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PubMed1993

Preterm delivery among black and white enlisted women in the United States Army.

OBJECTIVE: To examine black-white differences in preterm delivery in a healthy population who had unrestricted access to prenatal care. METHODS: We conducted a retrospective cohort study of 842 black and 1026 white enlisted servicewomen who delivered a singleton infant of 20 or more weeks' gestation from July 1, 1987 through September 30, 1990 at four Army Medical Centers in the United States. Data were collected by reviewing maternal and newborn records. We used logistic and proportional hazards regression models to analyze outcomes defined by length of gestation, cause of preterm delivery, and jointly by length and cause. RESULTS: Black enlisted women had a cumulative probability of preterm delivery (13.5%) that was higher than that for white enlisted women (10.5%) (hazard ratio 1.31, 95% confidence interval [CI] 1.002-1.70). However, the ratio of black-to-white hazards was not uniform. Black-white differences were small and nonsignificant from 33-36 weeks' gestation, when most preterm deliveries occur. The differences were also small and nonsignificant for deliveries related to spontaneous rupture of membranes or idiopathic preterm labor, the most common causes of preterm delivery. The black-to-white hazard ratios were greatest for all deliveries before 33 weeks' gestation and for medically indicated preterm deliveries. CONCLUSIONS: Efforts to reduce black-white differences in preterm delivery must go beyond providing prenatal care and eliminating recreational drug use. Future studies should consider black-white differences in environments during the mother's own development and in psychosocial and physical stresses during pregnancy.

Adolescent↗

PubMed1993

Management of preterm labor and prevention of premature delivery.

Preterm births continue to be the leading cause of perinatal mortality despite efforts to prevent preterm labor. Tocolytic therapy with beta-mimetic drugs was believed to be the solution for preterm labor, but the Canadian Preterm Labor Investigators Group recently reported that the use of ritodrine had no significant beneficial effect. Despite the various methods presently used for the management of preterm labor and prevention of premature delivery, the incidence of preterm birth remains unchanged. Health professionals must remain optimistic, however, and continue to investigate causes, whether they are social or medical, and to seek the unknown. Nursing personnel should play an important role in this area as health promoters and educators of patients. Nurses should also collaborate with other health professionals to determine effectiveness of therapy and the causes of preterm labor. For instance, this author is currently involved in a research project seeking barriers to prenatal care using a questionnaire and reviewing maternal records in order to determine length of labor and its relationship to subsequent preterm labors. The goals of the Year 2000 National Health Objective for low birth weight and infant mortality are not likely to be attained. Prematurity has gained national attention, however, and with public and professional awareness, perhaps this problem will decrease.

Ambulatory Care↗

PubMed1997

Ocular fundus morphology in preterm children. Influence of gestational age, birth size, perinatal morbidity, and postnatal growth.

PURPOSE: To determine the influence of gestational age, birth size, perinatal morbidity, and postnatal growth on fundus morphology in preterm children using digital image analysis of fundus photographs. METHODS: Thirty-nine preterm children (mean postmenstrual gestational age, 29.1 weeks; range, 24.6 to 32) were included in the study. Thirty-nine healthy children, born at term, were used as control subjects. Fundus photographs were obtained at a mean age of 4.8 years (preterm) and 6.1 years (control subjects). RESULTS: There was no difference in optic disc, excavation, or peripapillary crescent area between the two groups. In the group of preterm children, a large optic disc size was associated with a low birth weight (rs = -0.29, P = 0.07), duration of assisted ventilation (rs = 0.43, P = 0.006), and number of blood transfusions (rs = 0.33, P = 0.04). The girls born prematurely showed a negative relation between the length of gestation and the area of the optic disc (r2 = 0.28, P = 0.009). No such relation was found in boys. The preterm children had increased tortuosity of retinal vessels (P < 0.001 and P < 0.002 for arteries and veins, respectively) and reduced number of vascular branching points (P < 0.001) compared with those of the control subjects. There were no associations between these vascular abnormalities and the perinatal and postnatal variables studied. CONCLUSIONS: No difference in optic disc morphology between preterm children and control subjects was found. However, preterm birth seems to affect the retinal vascular pattern close to the optic disc, independently of retinopathy of prematurity. Among the girls born preterm, optic disc size was negatively correlated to gestational age.

Birth Weight↗

PubMed1998

[New markers of the risk of preterm delivery].

Preterm births account for 5.9% of all deliveries in France, a proportion that has not changed noticeably over the past 30 years. Neither risk scores nor systematic digital vaginal examinations at prenatal consultations have helped to diminish the incidence of prematurity. Because an indispensable prerequisite to reducing this incidence is better identification of the patients at risk, new approaches towards this end have been proposed in recent years. Various studies have shown that fetal fibronectin in cervico-vaginal secretions between 23 and 36 weeks' gestation can be used to identify, among patients with uterine contractions and clinically observable modifications of the cervix, a subgroup of women at very high risk of preterm delivery. Systematic assays for fetal fibronectin among low-risk women are not, however, valuable, because of both the low prevalence of preterm delivery in such a population and the poor positive predictive value. Transvaginal ultrasound of the cervix furnishes an objective and noninvasive method for ascertaining cervical status. Various studies have shown that, among patients presenting signs of preterm labor, the risk of preterm birth is higher when the cervical length, measured with ultrasound, is less than a given cut-off point (the good predictive values of which have been ascertained). Transvaginal ultrasound is also useful among the general population. Measurement of cervical length thus ought to be incorporated into the routine ultrasound performed in this population. Moreover, in addition to cervical shortening, other abnormal ultrasound findings independently associated with an increased risk of preterm delivery include the following: dilatation of the internal os, wedging, funneling (protrusion of amniotic membranes into the cervix), dynamic changes in the degree of dilation of the cervical canal (opening of the internal os or protrusion of membranes) observed, either spontaneously during contractions or after pressure on the fundus. Because fibronectin assays and cervical ultrasound allow patients at risk of true preterm labor to be identified earlier and more accurately, they should improve the chances that tocolytic treatment will succeed. They also ought to reduce the iatrogenic disorders related to prevention of preterm birth (excessive tocolysis and extended hospitalizations) without raising the incidence of such births.

Cervix Mucus↗

PubMed2000

Risk of preterm birth in multiparous teenagers.

BACKGROUND: Previous studies of teenage primiparas have found little or no association between young maternal age and preterm birth. However, the risk of preterm birth in teenage multiparas should not be overlooked because of the high rate of repeat teenage pregnancies. OBJECTIVE: To compare the risk of preterm birth in teenage and adult multiparas. DESIGN: Cross-sectional analysis of US Natality Files, 1990 to 1996. METHODS: We calculated the risk of very preterm birth (<33 weeks' gestation) for multiparas aged 10 to 20 years compared with 25-year-olds, stratified by age and race/ethnicity. Adjusted odds ratios (AORs) were estimated controlling for maternal education, marital status, prenatal care, and previous preterm births. Effects of smoking and interpregnancy interval were analyzed separately. RESULTS: Throughout adolescence, multiparas face higher AORs for very preterm births. For white non-Hispanic multiparas compared with 25-year-old multiparas, 10- to 14-year-olds had an AOR of 4.22 (95% confidence interval [CI], 2.26-7.88), 15- to 17-year-olds had an AOR of 2.19 (95% CI, 1.99-2.42), 18- and 19-year-olds had an AOR of 1.69 (95% CI, 1.58-1.80), and 20-year-olds had an AOR of 1.33 (95% CI, 1.24-1.41). A similar pattern of decreasing AOR with increasing maternal age was observed for black non-Hispanic and Hispanic mothers, although wide race/ethnicity disparities exist. Adjusting for maternal smoking and short interpregnancy interval did not change these results. CONCLUSIONS: Risk of very preterm birth in teenage multiparas is associated with young age after controlling for other risk factors. Interventions to prevent repeat pregnancies and the associated risk of premature birth deserve high priority.

Adolescent↗

PubMed2000

Long-chain polyunsaturated fatty acid supplementation in preterm infants.

BACKGROUND: This section is under preparation and will be included in the next issue. OBJECTIVES: The n-3 and n-6 essential fatty acids alpha linolenic acid and linoleic acid are the precursors of the n-3 and n-6 longchain polyunsaturated fatty acids (LCPUFA). Controversy exists over whether LCPUFA are essential nutrients for preterm infants who may not be able to synthesise sufficient amounts of LCPUFA to satisfy the needs of the developing brain and retina. The aim of this review is to assess whether supplementation of infant formula with LCPUFA is safe and of benefit to preterm infants. SEARCH STRATEGY: Trials were identified by MEDLINE and by checking reference lists of relevant articles and conference proceedings. SELECTION CRITERIA: All randomised trials of formula supplemented with LCPUFA and with clinical endpoints were reviewed. DATA COLLECTION AND ANALYSIS: Eight randomised trials were identified. Five were assessed as being of high quality and one is awaiting assessment. Problems with the remaining two included a change in assessment methodology mid-study (Memphis 1996) and assessment methodology that deviated from generally accepted international standards (Bologna 1996). MAIN RESULTS: Studies from Dallas (Uauy et al 1990, Birch et al 1992, Hoffman & Uauy 1992, Uauy et al 1994) and Memphis (Carlson et al 1991, Carlson et al 1992, Carlson et al 1993, Werkman & Carlson 1996) suggest that early visual development is better in formula-fed infants who receive a LCPUFA supplement compared with those fed standard formula. However, the effects were not long-term, with no differences detected between groups after 4 months of age. The Bologna group (Fadelli et al 1996) reported some differences in the visual evoked potential at 3 months post-term but their methodology was questionable making interpretation of the data difficult. In the largest study (the Mead Johnson study, Hansen et al 1997), no difference in visual acuity was demonstrated between LCPUFA supplemented and control infants at 2 and 4 months post-term. The Memphis studies used the Fagan Infantest (Fagan 1970) to measure infant development and demonstrated lower novelty preferences (possibly predictive of lower intelligence) in preterm infants supplemented with LCPUFA. However, the supplemented infants had more looks at the novel stimulus and each look was of shorter duration which may represent more rapid visual information processing. Normalised weight (expressed as SD from the mean for age) was lower in preterm infants who were fed supplemented formula in the Memphis studies. No difference in growth between supplemented and control infants was documented in the Dallas, Bologna, Alberta (Clandinin et al 1997) and Wyeth (Vanderhoof et al 1997) studies while the Mead Johnson study documented higher weights in supplemented infants compared with controls at two months post-term. The Dallas study documented little effect of LCPUFA supplements on bleeding time and membrane fragility. REVIEWER'S CONCLUSIONS: No long-term benefit has been demonstrated for preterm infants receiving formula supplemented with LCPUFA. There is some evidence that n-3 LCPUFA supplementation of formula increases the early rate of visual maturation in preterm infants. Supplementation of formula with n-3 and n-6 LCPUFA does not impair the growth of preterm infants.

Dietary Supplements↗

PubMed2000

Protein supplementation of human milk for promoting growth in preterm infants.

BACKGROUND: For term infants, human milk provides adequate nutrition to facilitate growth, as well as potential beneficial effects on immunity and the maternal-infant emotional state. However, the role of human milk in preterm infants is less well defined as it contains insufficient quantities of some nutrients to meet the estimated needs of the infant. Preterm infants require higher protein intakes than term infants to attain adequate growth rates, and have relatively higher protein turnover rates. Inadequate protein intakes may be partly responsible for low serum albumin and blood urea concentrations in preterm infants. OBJECTIVES: The main objective was to determine if addition of protein to human milk leads to improved growth and neurodevelopmental outcomes without significant adverse effects in preterm infants. SEARCH STRATEGY: The standard search strategy of the Cochrane Neonatal Review Group was used. This includes searches of the Oxford Database of Perinatal Trials, MEDLINE, previous reviews including cross references, abstracts, conferences and symposia proceedings, expert informants, and journal handsearching mainly in the English language. SELECTION CRITERIA: All trials utilizing random or quasi-random allocation to supplementation of human milk with protein or no supplementation in preterm infants who remained in hospital were eligible. DATA COLLECTION AND ANALYSIS: Data were extracting using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by each author and synthesis of data using relative risk and weighted mean difference. MAIN RESULTS: Protein supplementation of human milk results in increases in short term weight gain (WMD 3.6 g/kg/day, 95% CI 2.4 to 4.8 g/kg/day), linear growth (WMD 0.28 cm/week, 95% CI 0.18 to 0.38 cm/week) and head growth (WMD 0.15 cm/week, 95% CI 0.06 to 0.23 cm/week). There are insufficient data to evaluate long term neurodevelopmental and growth outcomes. There are too few infants studied to be certain that adverse effects of protein supplementation are not increased. Blood urea levels are increased (WMD 1.0 mmol/l, 95% CI 0.8 to 1.2 mmol/l). REVIEWER'S CONCLUSIONS: Protein supplementation of human milk in relatively well preterm infants results in increases in short term weight gain, linear and head growth. Urea levels are increased, which may reflect adequate rather than excessive dietary protein intake. Further research should be directed towards the evaluation of specific levels of protein intake in preterm infants and the clinical effects of supplementation with protein, including long term growth and neurodevelopmental outcomes. This may best be done in the context of refinement of available multicomponent fortifier preparations.

Dietary Proteins↗

PubMed2004

Adrenaline for prevention of morbidity and mortality in preterm infants with cardiovascular compromise.

BACKGROUND: Inotropes are widely used in preterm infants to treat cardiovascular compromise, which may result from early adaptive problems of the transitional circulation, perinatal asphyxia or sepsis. Sustained hypotension and poor organ blood flow are associated with brain injury including peri/intraventricular haemorrhage and subsequent poor neurodevelopmental outcomes. Adrenaline (epinephrine) infusions are used in preterm infants with clinical cardiovascular compromise. OBJECTIVES: To determine the effectiveness and safety of adrenaline compared to no treatment or other inotropes in reducing mortality and morbidity in preterm infants with cardiovascular compromise. SEARCH STRATEGY: Randomised controlled trials were identified by searching MEDLINE (1966-August 2003), The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2003) and EMBASE (1980 - 2003), supplemented with searches of reference lists of published trials and abstracts of conference proceedings. SELECTION CRITERIA: Randomised controlled trials of preterm newborn infants that compared adrenaline to no treatment or other inotropic agents (including dopamine, dobutamine, noradrenaline or isoprenaline). DATA COLLECTION AND ANALYSIS: Data were extracted and analysed independently by two reviewers. Treatment effects on the following outcomes were to be determined: mortality in the newborn period, long term neurodevelopmental outcomes, radiological evidence of brain injury, short term haemodynamic changes, adverse drug effects and short term neonatal outcomes. Study authors were contacted for additional information. Studies were analysed for methodological quality using the criteria of the Cochrane Neonatal Review Group. MAIN RESULTS: One ongoing study (Pellicer 2003) was identified. One study comparing adrenaline with dopamine infusion was included but was published in abstract form only (Phillipos 1996). It enrolled hypotensive, predominantly preterm infants in the first 24 hours. Only infants >1750g are included in this review (report for infants <=1750g appears incomplete). The study was reported as being randomised and double blinded, but methods were not reported. Both adrenaline and dopamine significantly increased heart rate and mean BP, with no statistically significant effect on left or right ventricular outputs. No other clinical outcomes were reported. No studies were identified that compared adrenaline to other inotropes, placebo or no treatment. REVIEWER'S CONCLUSIONS: There are insufficient data on the use of adrenaline infusions in preterm infants with cardiovascular compromise to make recommendations for practice. There is a need for larger trials to determine whether adrenaline is effective in reducing morbidity and mortality in preterm infants with cardiovascular compromise.

Cardiotonic Agents↗

PubMed2026

Magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus.

BACKGROUND: Magnesium sulphate is a common therapy in perinatal care. Its benefits when given to women at risk of preterm birth for fetal neuroprotection (prevention of cerebral palsy for children) were shown in a 2009 Cochrane review. Internationally, use of magnesium sulphate for preterm cerebral palsy prevention is now recommended practice. As new randomised controlled trials (RCTs) and longer-term follow-up of prior RCTs have since been conducted, this review updates the previously published version. OBJECTIVES: To assess the effectiveness and safety of magnesium sulphate as a fetal neuroprotective agent when given to women considered to be at risk of preterm birth. SEARCH METHODS: We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) on 17 March 2023, as well as reference lists of retrieved studies. SELECTION CRITERIA: We included RCTs and cluster-RCTs of women at risk of preterm birth that assessed prenatal magnesium sulphate for fetal neuroprotection compared with placebo or no treatment. All methods of administration (intravenous, intramuscular, and oral) were eligible. We did not include studies where magnesium sulphate was used with the primary aim of preterm labour tocolysis, or the prevention and/or treatment of eclampsia. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed RCTs for inclusion, extracted data, and assessed risk of bias and trustworthiness. Dichotomous data were presented as summary risk ratios (RR) with 95% confidence intervals (CI), and continuous data were presented as mean differences with 95% CI. We assessed the certainty of the evidence using the GRADE approach. MAIN RESULTS: We included six RCTs (5917 women and their 6759 fetuses alive at randomisation). All RCTs were conducted in high-income countries. The RCTs compared magnesium sulphate with placebo in women at risk of preterm birth at less than 34 weeks' gestation; however, treatment regimens and inclusion/exclusion criteria varied. Though the RCTs were at an overall low risk of bias, the certainty of evidence ranged from high to very low, due to concerns regarding study limitations, imprecision, and inconsistency. Primary outcomes for infants/children: Up to two years' corrected age, magnesium sulphate compared with placebo reduced cerebral palsy (RR 0.71, 95% CI 0.57 to 0.89; 6 RCTs, 6107 children; number needed to treat for additional beneficial outcome (NNTB) 60, 95% CI 41 to 158) and death or cerebral palsy (RR 0.87, 95% CI 0.77 to 0.98; 6 RCTs, 6481 children; NNTB 56, 95% CI 32 to 363) (both high-certainty evidence). Magnesium sulphate probably resulted in little to no difference in death (fetal, neonatal, or later) (RR 0.96, 95% CI 0.82 to 1.13; 6 RCTs, 6759 children); major neurodevelopmental disability (RR 1.09, 95% CI 0.83 to 1.44; 1 RCT, 987 children); or death or major neurodevelopmental disability (RR 0.95, 95% CI 0.85 to 1.07; 3 RCTs, 4279 children) (all moderate-certainty evidence). At early school age, magnesium sulphate may have resulted in little to no difference in death (fetal, neonatal, or later) (RR 0.82, 95% CI 0.66 to 1.02; 2 RCTs, 1758 children); cerebral palsy (RR 0.99, 95% CI 0.69 to 1.41; 2 RCTs, 1038 children); death or cerebral palsy (RR 0.90, 95% CI 0.67 to 1.20; 1 RCT, 503 children); and death or major neurodevelopmental disability (RR 0.81, 95% CI 0.59 to 1.12; 1 RCT, 503 children) (all low-certainty evidence). Magnesium sulphate may also have resulted in little to no difference in major neurodevelopmental disability, but the evidence is very uncertain (average RR 0.92, 95% CI 0.53 to 1.62; 2 RCTs, 940 children; very low-certainty evidence). Secondary outcomes for infants/children: Magnesium sulphate probably resulted in little to no difference in severe intraventricular haemorrhage (grade 3 or 4) (RR 0.81, 95% CI 0.64 to 1.04; 6 RCTs, 6542 infants; moderate-certainty evidence) and may have resulted in little to no difference in chronic lung disease/bronchopulmonary dysplasia (average RR 0.92, 95% CI 0.77 to 1.10; 5 RCTs, 6689 infants; low-certainty evidence). Primary outcomes for women: Magnesium sulphate may have resulted in little or no difference in severe maternal outcomes potentially related to treatment (death, cardiac arrest, respiratory arrest) (RR 0.32, 95% CI 0.01 to 7.92; 4 RCTs, 5300 women; low-certainty evidence). However, magnesium sulphate probably increased maternal adverse effects severe enough to stop treatment (average RR 3.21, 95% CI 1.88 to 5.48; 3 RCTs, 4736 women; moderate-certainty evidence). Secondary outcomes for women: Magnesium sulphate probably resulted in little to no difference in caesarean section (RR 0.96, 95% CI 0.91 to 1.02; 5 RCTs, 5861 women) and postpartum haemorrhage (RR 0.94, 95% CI 0.80 to 1.09; 2 RCTs, 2495 women) (both moderate-certainty evidence). Breastfeeding at hospital discharge and women's views of treatment were not reported. AUTHORS' CONCLUSIONS: The currently available evidence indicates that magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus, compared with placebo, reduces cerebral palsy, and death or cerebral palsy, in children up to two years' corrected age. Magnesium sulphate may result in little to no difference in outcomes in children at school age. While magnesium sulphate may result in little to no difference in severe maternal outcomes (death, cardiac arrest, respiratory arrest), it probably increases maternal adverse effects severe enough to stop treatment. Further research is needed on the longer-term benefits and harms for children, into adolescence and adulthood. Additional studies to determine variation in effects by characteristics of women treated and magnesium sulphate regimens used, along with the generalisability of findings to low- and middle-income countries, should be considered.

Humans↗

PubMed2006

Pre-discharge "car seat challenge" for preventing morbidity and mortality in preterm infants.

BACKGROUND: Physiological monitoring studies indicate that some preterm infants experience episodes of oxygen desaturation, apnoea, or bradycardia when seated in standard car safety seats. The American Academy of Pediatrics recommends that all preterm infants should be assessed for cardiorespiratory stability in their car seat prior to discharge - the "car seat challenge". We aimed to assess the evidence to support this practice, specifically to determine whether the use of the car seat challenge prevents morbidity and mortality in preterm infants. OBJECTIVES: To assess the available evidence from randomised controlled trials that pre-discharge cardiorespiratory monitoring in a car safety seat prevents morbidity and mortality in preterm infants. SEARCH STRATEGY: We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2005), MEDLINE (1966 - September 2005), EMBASE (1980 - September 2005), CINAHL (1982 - September 2005), conference proceedings, and previous reviews. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials that compared pre-discharge cardiorespiratory monitoring in a car seat versus no monitoring in preterm infants in the week prior to planned discharge from hospital. DATA COLLECTION AND ANALYSIS: The standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two review authors, and synthesis of data using relative risk, risk difference and weighted mean difference. MAIN RESULTS: We did not find any randomised controlled trials that fulfilled the eligibility criteria. AUTHORS' CONCLUSIONS: It is unclear whether undertaking a pre-discharge car seat challenge is beneficial or harmful to preterm infants. Further studies are needed to determine whether the car seat challenge accurately predicts the risk of clinically significant adverse events in preterm infants travelling in car seats. If this is shown to be the case then a large randomised controlled trial is needed to provide an unbiased assessment of its utility in pre-discharge assessment.

Humans↗

PubMedDate not supplied

Will cervicovaginal interleukin-6 combined with fetal fibronectin testing improve the prediction of preterm delivery?

OBJECTIVE: We sought to investigate if determination of cervicovaginal interleukin-6 (IL-6) levels would enhance the positive predictive value of fetal fibronectin (fFN) for preterm birth. METHODS: A prospective cohort study was undertaken of 135 women between 24 and 34 weeks gestation with symptoms of suspected preterm labor. Cervicovaginal secretions were collected for both IL-6 and fFN and measured by immunoassay and ELISA, respectively. Outcome variables included preterm delivery in less than 48 h, within 7 days, and prior to 37 weeks. Statistical analysis was performed with Fisher's exact test, regression for logarithmic transform levels, and multivariate logistic regression. ROC curves were created for IL-6 levels. RESULTS: IL-6 and fFN levels were both elevated in cervicovaginal secretions of women with symptoms of preterm labor. IL-6 values >100 pg/ml resulted in a odds ratio for delivery at <37 weeks of 1.57 (95%CI=0.89-2.75, P=.11), whereas fFN values >50 ng/ml resulted in a preterm delivery risk of 4.58 (95%CI=1.54-13.35, P=.003). Combining IL-6 and fFN results did not improve upon the predictive value of fFN alone for preterm birth [odds ratio 4.00 (95%CI=1.31-12.17, P=.015)]. CONCLUSION: Cervicovaginal IL-6 levels did not provide any additional, independent effect on the prediction of preterm birth beyond that of fFN testing alone.

Cervix Uteri↗

PubMed2004

Comparison of transperineal and transvaginal sonography in predicting preterm delivery.

PURPOSE: A major advantage of transperineal sonography (TPUS) is its ability to evaluate the cervix without causing any distortion. This study was performed to compare transvaginal sonography (TVUS) and TPUS at 24 weeks of gestation in predicting preterm delivery in low-risk pregnancy. METHODS: Three hundred fifty-seven pregnant women underwent TVUS and TPUS at 24 weeks of gestation. The relationship between cervical length and preterm delivery was assessed. Accuracy values of TVUS and TPUS at 24 weeks of gestation were compared in predicting preterm delivery. RESULTS: Preterm delivery (before 36 weeks of gestation) occurred in 22 pregnancies (6.2%). Mean cervical lengths measured by TVUS and TPUS were significantly different in preterm and term delivery groups (P < 0.05). Areas under the curves were 0.801 and 0.857 for the transvaginal and transperineal measurements, respectively. The coefficient of correlation between the transvaginal and transperineal cervical length measurements was 0.83. TPUS had a sensitivity of 77% in predicting preterm delivery, with a false-positive rate of 17% and a relative risk of 4.5 at the 32.5-mm cutoff value. CONCLUSIONS: When the cervix is well visualized, TPUS can predict preterm delivery as accurately as TVUS.

Adult↗

PubMed2004

Respiratory symptoms and lung function in relation to atopy in children born preterm.

Respiratory morbidity is a major health problem among children. The aim of this study was to compare the background of respiratory problems of children born preterm with that of children born full-term, with special reference to atopy. The study comprised two cohorts of 10-year-old children: a group of 72 children born preterm with birth weights of less than 1,501 g, and a group of 65 children born full-term with birth weights of over 2,500 g. Histories of respiratory and atopic symptoms, and of risk factors for atopy, were collected with a questionnaire. Predisposition to atopy was verified by skin-prick testing and by measuring serum total and antigen-specific IgEs. Lung function was evaluated by spirometry testing. Children born preterm had significantly more wheezing. In them, the lifetime prevalence of wheezing was 43%, vs. 17% in children born full-term (P = 0.001; odds ratio, 3.71; 95% confidence interval, 1.67-8.25). In the full-term group, wheezing was associated with atopy: 64% of wheezers were atopic; in the preterm group, 23% of wheezers were atopic (difference between groups, P = 0.024). Children born preterm expired significantly lower spirometry values of forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), FEV1/FVC ratio, forced expiratory flow after 50% of vital capacity has been exhaled (FEF50), and forced expiratory flow during middle half of FVC (FEF25-75). In the preterm group, wheezing, asthma, and low gestational age, but not atopy, were significantly associated with lower lung function values. Wheezers of the preterm group who still wheezed at age 10 were significantly more often atopic than those who no longer wheezed (62% vs. 9%, P = 0.006). In conclusion, we demonstrated a significant difference between groups in the association of atopy with respiratory problems. However, although atopy was not associated with a lifetime prevalence of respiratory symptoms in prematurely born children, an atopic predisposition in them was found to associate with persistence of wheezing.

Child↗

PubMed2005

Effect of preterm birth on hypoxia-inducible factors and vascular endothelial growth factor in primate lungs.

Diminished vascular and alveolar development is characteristic of bronchopulmonary dysplasia (BPD). The low fetal O(2) tension promotes angiogenic responses during ontogenesis, while preterm birth interrupts normal lung growth. Most of the angiogenic responses are governed by hypoxia-inducible factors (HIFs), the expressions of which are unknown in the lungs of preterm primates. Lung tissue was harvested from fetal third-trimester baboons as well as from preterm baboons (67% or 75% of term gestation) treated with mechanical ventilation and either pro re nata (PRN) or 100% O(2). Both groups of preterm animals developed lung hypoplasia similar to human BPD. Expression of HIF-1alpha protein by Western blotting of nuclear extracts of fetal baboon samples differed from that of HIF-2alpha in that both were high at early third trimester, but at term, HIF-1alpha was absent, whereas HIF-2alpha remained unchanged. Moreover, the expression of prolyl hydroxylase domain-containing proteins 2 and 3 (PHD-2 and -3), which degrade HIFs, was increased following term birth. HIF-1alpha was diminished both in 125-day and 140-day BPD models, whereas HIF-2alpha was reduced only in the latter. Surprisingly, vascular endothelial growth factor (VEGF) was enhanced in preterm baboons with BPD as compared with age-matched fetal controls, and there was a negative correlation between HIF-1alpha and/or HIF-2alpha and VEGF in BPD. Moreover, VEGF receptors KDR and/or Flt-1 were decreased in BPD. Preterm birth also prevented the end-gestational increase in the expression of endothelial cell marker platelet-endothelial cell adhesion molecule 1. These results suggest that selective downregulation of HIFs in lungs of preterm neonates may contribute to the pathophysiology of BPD.

Actins↗

PubMed2004

Sonographic cervical length in singleton pregnancies with intact membranes presenting with threatened preterm labor.

OBJECTIVE: Less than 10% of women presenting with preterm contractions progress to active labor and delivery. This study investigates whether cervical length measurements by ultrasound can discriminate between true and false labor in women presenting with threatened preterm labor. METHODS: Cervical length was measured by transvaginal ultrasound in 253 women with singleton pregnancies presenting with painful uterine contractions at a median age of 31 (range, 24-35) weeks of gestation. Women presenting in active labor, defined by the presence of cervical dilatation of >or = 3 cm, those with ruptured membranes and those that underwent prior or subsequent cervical cerclage were excluded from the study. The clinical management was determined by the attending obstetrician without taking into account the cervical length. Primary outcome of the study was delivery within 7 days of presentation based on the results of randomized studies on the use of tocolytics in women with preterm labor that reported a prolongation of pregnancy by 7 days. RESULTS: Delivery within 7 days of presentation occurred in 21/253 (8.3%) pregnancies and this was inversely related to cervical length. Receiver-operating characteristics (ROC) curves established a cervical length of 15 mm as the most relevant cut-off level for the prediction of preterm delivery within 7 days. In 217 cases the cervical length was > or = 15 mm and only four of these (1.8%) delivered within 7 days. In the 36 women with cervical length < 15 mm, delivery occurred in 17 (47.2%) within 7 days. Logistic regression analysis demonstrated that significant independent contribution in the prediction of delivery within 7 days was provided by cervical length, contraction frequency at presentation, previous history of preterm delivery and vaginal bleeding. There was no significant contribution from gestation at presentation, ethnic origin, maternal age, parity, cigarette smoking or the administration of tocolysis, antibiotics or steroids. Similar results were shown in a subanalysis of 162 patients presenting at a gestational age below 32 weeks: 9/19 patients (47.4%) with a cervical length below 15 mm delivered within 7 days compared to 3/143 (2.1%) with a cervical length > or = 15 mm. Univariate as well as multivariate analyses confirmed cervical length to be a significant independent predictor of delivery within 7 days in this population. CONCLUSIONS: Sonographic measurement of cervical length helps to avoid overdiagnosis of preterm labor in women with preterm contractions and intact membranes.

Adolescent↗

PubMed2005

The prevalence and clinical significance of amniotic fluid 'sludge' in patients with preterm labor and intact membranes.

OBJECTIVE: To determine the prevalence and clinical significance of amniotic fluid (AF) 'sludge' observed during transvaginal ultrasound examination of the cervix in patients with preterm labor and intact membranes, and in those with uncomplicated pregnancies. METHODS: This retrospective study included patients with preterm labor and intact membranes (n = 84) and those with uncomplicated term pregnancies (n = 298). The outcome variables included the occurrence of documented microbial invasion of the amniotic cavity (MIAC), histological chorioamnionitis, examination-to-delivery interval, admission to the neonatal intensive care unit (NICU), a composite neonatal morbidity, perinatal death, and delivery within 48 h, 7 days, and < 35 weeks and < 32 weeks. Statistical analysis included Chi-square test, stepwise logistic regression analysis and survival analysis. RESULTS: The prevalence of AF 'sludge' was 1% (3/298) in patients with uncomplicated term pregnancies and 22.6% (19/84) in those with preterm labor and intact membranes. Among patients with preterm labor and intact membranes: (1) cervical length < or = 15 mm was present in 58.3% (49/84) of the patients; (2) the prevalence of MIAC and histological chorioamnionitis was 12.1% (7/58) and 32.9% (25/76), respectively; (3) the rate of spontaneous preterm delivery within 48 h, 7 days, and < 32 weeks and < 35 weeks of gestation was 13.6% (8/59), 28.8% (17/59), 39.5% (17/43) and 50.8% (30/59), respectively; (4) patients with AF 'sludge' had a higher frequency of positive AF cultures [33.3% (6/18) vs. 2.5% (1/40), P = 0.003] and histological chorioamnionitis [77.8% (14/18) vs. 19% (11/58), P < 0.001] than those without AF 'sludge'; (5) a higher proportion of neonates born to patients with AF 'sludge' was admitted to the NICU [64.3% (9/14) vs. 12.9% (8/62), P < 0.01], had a composite neonatal morbidity [36.8% (7/19) vs. 13.8% (9/65), P = 0.04] and died in the perinatal period [36.8% (7/19) vs. 4.6% (3/65), P = 0.001] than those born to women without 'sludge'; (6) a higher proportion of patients with AF 'sludge' had spontaneous delivery within 48 h [42.9% (6/14) vs. 4.4% (2/45), P = 0.001], within 7 days [71.4% (10/14) vs. 15.6% (7/45), P < 0.001], < 32 weeks [75% (9/12) vs. 25.8% (8/31), P = 0.005] and < 35 weeks [92.9% (13/14) vs. 37.8% (17/45), P < 0.001] than those without AF 'sludge'; and (7) patients with AF 'sludge' had a shorter examination-to-delivery interval than those without AF 'sludge' [AF 'sludge' median, 1 (IQR, 1-5) days vs. no AF 'sludge' median, 33 (IQR, 18-58) days; P < 0.001]. CONCLUSION: The presence of AF 'sludge' in patients with preterm labor and intact membranes is a risk factor for MIAC, histological chorioamnionitis and impending preterm delivery.

Adult↗

PubMed1999

Cytokine release from placental endothelial cells, a process associated with preterm labour in the absence of intrauterine infection.

There is currently a great deal of interest in the role that cytokines may play in the processes mediating preterm as well as normal term labour. In case of preterm delivery a cause-effect relationship between infection, uncontrollable preterm labour, and increased uterine cytokine concentrations is widely accepted, but there is considerable information that increased uterine cytokine release is also a condition in normal term labour and preterm labour not due to infection. Thereby, the exact cellular sources of cytokine production have not yet been identified. In the present study, the authors used immunohistochemical analysis to localize interleukin 1beta (IL-1beta) interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-alpha) immunoreactivity within trophoblastic villi and fetal membranes. In the absence of chorioamnionitis, uncontrollable preterm labour, and also normal term labour was associated with strong immunoreactivity for IL-1beta and IL-6 in the endothelial cells within trophoblastic villi. In contrast, preterm delivery accompanied by histologically confirmed chorioamnionitis, was not associated with increased expression of cytokine antigens within endothelial cells of the fetal vascular system, but strong cytokine activity was found in polymorphonuclear cells infiltrating the amniochorionic membranes. Therefore, the data suggest two well-defined subgroups among patients delivering preterm. Thereby, increased uterine cytokine concentrations may be realized in both groups, but the cellular sources of cytokine production may be different.

Adult↗

PubMed1999

Intrauterine lead exposure and preterm birth.

The objective of this study was to determine the risk of preterm birth in relation to umbilical cord blood lead levels (UCL) among primiparous and multiparous women. A case-cohort study was performed in Mexico City during 1995. A total of 459 full-term births was compared with 161 preterm births (before 37 gestational weeks). Mothers were interviewed before the delivery about their reproductive histories and other related factors of preterm birth. Lead was determined by atomic absorption spectrophotometry. Lead levels were higher in primiparous women who had a preterm birth than in primiparous women with a full-term birth (9.77+/-2.0 microgram/dl vs 8.24+/-2.15 microgram/dl); this difference was marginally significant. After adjusting for other known preterm birth risk factors, the frequency of preterm birth was almost three times higher among women who had UCL levels greater or equal to 5.1 microgram/dl compared to those who had UCL levels lower than 5.1 microgram/dl. This difference was not observed among multiparous women. Our results suggest that intrauterine lead exposure may be associated with preterm birth in first deliveries but not in subsequent ones.

Adolescent↗