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PubMed1996

Elevation of amniotic fluid interleukin-4 concentrations in women with preterm labor and chorioamnionitis.

Preterm labor associated with intrauterine infection is characterized by increased amniotic fluid concentrations of various proinflammatory cytokines, including interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), IL-6, IL-8, and macrophage inflammatory protein-1alpha (MIP-1alpha). The purpose of this study was to determine if preterm labor in women with clinically evident chorioamnionitis is marked by elevations of the anti-inflammatory cytokine interleukin-4 (IL-4) and the T cell growth factor IL-2. Amniotic fluid samples were obtained from (1) women at term, not in labor (n = 10); (2) women at term, in labor (n = 10); (3) women with preterm contractions but undelivered within 1 week of amniotic fluid collection (n = 10); (4) women with preterm labor and delivery without clinically evident chorioamnionitis (n = 10); (5) women with preterm labor associated with chorioamnionitis (n = 8); and (6) women with preterm labor and delivery without infection matched with patients with chorioamnionitis (n = 8). Amniotic fluid concentrations of IL-4 and IL-2 were determined for each sample with a specific and sensitive enzyme-linked immunoassay. We found that women with infection-associated preterm labor and delivery had significantly higher concentrations of IL-4 when compared to appropriately matched controls (p < 0.05). Additionally, women with preterm labor and delivery not associated with infection had higher amniotic fluid IL-4 concentrations than women with preterm contractions but no labor (p < 0.05). Women with term labor had rare modest elevations of amniotic fluid IL-4. No IL-2 was detected in any sample. Our data indicate that amniotic fluid IL-4 is elevated in women with preterm labor and delivery, particularly in association with chorioamnionitis. We suggest that IL-4, although previously considered an anti-inflammatory agent, may have a paradoxical proinflammatory role in the pathogenesis of infection-associated preterm labor.

Adult↗

PubMed2001

Distinct molecular events suggest different pathways for preterm labor and premature rupture of membranes.

OBJECTIVE: On a clinical level, the etiologies associated with premature rupture of the membranes and preterm labor are virtually identical, though these conditions end in distinctly different events. This study was designed to determine differences between preterm labor and preterm premature rupture of membranes by using molecular markers of extracellular matrix degradation and apoptosis. STUDY DESIGN: Amniochorion and amniotic fluid samples were collected from gestational age-matched groups of women undergoing cesarean delivery before term. Samples were collected from 2 groups of women, women with premature rupture of membranes and women with preterm labor with no rupture of membranes. Changes in the expression pattern of messenger ribonucleic acid for matrix metalloproteinases (MMP), tissue inhibitor of metalloproteinases (TIMP), and pro-apoptotic (p53 and Bax) and anti-apoptotic (Bcl-2) proteins were identified by quantitative polymerase chain reaction. Enzyme-linked immunosorbent assay was used to determine the levels of these proteins in the amniotic fluid. Multiplex polymerase chain reaction was performed to study the expression of Fas-Fas ligand-associated pro-apoptotic genes. Unpaired nonparametric, 2-tailed Mann-Whitney U test was used to determine statistical significance of quantitative polymerase chain reaction and enzyme-linked immunosorbent assay (P <.05 was considered significant). RESULTS: Quantitative polymerase chain reaction results demonstrated an increased mRNA expression for MMP2, MMP9, and MT1-MMP and a decreased expression for TIMP2 in prematurely ruptured membranes compared with preterm labor membranes. Enzyme-linked immunosorbent assay documented increases in the amniotic fluid concentrations of immunoreactive and bioactive MMP2 and MMP9 and immunoreactive MMP3 and a decreased TIMP2 concentration in fluids obtained from the premature rupture of membranes group compared with the preterm labor group. The pro-apoptotic genes p53 and bax were up-regulated in premature rupture of membranes when compared with preterm labor. Anti-apoptotic gene (Bcl-2 ) expression was increased in preterm labor membranes compared with prematurely ruptured membranes. Interleukin-18 (a pro-apoptotic cytokine) was increased in the amniotic fluid during premature rupture of membranes compared with preterm labor. Prematurely ruptured membranes also demonstrated fragmented deoxyribonucleic acid and expression of Fas and caspase 8 (apoptosis initiator), which were all absent in preterm labor membranes. CONCLUSIONS: We have begun to delineate 2 divergent molecular pathways for premature rupture of membranes and preterm labor. Most likely, this is the beginning of the identification of differences that will become evident with the use of molecular biology.

Amniotic Fluid↗

PubMed2003

Evaluation of quantitative ultrasound tissue characterization of the cervix and cervical length in the prediction of premature delivery for patients with spontaneous preterm labor.

OBJECTIVE: This study was to evaluate the predictive value of the uterine cervix tissue with the use of quantitative ultrasound gray level analysis for preterm delivery. STUDY DESIGN: Sixty-eight patients with preterm labor between 20 and 35 weeks of gestation were included. When two-dimensional transvaginal ultrasound measurement of cervical length was completed, a region of interest of constant size was defined in the midsection of the posterior wall, and the tissue-specific gray scale was determined. Preterm delivery of <37 weeks of gestation was sought. RESULTS: Twenty-eight patients (41.2%) were delivered preterm. The risk for preterm delivery was increased significantly in patients with cervical length of </=2.5 cm (odds ratio, 7.67; 95% CI, 2.4-24.45), with Bishop score of >/=4 (odds ratio, 3.44; 95% CI, 1.21-9.75), and with decreased mean gray scale value (odds ratio, 12.13; 95% CI, 3.69-39.88). Parity and uterine contractions were not significant as predictors for preterm delivery, although the risk for preterm delivery increased with higher parity (odds ratio, 1.8; 95% CI, 0.68-4.79). The risk for preterm delivery remained nearly the same by uterine contractions (odds ratio, 0.92; 95% CI, 0.28-3.01). A mean scale value of </=6.54 had the best cutoff value for the prediction of preterm delivery. For preterm delivery, a mean gray value </=6.54 had a sensitivity of 82.1%, a specificity of 72.5%, a positive predictive value of 67.6%, and a negative predictive value 85.3%. Multiple logistic regression analysis indicated that, even when other variables are considered simultaneously, the mean gray scale value is the single best predictor of preterm delivery. CONCLUSION: Quantitative ultrasound tissue characterization of the uterine cervix predicts premature delivery and provides additional information in the prediction of potential premature delivery.

Adult↗

PubMed2001

Trends in preterm birth and neonatal mortality among blacks and whites in the United States from 1989 to 1997.

Preterm birth, a major determinant of infant mortality, has been increasing in recent years. The authors examined trends in preterm birth and its determinants by using the US birth and infant death files for 1989-1997. The impact of trends in preterm birth rates on neonatal and infant mortality was also evaluated. Among Whites, preterm births (<37 completed weeks of gestation) increased from 8.8% of livebirths in 1989 to 10.2% in 1997, a relative increase of 15.6%. On the other hand, preterm births among Blacks decreased by 7.6% (from 19.0% to 17.5%) during the same period. An increase in obstetric interventions contributed to increases in preterm births for both races but was outweighed by other unidentified favorable influences for Blacks. Neonatal mortality among preterm Whites dropped 34% during the 8 years of the study, while the decrease was only 24% among Blacks. This large disparity countered the changes in preterm birth rates so that the percentage decline in neonatal mortality was similar in the two racial groups (18-20%). In conclusion, the anticipated mortality benefit from a lower preterm birth rate for Blacks has been blunted by suboptimal improvement in mortality among the remaining preterm infants. The widening race gap in mortality among preterm infants merits attention.

Black or African American↗

PubMed2006

Perinatal risk factors altering regional brain structure in the preterm infant.

Neuroanatomical structure appears to be altered in preterm infants, but there has been little insight into the major perinatal risk factors associated with regional cerebral structural alterations. MR images were taken to quantitatively compare regional brain tissue volumes between term and preterm infants and to investigate associations between perinatal risk factors and regional neuroanatomical alterations in a large cohort of preterm infants. In a large prospective longitudinal cohort study of 202 preterm and 36 term infants, MR scans at term equivalent were undertaken for volumetric estimates of cortical and deep nuclear grey matter, unmyelinated and myelinated white matter (WM) and CSF within 8 parcellated regions for each hemisphere of the brain. Perinatal correlates analysed in relation to regional brain structure included gender, gestational age, intrauterine growth restriction, bronchopulmonary dysplasia, white matter injury (WMI) and intraventricular haemorrhage. Results revealed region-specific reductions in brain volumes in preterm infants compared with term controls in the parieto-occipital (preterm mean difference: -8.1%; 95% CI = -13.8--2.3%), sensorimotor (-11.6%; -18.2--5.0%), orbitofrontal (-30.6%; -49.8--11.3%) and premotor (-7.6%; -14.2--0.9%) regions. Within the sensorimotor and orbitofrontal regions cortical grey matter and unmyelinated WM were most clearly reduced in preterm infants, whereas deep nuclear grey matter was reduced mainly within the parieto-occipital and subgenual regions. CSF (ventricular and extracerebral) was doubled in volume within the superior regions in preterm infants compared with term controls. Cerebral WMI and intrauterine growth restriction were both associated with a more posterior reduction in brain volumes, whereas bronchopulmonary dysplasia was associated with a more global reduction across all regions. In contrast degree of immaturity was not related to regional brain structure among preterm infants. In summary, preterm birth is associated with regional cerebral tissue reductions, with the adverse pattern varying between risk factors. These findings add to our understanding of the potential pathways leading to altered brain structure and outcome in the preterm infant.

Brain↗

PubMed2004

History of induced abortion as a risk factor for preterm birth in European countries: results of the EUROPOP survey.

BACKGROUND: The objective of this study was to investigate the relationship between history of induced abortion and preterm delivery in various parts of Europe, and according to the main cause of preterm birth. METHODS: We used data from a case-control survey, the EUROPOP study; 2938 preterm births and 4781 controls at term from ten European countries were included. Based on national statistics, we distinguished three groups of countries with high, intermediate and low rates of induced abortion. RESULTS: Previous induced abortions were significantly associated with preterm delivery and the risk of preterm birth increased with the number of abortions. Odds ratios did not differ significantly between the three groups of countries. The extent of association with previous induced abortion varied according to the cause of preterm delivery. Previous induced abortions significantly increased the risk of preterm delivery after idiopathic preterm labour, preterm premature rupture of membranes and ante-partum haemorrhage, but not preterm delivery after maternal hypertension. The strength of the association increased with decreasing gestational age at birth. CONCLUSIONS: Identifying subgroups of preterm births on the basis of the complications involved in delivery increases our understanding of the mechanisms by which previous induced abortion affects subsequent pregnancy outcomes.

Abortion, Induced↗

PubMed1992

Preterm birth subtypes among blacks and whites.

The differences in preterm birth between blacks and whites are poorly understood. Our study examined subtypes of moderately preterm delivery (34-36 completed weeks of gestation) and very preterm delivery (20-33 weeks) in blacks and whites using North Carolina birth certificate data for 1988-1989. We divided the causes of preterm birth into three categories: preterm premature rupture of the membranes, indication of pregnancy complication, and idiopathic preterm deliveries. The overall prevalence of preterm birth was 8.0% and 16.7% for whites and blacks, respectively. The entire gestational age distribution of blacks was shifted to earlier ages relative to whites. More highly educated blacks still had higher risks of moderately and very preterm deliveries than less educated whites. Multivariate analysis, controlling for other factors, showed that blacks had 3.3, 2.5, and 3.5 times the risk of whites to have preterm premature rupture of the membranes, complication-related, and idiopathic delivery, respectively, among very preterm births, and 1.6, 1.9, and 2.0 times the risk of whites for moderately preterm births of the same three types.

Black People↗

PubMed2004

Heterogeneity of perinatal outcomes in the preterm delivery syndrome.

OBJECTIVE: Our aim was to document the differential neonatal morbidity and intrapartum and neonatal mortality of subgroups of preterm delivery. METHODS: This analysis included 38,319 singleton pregnancies, of which 3,304 (8.6%) were preterm deliveries (less than 37 completed weeks) enrolled in the World Health Organization randomized trial of a new antenatal care model. We classified them as preterm deliveries after spontaneous initiation of labor, either with or without maternal obstetric and medical complications; preterm deliveries after prelabor spontaneous rupture of amniotic membranes (PROM), either with or without obstetric and medical complications; and medically indicated preterm deliveries with maternal obstetric and medical complications. Severe neonatal morbidity and neonatal mortality were the primary outcomes. RESULTS: Fifty-six percent of all preterm deliveries were spontaneous, without maternal complications. Small for gestational age was increased only among the medically indicated preterm delivery group (22.3%). Very early preterm delivery (less than 32 weeks of gestation) was highest among PROM with complications (37%). For intrapartum fetal death and neonatal death, after adjusting by gestational age and other confounding variables, we found that the obstetric and medical complications preceding preterm delivery predicted the different risk levels. Conversely, for severe neonatal morbidity the clinical presentation, ie, PROM or medically indicated, predicted the increased risk. CONCLUSION: There are differential neonatal outcomes among preterm deliveries according to clinical presentation, pregnancy complications, gestational age at delivery, and its association with small for gestational age. This syndromic nature of the condition should be considered if preterm delivery is to be fully understood and thus reduced.

Adolescent↗

PubMed2006

Progressive periodontal disease and risk of very preterm delivery.

OBJECTIVE: The goal was to estimate whether maternal periodontal disease was predictive of preterm (less than 37 weeks) or very preterm (less than 32 weeks) births. METHODS: A prospective study of obstetric outcomes, entitled Oral Conditions and Pregnancy (OCAP), was conducted with 1,020 pregnant women who received both an antepartum and postpartum periodontal examination. Predictive models were developed to estimate whether maternal exposure to either periodontal disease at enrollment (less than 26 weeks) and/or periodontal disease progression during pregnancy, as determined by comparing postpartum with antepartum status, were predictive of preterm or very preterm births, adjusting for risk factors including previous preterm delivery, race, smoking, social domain variables, and other infections. RESULTS: Incidence of preterm birth was 11.2% among periodontally healthy women, compared with 28.6% in women with moderate-severe periodontal disease (adjusted risk ratio [RR] 1.6, 95% confidence interval [CI] 1.1-2.3). Antepartum moderate-severe periodontal disease was associated with an increased incidence of spontaneous preterm births (15.2% versus 24.9%, adjusted RR 2.0, 95% CI 1.2-3.2). Similarly, the unadjusted rate of very preterm delivery was 6.4% among women with periodontal disease progression, significantly higher than the 1.8% rate among women without disease progression (adjusted RR 2.4, 95% CI 1.1-5.2). CONCLUSION: The OCAP study demonstrates that maternal periodontal disease increases relative risk for preterm or spontaneous preterm births. Furthermore, periodontal disease progression during pregnancy was a predictor of the more severe adverse pregnancy outcome of very preterm birth, independently of traditional obstetric, periodontal, and social domain risk factors. LEVEL OF EVIDENCE: II-2.

Adolescent↗

PubMed2006

Paternal age and preterm birth in Italy, 1990 to 1998.

BACKGROUND: Advanced paternal age has been reported to impair pregnancy outcome. Here, we investigated the association of advanced paternal age with preterm birth by using a very large national data set. METHODS: We analyzed data from 1990 to 1998 on Italian firstborn singletons to mothers 20-24 and 25-29 years of age (n = 1,510,823). Odds ratios for overall preterm (<37 weeks' gestation), very preterm (<32 weeks), and moderate preterm (32-36 weeks) births were evaluated through logistic regression models in paternal age classes (20-24, 25-29, 30-34, 35-39, 40-44, 45-49, 50+ years) after adjustment for confounders. Nonparametric regression models were used to fit the effect of paternal ageing on the incidence of very preterm births. RESULTS: Odds ratios increased with paternal age more rapidly for very preterm than for moderate preterm births; among 45- to 49-year-old fathers, odds ratios for very preterm births reached 1.91 (95% confidence interval = 1.08-3.38) and 1.72 (1.25-2.36), respectively, in 20- to 24- and 25- to 29-year-old mothers. CONCLUSIONS: This study confirms that paternal age contributes to the risk of preterm birth. The effect is stronger on very preterm births but also influences moderate preterm births.

Adult↗

PubMed1995

Fetal fibronectin detection for prediction of preterm birth in low risk women.

OBJECTIVE: To evaluate the clinical value of cervical fetal fibronectin detection by a quantitative enzyme-linked immunosorbent assay (ELISA) (PTDcheck, Adeza Biomedical, Sunnyvale, California, USA) as a screening tool for the prediction of preterm contractions and preterm delivery in an unselected population of pregnant women globally considered to be at low risk for preterm delivery (n = 133). DESIGN: A prospective study in which cervical fetal fibronectin samples were collected at two-week intervals between 26 and 36 weeks of gestation. SETTING: A regional training hospital. SUBJECTS: One hundred and thirty-three singleton pregnancies presenting consecutively at an antenatal clinic. MAIN OUTCOME MEASURE: Occurrence of preterm contractions and preterm delivery (delivery at < 37 weeks of gestation). RESULTS: Twenty-four (18%) patients were considered positive for the presence of fetal fibronectin. Overall 15 patients (11%) developed preterm contractions and, despite therapeutic intervention, 10 patients (8%) were delivered preterm. As a predictor for preterm contractions, cervical fetal fibronectin detection had a sensitivity of 47%, a specificity of 86%, a positive predictive value of 29% and a negative predictive value of 93%. As a predictor for preterm delivery, cervical fetal fibronectin detection had a sensitivity of 60%, a specificity of 85% a positive predictive value of 25% and a negative predictive value of 96%. CONCLUSIONS: Cervical fetal fibronectin determinations at a two-week sampling frequency for prediction of preterm birth in a general obstetric population at low risk for preterm birth has limited clinical value as a routinely performed screening procedure.

Adult↗

PubMed1997

Impact of metronidazole therapy on preterm birth in women with bacterial vaginosis flora (Gardnerella vaginalis): a randomised, placebo controlled trial.

OBJECTIVE: To ascertain whether metronidazole treatment of women with a heavy growth of Gardnerella vaginalis during mid-pregnancy would reduce the risk of spontaneous preterm birth. DESIGN: A multicentre, randomised, placebo-controlled trial. SETTING: Four metropolitan hospitals. PARTICIPANTS: Eight hundred and seventy-nine singleton women with a heavy growth of G. vaginalis or Gram stain indicative of bacterial vaginosis at 19 weeks of gestation. INTERVENTIONS: Oral metronidazole (400 mg) or placebo twice daily for two days at 24 weeks of gestation, and at 29 weeks if G. vaginalis found in test-of-cure swab four weeks after treatment. MAIN OUTCOME MEASURES: Spontaneous preterm birth less than 37 weeks. RESULTS: Intention-to-treat analysis showed no difference between metronidazole and placebo groups in overall preterm birth (31/429 [7.2%] vs 32/428 [7.5%]) or spontaneous preterm birth (20/429 [4.7%] vs 24/428 [5.6%]). Among the 480 women with bacterial vaginosis treatment had no effect on spontaneous preterm birth (11/242 [4.5%] vs 15/238 [6.3%]). In the subset of 46 women with a previous preterm birth, women in the metronidazole group showed a significant reduction in spontaneous preterm birth (2/22 [9.1%] vs 10/24 [41.7%], OR 0.14, 95% CI 0.01-0.84). A treatment effect was also found in compliant women with a previous preterm birth and bacterial vaginosis (0/14 [0%] vs 6/17 [35.3%], OR 0.0, 95% CI 0.0-0.94). CONCLUSION: Metronidazole treatment of women with a heavy growth of G. vaginalis or bacterial vaginosis did not reduce the preterm birth rate. Among women with a previous preterm birth, treatment reduced the risk of spontaneous preterm birth. Further studies are required to confirm these findings.

Adult↗

PubMed2000

The relationship between intrauterine growth restriction and preterm delivery: an empirical approach using data from a European case-control study.

OBJECTIVE: To test whether being small for gestational age, defined as having a birthweight less than the 10th centile of intrauterine growth references, is a risk factor for preterm delivery for singleton live births. DESIGN: A case-control study. SETTING: Maternity hospitals in 16 European countries. SAMPLE: Four thousand and seven hundred preterm infants between 22 and 36 completed weeks of gestation and 6,460 control infants between 37 and 40 weeks of gestation. METHODS: Newborn babies are identified as being small for gestational age using customized reference standards derived from models of fetal growth. The impact of being small for gestational age on preterm delivery is estimated using logistic regression. MAIN OUTCOME MEASURE: Spontaneous or induced preterm delivery. RESULTS: Being small for gestational age is significantly associated with preterm birth, although the magnitude of this association differs greatly by type of delivery and gestational age. Over 40% of induced preterm births for reasons other than the premature rupture of membranes are small for gestational age compared with 10.7% of control infants (OR 6.41). For spontaneous or premature rupture of membranes related preterm births, the association is also significant, but weaker (OR 1.51). The relationship between growth restriction and preterm delivery is strongest for preterm births before 34 weeks of gestation. CONCLUSIONS: These findings highlight the phenomenon of abnormal fetal growth in all premature infants and, in particular, infants delivered by medical decision for reasons other than premature rupture of membranes. The observed association between being small for gestational age and preterm delivery among spontaneous preterm births merits further attention because the causal mechanisms are not well understood.

Case-Control Studies↗

PubMed2005

Primary predictors of preterm labour.

Spontaneous preterm birth accounts for 60% of all preterm births in developed countries. With the increase in multiple pregnancies, induced preterm birth and the progress in neonatal care for extremely preterm neonates, spontaneous preterm birth for singleton pregnancies in developed countries has probably decreased over the past 30 years. This decrease is likely to be related to better prenatal care for all pregnant women because the recognition of primary risk factors in early or late pregnancy remains a basic part of prenatal care. The failure to distinguish between induced and spontaneous preterm labour in most population-based studies makes it difficult to interpret results with respect to the primary predictors of preterm labour. Many such primary predictors of preterm labour have been used over the past 20-30 years. These include individual factors, socio-economic factors, working conditions and obstetric and gynaecological history. Risk scores have been proposed in order to produce these data. Unfortunately, the predictive value of these scores, especially their specificity, is poor, mainly because all of these factors are indirect. We still cannot identify the mechanisms that lead to preterm labour and birth. New markers more directly related to preterm labour have recently been proposed, some of which relate to direct causes of preterm labour such as cervical ultrasound measurement, fetal fibronectin (FFN), salivary estriol, serum CRH and bacterial vaginosis. Several of these have predictive values, which are potentially useful for clinical practice. Nonetheless, pregnant women in developed countries are already closely monitored throughout pregnancy. Before proposing new screening tests to be applied systematically to all pregnant women, their advantages and drawbacks must be fully evaluated.

Biomarkers↗

PubMed2006

Seasonal patterns and preterm birth: a systematic review of the literature and an analysis in a London-based cohort.

OBJECTIVE: The objectives of this study included a systematic review of the countries in which a seasonal pattern of preterm birth has been reported and an analysis on the seasonal variability of preterm birth in a London-based cohort. DESIGN: Cross-sectional study. SETTING: Eighteen maternity units in a London health region from 1988 to 2000. POPULATION: The study population comprised 482,765, live singleton births born after 24 weeks of gestation and weighing more than 200 g. METHODS: Systematic review and secondary analysis of seasonality over 13 years of births from the St Mary's Maternity Information System (SMMIS). MAIN OUTCOME MEASURE: Annual patterns of preterm birth and a comparison of risk by seasons. RESULTS: Three studies from developing countries and three from developed countries reported a seasonal pattern of preterm birth. One study from the USA reported no seasonal pattern of preterm birth. No British studies were located. Rates of preterm birth in developed countries were highest twice a year (once in winter and again in summer). In London (SMMIS data set), however, preterm births peaked only once a year, in winter. Babies born in winter were 10% more likely to be preterm compared with those born in spring (OR 1.10, 95% CI 1.07-1.14). CONCLUSION: Establishing a seasonal pattern of birth can have important implications for the delivery of healthcare services. Most studies from both developed and developing countries support the existence of preterm birth seasonality. This study has shown that the seasonality of preterm births in this London-based cohort differs from other developed countries that have previously reported a seasonal pattern of preterm birth.

Cohort Studies↗

PubMed2005

Periodontal status and preterm low birth weight: a case control study.

BACKGROUND: Previous studies have suggested that periodontal disease may be an important risk factor for preterm low birth weight. However, the link between periodontal health status of pregnant women and preterm low birth weight is contentious, as recent studies found no association between periodontitis and pregnancy outcome. OBJECTIVE: The aim of this study was to investigate this potential link in a German Caucasian population. METHODS: Fifty-nine pregnant women with a high risk for a preterm low birth weight infant (suffering from preterm contractions, cases, group 1) as well as 42 control women with no preterm contractions during pregnancy and having an infant appropriate for date and weight (>or= 37 weeks gestation, >or= 2500 g, group 2) were examined. Clinical periodontal status was recorded on a full mouth basis. Subgingival plaque samples were taken and periodontal pathogens were identified by polymerase chain reaction. Additionally, interleukin-1 beta level in gingival crevicular fluid was analysed. RESULTS: The mean percentage of sites showing moderate to advanced attachment loss (>or=3 mm) was low in all study groups (group 1: 9.9 +/- 11.2%; group 2:10.6 +/- 14.1%, respectively). No significant differences between the groups in any aspects of the studied periodontitis parameters could be detected. Using a logistic regression model controlling for known preterm low birth weight risk factors, no periodontitis-associated factors increased risk for preterm contractions or preterm low birth weight. The odds ratio (OR) was 1.19 for preterm contractions, the 95% confidence interval (CI) 0.46; 3.11 and 0.73 for preterm low birth weight; 95% CI: 0.13; 4.19, respectively. CONCLUSION: In this population, periodontitis was not a detectable risk factor for preterm low birth weight in pregnant women.

Adolescent↗

PubMed2005

Are the risk factors for SIDS different for preterm and term infants?

BACKGROUND: Mortality from SIDS has declined since the recommendation that infants are not placed prone to sleep. SIDS mortality is higher in infants born preterm than those born at term. AIM: To determine if risk factors for SIDS are any different for preterm and term infants. METHODS: Mortality data over time were used to determine whether the reduction in SIDS mortality rates had occurred equally in term and preterm infants. Data from two New Zealand studies (a case-control study and a case-cohort study) were used to determine if any differences existed in risk factors for SIDS between term and preterm infants before and after the SIDS prevention campaign. RESULTS: SIDS mortality appears to have decreased by similar proportions in term and preterm infants. Risk factors for SIDS were similar in preterm and term infants, except for parity where there was a significant interaction. Increasing parity was a risk factor for SIDS in term infants but not preterm infants. CONCLUSION: SIDS rates have decreased at comparable rates in term and preterm infants, but preterm birth still remains a risk factor for SIDS. The magnitude of the odds ratios associated with modifiable risk factors were similar for both groups. There may however be a difference in risk associated with parity between term and preterm infants. The messages for risk factors for SIDS are applicable to mothers of preterm as well as term infants.

Case-Control Studies↗

PubMed2000

Controlled trial of immune response of preterm infants to recombinant hepatitis B and inactivated poliovirus vaccines administered simultaneously shortly after birth.

AIM: The study was conducted to evaluate the immunogenicity of an early, extra dose of enhanced inactivated poliovirus vaccine (IPV) administered simultaneously with recombinant hepatitis B vaccine (HBV) to preterm infants shortly after birth. METHODS: Three groups were studied. Fifty preterm infants received IPV intramuscularly within 24 hours of birth, in addition to routine recommended childhood immunisations. Fifty two preterm infants and 35 full term infants received routine immunisations only (routine vaccination timing: HBV at birth, 1 and 6 months of age; IPV at 2 and 4 months; oral polio vaccine (OPV) at 4 and 6 months; diphtheria-tetanus-pertussis (DTP) at 2, 4, and 6 months; and Haemophilus influenzae B vaccine at 2 and 4 months). Blood samples were taken at birth, 3 and 7 months of age from all infants, and at 1 month of age from preterm infants only. RESULTS: At birth, a lower percentage of both study and control preterm infants had antipoliovirus type 3 titres >/= 1:8 than full term infants. At 1 and 3 months of age significantly more early IPV infants had antipoliovirus type 3 titres >/= 1:8 than routinely vaccinated preterm infants (p < 0.05). At 7 months of age there were no significant differences in percentage of antipoliovirus titres >/= 1:8 or geometric mean times (GMTs) between the early IPV group and the routinely vaccinated preterm group. At 3 and 7 months of age, the percentage of positive antihepatitis B titres (>/= 1:10) and the GMT of the early IPV preterm group did not differ significantly from those of preterm controls. There was no significant difference in percentage of positive antihepatitis B titres between the early IPV group and full term controls at any time. GMTs for hepatitis B antibodies were significantly lower in the early IPV preterm group than in full term controls at 3 and 7 months of age. CONCLUSIONS: Administration of an additional dose of IPV simultaneously with routine HBV to preterm infants shortly after birth provides early protection from poliovirus and hepatitis B infection, and does not interfere with poliovirus antibody production at the age of 7 months.

Antibodies, Viral↗