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PubMed2003

ACOG practice bulletin. Management of preterm labor. Number 43, May 2003.

Preterm birth is the leading cause of neonatal mortality in the United States, and preterm labor precedes 40-50% of preterm births. Preterm birth accounts for 35% of all U.S. health care spending for infants and 10% of all such spending for children. Approximately 467,000 live births annually (11.5% of all live births) occur before term in the United States, and preterm births are responsible for three quarters of neonatal mortality and one half of long-term neurologic impairments in children. The purpose of this document is to present the various methods proposed to manage preterm labor and the evidence for their roles in clinical practice. Despite the numerous management methods proposed the incidence of preterm birth has changed little over the past 40 years (Fig. 1). Uncertainty persists about the best strategies for managing preterm labor.

Female↗

PubMedDate not supplied

Mechanisms of full-term and preterm labor: factors influencing uterine activity.

OBJECTIVE: To review factors influencing uterine activity leading to delivery. DATA SOURCES: A search was conducted on MEDLINE and CINAHL under the terms "preterm labor," "preterm delivery," and "physiology of labor and preterm labor." STUDY SELECTION: One-hundred fifty articles were reviewed, with selection based on physiologic concepts judged to be most relevant to nursing practice. DATA SYNTHESIS: In this review, factors initiating labor and preterm labor (PTL) are identified, along with areas for further research. CONCLUSIONS: Despite research on what initiates labor, it is unknown how the various mechanisms are integrated. Nurses are in a position to conduct research to help further the understanding of the labor and PTL processes. Nurses can use their assessment skills to help identify women at risk for PTL and delivery.

Female↗

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↗

PubMed2000

Serum ferritin level as a marker of preterm labor.

OBJECTIVE: To compare the serum ferritin levels in women with preterm labor (PTL) or preterm premature rupture of membranes with those in normal gravid women. METHOD: The study group consisted of 50 consecutive subjects with preterm labor and 49 subjects with preterm premature rupture of membranes (PROM). The control group consisted of 50 subjects matched with the study group for hemoglobin (Hb) and gestation who did not have PTL or preterm PROM. Serum ferritin levels were assayed in both the groups. RESULTS: Mean serum ferritin levels in patients with preterm labor and preterm premature rupture of membranes were 23.24+/-12.13 ng/ml and 29.44+/-28.41 ng/ml, respectively. The mean serum ferritin in control subjects was 8.69+/-3.7 ng/ml. The difference was evaluated by Student's t-test and was found to be statistically significant. CONCLUSION: The serum ferritin level is significantly raised in pregnant women with preterm labor and preterm PROM.

Adult↗

PubMed1996

Physical activity and the risk of preterm labor: an epidemiological review and synthesis of recent literature.

Considerable recent research effort of physical activity and pregnancy has included evaluation of preterm labor, preterm delivery, and gestational age at delivery. This review specifically evaluates recent studies that included such assessments of gestational parameters. Methodological difficulties (eg, small sample size, selective clinical populations) have prevented clear generalizable findings regarding the impact of physical activity on preterm labor and delivery. The outcomes evaluated are often times not similar from study to study and, with the associated differences in research design, prevent valid meta-analyses of this topic. Because there is some evidence that gestation and birthweight may decrease among physically active women, larger-scale, randomized clinical trials designed specifically to evaluate whether this association is simply a minor change in gestation and birthweight, or if this difference is manifested clinically in higher rates of preterm labor and delivery and low birthweight, are warranted. Without larger, population-based randomized studies, clinicians will remain unclear about the potential risks and/or benefits related to gestational duration of maternal exercise in their populations.

Exercise↗

PubMedDate not supplied

Deciding when it's labor: the experience of women who have received antepartum care at home for preterm labor.

OBJECTIVE: To describe how women who had received antepartum care at home for preterm labor managed subsequent episodes of preterm labor symptoms. DESIGN: Grounded theory method. SETTING: 2 Canadian antepartum home care programs. PARTICIPANTS: 12 women who received antepartum care at home for preterm labor that had been diagnosed in hospital prior to 34 weeks gestation. RESULTS: The core psychosocial process was reconciling body knowledge and professional knowledge. Study participants reported knowing something's not right and followed decision guides to seek help. If, when they returned to the hospital to see what's going on, they felt dissonance between what their bodies were telling them (body knowledge) and what their health care providers were telling them (professional knowledge) an overriding tension developed between not wanting to take a risk for the baby versus not wanting to overreact. These women reestablished their baselines of nonthreatening symptoms at a higher level by setting a new normal to avoid the humiliation associated with appearing to overreact. Attempting to ignore recurring symptoms of preterm labor delayed help seeking and caused anxiety. CONCLUSIONS: To avoid delayed help seeking, nursing interventions should be geared to reducing anxiety and validating the experiences of women with recurring preterm labor symptoms.

Adult↗

PubMed1992

Transforming growth factor-beta opposes the stimulatory effects of interleukin-1 and tumor necrosis factor on amnion cell prostaglandin E2 production: implication for preterm labor.

OBJECTIVE: In preterm labor increased concentrations of interleukin-1 and tumor necrosis factor are present in amniotic fluid. These cytokines may promote labor by stimulating the production of prostaglandins by intrauterine tissues. In many biologic processes, transforming growth factor-beta modifies the actions of cytokines. We studied the effect of transforming growth factor-beta on the cytokine-induced prostaglandin E2 production by amnion cells. STUDY DESIGN: Human amnion cells in monolayer culture were treated with interleukin-1, tumor necrosis factor, or vehicle in the presence or absence of transforming growth factor-beta. The prostaglandin E2 production was measured. RESULTS: Transforming growth factor-beta decreased the interleukin-1- or tumor necrosis factor-induced prostaglandin E2 production by 70% to 80% and the basal prostaglandin E2 synthesis by 27%. The synergistic stimulation of prostaglandin E2 production by the combination of interleukin-1 with tumor necrosis factor was inhibited by 80% in cells treated with transforming growth factor-beta. Transforming growth factor-beta 1, -beta 2, and -beta 1,2 were equipotent. CONCLUSION: Transforming growth factor-beta suppresses the cytokine-induced prostaglandin E2 production by amnion cells and may be an important factor in maintaining pregnancy in the face of labor-promoting cytokines.

Amnion↗

PubMed1996

Pharmacologic intervention in the management of preterm labor: an update.

Preterm birth accounts for the majority of neonatal morbidity and mortality not associated with congenital anomalies. Its incidence has remained relatively unchanged over the past 15 to 20 years. Tocolytic therapy has been shown to be ineffective in the prevention of preterm labor but can delay delivery by approximately 48 hours. Four major drug groups are currently available. The article reviews each drug group, including mechanism of action, pharmacology, side effects, efficacy, and nursing implications.

Female↗

PubMed2006

Hypothetical role of prostaglandins in the onset of preterm labor after fetal surgery.

Preterm labor is one of the most important factors limiting the advancement of fetal surgery programs. While prostaglandins (PGs) have long been indicated as the key factor in the initiation of labor in humans, there is significant evidence showing that the chorionic membrane acts as a powerful barrier between the decidua/myometrium and amniotic PGs during normal pregnancy. After either open or endoscopic fetal surgery the imperfect, non-hermetical closure of the chorion permits leakage of PGs from the amnionic sac, allowing them to reach the decidua and myometrium. The surgical wound in the chorionic barrier could be the major factor involved in preterm labor and delivery after human fetal surgery.

Amniotic Fluid↗

PubMed1999

Impact of the fetal fibronectin assay on admissions for preterm labor.

OBJECTIVE: The aim of the study was to determine whether use of the fetal fibronectin assay would decrease the number of admissions to labor and delivery for diagnosis and treatment of preterm labor. STUDY DESIGN: A prospective cohort design was used to compare preterm labor admissions during a 12-month period of fetal fibronectin assay use (study) against a baseline period before fetal fibronectin assay was implemented as standard protocol. Patients coming to the physician's office or hospital with signs and symptoms of preterm labor had a sample obtained for fetal fibronectin assay per labeling criteria. Comparisons were made with the Mann-Whitney U test, independent Student t test, chi2 test, and Fisher exact test. P <.05 was considered significant. RESULTS: There was no difference noted in the number of deliveries between the baseline and study years. During the study year 251 of 330 patients evaluated for preterm labor met study criteria and had the fetal fibronectin assay completed. Eight patients did not have fetal fibronectin assay results available because of specimen handling errors, leaving 243 subjects available for study. Compared with the baseline year, the study year had significantly fewer admissions for preterm labor, preterm labor admissions per patient, and prescriptions written for tocolytic agents. In addition, the length of stay per admitted patient was significantly reduced. The study population had no differences in neonatal outcomes from the baseline population in terms of deliveries at <35.0 weeks' gestation, number of admissions to the neonatal intensive care unit, neonatal intensive care unit length of stay, or days of ventilatory support per patient admitted to the neonatal intensive care unit. CONCLUSIONS: Use of the fetal fibronectin assay resulted in significantly reduced preterm labor admissions, length of stay, and prescriptions for tocolytic agents. No negative impact on neonatal outcomes was observed. Reductions in admissions for preterm labor and in charges per admission resulted in approximately $486,000 saved during the study period. A trend toward increased corticosteroid administration (for neonates ultimately admitted to the neonatal intensive care unit) was noted.

Adolescent↗

PubMed2000

How to diagnose preterm labor: a clinical dilemma.

The clinician is faced with many dilemmas in the diagnosis of preterm labor. The tools at hand (no pun intended) yield subjective information and it is difficult to distinguish true labor from false labor. Because preterm labor is multifactorial in cause and can occur in primiparas, estimating risk for the individual patient is difficult. The cause of the preterm labor in the majority of patients is idiopathic; in this group, the use of salivary estriol as a biochemical marker for preterm labor can increase the accuracy of the diagnosis of true labor. It may also lend confidence to the diagnosis of false labor and may allay anxiety and prevent unnecessary interventions. On the horizon are two noninvasive methods: the EMG, to evaluate uterine contractility, and the collascope, to evaluate the cervix. Both show promise and may provide a more objective assessment of risk for preterm delivery among women with symptoms of preterm labor.

Collagen↗

PubMed2000

Endocrinology of preterm labor.

The clinical importance of preterm labor and delivery dictates that we understand the physiology and diagnostic usefulness of endocrine as well as other agents that may be helpful in this regard. Clearly, estrogen and progesterone establish the environment that allows parturition and probably preterm labor to occur. The use of salivary estriol, though not a foolproof test, is becoming more frequent and is commercially available. Fibronectin, though not an endocrine test, has a similar diagnostic usefulness. In the future, we would expect to see CRH and even the use of selective cytokines, probably IL-6, as possible diagnostic tests. Whereas all of these agents have some diagnostic usefulness, none of them can be expected to predict every case of preterm delivery and some battery of tests, not unlike the triple or quadruple tests that are used for prenatal diagnosis of Down syndrome, may be effective and should be examined in the future. The use of these tests, salivary estriol and fetal fibronectin in particular, has already had an effect on management and decision making involved in preterm labor, and the future should give us more options and hopefully, better choices to manage this most difficult condition.

Endocrine System↗

PubMed2003

Oxytocin and fetal membranes in preterm labor: current concepts and clinical implication.

Preterm birth is associated with up to 90% of perinatal deaths. In spite of numerous clinical and preclinical research programs, its incidence has not changed throughout the past decade. An observation that the oxytocin antagonist atosiban delays preterm labor and is significantly more potent than vasopressin(1a) receptors gave rise to research on the role of vasopressin blockade in tocolysis and vasopressin itself in preterm labor. Successful tocolysis allows the introduction of intrauterine steroid treatment of the fetus, which reduces the chance of developing infant respiratory distress syndrome and intracranial hemorrhage. Fetal membranes, decidua and placenta are considered a possible site of initiation of parturition, both term and preterm. Research on the biology of these tissues may shed new light on current concepts of the pathophysiology of preterm labor. We here present a short review on the role of oxytocin, oxytocin receptor blockade and fetal membranes in preterm labor.

Extraembryonic Membranes↗

PubMed2002

Treatment of preterm labor.

The ultimate goal of treating preterm labor is to prolong the pregnancy long enough to decrease the incidence of neonatal mortality and morbidity associated with prematurity, while minimizing maternal and fetal risks. There are many controversies in treating preterm labor. Much of this controversy stems from the difficulty in establishing efficacy and safety of interventions and uncertainty of the diagnosis of preterm labor. This article outlines conventional measures and tocolytic therapy directed at prolonging the pregnancy. A review of the effect of tocolytic agents, administration, side effects, and nursing interventions is included. Key words: preterm labor treatment,

Bed Rest↗

PubMed2000

Economic burden of hospitalizations for preterm labor in the United States.

OBJECTIVE: To determine patient factors associated with hospital care costs for preterm labor and to develop a clinically applicable cost model for evaluating economic consequences of interventions to reduce preterm-labor hospitalizations. METHODS: Maryland state hospital discharge data from 1993-1996 were used to identify hospitalizations for preterm labor without delivery and preterm labor with early delivery. Median regression was used to determine the association between patient factors and hospital care costs in Maryland and to develop a model to estimate hospital care costs nationally. National estimates of hospitalizations for preterm labor were from the 1994 National Hospital Discharge Survey. RESULTS: During the 4-year study period, there were 25,104 hospitalizations for preterm labor, undelivered, and preterm labor with early delivery in Maryland. Maternal comorbidity, antenatal procedures, types of insurance, and lengths of stay associated significantly with hospital costs for preterm labor. National costs for preterm labor, undelivered, were more than $360 million. Incremental costs for preterm labor with early delivery, compared with term delivery, ranged from $21 million to $191 million. Total expenditures for preterm-labor hospitalization for the United States were estimated in excess of $820 million. CONCLUSION: Hospitalizations for preterm labor comprise a substantial portion of maternal cost of perinatal care in the United States. Maternal comorbidity and procedures account for major differences in costs per admission. Strategies to reduce hospitalizations for preterm labor should focus on economic and clinical outcomes in evaluating their overall values.

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↗

PubMed1992

Endothelin-1,2 levels are increased in the amniotic fluid of women with preterm labor and microbial invasion of the amniotic cavity.

The purpose of this study was to determine the effect of gestational age, labor, and microbial invasion of the amniotic cavity on amniotic fluid concentrations of endothelin-1,2. Amniotic fluid was retrieved by amniocentesis from 148 women: patients at term with and without labor, patients with preterm labor with and without intraamniotic infection, and women in the second trimester of pregnancy. Endothelin-1,2 was measured by a sensitive and specific radioimmunoassay. Immunoreactive endothelin-1,2 was detectable in all samples of human amniotic fluid. Advancing gestational age and spontaneous term labor did not result in changes in amniotic fluid concentrations of endothelin-1,2. Women with preterm labor and positive amniotic fluid cultures for microorganisms had higher amniotic fluid concentrations of endothelin-1,2 than did those without microbial invasion of the amniotic cavity (p less than 0.05). These results support a role for endothelins in the mechanisms responsible for preterm delivery associated with intraamniotic infection.

Adult↗

PubMed1988

A prospective random trial of home uterine activity monitoring in pregnancies at increased risk of preterm labor. Part II.

Daily uterine activity monitoring has been reported to be helpful in improving the percentage of women with preterm labor eligible for tocolysis, with a corresponding decline in preterm delivery. The first year of our trial of ambulatory tocodynamometry in 157 women at risk of preterm labor did not reveal significant differences in rates of preterm labor and preterm delivery between two groups of women randomly assigned to receive preterm labor education, frequent (5 days/week) telephone contact, and self-palpation of uterine activity (group EP), or to preterm labor education, daily telephone contact, and the Term Guard ambulatory uterine activity monitor (group EM). We report results from the second year (n = 152), yielding a total study population of 309. Forty-three subjects were later excluded, producing 266 subjects who completed the study. Comparison of preterm labor and preterm delivery rates, mean birth weight, and gestational age at delivery revealed no significant differences between the groups for the second year or for the combined data from both years of the study. Interestingly, comparison of all subjects enrolled in year 1 with all those enrolled in year 2 reveals significant decreases in the rates of both preterm labor and preterm delivery. Frequent attention to symptoms and signs of preterm labor, and improved patient and physician education and awareness, may be responsible for this decline in preterm labor and delivery in high-risk pregnancies.

Female↗