechanical ventilation as well as subsequent growth and development in future studies. Responses to treatment would have to take account of co-interventions, such as nasal continuous airway pressure which is frequently used post-intubation.

Aminophylline↗

PubMed2000

Postnatal phenobarbitone for the prevention of intraventricular hemorrhage in preterm infants.

BACKGROUND: This section is under preparation and will be included in the next issue. OBJECTIVES: To determine whether postnatal administration of phenobarbitone to preterm infants reduces the risk of intraventricular hemorrhage (IVH), neurodevelopmental impairment or death. SEARCH STRATEGY: See the Search Strategy of the Neonatal Collaborative Review Group. The reviewer has been a active trialist in this area and has personal contact with many groups in this field. Journals handsearched from 1976 (when cranial CT scanning started) to November 1998 include: Pediatrics, J Pediatrics, Archives of Disease in Childhood, Pediatric Research, Developmental Medicine and Child Neurology, Acta Paediatrica, European J of Pediatrics, Neuropediatrics, New England J of Medicine, Lancet and British Medical J. The National Library of Medicine (USA) database (via PubMed) and the Cochrane Controlled Trials Register were searched through to November 1998 using the MeSH terms intraventricular hemorrhage, newborn infants, premature infant, intracranial hemorrhage, phenobarbitone, phenobarbital. The searches were not limited to the English language, as long as the article included an English abstract. Promising articles were read in the original language or translated. SELECTION CRITERIA: Included were randomized or quasi-randomized controlled trials in which phenobarbitone was given to preterm infants identified as being at risk of IVH because of gestational age below 34 weeks, birthweight below 1500 g, or respiratory failure. Adequate determination of IVH by ultrasound or CT was also required. DATA COLLECTION AND ANALYSIS: In addition to details of patient selection and control of bias, the details of the administration of phenobarbitone were extracted. The end-points searched for included: IVH ( with grading), posthemorrhagic ventricular dilatation or hydrocephalus, neurodevelopmental impairment and death. In addition, possible adverse effects of phenobarbitone such as hypotension, mechanical ventilation, pneumothorax, hypercapnia, and acidosis were searched for. MAIN RESULTS: Nine controlled trials were included with 740 infants recruited. There was heterogeneity between trials for the outcome IVH, with one trial finding a significant decrease in IVH and another trial finding an increase in IVH in the group receiving phenobarbitone. Meta-analysis showed no difference between the phenobarbitone treated group and the control group in either IVH (typical relative risk 1.04, CI 0.87, 1.25), severe IVH (typical relative risk 0.91, CI 0.66, 1.27), posthemorrhagic ventricular dilatation (typical relative risk 0.89, CI 0.38, 2.08), severe neurodevelopmental impairment (typical relative risk 1.44, CI 0.41, 5.04) or death before hospital discharge (typical relative risk 0.88, CI 0.64, 1.21) There was a consistent trend in the trials towards increased use of mechanical ventilation in the phenobarbitone treated group, which was supported by the meta-analysis (typical relative risk 1.18, CI 1.06, 1.32; typical risk difference 0.129, CI 0.045, 0.213), but there was no significant difference in pneumothorax, acidosis or hypercapnia. REVIEWER'S CONCLUSIONS: Postnatal administration of phenobarbitone cannot be recommended as prophylaxis to prevent IVH in preterm infants and is associated with an increased need for mechanical ventilation.

Cerebral Hemorrhage↗

PubMed2005

Expression of bone morphogenetic protein 2 in normal spontaneous labor at term, preterm labor, and preterm premature rupture of membranes.

OBJECTIVE: Genome-wide screening studies of the chorioamniotic membranes unexpectedly identified an increase in the expression of bone morphogenetic protein 2 in spontaneous labor at term. The objective of this study was to determine whether bone morphogenetic protein 2 messenger RNA and protein expression are altered in the chorioamniotic membranes of patients with term labor, preterm labor, and preterm premature rupture of membranes. STUDY DESIGN: Chorioamniotic membranes were obtained from patients at term (with and without labor), with preterm labor (with and without histologic chorioamnionitis), and with preterm premature rupture of membranes (with and without histologic chorioamnionitis). The expression of bone morphogenetic protein 2 was studied by real-time quantitative reverse transcriptase-polymerase chain reaction (n = 88) and immunohistochemistry (n = 124). Nonparametric statistics were used for analysis. Primary amnion cells obtained from women at term not in labor were treated with bone morphogenetic protein 2 to examine whether there was increased prostaglandin E2 expression. RESULTS: The median bone morphogenetic protein 2 messenger RNA and protein expression were significantly higher in the membranes of patients with spontaneous labor at term than in those of patients not in labor at term (P < .001 for both). Bone morphogenetic protein 2 messenger RNA and protein expression were increased in patients with preterm labor with histologic chorioamnionitis than in those without histologic chorioamnionitis (P < .05 and P < .001, respectively). There was no difference in bone morphogenetic protein 2 messenger RNA and protein expression in patients with preterm premature rupture of membranes, regardless of chorioamnionitis (P = .13 and P = .08, respectively). There was a correlation between bone morphogenetic protein 2 and cyclooxygenase 2 protein expression in chorioamniotic membranes (R = .34; P < .001). CONCLUSION: Bone morphogenetic protein 2 messenger RNA and protein expression are increased in the chorioamniotic membranes of patients with spontaneous labor at term and patients with preterm labor associated with histologic chorioamnionitis. Its expression pattern and biologic effects strongly suggest that bone morphogenetic protein 2 is involved in human parturition.

Amnion↗

PubMed2005

Plasma CRH measurement at 16 to 20 weeks' gestation does not predict preterm delivery in women at high-risk for preterm delivery.

OBJECTIVE: The purpose of this study was to examine the utility of a single second-trimester plasma corticotropin-releasing hormone measurement as a marker for preterm delivery in women at high risk for preterm delivery. STUDY DESIGN: This is an analysis of data from a multicenter placebo-controlled trial designed to evaluate the role of 17 alpha hydroxyprogesterone caproate (17P) in the prevention of recurrent preterm birth. Women with a documented history of a previous spontaneous preterm birth at <37 weeks were enrolled (16-20 wks) and randomly assigned in a 2 to 1 ratio to weekly injections of 17P or matching placebo. Blood was collected before treatment in 170 patients (113 assigned 17P and 57 placebo) who were enrolled at 11 of the 19 centers. Plasma levels of corticotropin-releasing hormone were compared between those who delivered preterm and those delivering at term. Data were analyzed using the Wilcoxon rank-sum test. RESULTS: The overall rates of preterm birth in this cohort of 170 patients were 35.9% at <37 weeks (31.9% progesterone, 43.9% placebo), and 19.4% at <35 weeks (18.6% vs 21.1%). The median levels of corticotropin-releasing hormone were similar between those delivering at <37 weeks and those delivering > or = 37 weeks (0.39 ng/mL vs 0.37 ng/mL, P = .08). In addition, there were no differences in corticotropin-releasing hormone levels among those who delivered at <35 weeks or > or = 35 weeks (0.36 vs 0.38, P = .90). Moreover, there were no differences in corticotropin-releasing hormone levels among those in the placebo group who delivered at <37 or > or = 37 weeks (0.40 vs 0.41, P = .72) and at <35 or > or = 35 weeks (P = .64). CONCLUSION: A single measurement of corticotropin-releasing hormone at 16 to 20 weeks' gestation is not a good biomarker for recurrent preterm delivery in patients at high risk for this complication.

Adult↗

PubMed1997

The preterm prediction study: patterns of cervicovaginal fetal fibronectin as predictors of spontaneous preterm delivery. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.

OBJECTIVE: Our purpose was to determine how various temporal patterns of fetal fibronectin positivity from 24 to 30 weeks predict subsequent fetal fibronectin test results and spontaneous preterm delivery. STUDY DESIGN: A total of 2929 women had vaginal and cervical fetal fibronectin tests obtained at least once at 24, 26, 28, or 30 weeks, and 1870 women had tests performed at all four gestational ages. Fetal fibronectin values > or = 50 ng/ml were considered positive. Various patterns of positive and negative tests were evaluated for prediction of (1) whether the next fetal fibronectin test would be positive or negative and (2) the percent of women with a spontaneous preterm delivery > or = 4 weeks after the last fetal fibronectin test at < 30, < 32, < 35, and < 37 weeks' gestational age. RESULTS: Women with previous negative test results had only a 3% chance of a subsequent positive test result; however, if the last test result was positive, 29% of the next tests were positive. Of the 1870 women with tests at 24, 26, 28, and 30 weeks, 89% had all negative results, 8.4% had one positive result, 1.8% had two positive results, and 0.8% had three or four positive results. The higher the percent of positive tests at 24 to 26 weeks, at 28 to 30 weeks, or at 24 to 30 weeks, the greater the risk of subsequent spontaneous preterm birth. As an example, the risk of spontaneous preterm birth at < 30 weeks for women with two negative fetal fibronectin test results at 24 and 26 weeks was 0.3% versus 16% for women with two positive results. CONCLUSION: The presence of a positive cervical or vaginal fetal fibronectin test result predicts subsequent positive fetal fibronectin positivity and subsequent spontaneous preterm birth. The greater the percent of positive results, the higher is the risk of spontaneous preterm birth. After a positive test result, two negative results are required before the risk of spontaneous preterm birth returns to baseline.

Cervix Uteri↗

PubMed2004

Changes in perinatal care and survival in very preterm and extremely preterm infants in The Netherlands between 1983 and 1995.

OBJECTIVE: To evaluate changes in obstetrical and neonatal care for very preterm and extremely preterm infants between 1983 and 1995 in The Netherlands and to evaluate the effect of those changes. STUDY DESIGN: Data on all very preterm or VLBW infants from the linked national obstetrical and neonatal databases of 1995 (N=2066) were compared to data on similar infants from a nation-wide study of very preterm infants born in 1983 (N=1338). RESULTS: Obstetrical and neonatal management changed over time, with an increased number of deliveries in tertiary centres (35.7-60.7%), an increase in C-sections (43.7-56.8%) and prolonged artificial ventilation (3.4-9.5%). Survival until discharge increased from 75 to 90% and neonatal morbidity decreased in relative terms. CONCLUSIONS: The short-term outcome for these very preterm and extremely preterm infants has improved. Long-term follow-up through to school age and adulthood of preterm infants is needed to investigate the changes in the sequelae of intensive obstetrical and neonatal care.

Apgar Score↗

PubMed2003

Infection in the prediction and antibiotics in the prevention of spontaneous preterm labour and preterm birth.

The association between infection and spontaneous preterm labour is now well established and thought to be responsible for preterm birth in up to 40% of cases. Preterm labour that is due to infection is refractory to the use of tocolytic agents. So the knowledge that infection may be the cause is unhelpful once a woman is admitted in spontaneous preterm labour, since by that time there may be irreversible changes in the uterine cervix, which renders futile those attempts to inhibit the process. It would be much more logical to use the association between infection and spontaneous preterm labour to identify a group of women at risk and to intervene using antibiotic prophylaxis. It is important to record, that the earlier in gestation at which abnormal genital tract colonisation is detected, the greater is the risk of an adverse outcome. For example, abnormal genital tract flora at 26-32 weeks gestation is associated with preterm birth with an odds ratio (OR) of 1.4 to 2, whereas abnormal genital tract flora at 7-16 weeks gestation carries an OR of 5 to 7.5. Intervention studies have used different antibiotics in different dosage regimes by different routes of administration to patients of differing risks at different gestational ages. Not surprisingly this has led to differing results. If intervention is to be successful, the antibiotics chosen should be active against bacterial vaginosis or bacterial vaginosis-related organisms and should be used early in pregnancy in those women with the greatest degree of abnormal genital tract flora. While there is logic in using intravaginal antibiotics to deliver a heavy antibiotic load to the vagina where heavy abnormal colonisation exists, there is also logic in considering systemic antibiotics to eradicate those organisms, which have already gained access to the decidua. It may be that the greatest chance of benefit would exist if both routes of administration were combined. Yet no study has evaluated the combination of both intravaginal and systemic antibiotics to eradicate abnormal genital tract flora for the prevention of preterm birth.

Antibiotic Prophylaxis↗

PubMed2000

The Preterm Prediction Study: association of second-trimester genitourinary chlamydia infection with subsequent spontaneous preterm birth.

OBJECTIVE: This study was undertaken to determine the association between genitourinary tract infection with Chlamydia trachomatis and spontaneous preterm birth. STUDY DESIGN: Genitourinary tract infection with C trachomatis was determined with a ligase chain reaction assay of voided urine samples collected at 24 weeks' gestation (22 weeks' to 24 weeks 6 days' gestation) and 28 weeks' gestation (27 weeks' to 28 weeks 6 days' gestation). Case patients (spontaneous preterm birth at <37 weeks' gestation; n = 190) and control subjects (delivery at >/=37 weeks' gestation, matched for race, parity, and center; n = 190) were selected from 2929 women enrolled in the Preterm Prediction Study of the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. RESULTS: Genitourinary C trachomatis infection (11% overall) was significantly more common among the case patients than among the control subjects at 24 weeks' gestation (15.8% vs 6.3%; P =.003) but not at 28 weeks' gestation (12.6% vs 10.9%; P =.61). Women with chlamydia infection were more likely to have bacterial vaginosis (57.1% vs 32.9%; P =.002) and a short cervical length (</=25 mm; 33.0% vs 17.9%; P =.02) but not a body mass index <19.8 kg/m(2) (35.0% vs 23.9%; P =.17) or a positive fetal fibronectin test result (7.1% vs 9.5%; P =.62). After adjustment for risk factors for spontaneous preterm birth, women with C trachomatis infection at 24 weeks' gestation were 2 times as likely as uninfected women to have a spontaneous preterm birth at <37 weeks' gestation (odds ratio, 2.2; 95% confidence interval, 1.03-4.78) and 3 times as likely to have a spontaneous preterm birth at <35 weeks' gestation (odds ratio, 3.2; 95% confidence interval, 1.08-9.57). CONCLUSION: Genitourinary C trachomatis infection at 24 weeks' gestation was associated with a 2-fold to 3-fold increased risk of subsequent spontaneous preterm birth.

Adolescent↗