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PubMed2006

Adenomyosis and risk of preterm delivery.

OBJECTIVE: To evaluate the risk of preterm delivery in patients with adenomyosis. DESIGN: A 1:2 nested case-control study. SETTING: Tertiary-care institution. POPULATION: A base cohort population of 2138 pregnant women who attended routine prenatal check-up between July 1999 and June 2005. METHODS: From this base cohort population, gravid women with singleton pregnancy who delivered prior to the completion of 37 weeks of gestation were identified and formed the study group. Singleton gravid women who had term delivery and who matched with age, body mass index, smoking, and status of previous preterm delivery were recruited concurrently and served as control group. Preterm delivery cases were further divided into spontaneous preterm delivery and preterm premature rupture of membranes (PPROM) cases. MAIN OUTCOME MEASURES: Risk analysis of preterm delivery between gravid women with and without adenomyosis. RESULTS: One-hundred and four preterm delivery case subjects and 208 control subjects were assessed. Overall, gravid women with adenomyosis were associated with significantly increased risk of preterm delivery (adjusted odds ratio 1.96, 95% CI 1.23-4.47, P=0.022). For subgroup analysis, gravid women with adenomyosis had an adjusted 1.84-fold risk of spontaneous preterm delivery (95% CI 1.32-4.31, P=0.012) and an adjusted 1.98-fold risk of PPROM (95% CI 1.39-3.15, P=0.017). CONCLUSIONS: Gravid women with adenomyosis were associated with increased risk of both spontaneous preterm delivery and PPROM. A common pathophysiological pathway may exist in these two disorders. Further in-depth biochemical and molecular studies are necessary to explore this phenomenon.

Case-Control Studies↗

PubMedDate not supplied

Adolescents' description and management of pregnancy and preterm labor.

OBJECTIVE: To describe adolescents' experiences with pregnancy and preterm labor. DESIGN: Naturalistic inquiry, a qualitative study using intensive, open-ended, tape-recorded interviews and constant comparative data analysis. SETTING: Antepartum units of two hospitals in the southeastern section of the United States. PARTICIPANTS: Eight African American and five white adolescents, ages 14-19 years, hospitalized for preterm labor. RESULTS: The findings are broadly conceptualized as (a) describing pregnancy and preterm labor and (b) managing pregnancy and preterm labor. "Responding to Pregnancy" consisted of descriptions of the adolescents' reactions to pregnancy (initial concern and dislike) and pathophysiologic responses that put the adolescents at risk for preterm labor. "Responding to Preterm Labor" included the various ways that adolescents became aware of preterm labor and their various understandings of the causes and consequences of preterm labor. Vignettes illustrate how adolescents managed pregnancy and preterm labor with ease or with difficulty. Adolescents who received support from others, especially their mothers, tended to deliver near or at full-term. CONCLUSIONS: Nurses can use the findings from this study as a guide for assessing and monitoring adolescents throughout pregnancy. Advanced practice nurses may have the educational background and philosophy of care to provide the most appropriate prenatal care to pregnant adolescents. Research is needed to further explore stressful experiences and support in adolescents' lives and how these are related to preterm labor and birth.

Adaptation, Psychological↗

PubMed2003

Absence of leukaemic fusion gene transcripts in preterm infants exposed to diagnostic x rays.

BACKGROUND: Childhood leukaemias express novel, clonotypic fusion genes that may already be present at birth before the clinical manifestation of leukaemia. Exposure of the fetus to diagnostic x rays is reported to increase the risk of childhood leukaemia, and may do so by generating leukaemic fusion genes. Advances in neonatal medicine in the past decade that have extended the limits of viability of preterm babies down to 23 weeks of gestation have resulted in the increased use of diagnostic x rays to monitor neonatal progress. AIM: To investigate whether exposure of very preterm infants to diagnostic x rays in the neonatal period leads to the development of leukaemic fusion genes. METHODS: Peripheral blood samples were collected at birth from very preterm infants (23-30 weeks gestation) and following exposure to diagnostic x rays at intervals of two weeks, until discharge. Cord blood samples from normal full term infants served as controls. Total RNA was extracted from the blood and the expression of the fusion genes TEL-AML1, MLL-AF4, and BCR-ABL, characteristic of three subtypes of childhood leukaemia, was investigated in the preterm and full term infant samples using a nested reverse transcriptase polymerase chain reaction method. Serial pre- and post-x ray samples from 42 preterm babies, pre-x ray samples from an additional 46 preterm infants, and cord blood samples from 100 normal full term infants were screened for fusion gene transcripts. RESULTS: No leukaemic fusion gene transcripts were detected in preterm infants following exposure to diagnostic x rays. A BCR-ABL transcript was identified in a single preterm infant prior to x ray exposure. TEL-AML1 transcripts were detected in cord blood samples from two full term infants. MLL-AF4 transcripts were not detected in any of the pre- or full term infants tested. CONCLUSIONS: Exposure of the preterm infants to x rays in this small series and at the doses used for diagnostic purposes did not induce leukaemic fusion gene expression, but we cannot exclude the possibility that a small proportion of preterm infants may be unusually sensitive to x rays.

Cell Line↗

PubMed1985

Neonatal adaptation: greater sympathoadrenal response in preterm than full-term fetal sheep at birth.

A marked increase in sympathoadrenal activity at birth has been described in animals and humans. Studies to determine whether the magnitude and duration of the catecholamine surge at birth in preterm lambs is similar to full-term lambs were undertaken using an acutely exteriorized fetal lamb. To maintain a physiologically stable preparation, all preterm lambs were given natural sheep surfactant intratracheally before the first breath. Base-line catecholamine values were similar in the full-term and preterm lambs. After umbilical cord cutting there was a marked increase in circulating norepinephrine (NE) and epinephrine (E) in both full-term and preterm animals. The preterm animals exhibited a delayed but exaggerated elevation of both NE and E relative to term animals. The peak preterm value for NE (3.8 +/- 1.2 ng/ml) occurred at 60 min and exceeded the peak NE value 1.2 ng/ml observed at 15 min in full-term animals. The peak E concentration in preterm animals was over 9 ng/ml between 2 and 3 h of age, whereas full-term animals reached a peak value of 1.1 ng/ml at 5 min. Heart rate and blood pressure rose abruptly to peak values by 5-15 min in full-term animals. Changes in heart rate and mean arterial pressure were less profound and more gradual in preterm animals. Full-term animals also demonstrated a five-to sevenfold increase in plasma free fatty acids, whereas concentrations in preterm animals increased only two- to threefold. There was a similarly blunted response in blood glucose in preterm animals. The catecholamine surge at birth may be an important adaptive phenomenon with physiological implications.

Adaptation, Physiological↗

PubMed1998

Longitudinal evaluation of salivary cortisol levels in full-term and preterm neonates.

The aim of the present study was to test the practicability of sequential cortisol determinations in saliva of low birth weight neonates and to evaluate the impact of systemic and inhaled glucocorticoid therapy on saliva concentrations of cortisol in preterm neonates with bronchopulmonary dysplasia (BPD). Salivary cortisol levels were measured by RIA in saliva samples from 10 full-term and 10 preterm healthy neonates and from 20 preterm neonates with BPD during systemic [dexamethasone (DEX); n = 10] or topical steroid therapy [budesonide (BUD); n = 10]. Saliva samples of each individual were collected on 3 consecutive days at 06.00, 12. 00, 18.00 and 24.00 h. Cortisol levels in saliva ranged from 0.8 to 60.6 nmol/l (median 6.5 nmol/l) in full-term neonates, from 0.6 to 52.1 nmol/l (median 5.5 nmol/l) in preterm neonates, from 0.4 to 14. 0 nmol/l (median 1.0 nmol/l) in preterm neonates treated with DEX and from 0.4 to 15.2 nmol/l (median 2.5 nmol/l) in preterm neonates treated with BUD. Autocorrelation analysis revealed a distinct endogenous cortisol rhythm in 2 of the 10 healthy full-term neonates and in 3 of the 10 healthy preterm neonates with a wavelength of 12-30 h. Salivary cortisol levels in preterm neonates treated with DEX or BUD were significantly lower than those measured in healthy preterm neonates. These results demonstrate that the measurement of salivary cortisol levels is a reliable and practicable way of assessing adrenal function in full-term and preterm neonates. This study also shows for the first time that some neonates display an endogenous cortisol rhythm which is not coupled to the exogenous day/night cycle. Furthermore, systemic and nebulized glucocorticoids suppress adrenal function in low-birth-weight neonates. After treatment these children should be closely monitored for potential adrenal insufficiency.

Administration, Topical↗

PubMed2005

Intrapartum magnesium sulfate exposure attenuates neutrophil function in preterm neonates.

BACKGROUND: Prenatal exposure to magnesium sulfate, a drug that is frequently used for attempted tocolysis in preterm labor, could alter neutrophil functional activity in infants born preterm. OBJECTIVES: To determine the association between maternal tocolysis with magnesium sulfate and the cord blood neutrophil functional activity of preterm neonates. METHODS: The chemotaxis, random motility, and chemiluminescence of neutrophils were compared in the cord blood of 10 preterm neonates born to mothers tocolysed with magnesium sulfate, 10 preterm infants whose mothers had not received any tocolysis, and 10 term infants. Data regarding the maternal and neonatal magnesium and calcium levels were collected and analyzed in association with the cord blood neutrophil functional activity of the preterm infants. RESULTS: Neutrophil functional activity in the cord blood of the preterm neonates was significantly lower than in term neonates. However, the alteration of neutrophil chemotaxis, random motility and chemiluminescence was more noticeable in neonates with intrapartum exposure to magnesium sulfate as compared to preterm infants whose mothers received no tocolysis (30.9 +/- 2.3 vs. 36.7 +/- 2.7 microm, p < 0.01; 26.6 +/- 1.9 vs. 33.1 +/- 3.1 microm, p < 0.01; and 74.3 +/- 6.5 vs. 89.9 +/- 6.25 x 10(3) counts per min (cpm), p < 0.01, respectively). Furthermore, the reduction in neutrophil functional activity of preterm infants with intrapartum exposure to magnesium was directly correlated with the maternal serum magnesium levels (r = -0.90 to -0.85, p < 0.01). CONCLUSION: In infants born preterm, intrapartum exposure to magnesium sulfate is a risk factor contributing to the alteration in neutrophil motility and post-phagocytic bactericidal capacity.

Calcium↗

PubMed2005

Polymorphisms of haemostasis genes as risk factors for preterm delivery.

Clinical trials evaluating the potential benefit of anticoagulant treatment in pregnant women with inherited thrombophilia are based on the observation that a genetic predisposition to thrombosis is associated with frequent abortions and preterm birth. It was the aim of our study to delineate the impact of genetic polymorphisms with prothrombotic and antithrombotic effects on the occurrence of preterm birth in a large cohort of very-low-birth-weight (VLBW)-infants and their mothers. We examined the factor V Leiden and the prothrombin G20210A mutation, the factor VII 121del/ins and the factor XIII Val34Leu polymorphism in preterm very-low-birth-weight (VLBW, n=593) and term-born-infants (n=278) and their mothers (n=785). The primary outcome was preterm vs.term birth. From all polymorphisms tested, the maternal factor VII-121del/ins polymorphism (26.2 vs. 17.6 %; p=0.009) and the infant's factor VII-121del/ins polymorphism (29.0 vs. 20.0 %; p=0.009) were more frequent in singleton VLBW and their mothers compared to term infants and their mothers. Furthermore, the frequency of the factor XIII-Val34Leu polymorphism was significantly lower in singleton VLBW than in term infant controls (5.1 vs. 9.6%, p=0.025). In a multivariate regression analysis, previous preterm delivery (OR=3.8, 95% CI: 1.7-8.4), the maternal carrier status of the factor-VII-121del/ins polymorphism (OR=1.7, 95% CI: 1.12-2.5, p=0.007) and the lower frequency of infant's factor-XIII-Val34Leu polymorphism (OR=0.53; 95% CI: 0.29-0.96; p=0.038) were found to be independently associated with preterm delivery. InVLBW mothers with pathological CTG as cause of preterm delivery, the frequency of factor V Leiden mutation was significantly increased compared to VLBW mothers without pathological CTG (14.1 vs. 6.1%, p=0.01). The investigated haemostasis gene polymorphisms have a much lower impact on subsequent preterm delivery than known risk factors such as previous preterm birth. The reported association of the factor-VII-121del/ins polymorphism on preterm delivery and its clinical relevance needs to be further elucidated.

Cohort Studies↗

PubMed2005

Alveolar epithelial cell differentiation and surfactant protein expression after mild preterm birth in sheep.

As the transition to extrauterine life at birth alters the proportions of type I and II alveolar epithelial cells (AECs), our aim was to determine the effect of mild preterm birth on AECs and surfactant protein (SP) gene expression. Preterm lambs were born at approximately 133 d of gestational age (DGA); controls were born at term (approximately 147 DGA). Lungs were collected from preterm lambs at term-equivalent age (TEA; approximately 2 wk after preterm birth) and 6 wk post-TEA. Control lung tissue was collected from fetuses (at 132 DGA), as well as from lambs at approximately 6 h (normal term) and 2, 6, and 8 wk of postnatal age (PNA). In controls, the proportion of type I AECs decreased from 65.1 +/- 3.9% at term to 50.9 +/- 3.3%, while the proportion of type II AECs increased from 33.7 +/- 3.9% to 48.5 +/- 3.3% at 6 wk PNA. At 2 wk after preterm birth, the proportions of type I and II AECs were similar in preterm lambs compared to 132-d fetal levels and term controls but differed from control values at 2 wk PNA; differences between control and preterm lambs persisted at 8 wk PNA. At approximately 2 wk after preterm birth, SP-A and SP-B, but not SP-C, mRNA levels were significantly reduced in preterm lambs compared with term controls, but these differences did not persist at 2 and 6 wk PNA. We conclude that mild preterm birth alters the normal postnatal changes in type I and II cell proportions but does not severely affect SP gene expression.

Animals↗

PubMed2001

Preterm birth: associated neuroendocrine, medical, and behavioral risk factors.

Increased CRH secretion by the placenta of pregnant women has been associated with preterm birth. Certain indices of risk, both medical and psychosocial in nature, have been linked to preterm delivery. Levels of total, bound, and free CRH, CRH-binding protein (CRH-BP), and cortisol were measured prospectively in a large sample of pregnant Danish women who delivered preterm and term infants. Measures of maternal serum hormones were taken at 7--23 and 27--37 weeks gestation and, for those who delivered at term, at 37--43 weeks gestation. At 7--23 weeks gestation, maternal levels of total CRH (P = 0.01), bound CRH (P = 0.03), and CRH-BP (P = 0.01) were higher in the preterm than in the term group. At 27--37 weeks gestation, levels of total CRH (P < 0.0001), bound CRH (P < 0.0001), free CRH (P < 0.0001), and cortisol (P < 0.0001) were all higher in the preterm than the term group, whereas levels of CRH-BP (P < 0.0001) were lower in the preterm than in the term group. The best medical and behavioral factors associated with preterm delivery were, respectively, previous preterm delivery (P < 0.0001) and engagement in certain risk-taking behaviors (P = 0.008). The positive relations between preterm delivery and various adverse medical and socioeconomic variables with increases in placental secretion of CRH suggest that the latter may participate in the pathophysiology of preterm delivery.

Adult↗

PubMed1999

Ventricular dominance patterns in preterm infants.

OBJECTIVE: The purpose of the study was to determine EKG and 2-D echocardiographic criteria of ventricular dominance in preterm infants and select those by which ventricular dominance could be established by EKG alone. METHODS: A database was constructed from EKG and 2-D echocardiographic measurements on preterm infants ranging in gestational ages from 23 to 34 weeks and birth weights from 555-2490 g, and fullterm controls. Twelve-lead EKGs were obtained in the first 4 days of life in 12 preterm infants and in the first 24 hours of 4 controls. 2-D echocardiograms were performed with sweeps from the subcostal, parasternal, apical and suprasternal views and M-mode measurements in the short axis parasternal view on 11 of the preterm infants and 9 fullterm controls. RESULTS: A definite leftward QRS axis for the preterm infants (+90 degrees, preterm; +133.75 degrees, term; t = -5.63; p < 0.001) indicated a left ventricular (LV) dominance. But R/S in favor of LV dominance for preterm infants was apparent in V6 only. A pooled amplitude index for each ventricle based on R and S wave from V1, V2, V5, and V6 leads, showed LV dominance for the preterm infants with a trend toward RV dominance with increasing gestational age (F = 20.82; p < 0.001). RVD/LVED M-mode echo ratios confirmed the LV dominance in preterm infants. CONCLUSION: A healthy full term infant is born with RV dominance. LV dominance with a trend toward RV dominance with increasing gestational age was found in preterm infants by EKG and echo criteria.

Child↗

PubMed2006

Regional brain development in serial magnetic resonance imaging of low-risk preterm infants.

OBJECTIVE: MRI studies have shown that preterm infants with brain injury have altered brain tissue volumes. Investigation of preterm infants without brain injury offers the opportunity to define the influence of early birth on brain development and provide normative data to assess effects of adverse conditions on the preterm brain. In this study, we investigated serial MRI of low-risk preterm infants with the aim to identify regions of altered brain development. METHODS: Twenty-three preterm infants appropriate for gestational age without magnetic resonance-visible brain injury underwent MRI twice at 32 and at 42 weeks' postmenstrual age. Fifteen term infants were scanned 2 weeks after birth. Brain tissue classification and parcellation were conducted to allow comparison of regional brain tissue volumes. Longitudinal brain growth was assessed from preterm infants' serial scans. RESULTS: At 42 weeks' postmenstrual age, gray matter volumes were not different between preterm and term infants. Myelinated white matter was decreased, as were unmyelinated white matter volumes in the region including the central gyri. The gray matter proportion of the brain parenchyma constituted 30% and 37% at 32 and 42 weeks' postmenstrual age, respectively. CONCLUSIONS: This MRI study of preterm infants appropriate for gestational age and without brain injury establishes the influence of early birth on brain development. No decreased cortical gray matter volumes were found, which is in contrast to findings in preterm infants with brain injury. Moderately decreased white matter volumes suggest an adverse influence of early birth on white matter development. We identified a sharp increase in cortical gray matter volume in preterm infants' serial data, which may correspond to a critical period for cortical development.

Brain↗

PubMed1999

[Preterm delivery: detection of risks and preventive treatment].

Every year around the world some 13 million premature children are born. Most of these children are born in developing countries, and they account for the largest share of perinatal morbidity and mortality. This review study analyzed scientifically validated data on interventions to prevent at least some portion of these preterm deliveries and to lessen their impact on neonatal health. The Cochrane and MEDLINE bibliographic databases were consulted. Fifty review pieces and research articles were studied, relating to the following aspects of preterm delivery: risk factors and early detection of the risk of preterm delivery; preventing the risk of preterm delivery; treating preterm delivery once it has begun; and preventing neonatal respiratory distress syndrome. There were few successful approaches to the prediction, prevention, or early detection of the threat of preterm delivery. The only measures that can be recommended for all pregnant women are screening for and treating asymptomatic bacteriuria as a part of prenatal check-ups. Screening for bacterial vaginosis and treating it reduce the incidence of preterm births in pregnant women with a history of premature delivery. In addition, prophylactic cerclage decreases the incidence of premature births in pregnant women who have had more than three preterm births. To treat a delivery that starts early, with or without premature membrane rupture, the interventions that have proved to be effective are administering betamimetics to the parturient woman in order to delay delivery for 48 hours, and using indomethacin for the same purpose, as the second-choice drug. The prenatal administration of corticosteroids to the pregnant woman can induce lung maturation in the fetus and reduce respiratory distress syndrome and ventricular hemorrhage, thus decreasing neonatal mortality. There is a need to continue and support basic and epidemiological research in order to develop new knowledge on the causes and mechanisms of preterm delivery and on preventing the morbidity and mortality that preterm delivery produces.

Female↗

PubMed2001

Insulin-like growth factor-binding protein-1 in cervical secretion as a predictor of preterm delivery.

BACKGROUND: The aim of the study was to evaluate whether the phosphorylated isoforms of insulin-like growth factor-binding protein-1 (IGFBP-1), a protein produced by the decidua, can be detected in cervical secretions of pregnant women with preterm uterine contractions, and whether their presence predicts an increased risk of preterm delivery. METHODS: A prospective analysis of sixty-three women who presented with preterm labor but intact fetal membranes at weeks 22-36+6 days of gestation at the Antenatal clinic at the Department of Obstetrics and Gynecology, Helsinki University Central Hospital. Phosphorylated IGFBP-1 (phIGFBP-1) was measured in cervical swab samples obtained at presentation, using an immunoenzymometric assay. The values > or =10 microg/L were considered as positive. In addition, 58 asymptomatic women at the same gestational stage were studied as controls. Multiple logistic regression was applied to control for confounding variables and to obtain adjusted odds ratios. RESULTS: The concentration of phIGFBP-1 in cervical samples ranged from undetectable to 95 microg/L. In 17 of the 63 (27%) women with preterm labor it was > or =10 microg/L. Seven of these 17 (41%) women with a positive phIGFBP-1 result delivered preterm, all before 35 weeks of gestation. Among the women with preterm labor and a negative phIGFBP-1 result, three of the 46 (7%) delivered before 37 weeks of gestation (adjusted OR 24, 95% CI 1.2-487), but all after 35 weeks of gestation. In the asymptomatic control population three out of 58 (5%) women had a positive cervical phIGFBP-1 test result but none delivered preterm. Among the controls with a negative cervical phIGFBP-1 test result (55 of 58, 95%), one woman delivered preterm (1 of 55, 2%). CONCLUSIONS: Pregnant women who are in preterm labor with intact fetal membranes and who have a positive phIGFBP-1 test result in cervical secretion have an increased risk of preterm delivery.

Adolescent↗

PubMed2003

Preterm deliveries in women with systemic lupus erythematosus.

OBJECTIVE: To compare the clinical, laboratory, and demographic variables of women in our clinic with systemic lupus erythematosus (SLE) who have had a pregnancy resulting in a live birth and identify any correlations with either term or preterm delivery. METHODS: Pregnancies in women with SLE from 1999 to 2001 were retrospectively reviewed. We recorded demographic data, disease activity (SLE Disease Activity Index, SLEDAI), obstetric history, prednisone dosage, other medications taken during pregnancy, history of renal disease, and autoantibody status [including antinuclear antibody, anti-DNA, anticardiolipin IgG (aCL), and lupus anticoagulant (LAC)]. Preterm delivery was defined as gestational age at delivery < 37 weeks. We performed a literature survey using PubMed and the key words SLE, pregnancy, and outcome. RESULTS: Of the 72 pregnancies, 28 (38.9%) resulted in preterm deliveries. There were no significant differences in any demographic or disease variables measured comparing term versus preterm delivery groups. More women in the preterm group were taking > or = 10 mg/day prednisone during their pregnancy (50.0% vs 22.2%; p = 0.028), and the mean dose was significantly higher than the term group taking > or = 10 mg/day (24.8 vs 16.7 mg/day; p = 0.047). There was a higher prevalence of women with aCL IgG in the preterm group (p = 0.023). The mean weeks gestation was shorter for women positive for aCL IgG compared to the group negative for aCL (34.9 +/- 4.4 vs 37.5 +/- 3.2 weeks, respectively; p = 0.032). There was no difference in second trimester disease activity between the term and preterm groups (33.3% and 36.4% of each group had a SLEDAI of 0). However, significantly more women in the term group received no medication during their pregnancies compared to women in the preterm group (20.0% vs 0.0%; p = 0.031). CONCLUSION: The rates of preterm deliveries, premature rupture of membranes, intrauterine growth restriction, and aPL in SLE pregnancies vary considerably in published reports, most of which are retrospective analyses. Our rates closely approximate the median values for all measures. We found preterm deliveries to be associated with disease activity (as determined by the use of any medication throughout pregnancy vs no medication, and prednisone dose > or = 10 mg/day) and the presence of aCL IgG but not LAC. Our results suggest that inactive disease rather than controlled disease at the onset of pregnancy may be the determining factor in extending SLE pregnancies to full term, thereby decreasing maternal and fetal morbidity.

Anti-Inflammatory Agents↗

PubMed2003

Value of routine urine culture in the assessment of preterm labor.

OBJECTIVE: To assess the utility and expense of routine urine culture in women evaluated for preterm labor. STUDY DESIGN: A retrospective study of 1,429 patients evaluated for preterm labor over a calendar year. Patients evaluated for preterm labor were identified using the hospital's admissions database and then cross-referenced with the hospital microbiology laboratory's database to identify those who had urine cultures sent as part of their evaluation. The charts of patients with a positive urine culture were further reviewed to evaluate the diagnosis and outcome. RESULTS: Five hundred twelve urine cultures were sent for analysis of preterm labor, and 6 (1.2%) reported growth of > 100,000 colonies of a single bacterium. Of these 6 patients, 5 reported symptoms consistent with a urinary tract infection, while the 6th was asymptomatic. Fisher's exact test showed no clinical significance for a positive urine culture as a predictor of preterm delivery (P = .68). Sensitivity was 0.7% (95% CI, 0.0-4.3), and specificity was 98.6% (95% CI, 96.7-99.5). A cost difference of $29,676 existed between charges and reimbursements. A positive culture was not a significant risk factor for preterm delivery. The 1 patient who delivered preterm with a positive culture probably had cervical incompetence as the cause of preterm delivery. CONCLUSION: The routine use of urine cultures in the assessment of preterm labor is costly and adds little value to obtaining a diagnosis except in the presence of specific complaints at our institution. Urine culture identified a single patient with asymptomatic bacteriuria being evaluated for preterm labor, and she probably had another etiology for her advanced cervical examination.

Adult↗

PubMed1993

Clinical and environmental predictors of preterm labor.

OBJECTIVE: To determine the magnitude of risk for preterm labor associated with specific clinical and environmental factors. METHODS: Using a case-control design, 266 women with preterm labor and 512 controls were interviewed and their medical records reviewed. Crude and adjusted odds ratios were calculated for each risk factor. Population-attributable risks were estimated. RESULTS: Third-trimester bleeding, twin gestation, and chorioamnionitis at presentation were strongly associated with preterm labor (odds ratios 11.2-48.3). A history of a prior preterm delivery, vaginal bleeding in the first or second trimester, maternal diethylstilbestrol exposure, uterine anomalies, and urinary tract infection during pregnancy were associated to a lesser extent (odds ratios 1.6-5.4), as were cigarette smoking and drug use (odds ratios 2.0 and 3.0). Cases who had preterm labor preceded by premature rupture of the membranes had a substantially higher risk of preterm labor if chorioamnionitis, vaginal bleeding early in pregnancy, or urinary tract infection was present. By contrast, women who had intact membranes at the onset of preterm labor carried higher risk when twin gestation, placental abruption, or uterine anomaly was present. The highest population-attributable risks for preterm labor were found in patients with a twin gestation or third-trimester bleeding. CONCLUSIONS: Programs to reduce the preterm delivery rate should consider the attributable risks for the factors they are intended to modify. The attributable risks we obtained suggest that medical strategies to reduce the impact of the clinical variables, especially multiple gestation, and educational programs to decrease smoking and drug use should reduce the preterm delivery rate.

Adult↗

PubMed1998

Secular trends in preterm birth: a hospital-based cohort study.

CONTEXT: Canada and the United States have reported a recent increase in the incidence of preterm birth, but the reasons for this increase are unknown. OBJECTIVE: To assess secular trends in preterm birth and its potential determinants. DESIGN: Hospital-based cohort study. SETTING: Canadian tertiary care university teaching hospital, 1978-1996. PARTICIPANTS: A total of 65574 nonreferred live births and stillbirths. MAIN OUTCOME MEASURES: Changes in occurrence of preterm birth, before and after adjustment for changes in method of gestational age assessment, obstetric intervention, registration of births weighing less than 500 g, and sociodemographic, behavioral, and clinical determinants. RESULTS: A crude secular increase in preterm births was seen for births less than 37, 34, and 32 completed weeks using 3 alternative gestational age estimation methods. Based on an algorithm incorporating both menstrual and early ultrasound gestational age estimates, rates increased from 6.6% to 9.8% for births at less than 37 weeks' gestation, 1.7% to 2.3% at less than 34 weeks, and 1.0% to 1.2% at less than 32 weeks. Exclusion of births weighing less than 500 g and those with induction or preterm cesarean delivery without labor before each of the corresponding gestational age cutoffs eliminated the secular trends for births before 34 and 32 weeks and attenuated the trend for births before 37 weeks. Nearly half of the remaining trend for births before 37 weeks was accounted for by the increasing use of early ultrasound dating. The residual trend was eliminated after controlling for secular increases in unmarried status and the proportion of women aged 35 years or older. These factors, combined with a decrease in alcohol consumption and increases in histological chorioamnionitis and cocaine use, appear to have counteracted a reduction in preterm birth since the mid-1980s that otherwise would have been observed. CONCLUSIONS: This hospital's increase in preterm births since 1978 parallels increases reported in population-based national studies from the United States and Canada. This trend appears largely attributable to the increasing use of early ultrasound dating, preterm induction and preterm cesarean delivery without labor, and changes in sociodemographic and behavioral factors.

Canada↗

PubMed2001

Mid-trimester endovaginal sonography in women at high risk for spontaneous preterm birth.

CONTEXT: Although shortened cervical length has been consistently associated with spontaneous preterm birth, it is not known when in gestation this risk factor becomes apparent. OBJECTIVE: To determine whether sonographic cervical findings between 16 weeks' and 18 weeks 6 days' gestation predict spontaneous preterm birth and whether serial evaluations up to 23 weeks 6 days' gestation improve prediction in high-risk women. DESIGN, SETTING, AND PARTICIPANTS: Blinded observational study performed between March 1997 and November 1999 at 9 university-affiliated medical centers in the United States in 183 women with singleton gestations who previously had experienced a spontaneous birth before 32 weeks' gestation. OBSERVATION: Certified sonologists performed 590 endovaginal sonographic examinations at 2-week intervals. Cervical length was measured from the external os to the functional internal os along a closed endocervical canal. Funneling and dynamic cervical shortening were also recorded. MAIN OUTCOME MEASURE: Spontaneous preterm birth before 35 weeks' gestation, analyzed by selected cutoff values of cervical length. RESULTS: Forty-eight women (26%) experienced spontaneous preterm birth before 35 weeks' gestation. A cervical length of less than 25 mm at the initial sonographic examination was associated with a relative risk (RR) for spontaneous preterm birth of 3.3 (95% confidence interval [CI], 2.1-5.0; sensitivity = 19%; specificity = 98%; positive predictive value = 75%). After controlling for cervical length, neither funneling (P =.24) nor dynamic shortening (P =.054) were significant independent predictors of spontaneous preterm birth. However, using the shortest ever observed cervical length on serial evaluations, after any dynamic shortening, the RR of a cervical length of less than 25 mm for spontaneous preterm birth increased to 4.5 (95% CI, 2.7-7.6; sensitivity = 69%; specificity = 80%; positive predictive value = 55%). Compared with a single cervical measurement at 16 weeks' to 18 weeks 6 days' gestation, serial measurements at up to 23 weeks 6 days significantly improved the prediction of spontaneous preterm birth in a receiver operating characteristic curve analysis (P =.03). CONCLUSIONS: Cervical length assessed by endovaginal sonography between 16 weeks' and 18 weeks 6 days' gestation, augmented by serial evaluations, predicts spontaneous preterm birth before 35 weeks' gestation in high-risk women.

Adult↗