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PubMed1991

Comparison of nifedipine and ritodrine for the treatment of preterm labor.

Treatment of preterm labor with beta-sympathomimetics has been questioned because of the many maternal and fetal complications associated with its use. Nifedipine, a calcium antagonist, has been shown to suppress uterine activity in vitro and in vivo. A randomized prospective study was performed to compare the efficacy of nifedipine to ritodrine in the suppression of preterm labor. Data obtained from 42 women, of which 19 were randomized to the ritodrine group and 23 to the nifedipine group, were analyzed. Ritodrine and nifedipine proved to be equally effective in the suppression of preterm labor. However, the nifedipine group had fewer maternal and fetal complications.

Adult↗
PubMed2003

Obstetric, neonatal and anesthetic considerations for preterm labor and delivery.

Preterm birth is a continuing obstetric problem that contributes significantly to the incidence of perinatal death and long-term handicap. In this context, various studies have shown preterm births account for between 69% and 83% of neonatal deaths. Despite this, the incidence of preterm birth has remained static for many years. One explanation for this is that the management of preterm labor has altered very little in the past 30 years. Strategies aimed at reducing the incidence of preterm birth include the identification of risk factors that increase the likelihood of preterm delivery. Treatment is then designed to target those risk factors and limit their effect. Although perinatal mortality has declined, mostly due to the improved management of very low birthweight babies rather than prevention of preterm labor, efforts to prevent preterm birth have been largely unsuccessful so far and preterm birth still represents a major health care problem to both developed and developing countries.

Anesthesia, Obstetrical↗
PubMed1996

Asymptomatic maternal shedding of herpes simplex virus at the onset of labor: relationship to preterm labor.

OBJECTIVE: To determine if fetal growth restriction and prematurity are observed with subclinical shedding of herpes simplex virus (HSV) at the onset of labor. METHODS: Within 48 hours of delivery, cultures were taken from the cervix and external genitalia of 15,923 asymptomatic pregnant women without symptoms or signs of genital HSV infection; results were positive for HSV in 57. Each of these 57 women were compared with a control group composed of the three culture-negative women delivering immediately before and the three delivering immediately after each woman shedding HSV. RESULTS: The median birth weight for infants born to the 57 women with asymptomatic shedding was 3050 g, compared with 3360 g among the 342 women without asymptomatic shedding, a statistically significant difference (P < .002). These differences were due to very low birth weight (LBW) among the five infants of women with subclinical viral shedding secondary to recently acquired primary genital herpes; these five infants had a median gestational age of 33 weeks, compared with 37 weeks for the 14 infants of mothers with nonprimary, first-episode disease and 39 weeks for the 33 infants of women with reactivation disease, also a significant difference (P = .018). CONCLUSIONS: Asymptomatic genital shedding of HSV at the onset of labor because of subclinical primary genital HSV infection is associated with preterm delivery. Women who acquire genital HSV-2 before pregnancy and are shedding subclinically at the onset of labor experience no increase in adverse outcome. Thus, prevention of the prematurity and LBW associated with genital herpes means that acquisition of the infection in late pregnancy must be prevented.

Birth Weight↗
PubMedDate not supplied

Nursing's contribution to the literature on preterm labor and birth.

Although preterm labor and birth continues to plague us as an unsolved mystery in maternal/child health, much has actually been learned over the past few decades. Most reviews of the preterm labor literature examine the research in an interdisciplinary manner; this article instead looks at the active role that nurses have taken in the research concerning preterm labor and birth. This article will categorize research conducted by nurses over the past 30 years on preterm labor and birth, emphasizing some of the changes in nursing practice engendered by nursing's important research effort.

Female↗
PubMed2006

Thrombin and interleukin-1beta regulate HOXA10 expression in human term decidual cells: implications for preterm labor.

CONTEXT: Preterm delivery is commonly caused by intraamniotic infection with expression of proinflammatory cytokines (IL-1beta) or by abruption resulting in generation of decidual thrombin. Although human parturition is not preceded by overt progesterone withdrawal, progesterone resistance likely leads to labor. The uteri of Hoxa10(-/-) mice demonstrate progesterone resistance; several genes, including prostaglandin receptors, are inappropriately regulated in response to progesterone. OBJECTIVE: We hypothesized that IL-1beta or thrombin would decrease HOXA10 expression, contributing to the progestin-resistant environment. We analyzed expression of HOX genes and their regulation by IL-1beta or thrombin in decidual cells. DESIGN AND SETTING: We conducted an in vitro experiment at an academic medical center. INTERVENTION: Term decidual cells were treated with estradiol (E(2)) or E(2) plus medroxyprogesterone acetate followed by addition of thrombin or IL-1beta. MAIN OUTCOME MEASURE: HOX mRNA was evaluated by microarray and confirmed by quantitative RT-PCR. Protein expression was detected using immunohistochemistry and Western analysis. RESULTS: HOXA9, HOXA10, and HOXA11 were expressed in decidual cells and regulated by IL-1beta and thrombin. HOXA10 was further analyzed because of its association with progesterone responsiveness. After E(2) treatment, IL-1beta and thrombin decreased HOXA10 mRNA by 94 and 81%, respectively. After E(2) plus medroxyprogesterone acetate treatment, IL-1beta and thrombin resulted in an 86 and 72% decrease in HOXA10 mRNA, respectively. A similar decrease was noted in HOXA10 protein expression. CONCLUSION: The expression of HOXA10 protein at term indicates that it may have a role in maintaining decidual cell phenotype and pregnancy. The dramatic decrease of HOXA10 in response to IL-1beta or thrombin may contribute to progestin resistance in preterm labor, mimicking progesterone resistance seen in Hoxa10(-/-) mice.

Cells, Cultured↗
PubMed2000

[Tumor necrosis factor-alpha and interleukin-1 beta in maternal, fetal and retroplacental intravascular compartments at term and preterm labor].

Neonato preterm birth (before 37 pregnancy weeks) account more than 80% perinatal deaths not attributable to congenital malformations. Preterm and term labor full mechanisms are unknown at present. Proinflammatory cytokinesis direct participation have been involved in the phenomena by several experimental evidence. The study's aim was to determine TNF-alpha and IL-1 beta concentration at maternal, fetal and fetal-maternal vascular compartments in women with term and preterm delivery and in women at term childbirth without labor. TNF-alpha and IL-1 beta concentration were determinated by commercial immunoassay. TNF-alpha concentration showed a tendency to be in more proportion at fetal and fetal-maternal compartments in preterm and term childbirth groups versus TNF-alpha concentration in term group without labor at same places. IL-1 beta concentration showed same tendency of increase than TNF-alpha in preterm and term childbirth groups, but alone at fetal-maternal compartment. Statistical difference were not documented at any compartment or group compared. Data allow to identify fetal-maternal compartments as target places where TNF-alpha and IL-1 beta were synthesized. Gradient concentration synthesis of cytokinesis allows to intend fetus as TNF-alpha initial producer.

Adult↗
PubMed2001

New developments in the management of preterm labor.

Current management of preterm labor has not changed the incidence of preterm delivery; therefore, significant research effort has been concentrated on the search for new methods of management. New tocolytics like inhibitors of cyclooxygenase 2 and nitric oxide donors have been tested in animal models and in preliminary clinical trials with promising results. Inhibition of cervical ripening may be one alternative to tocolysis. This new approach has a potential to be a valuable method of management of preterm labor if human studies confirm the promising results reported in animals. Growing evidence suggests that premature delivery may be associated with infection or fetal growth abnormalities, with dire consequences to the fetus. If these associations are to be included in risk and benefit assessment, then inhibition of preterm labor may prove to be detrimental to the fetus.

Cerebral Palsy↗
PubMed1998

Preterm labor: diagnosis and treatment.

Preterm labor and delivery are among the most challenging obstetric complications encountered by the family physician. In the United States, preterm delivery affects approximately one in 10 births and is the cause of at least 75 percent of neonatal deaths, excluding those related to congenital malformations. Although the cause of preterm labor is unknown, family physicians who provide obstetric care should familiarize themselves and their patients with the predisposing risk factors. Preconception counseling should emphasize family planning, nutrition, "safe sex techniques", treatment of sexually transmitted diseases, and avoidance of cigarettes, alcohol, abusive drugs and harmful work conditions. The rate of fetal morbidity can be reduced with the early and accurate diagnosis of preterm labor, intervention to delay preterm delivery, administration of corticosteroids and provision of neonatal care. Research into biochemical markers such as fetal fibronectin, possible infectious etiologies such as bacterial vaginosis, and the use of more selective tocolytic therapy offers hope that new therapeutic approaches may increase rates of fetal survival.

Female↗
PubMed1993

Management of preterm labor and prevention of premature delivery.

Preterm births continue to be the leading cause of perinatal mortality despite efforts to prevent preterm labor. Tocolytic therapy with beta-mimetic drugs was believed to be the solution for preterm labor, but the Canadian Preterm Labor Investigators Group recently reported that the use of ritodrine had no significant beneficial effect. Despite the various methods presently used for the management of preterm labor and prevention of premature delivery, the incidence of preterm birth remains unchanged. Health professionals must remain optimistic, however, and continue to investigate causes, whether they are social or medical, and to seek the unknown. Nursing personnel should play an important role in this area as health promoters and educators of patients. Nurses should also collaborate with other health professionals to determine effectiveness of therapy and the causes of preterm labor. For instance, this author is currently involved in a research project seeking barriers to prenatal care using a questionnaire and reviewing maternal records in order to determine length of labor and its relationship to subsequent preterm labors. The goals of the Year 2000 National Health Objective for low birth weight and infant mortality are not likely to be attained. Prematurity has gained national attention, however, and with public and professional awareness, perhaps this problem will decrease.

Ambulatory Care↗
PubMed1998

Prostaglandin endoperoxide H synthase (PGHS) activity and PGHS-1 and -2 messenger ribonucleic acid abundance in human chorion throughout gestation and with preterm labor.

Term and preterm parturition is associated with elevated intrauterine PG production. Although an increase of PG synthesis by the fetal membranes during term labor is well documented, there is little data available regarding the prostanoid production of these tissues at term, before the spontaneous onset of labor. In the present study, we determined the expression of PG H2 synthase (PGHS), the committing and rate-limiting enzyme of prostanoid biosynthesis, in the chorion laeve during gestation. Tissues were collected from 18 patients at term (37-41 weeks of gestation) and from 13 patients between 17 and 35 weeks of pregnancy. None of the patients were in labor. PGHS-specific activity and the abundance of messenger RNAs (mRNAs) encoding the two PGHS isoenzymes (the constitutive PGHS-1 and the inducible PGHS-2) were measured by a cell-free enzyme assay and specific ribonuclease protection assays, respectively. PGHS-specific activity as well as PGHS-1 and -2 mRNA levels were significantly (P < 0.01) higher at term before labor than earlier during gestation. Furthermore, PGHS activity at term exhibited significant positive correlation with PGHS-2 mRNA levels, but not with PGHS-1 mRNA levels. In situ hybridization indicated that the expression of both PGHS mRNAs increased in the epithelial and the mesenchymal cells of the amnion and the chorion laeve at term. Additionally, PGHS activity and mRNA levels were determined in the chorion laeve of a group of patients who gave birth spontaneously before term (30.6 +/- 1 weeks, mean +/- SEM, n = 5), and the values were compared with a group who delivered by cesarean section before labor at a similar gestational age (31.9 +/- 1.4 weeks, n = 5, P > 0.05 vs. the preterm labor group). None of the patients exhibited signs of genital tract infection. PGHS-specific activity and PGHS-1 and -2 mRNA levels were significantly higher in the preterm labor group than in the group who delivered preterm without labor. In situ hybridization suggested that the enhanced PGHS-1 and -2 mRNA expression occurred predominantly in the mesenchymal cells of the fetal membranes at preterm labor. Thus, PGHS-1 and -2 expression increases in the chorion laeve at term before labor, with PGHS-2 as the functionally prevalent isoform. This supports the possibility that PGs originating in the fetal membranes promote the onset of normal labor. Furthermore, preterm labor is associated with the elevated expression of the two PGHS isoenzymes in the chorion laeve. The maturation of the fetal membranes in preparation for term labor involves both the epithelial and the mesenchymal cells, whereas preterm labor is accompanied by the maturation of the mesenchymal tissue components, as reflected by PGHS expression. This difference may have implications in the early recognition of preterm labor.

Adult↗
PubMed1980

Oral ritodrine maintenance in the treatment of preterm labor.

Seventy patients with preterm labor and intact membranes were initially treated with ritodrine hydrochloride to delay preterm delivery. Tocolysis beyond 24 hours was achieved in 59 patients. Fifty-five of the 59 patients were then placed on either oral ritodrine or placebo as maintenance therapy in a randomized double-blind manner. If preterm labor recurred, the sequence of intramuscular and then oral treatment was repeated. The number of days gained after initiation of intramuscular treatment was similar in both groups (oral ritodrine = 34 days, oral placebo = 36 days). In those 55 patients receiving oral treatment, there was a smaller number of relapses requiring repeat intramuscular treatment in the oral ritodrine group (1.11 in the ritodrine patient vs. 2.71 in the placebo patient, p less than 0.05), and the mean interval between beginning oral treatment and the first relapse/delivery was 5.8 days in the oral placebo group and 25.9 in those receiving oral ritodrine (p less than 0.05). Cardiovascular side effects, notably maternal tachycardia and palpitations were frequent but well tolerated. The results suggest that oral ritodrine maintenance will decrease the incidence of recurrent preterm labor in patients who have had initial successful tocolysis.

Administration, Oral↗
PubMed2004

Choosing calcium channel blockers for pregnant women with paroxysmal supraventriclar tachycardia and preterm labor: a case report.

Preterm labor is a major clinical hazard causing both maternal and neonatal morbidity and mortality. Paroxysmal supraventricular tachycardia (PSVT) complicated by preterm labor is rare. Of the many drugs used to treat PSVT, only calcium channel blockers are tocolytics. Here, we present the case of a 29-year-old female admitted to our ward with previously diagnosed PSVT and preterm labor at 31 weeks' gestation of her fourth pregnancy. Calcium channel blockers were administered and her uterine contractions subsided. Afterwards, no side effects were noted and she suffered no further tachycardic attacks during her pregnancy. She successfully delivered a full-term baby and received subsequent regular follow-up at the outpatient clinic.

Adult↗
PubMed1990

Ambulatory uterine activity monitoring in the post-hospital care of patients with preterm labor.

Care of women with preterm labor has been reported by Katz et al to be enhanced by use of an electronic uterine contraction monitor. We enrolled 76 women with singleton gestations who had been successfully treated for preterm labor into a prospective randomized trial, assigning subjects in a ratio of 1:2 to a group of 27 receiving education and self-palpation (EP) or to a group of 49 receiving education and an ambulatory monitor (EM). Subjects in both groups received an intensive education session at entry and were contacted frequently (5 days/week in EP and daily in EM) thereafter to report symptoms and frequency of contractions. Physicians were advised to adjust the dosage of oral tocolytic to maintain fewer than four contractions per hour. Rates of recurrent preterm labor and preterm delivery did not differ between the groups. Although the sample size in this study is too small to exclude entirely the possibility of alpha error, our inability to demonstrate a difference suggests that the improvement reported by others in pregnancy outcome associated with use of an electronic ambulatory contraction monitor may be the result of daily attention to symptoms and signs of preterm labor.

Ambulatory Care↗
PubMed1980

Prevention of preterm labor.

Ideally, prevention of preterm labor is preferable to efforts to inhibit the process once it has begun. However, before preventive treatment can be properly assessed, there is a need to delineate those patients that could benefit from therapy. Mathematical formulae based on epidemiology data are available to assist in prediction of preterm labor. Although their discriminatory powers are not yet at the level necessary for routine clinical usage, the systems can serve as a basis for attempts to improve the precision of prediction. If the predictive systems can be improved, we would then have a defined population on which preventive measures could be assessed. To date, there is no form of treatment that has been proven to prevent the onset of preterm labor.

Adult↗
PubMed1986

Preterm labor: its diagnosis and management.

Preterm labor and delivery remain a significant problem in contemporary obstetric practice. Although the exact cause remains unclear, it is most likely to be multifactorial in nature. No satisfactory screening tool or marker currently exists to firmly establish the diagnosis of impending labor. However, epidemiologic and historical variables associated with preterm delivery show some promise in this regard and are currently being evaluated in preterm prevention programs. Appropriate management of preterm labor mandates early recognition of subtle signs and symptoms; successful therapy is dependent on this issue. The approach to the clinical management of the patient in preterm labor used at our institution is described. Therapy with beta-adrenergic receptor agonists is currently the recommended pharmacologic treatment of this disorder. A review of other tocolytic agents and their usefulness in the management of preterm labor are presented.

Adolescent↗
PubMedDate not supplied

Preterm labor in the triage setting.

Preterm birth is one of the most devastating problems facing obstetrics today. Despite all of the available sophisticated research and therapeutic technology, the preterm birth rate has remained the same for the last 40 years. One birth in 10 occurs prematurely. Preterm labor manifests itself in a variety of ways. It is essential to promptly differentiate true preterm labor from preterm contractions or other conditions that present with similar symptoms. True preterm labor requires prompt clinical intervention in the obstetric triage setting.

Adolescent↗
PubMed1997

High levels of fetal membrane activin beta A and activin receptor IIB mRNAs and augmented concentration of amniotic fluid activin A in women in term or preterm labor.

The aim of the present study was to evaluate whether spontaneous labor at term and pathological preterm labor are associated with changes in the expression of activin A and activin receptor mRNAs in fetal membranes. In addition, amniotic fluid activin A concentration in women delivering at term or undergoing preterm labor was also measured. The expression of activin beta A subunit and activin receptor type II and type IIB mRNAs was assessed by reverse transcriptase-PCR on specimens of amnion and chorion collected from patients delivering at term or undergoing preterm labor. Control specimens were collected from women delivered by elective cesarean section who had not experienced labor. A specific two-site ELISA was used to measure activin A concentrations in the amniotic fluid. A cross-sectional study of amniotic fluid retrieved by amniocentesis from 109 pregnant women was carried out. Patients were classified into the following groups: (1) healthy controls at term but not in labor (n = 25); (2) healthy controls at term in spontaneous labor (n = 40); (3) healthy controls between 23 and 36 weeks of gestation (n = 12); (4) patients in preterm labor responding to tocolytic treatment (n = 19); (5) patients in preterm labor with subsequent delivery (n = 13). Activin beta A subunit and activin receptor type IIB mRNA levels in both the chorion and amnion in women delivering at term or after preterm labor were significantly higher than in women delivering without undergoing labor (P < 0.01). Expression of activin receptor type II mRNA in membranes did not differ among the three groups of women. Amniotic fluid activin A concentration in patients in labor was significantly higher than in those at term but not in labor (P < 0.01). Patients in preterm labor had significantly higher amniotic fluid activin A concentrations than women at the same stage of gestation (P < 0.01). The highest values were found in women undergoing preterm labor and subsequent delivery. In conclusion, spontaneous labor and preterm labor are characterized by increased synthesis and release of activin A from amniotic and chorionic cells and by an augmented expression of activin type IIB receptor.

Activin Receptors↗
PubMed2003

Maternal serum interleukin-6, interleukin-8, tumor necrosis factor-alpha and interferon-gamma in preterm labor.

BACKGROUND: To find out whether preterm labor is associated with raised maternal serum concentrations of interleukin (IL)-6, IL-8, tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) and whether the measurement of these cytokines can be used to detect early intrauterine infection in preterm labor. METHODS: Cross-sectional study: 77 women in preterm labor, 47 controls of healthy preterm women not in labor and 19 women in term labor. The serum cytokines levels were measured by enzyme-linked immunosorbent assay (ELISA). The newborns of women who were in labor were followed up for evidence of infection. Differences between groups were tested using analysis of variance, Student's t-test and chi2-test. RESULTS: There was no significant difference in the concentration of all the cytokines measured between the different groups. No statistical difference was found in the concentration of the cytokines between women in preterm labor with ruptured membranes and those with intact membranes. There was also no difference found in the concentration of cytokines between women whose newborns had positive bacterial culture and those with negative culture. There was a positive correlation between the concentrations of IL-6, IL-8 and TNF-alpha. CONCLUSION: Serum levels of interleukin-6, interleukin-8 and tumor necrosis factor-alpha were not increased in preterm labor compared to normal control women. There is doubt regarding the usefulness of maternal serum measurement of these cytokines for the detection of early fetal infection in preterm labor, but this needs further evaluation.

Adolescent↗