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PubMed1987

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

In a prospective trial we enrolled 157 women at increased risk of preterm birth, randomly assigning women in a ratio of 1:2 to receive either frequent (greater than or equal to 5 days/wk) nursing contact, education in preterm labor symptoms, and self-palpation of uterine activity (group E, n = 50), or daily nursing contact, preterm labor education, and the Term Guard home uterine activity monitor (group EM, n = 107). Comparison of the rate of preterm birth, the incidence of preterm labor and successful tocolysis, and the mean birth weight and gestational age revealed no significant differences and suggested that beneficial effects previously attributed to monitored contraction data may in fact be the result of frequent (five or more times per week) nursing contact and careful attention to preterm labor symptoms and perceived contractions.

Clinical Trials as Topic↗
PubMed1990

Changes in amniotic fluid concentrations of prostaglandins E2 and F2 alpha in women with preterm labor.

There is a paucity of data regarding the concentration of prostaglandins (PGs) in the amniotic fluid of women with preterm labor. The purpose of this study was to determine if preterm labor is associated with changes in amniotic fluid concentration of prostaglandins E2 and F2 alpha. Amniotic fluid was retrieved by transabdominal amniocentesis from women with preterm labor and intact membranes. Patients were classified into three groups according to the response to tocolysis and the presence or absence of intra-amniotic infection. PGE2 and PGF2 alpha were measured using specific and sensitive RIA kits. Amniotic fluid concentrations of PGE2 and PGF2 alpha were significantly higher in women with preterm labor and intra-amniotic infection than in women without infection, regardless of the response to tocolysis. These data suggest that both PGs are involved in the mechanism of preterm labor and may have prognostic value.

Amniotic Fluid↗
PubMed2001

[A study of the relationship among interleukin-8, cortisol and idiopathic preterm labor].

OBJECTIVE: To assess the effect of interleukin-8 and cortisol on the onset of idiopathic preterm labor (PL). METHODS: In 35 women with preterm labor and 17 controls, maternal serum and urine samples were collected. Interleukin-8 concentration was measured by enzyme-linked immunosorbant assay, serum cortisol level was measured by radioimmunoassay. RESULTS: The concentration of interleukin-8 in maternal serum and urine and cortisol in serum were significantly higher in PL group than those in the control [(0.26 +/- 0.13) microg/L vs (0.16 +/- 0.08) microg/L, (0.16 +/- 0.15) x 10(-2) g/mol Cr vs (0.04 +/- 0.02) x 10(-2) g/mol Cr, (765.83 +/- 408.55) microg/L vs (512.41 +/- 142.65) microg/L; P < 0.05, P < 0.01, P < 0.01, respectively]. A strong correlation was found ammong interleukin-8 and cortisol concentration in maternal serum in PL (r = 0.448; P < 0.05). CONCLUSIONS: There is a strong relationship between interleukin-8 and cortisol in the onset of preterm labor. Immune system and endocrine system might be involved in the mechanisms of idiopathic preterm labor.

Case-Control Studies↗
PubMed1995

Maternal anthropometry and idiopathic preterm labor.

OBJECTIVE: To assess the etiologic role of maternal short stature, low pre-pregnancy body mass index (BMI), and low rate of gestational weight gain in idiopathic preterm labor. METHODS: We carried out a three-center case-control study of 555 women with idiopathic onset of preterm labor (before 37 completed weeks), including two overlapping (ie, nonmutually exclusive) subsamples: cases with early preterm labor (before 34 completed weeks) and cases with recurrent preterm labor (before 37 completed weeks plus a history of prior preterm delivery or second-trimester miscarriage). Controls were matched to cases by race and smoking history. All subjects responded in person to questions about height, pre-pregnancy weight, gestational weight gain, and obstetric and sociodemographic histories. RESULTS: Maternal height, pre-pregnancy weight, and gestational weight gain demonstrated excellent test-retest reliability, with intra-class correlation coefficients of 0.97, 0.99, and 0.91, respectively. Based on matched analyses, women with a height of 157.5 cm or less had an increased risk of idiopathic preterm labor (odds ratio [OR] 1.85, 95% confidence interval [CI] 1.25-2.74), as did those with a pre-pregnancy BMI less than 19.8 kg/m2 (OR 1.63, 95% CI 1.09-2.44) or a gestational weight gain rate less than 0.27 kg/week (OR 1.74, 95% CI 1.16-2.62). Conditional logistic regression models containing all three anthropometric variables and controlling for parity, marital status, language, age, and education yielded virtually identical point estimates and CIs. CONCLUSION: Maternal short stature, low pre-pregnancy BMI, and low rate of gestational weight gain may lead to shortened gestation by increasing the risk of idiopathic preterm labor.

Anthropometry↗
PubMed1992

[Magnesium sulfate in prevention of preterm labor].

To observe the efficacy of magnesium sulfate in the treatment of preterm labor, 65 uncomplicated cases of preterm labor between 28 and 36 weeks of gestation were studied prospectively during Sep. 1988-May 1991. They were divided into two groups randomly. 30 cases were treated with magnesium sulfate and 35 cases with barbiturates or bed rest. The prevention of delivery for at least 48 hours after the initiation of therapy was achieved in 23 of the 30 cases (76.67%) of the magnesium sulfate group and in 3 of the 35 cases (8.57%) in the control group. Delay of more than 7 days was achieved in 17 of the 30 cases (56.67%) and in 2 of the 35 cases (5.71%). The postponement of delivery between the two groups. There was highly significantly difference (P less than 0.01). There was a significant correlation of cervical dilation at the onset of treatment to success of controlling preterm labor. In the magnesium sulfate group, the mean magnesium level to achieve tocolysis was 2.8 +/- 0.35 mmol/L (mean +/- s). The side effects to the mothers, fetus, and the neonates were mild and not prominent.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed2001

The epidemiology of preterm labor.

There are many factors that are associated with preterm labor and delivery. These include maternal conditions such as medical illness, anemia and uterine malformation. They may be related to past events such as prior obstetric complication, previous preterm labor, cervical surgery or induced abortion. They may be intrinsic to the current pregnancy, such as reproductive tract infection, multifetal gestation, maternal age, short interpregnancy interval or prolonged menstrual conception interval. Maternal behaviors such as smoking and substance abuse can be risk factors for a short gestation. Demographic variables such as race, employment and socioeconomic status can also be associated with preterm labor. This article briefly reviews these subjects.

Anemia↗
PubMed2000

Elevations of group II phospholipase A2 concentrations in serum and amniotic fluid in association with preterm labor.

OBJECTIVE: The purpose of this study was to determine whether the elevation of secretory group II phospholipase A(2) concentration in the serum and amniotic fluid in preterm labor is associated with intrauterine inflammation. STUDY DESIGN: Serum and amniotic fluid were collected from women with preterm delivery (<37 weeks' gestation; n = 38) and term delivery (n = 20). Phospholipase activity was measured with a highly sensitive system that was based on reverse-phase high-performance liquid chromatographic separation of 9-anthracenylmethyl derivatives of fatty acids released by phospholipase A(2). The concentrations of immunoreactive isozymes (group I or II) of secretory phospholipase A(2) were assayed with a radioimmunoassay kit with a monoclonal antibody against human pancreatic phospholipase A(2) and splenic IIA phospholipase A(2). Localization of immunoreactive group II phospholipase A(2) in the amniotic membrane was determined by immunostaining visualized with the Vectastain ABC (Vector Laboratories, Inc, Burlingame, Calif) method. RESULTS: Enzymatic activities of phospholipase A(2) in the serum and amniotic fluid specimens obtained from patients in preterm labor with chorioamnionitis were significantly higher than those in specimens from patients in term labor. Significant elevations of phospholipase A(2) activities were observed in patients with preterm labor without histologically evident chorioamnionitis. The activity of phospholipase A(2) was clearly correlated with the concentration of the immunoreactive group II phospholipase A(2). Group II phospholipase A(2) was localized in amniotic cells obtained from patients with a pathologically determined diagnosis of chorioamnionitis. The predictive value for chorioamnionitis of the group II phospholipase A(2) concentration was relatively higher than the predictive values of the concentrations of C-reactive protein and interleukins 6 and 8. CONCLUSION: Significant elevations of group II phospholipase A(2) concentrations were detected in the serum and amniotic fluid of women with preterm labor. Group II phospholipase A(2) concentration may be a useful indicator for preterm labor, and phospholipid metabolism is certainly activated both in preterm labor and in apparent inflammatory diseases.

Amniotic Fluid↗
PubMed1995

Risk of preterm delivery from preterm labor in high-risk patients.

This study aimed to determine the incidence of preterm labor and birth (< 37 weeks' gestation) in patients at high risk for early delivery. In this retrospective, descriptive study, 17,186 women with high-risk factors for early delivery were studied over a five-year period (1986-1990). Study groups included women with prior preterm delivery, multifetal gestations, uterine abnormalities and cervical factors. The rate of preterm labor for all patients averaged 40% (range, 30-46%). The rate of preterm delivery in the four groups ranged from 14% to 30% and averaged 19.7%. In those who experienced preterm delivery, only 32% of cases were due to preterm labor with advanced cervical dilatation, failed tocolysis or preterm premature rupture of membranes. The majority of early deliveries were due to medical or obstetric disorders as well as to patient/physician factors. The incidence of preterm labor remains significant when women have high-risk factors for preterm delivery. However, the incidence of preterm delivery, particularly that due to avoidable factors, such as failed tocolysis and preterm rupture of the membranes, is considerably lower than that quoted in the literature.

Adult↗
PubMed2001

Phenotypic and metabolic characteristics of maternal monocytes and granulocytes in preterm labor with intact membranes.

OBJECTIVE: Experimental and clinical studies support a role for the fetus in the control of the onset of labor. Fetal systemic inflammation, but not a maternal inflammatory response, has been linked to the onset of preterm labor and delivery on the basis of the determination of inflammatory cytokines in fetal and maternal blood. We propose that parturition requires fetomaternal cooperation and that inflammation is an integral part of the parturitional process. This study used flow cytometry, a sensitive technique for the detection of intravascular inflammation, to assess whether maternal inflammation is present in preterm labor. STUDY DESIGN: A prospective cross-sectional study was performed including patients with preterm labor (n = 55) and women with normal pregnancy (n = 50). Intravascular inflammation was studied by using flow cytometry. Maternal blood was assayed to determine granulocyte and monocyte phenotype by using monoclonal antibodies, which included the following cluster of differentiation (CD) markers: CD11b, CD14, CD15, CD16, CD18, CD49d, CD62L, CD64, CD66b, and HLA-DR. Oxidative burst and generation of basal intracellular oxygen radical species were assessed. Statistical analysis was conducted with the use of nonparametric methods. A P value of <.01 was considered statistically significant. RESULTS: Preterm labor was associated with a significant increase in the median mean channel brightness of CD11b, CD15, and CD66b on granulocytes and median mean channel brightness of CD11b and CD15 on monocytes. The ratio of oxidative burst over basal intracellular oxygen radical species in both granulocytes and monocytes was increased in preterm labor (P <. 01). CONCLUSION: Preterm labor with intact membranes is associated with phenotypic and metabolic changes of maternal granulocytes and monocytes.

Adult↗
PubMed1993

Randomized comparison of home uterine activity monitoring and routine care in patients discharged after treatment for preterm labor.

OBJECTIVE: To determine whether home uterine activity monitoring reduces the likelihood of preterm birth in women successfully treated for preterm labor in their current pregnancies. METHODS: Women between 20-34 weeks' gestation who had been treated successfully for preterm labor were solicited to participate in a randomized clinical trial of home uterine activity monitoring versus routine high-risk care. The sample size of 56 was based on power calculations using the results of earlier investigators. Twenty-eight women were randomized to home uterine activity monitoring and 29 were assigned to the type of care appropriate for women discharged after hospitalization for parenteral treatment of preterm labor. One of the routine-care subjects was lost to follow-up. The two groups were comparable in distribution for race, insurance status, multiple gestation, marital status, gestational age at beginning of the study, and incidence of prior preterm birth. RESULTS: The 28 women receiving routine care had a 54% incidence of preterm birth, whereas the incidence was 57% in monitored women (relative risk 1.08, 95% confidence interval 0.6-1.9; P = .79). The incidences of delivery before 32 weeks and 34 weeks also were unaffected by the intervention. CONCLUSION: Home uterine activity monitoring is not effective in reducing the likelihood of preterm delivery in patients successfully treated for preterm labor in their current pregnancies.

Cardiotocography↗
PubMed1979

Induction of preterm labor in the rat by antiprogesterone.

The validity of a new concept, predicting that preterm labor can be induced without oxytocic stimulation by a regulatory imbalance, generated by antiprogesterone (A-P)-provoked P withdrawal (Pw), has been examined in the rat model. At day 19 of pregnancy a single oral dose of the steroidal A-O isoxazol, which inhibits P synthesis, significantly reduced uterine P levels, increased uterine estradiol and prostaglandin F levels, and induced preterm labor. This precocious regulatory imbalance and preterm labor were prevented, by blocking the A-P-induced Pw with P treatment. The regulatory imbalance which triggered the onset of spontaneous labor in the control animals was similar, but it occurred at term rather than before term. The potential of this method in improving the management of medically indicated induction of preterm labor is discussed.

Administration, Oral↗
PubMed1991

Multicenter randomized clinical trial of home uterine activity monitoring for detection of preterm labor.

Home uterine activity monitoring has been described as an effective means of detecting uterine contractions, but controversy exists whether it is home uterine activity monitoring or increased nursing support in conjunction with it that contributes to earlier detection of preterm labor. In this study 377 women at risk for preterm labor from three centers were prospectively, randomly assigned to high-risk prenatal care alone (not monitored) or to the same care with twice-daily home uterine activity monitoring without increased nursing support (monitored). The two groups were medically and demographically similar at entry into the study. Routine visits, nonroutine visits, and gestational age at diagnosis of preterm labor were similar in both groups. Preterm labor occurred in 41 of 198 monitored and 39 of 179 not monitored patients. Mean cervical dilatation was 1.4 cm in 41 monitored compared with 2.5 cm for 37 not monitored (p = 0.0006); 73.1% of monitored and 27.5% of not monitored had preterm labor detected before 2 cm dilatation (p = 0.00009). Neonatal outcome of singleton pregnancies showed greater birth weight, fewer days in the neonatal intensive care unit, and fewer babies requiring oxygen therapy and mechanical ventilation in the monitored group. The better outcomes are probably due to the increased likelihood of diagnosis of preterm labor before advanced cervical dilatation with home uterine activity monitoring, thus providing the clinician with a better chance to initiate tocolytic therapy directed at improving pregnancy outcome.

Birth Weight↗
PubMed1996

Elevations of amniotic fluid macrophage inflammatory protein-1 alpha concentrations in women during term and preterm labor.

OBJECTIVE: To determine whether elevated concentrations of macrophage inflammatory protein-1 alpha (MIP-1 alpha) in amniotic fluid (AF) are related to term and preterm labor. METHODS: Amniotic fluid was obtained from women from five different clinical situations: 1) term cesarean delivery, no labor (n = 29); 2) normal term labor, no infection (n = 36); 3) preterm labor, delivery more than 1 week from sampling, no infection (n = 19); 4) preterm labor, delivery within 1 week from sampling, no infection (n = 18); and 5) preterm chorioamnionitis (n = 8). Amniotic fluid was collected aseptically at the time of amniocentesis, amniotomy, or hysterotomy. Concentrations of MIP-1 alpha were determined by enzyme-linked immunosorbent assay. Statistical analysis was by Wilcoxon rank-sum test, Kruskal-Wallis test, and unpaired t test. RESULTS: Women in normal term labor had significant elevations of AF MIP-1 alpha concentrations when compared with women at term undergoing repeat cesarean delivery (P < .001). In women with term gestation, AF MIP-1 alpha correlated well with cervical dilation (r2 = 0.479, P < .001). In women with preterm labor who later delivered within 1 week of presentation, AF MIP-1 alpha concentrations were higher than those from women who did not deliver within 1 week. Women who presented with clinically evident chorioamnionitis had the highest concentrations of AF MIP-1 alpha (P = .001). CONCLUSION: Women in labor have significantly elevated AF concentrations of MIP-1 alpha, particularly if labor is associated with intrauterine infection. We suggest that MIP-1 alpha is involved in the physiology of normal labor and in the pathogenesis of infection-associated preterm labor.

Amniotic Fluid↗
PubMed1990

Management of preterm labor patients at home: does daily uterine activity monitoring and nursing support make a difference?

Daily home uterine activity monitoring and perinatal nursing support were compared with standard care in managing patients with recurrent preterm labor during the current pregnancy in an effort to reduce preterm birth. Sixty-seven successfully treated preterm labor patients were randomly assigned in this multicenter study to daily home uterine activity monitoring and perinatal nursing support or to a standard-care group. Recurrent preterm labor occurred in 15 (45%) of monitored patients and 19 (56%) of standard-care patients. The risk of preterm birth (before 37 weeks) for patients with recurrent preterm labor was significantly reduced (P = .025) in the monitored group (seven, or 47%) compared with the standard-care group (16, or 84%). The relative risk of delivering because of failed tocolysis was 2.8 for the standard-care group versus the monitored group. There were no patients in the monitored group who delivered at the first recurrence of preterm labor for failed tocolysis. The data suggest that home uterine activity monitoring and perinatal nursing support are helpful in achieving term birth through earlier detection and treatment of recurrent preterm labor.

Adult↗
PubMed1989

Efficacy and safety of indomethacin versus ritodrine in the management of preterm labor: a randomized study.

One hundred six patients in preterm labor with intact amniotic membranes and gestational age less than or equal to 32 weeks were randomized to receive either ritodrine hydrochloride or a 48-hour course of indomethacin for tocolysis. The relative efficacy, maternal and neonatal safety, and costs were evaluated to determine which may be the more appropriate first-line pharmacologic agent used to manage preterm labor. Fifty-four patients and 52 patients were randomized to receive ritodrine hydrochloride or indomethacin, respectively. Ritodrine hydrochloride and indomethacin were equally effective in inhibiting uterine contractions and delaying delivery. Delivery was delayed for at least 48 hours in 83 and 94%, and for at least 7 days in 70 and 75% of patients receiving ritodrine or indomethacin, respectively. Tocolysis with indomethacin was associated with no maternal side effects, whereas tocolysis with ritodrine hydrochloride was associated with a 24% incidence of serious cardiovascular and metabolic adverse effects prompting discontinuation of the drug. There were no differences in outcome between the infants exposed to indomethacin versus ritodrine hydrochloride when delivered either remote from therapy or during therapy, except for a statistically higher serum glucose in the infants exposed to ritodrine hydrochloride when delivered during tocolytic therapy. There were no cases of premature closure of the ductus arteriosus or pulmonary hypertension. Tocolysis with indomethacin was 17 times less costly than tocolysis with ritodrine hydrochloride. For gestations less than or equal to 32 weeks complicated by preterm labor, indomethacin may be an appropriate alternative as a first-line tocolytic agent.

Adult↗
PubMed1997

Rapid fetal fibronectin swab-test in preterm labor patients treated by betamimetics.

OBJECTIVE: A preliminary study to examine the value of a rapid fetal fibronectin swab-test used as a bedside test in the prognosis of preterm labor. STUDY DESIGN: Women presenting with preterm labor and intact membranes and less than 3 cm dilated were enrolled in a single referral center. Cervicovaginal swabs were assessed for the presence or absence of fetal fibronectin by means of a rapid monoclonal antibody assay the positivity of which was revealed by a colorimetric reaction. Results were compared with uterine contractions frequency, Bishop cervical score, duration of tocolysis and interval to delivery. The predictive value of fetal fibronectin test for delivery within 7, 14 or 21 days from sampling and before 32 and 37 weeks' of gestation was assessed in the two groups. RESULTS: Among 124 eligible patients, 19 presented with a positive fibronectin test and 105 with a negative one. Gestational age at sampling, Bishop cervical score and duration of tocolysis were identical in the two groups. The number of contractions was significantly lower and gestational age at delivery was significantly higher in the fibronectin negative group. Fetal fibronectin in cervicovaginal secretions has a high sensitivity (89%) for delivery within 7 days. Absence of fetal fibronectin in cervicovaginal secretions of patients presenting with uterine contractions could rule out preterm labor within 7 and 14 days with a predictive value of 99 and 95.2%, respectively. In negative fetal fibronectin patients, preterm delivery before 32 and 37 weeks' is unlikely to occur with a predictive value of 97 and 85%, respectively. CONCLUSION: Cervicovaginal fetal fibronectin detected by a rapid bedside swab-test in women with symptoms of preterm labor compares favourably with quantitative assays and could prove useful in the management of preterm labor. This should be confirmed in a longer prospective study.

Adrenergic beta-Agonists↗
PubMed1996

Intraamniotic infection in patients with preterm labor and twin pregnancies.

BACKGROUND: Microbial invasion of the amniotic cavity plays a major role in the pathogenesis of preterm labor and delivery in singleton pregnancy. Nevertheless, this association is not well established among patients with multiple gestations. The purpose of our study was to explore the role of intraamniotic infection in the setting of twin pregnancies. METHODS: Consecutive women with twin gestations, intact membranes and preterm labor who underwent transabdominal amniocentesis under sonographic guidance. Amniotic fluid (AF) was retrieved from both sacs and cultured for aerobic and anaerobic microorganisms as well as for Mycoplasma species. Intraamniotic infection was defined as a positive AF culture for microorganisms. Mann Whitney U test or Student t-test or Fisher's exact test were utilized for analysis. RESULTS: Amniotic fluid was obtained from 74 patients. Sixty-eight women delivered prematurely (91.9%). Amniotic fluid culture results were positive for microorganisms in nine cases and all women with intraamniotic infection delivered prematurely as well as 59 (90.7%) patients with negative culture. Among the nine patients with intraamniotic infection, microorganisms were isolated from the presenting sac in five cases (55.6%), from both sacs in three patients (33.3%) and from the upper sac in the remaining case (11.1%). Patients with a positive AF culture had a more advanced cervical dilatation, a shorter interval amniocentesis-to-delivery and a higher incidence of clinical chorioamnionitis than those with a negative AF culture. CONCLUSIONS: The prevalence of intraamniotic infection and clinical and histological chorioamnionitis in twin pregnancies and preterm labor is similar to singleton pregnancies and preterm labor. Therefore, women with multiple gestations and preterm labor should be managed as singleton pregnancies.

Amniotic Fluid↗
PubMed1988

Psychological factors in preterm labor: critical review and theoretical synthesis.

Cumulative or chronic environmental stress and high scores on psychopathology scales have been consistently linked to preterm labor. In the laboratory, psychological stimuli have also been shown to affect uterine activity. Clinical studies suggest that interventions which reduce tension and anxiety can prevent or inhibit preterm labor. A model is proposed that links preterm labor to a disorder of arousal manifested physiologically as a hyperreactivity of the limbic circuitry and its efferent components. Autonomic hyperreactivity has been found repeatedly in women who experience preterm labor. This central hyperreactivity could unleash a cascade of psychophysiological reactions that could cause uterine excitation and facilitate preterm labor.

Arousal↗