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PubMed2005

Risk factors for preterm birth in Korea: a multicenter prospective study.

Preterm birth is a major determinant of neonatal morbidity and mortality and remains one of the most serious problems in obstetrics. The aim of this study was to investigate the risk factors for preterm birth in Korean pregnant women. A total of 2,645 women were evaluated between 20 and 42 weeks' gestation at 5 centers using a prospective study design. The patient population is limited to singleton gestations. Demographic factors, socioeconomic statuses, previous and current medical histories, complications of current gestation, and drug and alcohol abuse were evaluated, and univariate and multivariate logistic regression analyses performed. Among nulliparous women, the factors that showed a significant association with preterm delivery were as follows; vaginal bleeding during pregnancy (OR 2.6, CI 1.7-4.2), and below USD 1,000 average income (OR 5.1, CI 1.9-13.5). The factors that showed a significant association with preterm delivery among multiparous women were as follows; a history of spontaneous abortion (OR 2.4, CI 1.1-5.2), and a history of preterm delivery (OR 3.5, CI 1.02-11.8). In conclusion, vaginal bleeding during pregnancy, below USD 1,000 of average income, prior spontaneous abortion, and prior preterm delivery, were positively associated with preterm birth.

Adult↗

PubMed2005

Value of endocervical ureaplasma species colonization as a marker of preterm delivery.

AIMS: To study the predictive value for preterm delivery of colonization of the cervix and vagina by ureaplasmas and other potentially pathogenic microorganisms. METHODS: Prospective analysis of a study group of 200 pregnant women with preterm labor and intact membranes, and a control group of 50 pregnant women. The subjects in both groups were between 24 and 34 weeks of gestation. Ureaplasma spp. and Mycoplasma hominis endocervical cultures were performed for both groups. RESULTS: In the study group, 70 of the women delivered preterm, and all women in the control group carried their pregnancies to full term. Cervical cultures for Ureaplasma spp. were positive in 119 women, and were isolated more frequently in the study group (51.5%) than in the control group (32%), and more frequently in subjects in the study group who delivered preterm (65%) than in those who had a full-term delivery (45%), differences that were statistically significant. CONCLUSION: Detection of Ureaplasma spp. in the endocervix has a statistically significant relationship to preterm labor (p = 0.03) and preterm delivery (p = 0.02) in pregnant women with preterm labor and intact membranes.

Adult↗

PubMed1986

Protein and RNA turnover in preterm infants and adults: a comparison based on urinary excretion of 3-methylhistidine and of modified one-way RNA catabolites.

Urinary excretion of 3-methylhistidine in preterm infants (n = 42; 1,712 +/- 408 g, 4-91 days old) was 24.2 +/- 6 mumol/mmol creatinine or 2.26 +/- 0.56 mumol/kg body weight X day. In adults (n = 6; 66 +/- 10 kg, 17-50 years), the corresponding values were 10.5 +/- 1.1 mumol/mmol creatinine and 2.21 +/- 0.23 mumol/kg body weight X day. For both collectives, the breakdown per kg body weight of 3-methylhistidine-containing protein (i.e. actin and myosin) was similar, at approximately 0.7 g/kg X day (preterm infants 0.84, adults 0.60). Since the preterm infants studied contain approximately 21% muscle instead of the 43% found in adults, the 3-methylhistidine excretion in preterm infants probably indicates muscle (and intestinal) protein turnover to be about 3 times higher than in adults, a figure in accord with data on whole-body protein turnover in preterm infants and adults (approximately 15 g/kg X day and approximately 4 g/kg X day, respectively). Urinary excretion of pseudouridine (psi), 7-methylguanine (m7Gua) and N2, N2-dimethylguanosine (m2(2)G) can be used to estimate the turnover of rRNA, mRNA and tRNA, respectively. The values obtained (in mumol/mmol creatinine) in preterm infants are for psi: 164 +/- 32; for m7Gua: 39.1 +/- 9; and for m2(2)G: 10.6 +/- 2.1. In adults, the values are for psi: 25.3 +/- 3.1; for m7Gua: 4.8 +/- 0.89; and for m2(2)G: 1.53 +/- 0.38. This yields 3-4 times higher turnover rates in preterm infants than in adults for all 3 RNA classes: rRNA, 0.1 versus 0.038; tRNA, 1.87 versus 0.66; mRNA 2.35 versus 0.64 mumol/kg X day.

Guanine↗

PubMedDate not supplied

Is inflammation on Papanicolaou smear a risk factor for preterm delivery?

OBJECTIVE: Inflammation on Papanicolaou (Pap) smear has been associated with a 30-50% incidence of bacterial vaginosis (BV), a recognized risk factor for preterm delivery. We determined whether inflammation on Pap smear is associated with preterm delivery. STUDY DESIGN: 5,348 cases were studied with complete prenatal data including the potential confounder of treatment with antibiotics. Cases were categorized by presence (n = 1,139) or absence (n = 4,209) of inflammation on Pap smear. RESULTS: In the inflammation group the proportion of African Americans was lower (66.9 vs. 74.5%; p < 0.001). There were no significant differences (t test) for maternal age, gravidity, history of preterm delivery, or gestational age at delivery between inflammation and noninflammation groups. Multiple stepwise regression analysis showed that maternal age, history of preterm delivery, and African American race were all significantly positively associated with preterm delivery. Treatment with metronidazole during the pregnancy was significantly negatively associated with preterm delivery. Inflammation on Pap smear, gonorrhea detected during the pregnancy and prenatal treatment with erythromycin were not associated. CONCLUSION: Unlike bacterial vaginosis, inflammation on routine Pap smear does not appear to be a risk for subsequent preterm birth. We are unable to use inflammation on Pap smear as a surrogate for more specific diagnosis of bacterial vaginosis.

Adult↗

PubMed1996

Effects of urinary trypsin inhibitor on myometrial contraction in term and preterm deliveries.

The aim of this research was to study the concentration of urinary trypsin inhibitor in amniotic fluid (AF) and its effect on myometrial contraction in term and preterm deliveries. Urinary trypsin inhibitor was measured in AF of term and preterm labor. Immunohistochemical staining of amnion and myometrium was carried out. Isometric uterine contraction was studied to elucidate the effect of AF and urinary trypsin inhibitor on the contractile activity of term and preterm myometrium. The effect of urinary trypsin inhibitor on the production of prostaglandin E2 (PGE2) from myometrial cultures stimulated by IL-8, IL-1 and LPS was verified. Urinary trypsin inhibitor was significantly increased in AF of cases of preterm delivery (p < 0.0001). Amnion and myometrium of preterm deliveries were faintly stained for urinary trypsin inhibitor compared to term delivery. Amniotic fluid and urinary trypsin inhibitor could successfully inhibit-myometrial contraction. Also, urinary trypsin inhibitor could significantly inhibit the production of PGE2 in the myometrial cell cultures stimulated by IL-1 and LPS (p < 0.001 and 0.0005). IL-8 has no significant effect on PGE2 production from myometrial cell culture. Urinary trypsin inhibitor suppresses myometrial contraction in term and preterm deliveries. It may play a role in maintaining normal pregnancy and preventing preterm delivery.

Amnion↗

PubMed1995

Endocervical pathogens in women with preterm and term labour.

The purpose of this study was to compare the endocervical microflora of women in preterm and term labour and to determine whether the presence of a specific microflora is significantly associated with preterm labor. A prospective study was performed in Lithuania among 212 women in preterm labour (latent phase, n = 110; active phase, n = 102) and among 62 healthy women in term labour. Microbiological assessment included cultures for aerobic bacteria, yeasts, and Trichomonas vaginalis and direct immunofluorescence reaction for Chlamydia trachomatis, Escherichia coli (odds ratio 8.16; 95% confidence interval 1.27-340.23) and Staphylococcus aureus (odds ratio 7.79; 95% confidence interval 1.21-325.40) were significantly more often isolated from women in preterm than from women in term labour. The prevalence of C. trachomatis was the same in the preterm and in the term labour group. The pregnancy outcome during the latent or active phase of preterm labour with or without C. trachomatis infection did not differ. It is concluded that E. coli and S. aureus are significantly more prevalent in endocervical cultures from Lithuanian women in preterm than from those in term labour.

Adult↗

PubMed1990

Serum-specific antibodies for Chlamydia trachomatis in preterm premature rupture of the membranes.

A case control study was performed to examine possible morbidity associated with Chlamydia trachomatis in 15 pregnant women with idiopathic preterm premature rupture of the membranes (PROM; group A), and in two control groups, 35 healthy preterm pregnant women (group B), and 43 healthy pregnant women at term (group C). Serum C. trachomatis IgG and IgA specific antibodies were determined using the single serovar (L2) inclusion immunoperoxidase assay. There were no significant differences in the prevalence rate of elevated levels of chlamydia IgG specific antibodies (titer greater than or equal to 1:128) between pregnant women suffering from idiopathic preterm PROM, as compared to healthy preterm and term pregnant women (20, 28 and 26%, respectively). Nor were there any significant differences in the prevalence rate of elevated levels of chlamydia IgA specific antibodies (titer greater than or equal to 1:16) between pregnant women with idiopathic preterm PROM, as compared to healthy preterm and term pregnant women (20, 20 and 17%, respectively). These findings do not support the assumption that C. trachomatis may play role in preterm PROM.

Adult↗

PubMed1992

Intrapulmonary bacterial clearance of type III group B streptococcus is reduced in preterm compared with term rabbits and occurs independent of antibody.

Intrapulmonary clearance of type III group B streptococcus (GBS) and related phagocytic recruitment was studied in preterm and term rabbits at 4 and 8 h after aerosol infection using left lung homogenates to quantify GBS and right lung bronchoalveolar lavage (BAL) to recover phagocytes. Opsonophagocytosis of type III GBS by pulmonary alveolar macrophages (PAM) was studied in vitro with a modified differential fluorescence-quenching method using PAM lavaged from preterm, term, and adult rabbits. Sera of experimental animals were tested for opsonization of type III GBS using fluorescein-labeled antibodies to rabbit IgG and C3. Although term animals showed some clearance at 8 h, preterm animals had marked intrapulmonary proliferation of GBS. The number of PAM in BAL fluid was 20-fold higher in term than in preterm rabbits at 0 h, but by 8 h, preterm rabbits had a large influx of PAM, whereas PAM remained constant in term BAL fluid. Rates of phagocytosis of GBS were twice as high in term versus preterm PAM during in vivo and in vitro studies. Among PAM from term and adult animals, opsonization of GBS with MgEGTA-sera promoted phagocytosis in vitro at levels comparable to pooled adult sera, whereas opsonization with EDTA-sera resulted in a significantly lower rate of ingestion. None of the experimental animals' sera were able to deposit IgG, but all deposited C3 on the surface of GBS. In summary, preterm rabbits had a diminished bronchoalveolar PAM population that did not ingest GBS as well via the alternative complement pathway when compared with term rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2004

Endotoxin-induced chorioamnionitis modulates innate immunity of monocytes in preterm sheep.

The preterm fetus is immune naive and has immature innate immune function. Although the preterm fetus is frequently exposed to chorioamnionitis, the effects of exposure of the fetal lung to inflammation on innate immune responses are unknown. Using the fetal sheep model of chorioamnionitis, cord blood monocytes were isolated from preterm lambs 1 to 14 days after intra-amniotic endotoxin injection, cultured for approximately 16 hours, and challenged with endotoxin in vitro. Compared with monocytes from adult sheep, the preterm monocytes produced less H(2)O(2) and interleukin-6, and toll-like receptor 4 expression was decreased. Three days after intra-amniotic endotoxin exposure, preterm monocyte responses to in vitro endotoxin challenge demonstrated decreased H(2)O(2) and interleukin-6 production and decreased CD14 and major histocompatibility complex class II expression. Preterm monocyte responses 7 to 14 days after endotoxin tended to exceed those of adults and preterm control animals indicating augmented function. In contrast, a second intra-amniotic endotoxin injection 7 days after the initial endotoxin exposure suppressed monocyte function at 14 days. The fetal monocytes demonstrated patterns of responses consistent with endotoxin tolerance (immune paralysis) as well as maturation of function. Modulation of fetal innate immune responses by exposure to inflammation may alter subsequent immune adaptation after birth.

Amnion↗

PubMedDate not supplied

Implications of kangaroo care for growth and development in preterm infants.

OBJECTIVE: To review research on kangaroo care with implications for growth and development in preterm infants. DATA SOURCES: Nursing, medical, and child development research literature was searched through PubMed through 2003 using the search terms kangaroo Care, skin-to-skin, growth/development, and premature infants. STUDY SELECTION: Randomized controlled trials, pretest-posttest designs, and other comparative studies of kangaroo care were reviewed. Reports exploring parent perspectives were examined for attachment and parent-infant interaction findings. Theory and research regarding growth in preterm infants were explored. DATA EXTRACTION: Research on topics of kangaroo care, skin-to-skin contact, preterm infant growth, preterm infant weight gain, and failure to thrive was evaluated. DATA SYNTHESIS: Research on kangaroo care reports physiologic safety for preterm infants and increased attachment for parents. Attachment promotes nurturing behaviors that support growth and development. Weight gain as a benefit of kangaroo care remains in question. CONCLUSIONS: Kangaroo care is safe for preterm infants and may have important benefits for growth and development. Suggestions are made for future research on effects of KC on preterm infants.

Body Temperature Regulation↗

PubMed2006

Gut responses to enteral nutrition in preterm infants and animals.

Preterm birth is associated with immature digestive function that may require the use of total parenteral nutrition and special oral feeding regimens. Little is known about the responses to oral food in the preterm neonate and how enteral nutrients affect the immature gastrointestinal tract (GIT). In vivo studies are difficult to perform in laboratory rodents because of their small body size and that of immature organs at birth, and this makes the large farm animals (e.g., pigs, cattle, sheep) more attractive models in this field. In these species, preterm delivery at 88%-95% gestation is associated clinical complications and degrees of GIT immaturity similar to those in infants born at 70%-90% gestation. Studies in both animals and infants indicate that the immature GIT responds to the first enteral food with rapid increases in gut mass and surface area, blood flow, motility, digestive capacity, and nutrient absorption. To a large extent, the enteral food responses are birth independent, and can be elicited also in utero, at least during late gestation. Nevertheless, preterm neonates show compromised GIT structure, function, and immunology, particularly when delivered by caesarean section and fed diets other than mother's milk. Formula-fed preterm infants are thus at increased risk of developing diseases such as necrotizing enterocolitis, unless special care is taken to avoid excessive nutrient fermentation and bacterial overgrowth. The extent to which results obtained in preterm animals (most notably the pig) can be used to reflect similar conditions in preterm infants is discussed.

Animal Feed↗

PubMed2005

mRNA expression and localization of bNOS, eNOS and iNOS in human cervix at preterm and term labour.

BACKGROUND: Preterm birth is the primary cause of the neonatal mortality and morbidity. There will be no preterm birth without a cervical softening. Nitric oxide (NO) is shown to be a mediator of term cervical ripening. The aim of this study was to investigate mRNA expression of the three isomers of NO synthases (NOS) and to identify them by immunohistochemistry in the human cervix at preterm birth compared to term. METHODS: The three isomers of NOS--inducible (iNOS), endothelial (eNOS) and neuronal (bNOS)--were investigated in the human cervix. The expression of mRNA was determined using Real-Time Multiplex RT-PCR. The localisation of synthases in the cervical tissue was analysed using immunohistochemistry. Cervical biopsies were obtained from 4 groups of women without clinical signs of infection: preterm (PTL), term labour (TL), preterm not in labour (PTnotL) and term not in labour (TnotL) patients. One-Way ANOVA, Kruskal-Wallis, Student t-test or Mann-Whitney test were applied as appropriate to determine statistically significant differences among the groups. RESULTS: Patients in preterm labour had significantly (p < 0.01) higher mRNA levels of all the three NOS isomers compared to those in term labour. Women not in labour, irrespective of gestational age, thus with unripe cervices, had significantly lower eNOS mRNA levels compared to those in labour (p < 0.01). Immunoreactivity for all three NO synthases was observed in each examined sample in all groups. The bNOS staining was the most prominent. CONCLUSION: The mRNA levels were higher in the preterm labour group compared to the women at term labour. The significant increase of the eNOS mRNA expression, from the unripe to the favourable cervical state during labour, may indicate a role of eNOS and supports the role of NO in the cervical ripening process. All the three synthases were identified by immunohistochemistry in all the groups of study.

Cervix Uteri↗

PubMed1979

Adaptive gluconeogenesis in preterm and term rabbits.

UNLABELLED: Carbohydrate metabolism in the developing rabbit was investigated for deficiencies that may be responsible for the failure of many preterm (28 1/2--29 1/2 day) animals to survive the first hours of life. The preterm animal shows an inability to reverse glycogenolysis or initiate gluconeogenesis from lactate or alanine in the first hours of life. This impairment, coupled with 50% less liver glycogen stores than the term animal, places the preterm animal at jeopardy for energy substrate early on in life. Unexpected was the early, rapid conversion of glycerol to glucose by the preterm animal. This ability seemed to be the primary difference in carbohydrate metabolism between the surviving and nonsurviving preterm rabbit. SPECULATION: Impaired glyconeogenesis from lactate and alanine in the preterm animal coupled with active gluconeogenesis from glycerol suggests that substrates from lipolysis may be very important for early adaptation. Preterm animals endowed with limited fat stores, thus, minimal available glycerol, would be incapable of survival.

Animals↗

PubMed1996

Characterization of natural killer and antibody-dependent cellular cytotoxicity of preterm infants against human immunodeficiency virus-infected cells.

The odds risk of vertical transmission of human immunodeficiency virus (HIV) to preterm infants is almost four times that of term infants and may relate to maternal and neonatal factors. We characterized the competence of early nonspecific cellular immunity, namely natural killer cytotoxicity (NKC) and antibody-dependent cellular cytotoxicity (ADCC), of peripheral blood mononuclear cells (PBMC) from preterm (n = 20) and term neonates (n = 28) versus adult controls against a T cell line infected with the human T cell lymphotrophic virus-III(B) using a chromium-51 release assay. PBMC from term neonates exhibited levels of NKC activity equal to adults against HIV-infected targets, yet the NKC capacity of preterm neonatal PBMC was significantly diminished. The ADCC activity of both term and preterm neonatal PBMC against HIV-infected targets was significantly less than that of adult PBMC. Overnight stimulation of a subset of samples with IL-12 augmented the NKC activity of both infant groups and adults, whereas the ADCC activity remained unchanged. These findings demonstrate that term neonates are deficient in ADCC against HIV-infected targets, whereas preterm infants are deficient in both NKC and ADCC, which may relate, in part, to the increased risk of transmission of HIV with preterm delivery. In addition, IL-12 has the potential to augment both term and preterm neonatal antiviral defense.

Adult↗

PubMed1997

Alternative pathway activation of the complement system in preterm infants with early onset infection.

The increased incidence of infection in preterm neonates has been related in part to their relative deficiency of most complement components, because complement is known to participate in the defense against bacterial and viral infections. In a prospective study, complement activation products were determined in 52 preterm infants. Twenty preterm infants suffered from proven early onset infection, 11 infants were presumed to suffer from infection, which could not be confirmed. Twenty-one preterm infants without infection or perinatal asphyxia formed the control group. EDTA plasma was obtained within the first 6 h after birth, and follow-up examinations were done in 15 patients with proven infection during the next 24 h. The complement activation products C3a-desArg, C3bBbP, and sC5b-9 were measured with enzyme immunoassay systems. In preterm neonates with early onset infection, a significant elevation of C3a-desArg was found in the very early course of the disease. C3a-desArg generation resulted from alternative pathway activation as shown by a concurrent increase of C3bBbP concentration. In addition, significantly higher concentrations of sC5b-9 predicted infection in the first few hours after birth. Thus, despite very low levels of native complement proteins, preterm babies are able to generate remarkable amounts of activation products of the complement cascade. The elevation of these activation products preceded by hours significant changes of routine laboratory markers of infection, such as leukocyte count, differential blood count, and C-reactive protein. Thus they might help to identify preterm neonates with severe systemic infection earlier than other laboratory parameters.

Age of Onset↗

PubMed1998

Feeding preterm infants after hospital discharge: effect of dietary manipulation on nutrient intake and growth.

The objective of this study was to compare formula intake, the time of weaning, and growth in preterm infants (< or = 1750-g birth weight, < or = 34-wk gestation) fed a standard term or preterm infant formula after initial hospital discharge. Infants were randomized at hospital discharge to be fed a preterm infant formula from discharge to 6 mo corrected age (group A), a term formula from discharge to 6 mo (group B), or the preterm formula (discharge to term) and the term formula (term to 6 mo (group C). Infants were seen biweekly (discharge to term) and monthly (term to 6 mo), when intake was measured and anthropometry and blood sampling were performed. The results were analyzed using ANOVA. Although nutrient intake was similar, at 6 mo girls were lighter (6829 versus 7280 g) and shorter (64.4 versus 66.0 cm) than boys (p < 0.05). Patient characteristics were similar between the treatment groups. Although the volume of intake differed (B > C > A; p < 0.001), energy intake was similar in the groups. Because of differences in formula composition, protein, calcium, and phosphorus intakes differed (B < C < A; p < 0.001). Lower protein intakes were related to lower blood urea nitrogen levels (B < C < A; p < 0.001). At 6 mo, infant boys in B and C were lighter (6933, 6660 < 7949 g), shorter (65.3, 64.9 < 67.1 cm), and had a smaller head circumference (43.7, 43.7 < 44.8 cm; p < 0.05) than infants in group A. Preterm infants were found to increase their volume of intake to compensate for differences in energy density between formulas. After hospital discharge, infant boys fed a preterm formula grew faster than infant girls fed a preterm formula or infant boys fed a term formula.

Blood Urea Nitrogen↗

PubMed2000

Plasma concentrations of the carboxyterminal propeptide of type I procollagen (PICP) in preterm neonates from birth to term.

Carboxyterminal propeptide of type I procollagen (PICP), a marker of bone formation, has not yet been studied in preterm infants. In this study, PICP concentrations were measured longitudinally for 12 wk after birth using the ELISA technique in 43 preterm infants with a gestational age (GA) ranging from 24-29 wk and in 35 preterm infants with a GA ranging from 30-34 wk. PICP values in these preterm infants were higher than in children and adults. In cord plasma of preterm infants there was a significant gender difference, with higher PICP concentrations in male infants. A characteristic longitudinal pattern with an initial decrease during the first 3 postnatal days followed by a rapid increase from d 7 to d 28 was seen in both groups. Regarding the individual gestational ages, all preterm infants attained maximum PICP concentrations around 36 wk postmenstrual age. Multiple regression analysis revealed cord plasma PICP concentrations were significantly associated with GA, birth weight, sex, and IGF-I. A significant correlation between PICP concentrations and GA was seen at wk 1-4 and between PICP concentrations and protein intake at wk 1. Body weight and energy intake were shown to exert a significant effect on the PICP concentrations at 2 wk. The collected data in preterm infants may serve further studies evaluating PICP as a marker for bone formation and growth in very low birth weight premature infants.

Adult↗

PubMed2002

Enhanced interleukin-6 and interleukin-8 synthesis in term and preterm infants.

There is growing evidence that sepsis-related complications in neonates are crucially mediated by the action of proinflammatory cytokines. It has previously been demonstrated that elevated IL-6 and IL-8 levels can predict brain damage and chronic lung disease in preterm infants. However, it is the current view that neonates have a reduced capability to produce proinflammatory cytokines. To clarify this issue, we analyzed the inflammatory response in term and preterm infants directly at the single cell level by flow cytometry. Endotoxin challenge was performed under defined conditions on monocytes obtained from 50 healthy adults and 119 neonates, which consist of 45 term infants, 63 preterm infants (26.1-36.7 wk of gestational age), and 11 preterm infants with proven infection (24.6-29.9 wk). Our results challenge the existing view of an immature inflammatory response by demonstrating that term infants and preterm infants display a higher percentage of IL-6- and IL-8-positive cells than adults. After preincubation with dexamethasone the number of cytokine-positive cells decreased in all groups, but the number of IL-8-positive cells remained higher in term and preterm infants >32 wk compared with adults. These observations demonstrate not only a well-developed but also an enhanced inflammatory response in term and preterm infants. Under consideration of several detrimental effects of IL-6 and IL-8, our data may have major implications on the pathophysiology of inflammatory-triggered neonatal diseases.

Adrenal Cortex Hormones↗