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PubMed2000

Prophylactic corticosteroids for preterm birth.

BACKGROUND: Respiratory distress syndrome is a serious complication of prematurity causing significant immediate and long-term mortality and morbidity. OBJECTIVES: The objective of this review was to assess the effects of corticosteroids administered to pregnant women to accelerate fetal lung maturity prior to preterm delivery. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register was searched. SELECTION CRITERIA: Randomised and quasi-randomised trials of corticosteroid drugs capable of crossing the placenta compared with placebo or no treatment in women expected to deliver preterm as a result of either spontaneous preterm labour, prelabour rupture of the membranes preterm, or elective preterm delivery. DATA COLLECTION AND ANALYSIS: Eligibility and trial quality were assessed by one reviewer. MAIN RESULTS: Eighteen trials including data on over 3700 babies were included. Antenatal administration of 24 milligrams of betamethasone, of 24 milligrams of dexamethasone, or two grams of hydrocortisone to women expected to give birth preterm was associated with a significant reduction in mortality (odds ratio 0.60, 95% confidence interval 0.48 to 0.75), respiratory distress syndrome (odds ratio 0.53, 95% confidence interval 0.44 to 0.63) and intraventricular haemorrhage in preterm infants. These benefits extended to a broad range of gestational ages and were not limited by gender or race. No adverse consequences of prophylactic corticosteroids for preterm birth have been identified. REVIEWER'S CONCLUSIONS: Corticosteroids given prior to preterm birth (as a result of either preterm labour or elective preterm delivery) are effective in preventing respiratory distress syndrome and neonatal mortality. However there is not enough evidence to evaluate the use of repeated doses of corticosteroids in women who remain undelivered, but who are at continued risk of preterm birth. (This abstract has been prepared centrally.)

Female↗

PubMed2006

The effect of health compromising behaviors on preterm births.

OBJECTIVES: The objective of our study was to determine whether there were combined effects of smoking, alcohol, and illicit drug use during pregnancy on the frequency of preterm births, and if so, the magnitude of the association after adjusting for confounding factors. METHODS: We conducted a retrospective cohort study of singleton live births in Kansas City, Missouri from 1990-2002. We defined health compromising behaviors as the use of cigarettes, alcohol, and illicit drugs. The effect of these behaviors on preterm births was considered for each substance individually, and in combination. The rates of preterm births for these groups were calculated. Using logistic regression, adjusted odds ratios were used to estimate the relative risk of preterm births among these groups. RESULTS: Over 13% of infants born to women who smoked were preterm, compared to 9.6% for non-smokers. Of infants born to women who reported alcohol use, 17.3% were preterm compared to 10.1% for non-drinkers. Smoking and alcohol use in combination was associated with 18.0% preterm births, while alcohol and drug use in combination was associated with 20.8% preterm births. The use of all three substances was associated with 31.4% preterm births. CONCLUSION: Women who engaged in health compromising behaviors during pregnancy showed an increased proportion of preterm births compared to those who did not. There is significant interaction between these behaviors leading to higher rates of preterm births than predicted by their additive effects. To decrease preterm births, we must deal with the effects of smoking, drinking, and drug use simultaneously.

Adult↗

PubMed2005

The epidemiology of threatened preterm labor: a prospective cohort study.

OBJECTIVE: The purpose of this study was to describe the occurrence, timing, and outcomes of hospital-based diagnoses of preterm labor. STUDY DESIGN: Administrative records identified hospital admissions for preterm labor among 2534 women in an ongoing cohort study. Factors that were considered risks for prematurity were examined by logistic regression for an association with any preterm labor diagnosis, a preterm labor diagnosis <33 weeks of gestation, or > or =33 weeks of gestation. RESULTS: Of 234 women (9%) who experienced hospitalization for preterm labor, 90 women (38%) were delivered in the first episode. Previous preterm birth consistently was associated with a diagnosis of preterm labor. Reporting a sexually transmitted infection (odds ratio, 1.8; 95% CI, 1.1-3.0) or bacterial vaginosis (odds ratio, 2.6; 95% CI, 1.7-4.1) early in pregnancy was associated with hospitalization for preterm labor between 24 and 32 weeks of gestation. CONCLUSION: The incidence of first-time hospitalization for preterm labor was 9%, with most episodes not resulting in preterm birth. Previous preterm birth was associated therefore with a preterm labor diagnosis.

Adolescent↗

PubMed2005

Trends in twin preterm birth subtypes in the United States, 1989 through 2000: impact on perinatal mortality.

OBJECTIVE: We examined trends in twin preterm birth <37 weeks following ruptured membranes (ROM), medically indicated preterm birth, and preterm birth following spontaneous onset of labor (PTL). We further examined whether the changes in preterm birth subtypes were associated with trends in twin perinatal mortality. STUDY DESIGN: We carried out a retrospective cohort study of 1,172,405 twin live births and stillbirths delivered in the US between 1989 and 2000. Trends in preterm birth subtypes and perinatal mortality (stillbirths at > or = 22 weeks plus neonatal deaths within 28 days) were examined through ecological logistic regression models after adjusting for confounders. RESULTS: Twin preterm birth among whites increased from 46.6% in 1989 to 1990 to 56.7% in 1999 to 2000, and from 56.1% to 61.0% among blacks over the same period. Medically indicated preterm birth increased by 50% (95% CI 49-52) among whites, and by 33% (95% CI 29-36) among blacks. PTL increased by 24% among whites, but remained fairly unchanged among blacks between the two periods. Preterm birth following ROM also did not change between the 2 periods among whites, but declined by 7% among blacks. Perinatal mortality among twin births declined by 41% (95% CI 38-44) among whites, and by 37% (95% CI 32-42) among blacks between 1989 and 1990 and 1999 and 2000. This mortality decline was most closely associated with the increase in medically indicated preterm birth among whites, and with the decrease in preterm birth following ROM among blacks. CONCLUSION: Temporal trends in twin preterm birth varied substantially based on underlying subtypes and race. The increase in medically indicated preterm birth is associated with a large reduction in perinatal mortality.

Adult↗

PubMed2006

Maternal-fetal conditions necessitating a medical intervention resulting in preterm birth.

OBJECTIVE: The objective of the study was to evaluate the extent to which maternal and fetal conditions necessitate medically indicated preterm birth. STUDY DESIGN: A population-based, retrospective, cohort study of women who delivered a singleton live birth at 20 weeks or longer in Missouri, 1989 to 1997 was performed (n = 684,711). Maternal-fetal conditions that necessitated iatrogenic preterm birth included preeclampsia, small-for-gestational-age birth, fetal distress, placental abruption, placenta previa, unexplained vaginal bleeding, pregestational and gestational diabetes, renal disease, Rh sensitization, and congenital malformations. We examined the association between each of the aforementioned conditions and risk of medically indicated preterm birth at less than 35 weeks. Medically indicated preterm birth was defined as a labor induction or a prelabor cesarean in the absence of premature rupture of membranes at preterm gestations. Adjusted relative risk with 95% confidence interval for preterm birth was derived from multivariable logistic regression models, and population attributable fractions were calculated. RESULTS: The preterm birth rate (less than 35 weeks) was 4.6% (n = 31,238), with 23.5% (n = 7,347) of such births being medically indicated. Preeclampsia, fetal distress, small-for-gestational-age, and placental abruption were the most common indications for a medical intervention resulting in preterm birth, with at least 1 of these conditions present in 53.2% of medically indicated preterm births and in 17.7% of term births (relative risk 4.9, 95% confidence interval 4.7, 5.2). CONCLUSION: Preeclampsia, fetal distress, small-for-gestational-age, and placental abruption, conditions that are associated with ischemic placental disease, are implicated in well over half of all medically indicated preterm births. Although the etiology of preterm birth is heterogeneous, it is reasonable that ischemic placental disease may serve as an important pathway to preterm birth.

Abruptio Placentae↗

PubMedDate not supplied

[Socio-economic factors associated with preterm delivery. Results of the European project in Spain].

OBJECTIVES: The objectives of this paper were to analyse the effect of social, personal and medical risk factors on preterm birth (moderate versus very preterm) or on two preterm birth groups (spontaneous versus indicated). METHODS: Results from the Spanish collaborating centre of the European multicentre case-control study EUROPOP (European Program of Occupational Risks and Pregnancy Outcome) are presented. All preterm births (529) between 22 and 36 completed weeks of amenorrhea and 788 births of 37 or more completed weeks of amenorrhea (control group) are included. Explicative variables are divided in social, personal and medical factors. A univariate and multivariate analysis by means of a logistic regression were carried out. RESULTS: Very preterm birth risk was higher for women over 34 years, adjusted OR: 2.53 (1.42-4.52), with lower educational level, adjusted OR: 1.79 (1.07-2.98), for primigravid women or multigravid women with only first trimestre abortion, adjusted OR: 1.86 (1.13-3.04), and for multigravid women with previous preterm birth or second trimestre abortion, adjusted OR: 5.53 (2.97-10.35). A similar trend was observed for moderate preterm birth. Probability of spontaneous preterm birth was higher for mother over 34 years, adjusted OR: 1.51 (1.01-2.26), with lower income, adjusted OR: 1.75 (1.07-2.88) and for multigravid women with previous preterm birth or second trimestre abortion, adjusted OR: 2.96 (1.86-4.71). Results were similar for indicated preterm birth. CONCLUSION: Social differences were found to be related to moderate and very preterm birth. No differences were observed between risk factors and kind of preterm birth: spontaneous or indicated.

Adult↗

PubMed2003

Monocyte chemotactic protein-1 in cervical and amniotic fluid: relationship to microbial invasion of the amniotic cavity, intra-amniotic inflammation, and preterm delivery.

OBJECTIVE: The purpose of this study was to evaluate the role of monocyte chemotactic protein-1 in cervical and amniotic fluid in women in preterm labor and with preterm premature rupture of membranes. STUDY DESIGN: Women with singleton pregnancies (<or=34 weeks) in preterm labor (n=75 women), with preterm premature rupture of membranes (n=47 women), and at term (n=45 women) who were undergoing elective cesarean delivery were included. Cervical and amniotic fluid were sampled. RESULTS: Monocyte chemotactic protein-1 in cervical and amniotic fluid was higher in women in preterm labor than in women at term. Cervical monocyte chemotactic protein-1 in women in preterm labor was associated with microbial invasion of the amniotic cavity, intra-amniotic inflammation, delivery within 7 days, and at <or=34 weeks. Amniotic monocyte chemotactic protein-1 correlated to microbial invasion of the amniotic cavity in women with preterm premature rupture of membranes, intra-amniotic inflammation in preterm labor, preterm premature rupture of membranes, delivery within 7 days, and delivery at <or=34 weeks in women in preterm labor. CONCLUSION: Monocyte chemotactic protein-1 in cervical and amniotic fluid levels are elevated in preterm labor and preterm premature rupture of membranes and correlate to intra-amniotic infection/inflammation.

Amniotic Fluid↗

PubMed2004

Maternal genital colonization with Ureaplasma urealyticum promotes preterm delivery: association of the respiratory colonization of premature infants with chronic lung disease and increased mortality.

BACKGROUND: Infection of the chorioamnion with Ureaplasma urealyticum has been associated with low birth weight. Respiratory tract colonization in preterm infants has been associated with the development of chronic lung disease (CLD). The purpose of the present study was to determine the frequency of colonization of the mother's vagina and the preterm infant's respiratory tract and to associate U. urealyticum with premature birth and with development of CLD in the newborn. METHODS: The present prospective study involved 126 mothers with preterm delivery and 125 mothers with full-term delivery, as well as their offspring. Vaginal secretion specimens were obtained from each mother before delivery. Rhinopharyngeal secretion or tracheal lavage specimens were collected after the birth of each premature and full-term infant and then periodically during hospitalization. RESULTS: Vaginal Ureaplasma colonization occurred among 36.5% of mothers with preterm delivery and among 38% of mothers with full-term delivery. The rate of vertical transmission was 33% and 17% for mothers with preterm delivery and mothers with full-term delivery, respectively. The transmission rate for infants, according to birth weight, was as follows: 60%, for infants with a birth weight of <1000 g; 50%, for infants with a birth weight of 1000-1500 g; and 15.3%, for infants with a birth weight of > or =1500 g (P=.001). The median gestational age of preterm infants born to colonized mothers was 28.5 weeks, and that of preterm infants born to noncolonized mothers was 32 weeks (P<.0001). The median birth weight of colonized preterm infants was 1135 g, and that of noncolonized infants was 1670 g (P<.0001). Twenty-four percent of preterm infants and 10% of full-term infants were colonized with U. urealyticum. Of colonized preterm infants, 27% developed CLD, compared with 9% of noncolonized infants (P=.03). Mortality was significantly higher among colonized preterm infants (P=.003). CONCLUSIONS: The rate of vertical transmission is highest among preterm infants with a birth weight of <1500 g. Vaginal colonization with Ureaplasma organisms is associated with premature delivery. Colonization of the respiratory tract of infants is associated with the development of CLD and with increased mortality.

Adult↗

PubMed1995

Mannose-binding protein in preterm infants: developmental profile and clinical significance.

The aim of this study was to determine the developmental profile of mannose-binding protein (MBP) in preterm infants. MBP was measured in 885 longitudinally collected serum samples from 168 preterm infants, and 63 were genotyped with respect to the codon 54 mutation in the MBP gene. MBP level/codon 54 genotyping were also determined on the cord blood of 146/123 term infants and 138/123 adults, respectively. The best cut-off values of MBP for dividing preterm, term infants and adults into 'low' and 'high' MBP groups were 400 ng/ml (55 low, 113 high), 700 ng/ml (35 low, 111 high) and 750 ng/ml (33 low, 105 high), respectively, by achieving the least number of misclassifications according to the codon 54 mutation. The relative risk of the 'low' groups for presence of the codon 54 mutation compared with 'high' groups were 42.4, 67.9 and 22.9 for preterm, term infants and adults, respectively (P < 0.00001). The gestational age and birth weight of the 'low' (n = 55) and 'high' (n = 113) MBP groups of the 168 preterm infants were 29.5 +/- 2.8 weeks, 30.5 +/- 2.8 weeks (P = 0.03) and 1230 +/- 317 g, 1277 +/- 289 g (P = 0.35), respectively. The mean MBP levels of these two groups of preterm infants were different (P < 0.001) at all ages measured. As a whole group, the MBP level rose from a mean of 500 ng/ml at 25 weeks gestation to 1700 ng/ml at 20 weeks post full-term. The mortality rates of 'low' and 'high' MBP groups of preterm infants were 22% and 12%, respectively (P = 0.113). This difference in mortality was due to gestational age and birth weight standard deviation score (SDS) after adjusting for length of gestation and gender (P = 0.0001) rather than to low MBP levels (P = 0.65). MBP levels were not related to birthweight SDS score (P = 0.26). The mean +/- s.d. MBP levels for preterm, term infants and adults without the codon 54 mutation were 1225 +/- 701 ng/ml (n = 45), 2064 +/- 829 ng/ml (n = 88) and 2473 +/- 1395 ng/ml (n = 95), respectively; the corresponding values for those with the codon 54 mutation were 130 +/- 275 ng/ml (n = 18), 533 +/- 665 ng/ml (n = 35) and 330 +/- 225 ng/ml (n = 28), respectively. Intra-uterine growth retardation in preterm infants does not influence MBP levels. For those without the codon 54 mutation, there is a significant difference in MBP level between the three age groups. For those with the codon 54 mutation, there is a significant difference between preterm and term infants, but not between term infants and adults. We conclude that there is a maturation in MBP levels for preterm infants, and that a moderately low MBP phenotype does not affect survival. We cannot exclude an effect of profoundly reduced MBP levels (characteristic of individuals homozygous for the codon 54 mutation), since no such preterm infant was identified in this study.

Adult↗

PubMed1995

Racial differences in the patterns of preterm delivery in central North Carolina, USA.

In order to assess racial differences in rates of idiopathic preterm labour, preterm premature rupture of membranes, and medically indicated preterm delivery, the authors analysed data on 388 preterm (< 37 completed weeks of gestation) births (7.9% of all births) occurring between 1 September 1988 and 31 August 1989, in three central North Carolina counties. The crude relative risk (RR) of preterm birth among black women compared with white women was 2.6 [95% confidence interval (CI) 2.1, 3.1]. With adjustment for age, gravidity, marital status, education, and county of residence, the estimated relative risk for black women compared with white women was 2.1 (95% CI 1.1, 4.1) for medically indicated preterm delivery, 1.6 (95% CI 1.1, 2.3) for preterm birth as a result of preterm labour, and 1.9 (95% CI 1.2, 3.1) for preterm premature rupture of membranes. Compared with white women, black women were at the highest risk of a preterm birth before 34 weeks of gestation (RR = 2.9; 95% CI 1.8, 4.7). The risk of medically indicated preterm delivery at 36 weeks was considerably higher for black women than for white women (RR = 3.4; 95% CI 1.1, 10.2). For a better understanding and ultimately a reduction of the risk for preterm delivery among black women, investigation of specific aetiological pathways and gestational age groups may be required.

Adolescent↗

PubMed1992

Prenatal microbiological risk factors associated with preterm birth.

OBJECTIVE: To study the vaginal flora of pregnant women at 22-28 weeks gestation to determine whether the presence of specific micro-organisms is significantly associated with preterm birth and prelabour rupture of the membranes. DESIGN: A comprehensive descriptive prospective study of the vaginal micro-flora of women between 22-28 weeks gestation comparing those who gave birth preterm (less than 37 weeks) with those who gave birth at term. Microbiological assessment included cultures for aerobic and anaerobic bacteria, yeasts, genital mycoplasmas and Trichomonas vaginalis. Multiple logistic regression analysis was used to account for confounding obstetric and demographic variables. SETTING: The Queen Victoria Hospital, Adelaide, South Australia. SUBJECTS: 135 women who gave birth preterm compared to 651 women who gave birth at term. MAIN OUTCOME MEASURE: Preterm birth and preterm prelabour rupture of membranes (PROM) RESULTS: The prevalence of Gardnerella vaginalis between 22-28 weeks was significantly higher in women who gave birth preterm compared to women who gave birth at term (23% vs 15%; multiple logistic regression odds ratio (OR) 1.8, 95% confidence intervals (CI) 1.01-3.2, P less than 0.05. Ureaplasma urealyticum was also found in a higher proportion of women who gave birth preterm (49% vs 32% OR 1.7, 95% CI 1.1-2.6, P less than 0.0005). Preterm PROM occurred in 42% of whom 60% were carriers of U. urealyticum between 22-28 weeks, compared with 32% in the term group (OR 3.2, CI 1.7-6.1, P less than 0.0005). When women who received antibiotics between the midtrimester swab and labour were excluded, G. vaginalis was also significantly associated with preterm PROM (OR 2.7, CI 1.1-6.5, P less than 0.05). The presence of vaginal enteropharyngeal bacteria (E. coli, Klebsiella spp., Haemophilus spp., Staph. aureus) in the midtrimester was not predictive of preterm birth, but when these organisms were found in labour, they appeared to have been acquired later in the pregnancy. CONCLUSION: Women carrying G. vaginalis or U. urealyticum during the midtrimester had nearly twice the risk of preterm birth, while women positive for U. urealyticum had more than a threefold risk of preterm PROM.

Adult↗

PubMed1996

Smoking during pregnancy and preterm birth.

OBJECTIVE: To evaluate the association between smoking during pregnancy and preterm birth. DESIGN: A follow up study. SETTING: Department of Gynaecology and Obstetrics, Aarhus University Hospital, Denmark. PARTICIPANTS: Four thousand one hundred and eleven nulliparous women with singleton pregnancies who returned questionnaires about smoking habits at 16 weeks of gestation. RESULTS: The overall rate of preterm delivery was 4.3%. Smokers had a 40% higher risk of preterm birth compared with nonsmokers. A dose response relationship was found between smoking and risk of preterm birth. Adjustment for women's height, prepregnancy weight, age of the mother, marital status, education, occupational status, and alcohol intake did not change the results. Among women with an intake of less than 400 mg of caffeine per day no difference in the risk of preterm birth between smokers and nonsmokers was found. However, among women with an intake of more than 400 mg of caffeine per day, the risk of preterm birth was increased almost threefold among smokers compared with nonsmokers. Furthermore, among women with a high intake of caffeine a dose-response relationship was found; women smoking one to five cigarettes per day had no increased risk of preterm birth compared with nonsmokers with the same intake of caffeine, women smoking six to ten cigarettes per day had almost three times higher risk of preterm birth, and women smoking more than 10 cigarettes per day had almost five times higher risk of preterm birth compared with nonsmokers with the same intake of caffeine. CONCLUSIONS: Smoking increases the risk of preterm birth. The association between smoking and preterm birth was only present among women with a high intake of caffeine. However, whether smoking alone influences the risk of preterm birth among heavy consumers of caffeine needs further investigation.

Adolescent↗

PubMed2001

Combination of cervical interleukin-6 and -8, phosphorylated insulin-like growth factor-binding protein-1 and transvaginal cervical ultrasonography in assessment of the risk of preterm birth.

OBJECTIVE: To determine the value of combinations of cervical interleukin-6 (IL-6), cervical interleukin-8 (IL-8), the phosphorylated isoform of insulin-like growth-factor binding protein-1 (IGFBP-1), and cervical ultrasonography in the prediction of preterm birth. DESIGN: Prospective follow up. SETTING: Oulu University Hospital maternity clinic from February 1997 to July 1998. POPULATION: Women with singleton pregnancies (n = 77), referred from outpatient clinics at 22-32 weeks of gestation with symptoms (uterine contractions) or signs (cervical change) of threatened preterm birth. Symptomless women (n = 78) matched for gestational age, parity and maternal age at recruitment were studied as a reference group. METHODS: A urine sample for bacterial culture was collected, and cervical swab samples for assays of interleukin-6 and -8 and phoshorylated IGFBP-1 were taken before digital cervical examination. A Pap smear for analysis of bacterial vaginosis and samples for analysis of chlamydia and streptococci were also obtained. Cervical measurements were made by transvaginal ultrasonography. The same sampling and cervical measurement were repeated twice at two-week intervals. The cutoff values of the markers were determined by receiver-operating characteristic curve analysis. MAIN OUTCOME MEASURE: Preterm birth (<37 weeks). RESULTS: The preterm birth (<37 weeks) rate for women in the study group was 16% (12/77). The cervical interleukin-6 cutoff value (61 ng/L) at first visit had a sensitivity of 73% and a specificity of 61% in predicting preterm birth, with a positive likelihood ratio (LR+ ) of 1.9 (95% CI 1.2-3.0). An ultrasonographically measured cervical index value of > 0.36 at recruitment predicted preterm birth in 25% (5/20) of the study group compared with 9% (5/54); LR+ 2.2 (95% CI 1.03-4.7). Cervical phosphorylated IGFBP-1 > 6.4 microg/L [LR+ 1.8 (95% CI 0.7-2.9)], interleukin-8 > 3739 ng/L [LR+ 1.4 (95% CI 0.9-2.4)], and ultrasonograpic cervical length < 29.3 mm [LR+ 2.7 (95% CI 0.8-9.7)] increased the risk of preterm birth. According to the logistic regression model, a combination of IL-6, and IL-8 and cervical index increased the specificity to 97%, but the sensitivity fell to 30% in detecting preterm birth. There was a significantly increased incidence of puerperal infections if phosphorylated IGFBP-1 concentrations were elevated (> 21.0 microg/L), 36% (4/11) compared with 4.6% (3/65), LR+ 6.7 (95% CI 2.7-17), the sensitivity being 67% (4/6) and the specificity 90% (63/70). Elevated phosphorylated IGFBP-1 concentrations (> 21.6 microg/L) were also associated with an increased risk of neonatal infections; LR+ 8.0 (95% CI 3.5-18). CONCLUSIONS: An increase in cervical IL-6 concentration and the ultrasonographically measured cervical index appear to be associated with preterm birth. A combination of these markers with measurement of cervical IL-8 appears to be the best predictor of preterm birth. Neither the sensitivity nor specificity of the tests used in this study are good enough to predict preterm birth for clinical decision making. Cervical phosphorylated IGFBP-1 seems to be a marker of puerperal and neonatal infectious morbidity in cases of threatened preterm delivery, suggesting early tissue degradation at the choriodecidual interface.

Adult↗

PubMed2002

Deposition of whole blood platelets on extracellular matrix under flow conditions in preterm infants.

BACKGROUND: A previous study showed greater adhesion by platelets of healthy full term infants to subendothelial extracellular matrix (ECM) under flow conditions compared with healthy adult platelets. AIM: To investigate the adhesion and aggregation of platelets from preterm infants on ECM under defined shear conditions. METHODS: In vitro platelet function was investigated in 106 preterm infants, 74 full term infants, and 26 healthy adults. Blood samples were obtained from all infants within 24 hours of birth, and weekly until discharge from preterm infants only. Citrated whole blood was placed in ECM precoated tissue culture plates and subjected to shear stress (1300 s-1) for two minutes using a rotating Teflon cone. Platelet adhesion (surface coverage) and aggregation (average size) to ECM were assayed using an image analyser. Assays for von Willebrand factor (vWF) antigen, ristocetin cofactor, and vWF collagen-binding activity were performed on samples from an additional 70 preterm infants, 23 healthy full term infants, and 24 healthy adults. Preterm infants with hyaline membrane disease (HMD) were analysed separately in both cohorts. RESULTS: Platelets from preterm infants displayed significantly less platelet adhesion than those from full term infants but similar aggregation and levels of vWF antigen, ristocetin cofactor, and collagen binding activity. Mean surface coverage was 22.0 (8.4)% for preterm infants with HMD, 28.7 (8.0)% for healthy preterm infants, and 35.7 (7.9)% for full term infants. Surface coverage in the preterm infants correlated with gestational age during the first 24 hours only, and did not reach full term levels during 10 weeks of follow up. CONCLUSION: Platelet adhesion to ECM is significantly poorer in preterm than in full term infants, and poorer in preterm infants with HMD than in healthy preterm infants. Intrinsic platelet properties rather than the concentration or activity of vWF may be responsible for this difference.

Adult↗

PubMed2004

Factors associated with preterm delivery in women with type 1 diabetes: a cohort study.

OBJECTIVE: The reported rate of preterm delivery in women with type 1 diabetes ranges from 22 to 45%, but the reasons are unclear. The purpose of this study was to identify factors associated with preterm delivery in these women. RESEARCH DESIGN AND METHODS: We studied the influence of maternal and diabetes-related factors on the occurrence of preterm delivery in 168 single pregnancies occurring in 127 women with type 1 diabetes. Women with spontaneous or indicated preterm delivery were compared with those who delivered after 37 weeks of gestation using polytomous logistic regression. RESULTS: The overall rate of preterm delivery was 24%, fivefold higher than the French prematurity rate in single pregnancy. Preterm delivery was spontaneous in 9% and indicated in 15%. HbA1c > or =7% at delivery was associated with spontaneous preterm delivery (odds ratio [OR] 5.3 [95% CI 1.1-26.8]). Nulliparity (12.0 [2.3-64.1]), progression of nephropathy (7.7 [1.3-46.9]), preeclampsia (12.0 [3.1-47.1]), and HbA1c > or =7% (7.5 [1.5-37.9]) at delivery were all associated with indicated preterm delivery. Preterm delivery was associated with significant neonatal morbidity as the risks for neonatal hypoglycemia and respiratory distress syndrome were increased by three- to sixfold compared with the reference group. CONCLUSIONS: The rate of preterm delivery remains high in women with type 1 diabetes. Different factors were associated with spontaneous and indicated preterm delivery, respectively. Because poor glycemic control was a risk factor for both outcomes, part of preterm delivery might be preventable.

Adult↗

PubMed1999

[Value of multinomial model in epidemiology: application to the comparison of risk factors for severely and moderately preterm births].

BACKGROUND: The multinomial logistic regression model is employed to model the relationship between an outcome variable with more than two categories and a set of covariates. This model is not widely used in epidemiology. We discuss the value of the multinomial model by comparing it with the binary logistic model, and we present a statistical comparison of odds ratios (OR) using the multinomial model. We studied the associations between obstetric history and very (< 33 weeks of amenorrhea) and moderate (33-36 weeks) preterm births. METHODS: Parameters (lnOR) of very and moderate preterm births, associated with the severity of obstetric history (none=0, moderate=1, severe=2), were estimated using two logistic binary models (moderate preterm births vs full-term births (>=37 weeks), and very preterm births vs full-term births) and one logistic multinomial model which compared very and moderate preterm births to full-term births. These analyses were performed before and after adjustment for a covariate: the country of survey. Parameters of very preterm birth and moderate preterm birth, estimated from multinomial model, were compared using Wald test. These analyses were performed using data from a large case-control survey in Europe, the EUROPOP survey; 1 675 very preterm births, 3 652 moderate preterm births and 7 965 full-term births were included. RESULTS: Crude parameters of very and moderate preterm births were similar, regardless the logistic regression model, binary or multinomial. The estimated parameters slightly differ after adjustment for the covariate, but lower variance estimates were obtained using multinomial logistic regression model. Parameters of very preterm birth associated with moderate obstetric history, B(gp)=0.5040, and severe obstetric history, B(gp)'=1.545, differ significantly from those of moderate preterm birth, B(pm)=0.4434 and B(pm)'=1.223 respectively (p < 0.001). CONCLUSION: Parameters obtained in separate logistic binary models are close to those obtained in a multinomial model. The multinomial model is useful for testing the heterogeneity of risk factors for distinct health problems.

Gestational Age↗

PubMedDate not supplied

Does evidence of inflammation on Papanicolaou smears of pregnant women predict preterm labor and delivery?

BACKGROUND: Preterm delivery is the most common cause of neonatal morbidity and mortality in the United States. There is evidence that cervicovaginal infection could predispose to preterm labor. This study explored a possible association of evidence of inflammation on an otherwise normal Papanicolaou smear obtained during pregnancy with subsequent preterm labor and preterm delivery. METHODS: Using a retrospective matched cohort design, we studied women who gave birth to live singleton infants at the University of Missouri Hospital and Clinics during a 21-month period. Papanicolaou smears were obtained from 1 to 8 months before delivery and were interpreted in the same cytopathology laboratory. Data pertaining to outcome variables and potential confounding variables were collected from hospital charts. RESULTS: Incidence rates were 14.4 percent for labor < 37 weeks' gestation (preterm labor), 12.3 percent for hospitalization for preterm labor, 9.9 percent for delivery < 37 weeks (preterm delivery), 2.6 percent for delivery < 34 weeks, and 7.5 percent for birth weight < 2500 g. On univariate and multivariate analyses, there were no significant differences in any outcome between the 293 women with inflammation and the 284 women without inflammation on Papanicolaou smear. Results were unchanged when the analysis was limited to the 412 women who received no antibiotics during pregnancy. Among the 38 women with a history of preterm labor or preterm delivery, those with cervical inflammation had a higher rate of preterm labor than those without inflammation. CONCLUSIONS: In the sample as a whole, there was little evidence that findings of inflammation on Papanicolaou smear constituted a risk factor for preterm labor or preterm delivery. The data suggest that inflammation could be associated with an increased risk in a subgroup of women at higher risk by virtue of their obstetric history.

Adult↗

PubMed1992

A critical assessment of preterm labor prevention strategies.

Preterm birth is second only to congenital diseases in causing morbidity and mortality in infants. To prevent preterm labor and delivery, a number of strategies have been developed. When choosing a strategy to prevent preterm birth, however, physicians must remember that preterm delivery arises from three separate conditions: iatrogenic preterm labor, premature rupture of membranes, and idiopathic preterm labor. Many of the programs that have been developed focus on patients who are at high risk for iatrogenic preterm birth and premature rupture of membranes, but do not include patients who are likely to experience idiopathic preterm labor. Since idiopathic preterm labor is the most common cause of preterm birth and is the most amenable to early intervention with tocolytic agents, more preterm labor education efforts should be included in prenatal care programs. In addition, further research is needed to delineate which features of preterm birth prevention programs are responsible for the beneficial effects that have been observed.

Clinical Trials as Topic↗