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PubMed1993

Delayed birth intervals of immature fraternal triplets in preterm labor. A case report.

The preterm birth of immature triplets before 28 weeks is associated with excess morbidity and mortality risks attributable to extreme immaturity. We report a case of fraternal triplets in preterm labor in which the second and third triplet births were delayed 11 days after the first birth, at 26 4/7 weeks' gestation. The later-born sibs were heavier at birth and throughout their neonatal course in the hospital and suffered less severe complications as compared to the first-born triplet. Delayed birth intervals of triplets in preterm labor should be considered to improve perinatal salvage of immature triplets, although a successful outcome is rare and unexpected.

Adult↗
PubMed1989

Infection and labor. V. Prevalence, microbiology, and clinical significance of intraamniotic infection in women with preterm labor and intact membranes.

Amniotic fluid was retrieved by amniocentesis from 264 patients with preterm labor and intact membranes admitted to Yale-New Haven Hospital from Jan. 1, 1985, to July 31, 1988. The prevalence of a positive amniotic fluid culture was 9.1% (24/264). A total of 111 patients (42%) delivered preterm neonates, and 24 (21.6%) of those had positive amniotic fluid cultures. The diagnostic indexes of the Gram stain of amniotic fluid in the prediction of a positive amniotic fluid culture were as follows: sensitivity, 79.1%; specificity, 99.6%; positive predictive value, 95%; and negative predictive value, 98%. Endotoxin was detected with the limulus amebocyte lysate assay in 4.9% (13/264) of patients with preterm labor. All patients with endotoxin in the amniotic fluid delivered preterm neonates. The three most frequently isolated organisms were Ureaplasma urealyticum (n = 6), Fusobacterium species (n = 5), and Mycoplasma hominis (n = 4). Clinical chorioamnionitis was present in only 12.5% of the patients with positive amniotic fluid cultures. Women with positive amniotic fluid cultures had lower gestational ages and more advanced cervical dilatation on admission than women with negative cultures. Preterm infants born to mothers with positive amniotic fluid cultures had a higher incidence of respiratory distress syndrome and infectious complications than preterm neonates born after negative amniotic fluid cultures. These data underscore the frequency and importance of intraamniotic infections in women with preterm labor.

Amniocentesis↗
PubMed2003

The effect of treating bacterial vaginosis on preterm labor.

OBJECTIVE: Multiple studies suggest that bacterial vaginosis (BV) causes preterm labor; yet its routine treatment remains controversial. In order to help to elucidate this controversy, we performed a thorough review of studies with levels of evidence ranging from I to II-II. METHODS: We searched for all of the studies from the years 1994 to 2001 via Medline's database, including MD Consult and Ovid Mednet. RESULTS: Several trials discovered a decrease in the incidence of preterm labor when BV was treated, but most of those trials were performed on women with a history of preterm labor. However, the majority of trials reviewed advise against treatment of a general low-risk obstetric population, as there was no significant decrease in preterm labor. CONCLUSIONS: Therefore, based on the above studies and the current guidelines of the Centers for Disease Control and Prevention (CDC), treating pregnant women in high-risk populations who are diagnosed with BV provides the clinician with an opportunity to possibly prevent preterm labor in this population. In nulliparous women without a history of preterm birth, treatment is recommended if other risk factors are present (e.g. gonorrhea or chlamydia). However, in the general low-risk populations, routine screening is not indicated.

Adult↗
PubMed1997

An association between the heat-humidity index and preterm labor and delivery: a preliminary analysis.

OBJECTIVES: The goal of this study was to determine whether a relationship exists between heat-humidity indexes and rates of preterm labor and preterm delivery. METHODS: Preterm labor and delivery rates were compared during the 2 summer and 2 winter weeks with the highest and lowest heat-humidity indexes for each season. RESULTS: The rate of preterm labor increased consistently from 1.23% to 3.00% as the heat-humidity index rose. When preterm births were examined, the trend was similar but not statistically significant. CONCLUSIONS: Given the public health import of preterm labor and the frequency with which pregnant women may be exposed to extremes of heat, studies designed to confirm or refuse our preliminary observations are warranted.

Delivery, Obstetric↗
PubMed1987

Subclinical intra-amniotic infection in asymptomatic patients with refractory preterm labor.

The purpose of this prospective investigation was to determine the incidence of subclinical intra-amniotic infection in asymptomatic patients who had intact membranes and refractory preterm labor. Refractory preterm labor was defined as persistent uterine contractions despite maximum recommended doses of parenteral tocolytics, or recurrent preterm labor within three days of successful transition to oral tocolytics. Amniotic fluid was cultured aerobically and anaerobically and prepared for Gram stain and group B streptococci latex fixation test. One of 24 women had a positive latex fixation test, but the culture was negative. One culture was positive for isolated colonies of Corynebacterium sp. None of the patients developed clinical evidence of intra-amniotic infection or postpartum endometritis. The mean prolongation of pregnancy was 31 days (range 1-63). None of the infants had evidence of sepsis in the immediate neonatal period. In this population, subclinical infection was an uncommon cause of refractory preterm labor.

Amniocentesis↗
PubMed1994

A prospective evaluation of the signs and symptoms of preterm labor.

OBJECTIVE: To describe the time relation between symptoms, contractions, and the clinical diagnosis of preterm labor. METHODS: We analyzed the records from 57 women who were enrolled in a previously reported trial of home uterine monitoring and who developed preterm labor while using the monitor. In a post hoc descriptive study of signs and symptoms during the 7 days preceding a diagnosis of preterm labor, we reviewed uterine contraction records and study records of the responses to a standard list of questions about potential symptoms of preterm labor. RESULTS: Monitored contraction frequency increased on the day of preterm labor diagnosis, from an average of fewer than three per hour to five per hour, but was not increased on any of the days before the day of diagnosis. Neither symptoms nor contraction monitoring strips indicated any significant changes more than 24 hours before the clinical diagnosis was made. Self-palpated and monitored contractions were the most common symptoms of preterm labor. CONCLUSION: A clinical diagnosis of preterm labor is preceded by an increase in self-palpated and monitored contractions and other symptoms for less than 24 hours.

Adult↗
PubMed2006

Cervical length in women in preterm labor with intact membranes: relationship to intra-amniotic inflammation/microbial invasion, cervical inflammation and preterm delivery.

OBJECTIVE: Intra-amniotic infection, diagnosed by microbial invasion of the amniotic cavity (MIAC) and/or the presence of intra-amniotic inflammation (IAI), is related to adverse perinatal outcome in women with preterm labor. Due to the subclinical nature of IAI, a correct diagnosis depends on amniocentesis, which is an invasive method not performed as a clinical routine. The aim of this study was to evaluate if cervical length measured by transvaginal sonography could assist in the identification of women at high risk for IAI. METHODS: Cervical length was assessed by transvaginal sonography in 87 women with singleton pregnancies in preterm labor (<34 weeks of gestation). Cervical (n=87) and amniotic (n=55) fluids were collected. Polymerase chain reactions for Ureaplasma urealyticum and Mycoplasma hominis, and culture for aerobic and anaerobic bacteria, were performed. Interleukin (IL)-6 and IL-8 were analyzed by enzyme-linked immunosorbent assay. RESULTS: IAI was present in 25/55 (45%) of the patients presenting with preterm labor who underwent amniocentesis. Women with IAI had a significantly shorter cervical length (median, 10 (range, 0-34) mm) than had those without IAI (median, 21 (range, 11-43) mm) (P<0.0001). Receiver-operating characteristics curve analysis showed that a cervical length (cut-off of 15 mm) predicted IAI (relative risk, 3.6; CI, 1.9-10.0) with a sensitivity of 72%, specificity of 83%, positive predictive value of 78% and negative predictive value of 78%. Cervical length was also significantly associated with preterm birth up to 7 days from sampling and at <or=34 weeks. CONCLUSION: Cervical length assessed by transvaginal sonography predicts IAI as well as preterm birth and could thereby be a useful clinical tool in the management of patients in preterm labor.

Adult↗
PubMed2006

An initial proteomic analysis of human preterm labor: placental membranes.

Human preterm labor (PL) is the single most significant problem in modern Obstetrics and Gynecology, affecting approximately 10% of pregnancies worldwide, constituting the leading cause of perinatal mortality and morbidity, and contributing significantly to chronic childhood disease. Currently, our molecular understanding of PL remains staggeringly inadequate to reliably diagnose or rationally intervene in PL events; several molecular alterations have been implicated in PL, but these have proven of limited value as diagnostic/prognostic markers. The majority of PL events remain spontaneous and unpredictable: critical care emergencies. Here, we apply functional proteomics to dissect molecular mechanisms of human PL. Human placental tissue was collected in clearly differentiated cases of preterm and term labor. Highly refined two-dimensional gel electrophoresis (2DE) was used for protein separation, coupled with automated differential gel image analysis to compare the resulting proteomic maps. For this initial study, only the most important protein differences were selected for further analysis, that is, proteins that were unique to one sample, and absent from the other, with 100% reproducibility across the sample population. In total, 11 such proteins were identified by tandem mass spectrometry, falling into three distinct functional classes: structural/cytoskeletal components, ER lumenal proteins with enzymatic or chaperone functions, and proteins with anticoagulant properties. These expression changes form the groundwork for further molecular investigation of this devastating medical condition. This approach therefore holds the potential not only to define the underlying molecular components, but also to identify novel diagnostic tools and targets for rational drug intervention.

Anticoagulants↗
PubMed2001

[Evaluation of fetal breathing movements in prognosis of preterm labor].

The relationship between fetal breathing activity and preterm labor among patients with signs of preterm labor has been analyzed. The assessment concerned pregnant women admitted to the hospital because of regular uterine contractions, uterine contractility and bleeding or premature rupture of membranes. It has been found the significant correlation between the absence of fetal breathing movements and preterm labor.

Female↗
PubMed1999

Amniotic fluid concentrations of adrenomedullin in preterm labor.

OBJECTIVE: To determine whether adrenomedullin levels in amniotic fluid were associated with preterm labor. METHODS: We measured immunoreactive adrenomedullin in amniotic fluid collected by amniocentesis from 36 women with clinical diagnosis of preterm labor or preterm premature rupture of membranes (PROM) and from 18 normal pregnant women. RESULTS: Amniotic fluid from cases of PROM and failure to respond to tocolysis were associated significantly with higher amniotic fluid adrenomedullin concentrations (177.0 +/- 22.5 pg/mL and 182.7 +/- 22.0 pg/mL, respectively, P < .01) than that from uncomplicated pregnancies (101.2 +/- 28.1 pg/mL) or preterm labor responsive to tocolysis (102.3 +/- 26.8 pg/mL). CONCLUSION: Amniotic fluid adrenomedullin is higher than normal in cases of PROM and preterm labor unresponsive to tocolysis, perhaps indicating enhanced synthesis from placenta or fetal membranes being stimulated by bacterial products.

Adrenomedullin↗
PubMed1995

Risk factors for the development of preterm premature rupture of the membranes after arrest of preterm labor.

OBJECTIVE: Our purpose was to determine risk factors predictive of preterm premature rupture of the membranes in women treated for preterm labor with intact membranes. STUDY DESIGN: Women with intact membranes participating in a National Institute of Child Health and Human Development multicenter randomized trial of adjunctive antibiotic therapy for preterm labor (24 to 34 weeks) were studied (n = 275). After randomization, 22 women continued to have contractions and were delivered of their infants. The remaining 253 women whose contractions had ceased composed our study population. Preterm premature rupture of the membranes was diagnosed if ruptured membranes occurred > or = 1 hour before the onset of recurrent preterm labor. As part of the study protocol, most women underwent amniocentesis on admission. RESULTS: Preterm premature rupture of the membranes developed in 44% women (17.4%). Women who had preterm premature rupture of the membranes were more likely to be black (p = 0.004), to be multiparous (p = 0.014), to have a history of abortion(s) (p = 0.001), to have had a preterm birth(s) (p = 0.036), to have early onset preterm labor (p = 0.04), to have more advanced cervical dilatation (p = 0.0001), to have one or more amniotic fluid markers suggestive of infection (p = 0.01, odds ratio 4.2), and to have positive amniotic fluid cultures (p = 0.0007, odds ratio 27). Assignment to antibiotic therapy did not prevent preterm premature rupture of the membranes in the 253 women randomized or in the 16 women with a positive amniotic fluid marker(s) of infection. CONCLUSION: Black race, multiparity, a history of abortion or preterm birth, advanced dilatation, and a positive amniotic fluid marker(s) are associated with preterm premature rupture of the membranes in women with preterm labor. Antibiotic treatment did not prevent preterm premature rupture of the membranes.

Abortion, Spontaneous↗
PubMedDate not supplied

Pharmacotherapy of preterm labor.

Physiological factors initiating the birth process, problems associated with preterm labor, and use of pharmacotherapeutic agents to treat preterm labor are reviewed. Human parturition appears to be initiated by a combination of factors, the interplay of which is not well understood. In many cases, the threat posed by preterm labor is difficult to assess. Because the stringency of patient-selection criteria varies widely among studies, success rates of different drugs used to arrest labor are difficult to compare. For both short-term and long-term tocolysis, beta 2-sympathomimetic agents (betamimetics) can be used. These drugs, which include isoxsuprine, ritodrine, terbutaline, albuterol, nylidrin, fenoterol, metaproterenol, and hexoprenaline, are believed to affect intracellular calcium concentrations in the myometrium. Ritodrine is the only drug in this class currently approved by the FDA for inhibition of labor. Terbutaline has been shown to be effective in halting uterine contractions and is substantially less expensive than ritodrine. Calcium channel-blocking agents such as nifedipine and verapamil are being investigated for inhibition of labor. Magnesium sulfate, another calcium antagonist, has long been used as a tocolytic. Other agents discussed are ethanol, diazoxide, the prostaglandin synthetase inhibitors (e.g., indomethacin and aspirin), and progestational steroids. Pharmacotherapy should be individualized on the basis of the patient's clinical condition, presence of other disease states, and side effects associated with available tocolytic agents. To date, a betamimetic with selective beta 2 effects, such as terbutaline or ritodrine, is the most valuable agent for inhibition of preterm labor.

Adrenergic beta-Agonists↗
PubMed1987

Prostaglandin concentrations in amniotic fluid of women with intra-amniotic infection and preterm labor.

This study was undertaken to examine the effects of intrauterine infection and preterm labor on the amniotic fluid concentrations of prostaglandins in women with premature rupture of the membranes. Amniotic fluid was obtained from four groups of patients with premature rupture of the membranes: group 1, patients without labor or infection; group 2, patients with labor but without infection; group 3, patients with an intra-amniotic infection but without labor; group 4, patients with both infection and labor. Prostaglandins E2 and F2a were measured by radioimmunoassays. Preterm labor, in the absence of infection, was not associated with significant increases in amniotic fluid concentrations of prostaglandins. Women with preterm labor and intra-amniotic infections had higher amniotic fluid concentrations of prostaglandins than women with preterm labor in the absence of infection or women with intra-amniotic infection in the absence of labor. These observations are compatible with the participation of prostaglandins in the mechanisms of onset of preterm labor associated with intra-amniotic infection.

Adult↗
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↗
PubMed1986

Preterm labor associated with subclinical amniotic fluid infection and with bacterial vaginosis.

Maternal genital infection, particularly subclinical amniotic fluid infection, may cause preterm labor and a premature delivery. The prevalence of subclinical amniotic fluid infection was studied in 54 consecutive afebrile women in preterm labor with singleton gestations and intact fetal membranes. Microorganisms were recovered from the amniotic fluid by transabdominal amniocentesis in 13 (24%) of 54 patients. Bacteria or Candida albicans were recovered from six (11%), and genital mycoplasmas from seven (13%). Compared with women with sterile amniotic fluid, patients whose amniotic fluid contained bacteria or Candida organisms had a shorter interval from onset of preterm labor until delivery (0.6 versus 34.3 days, P less than .01), were less responsive to tocolytic therapy (0 versus 81% success rate, P less than .005), and more frequently developed subsequent intrapartum fever (83 versus 2.4%, P less than .005). In contrast, women whose amniotic fluid contained genital mycoplasmas did not differ in these parameters from those with sterile fluid. Also compared was cervical-vaginal infection among these patients in preterm labor with matched control subjects without preterm labor. In this analysis, bacterial vaginosis was identified in 43% of patients with and 14% of women without preterm labor (P = .02), yielding a relative risk of preterm labor for patients with bacterial vaginosis of 3.8. These data underscore the importance of amniotic fluid bacterial infections in preterm labor and premature delivery, and suggest that bacterial vaginosis is associated with prematurity.

Adult↗
PubMed1994

Erythropoietin umbilical serum levels during labor in women with preeclampsia, diabetes, and preterm labor.

In this study we determine the erythropoietin levels and hematocrit in 22 women with preterm labor, 21 with insulin-dependent diabetes, 22 with preeclampsia, and 20 with normal gestation. The erythropoietin level was higher in the preeclamptic group than in the diabetic group compared with the normal and premature groups. There were no hypoxic fetuses. From this study, we found that the mechanism of increased erythropoietin levels in neonates can be different from fetal hypoxia. Further studies are needed on this subject.

Adult↗
PubMed1989

Ceramide lactoside in amniotic fluid: high concentration in chorioamnionitis and in preterm labor.

The mechanisms responsible for the onset and progression of preterm labor are poorly understood. In the present study a total of 115 amniotic fluid specimens were analyzed for a lipid that has not previously been detected in amniotic fluid. This glycolipid was identified as ceramide lactoside. It was found in two-dimensional thin-layer chromatograms for evaluation of lung maturity and quantified by gas chromatography. Ceramide lactoside concentrations in amniotic fluid were low in spontaneous labor at term (1.7 +/- 0.7 nmol/ml) and in pregnancies that were not associated with spontaneous preterm labor (1.4 +/- 0.6 nmol/ml). The concentrations were high in chorioamnionitis with signs of infection (11.8 +/- 5.8 nmol/ml) and in preterm labor without clinical signs of chorioamnionitis (5.4 +/- 4.0 nmol/ml). A high ceramide lactoside (greater than or equal to 5 nmol/ml) predicted chorioamnionitis with signs of infection at a sensitivity and a specificity of 94% and 95%, respectively. A moderately high ceramide lactoside concentration (greater than or equal to 2.5 nmol/ml) predicted spontaneous preterm labor: sensitivity, 82%; specificity, 95%. Little, if any, ceramide lactoside was present in urine, vernix, normal fetal membranes, or lung effluent, whereas this glycolipid was present in large amounts in granulocytes and in inflamed fetal membranes. We propose that phagocytosing granulocytes release ceramide lactoside into amniotic fluid.

Amniocentesis↗
PubMed1982

Preterm labor: cause and management.

Preterm labor has not been eradicated by the introduction of the betamimetic agents. However, with the more effective agents, a marked prolongation of intrauterine existence has allowed further growth and development of small preterm fetuses. This has reduced morbidity and mortality significantly. Further work is necessary. Despite the capability of inhibiting labor with any of several drugs, a major factor in the improved survival of small preterm infants has been instant availability and access to the infant of a neonatologist. In most instances this requires transport to at least a secondary and in most cases to a tertiary care facility. With infants estimated to be under 1500 gm, tocolysis should be employed as an adjunct to transfer of the maternal-fetal unit to a tertiary care facility.

Adrenergic beta-Agonists↗