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.     

Timing of cerclage removal after preterm premature rupture of membranes: maternal and neonatal outcomes

OBJECTIVE: Our aim was to evaluate immediate versus delayed removal of cerclage for women with preterm premature rupture of membranes with respect to maternal and neonatal outcomes. STUDY DESIGN: We retrospectively analyzed women with preterm premature rupture of membranes at <34 weeks' gestation with prior cerclage placement. Exclusion criteria included presentation with chorioamnionitis, active labor, or nonreassuring fetal status. Timing of cerclage removal, immediate (<24 hours) or delayed (>24 hours), was compared. RESULTS: There were 25 women in the delayed-removal group and 37 in the immediate-removal group. Average times to removal were 206.8 +/- 7.4 and 5.4 +/- 0.2 hours, respectively. Use of betamethasone was similar for both groups; however, antenatal antibiotic use (100% vs 80%; P =.03) and short-term tocolytic use (20% vs 3%; P =.04) were higher in the delayed-removal group. Duration of latency was significantly longer with delayed removal (10.1 vs 5.0 days; P <. 001). Delivery occurred >48 hours from preterm premature rupture of membranes in 96% (24/25) versus 54% (20/37; P <.001) and >7 days from rupture in 56% (14/25) versus 24% (9/37; P =.02), respectively. Rates of neonatal sepsis (at <10 days) and maternal infection were not statistically different. Neonatal outcomes did not significantly differ regarding mortality, respiratory distress syndrome, birth weight, or duration of stay in the intensive care nursery. CONCLUSION: With the current management scheme for preterm premature rupture of membranes, cerclage retention significantly increases duration of latency without significantly altering maternal or neonatal outcomes.     

Objective tocodynamometry identifies labor onset earlier than subjective maternal perception

The ability of women instructed in self-detection of uterine contractions to identify the abrupt rise in uterine activity known to precede the onset of labor has not been evaluated. This study was designed to assess the temporal relationship between objective uterine activity monitoring, subjective maternal perception of uterine activity above a commonly used threshold value (four or more contractions per hour), and progressive cervical change. Daily tocodynamometry (7-9 AM) was recorded in 79 women with preterm premature rupture of the membranes from admission until the onset of spontaneous labor (5.3 +/- 6.3 days). The subjects were at bed rest, received no tocolytic therapy, and were instructed in the signs of labor and uterine self-palpation. Patients simultaneously provided a subjective assessment of uterine activity (four or more contractions per hour). The majority of uterine activity recordings (78%) revealed fewer than four contractions per hour, and the patients' subjective reports agreed in almost all instances (97.6%). On 91 days, four or more contractions per hour were recorded objectively, but the patients' subjective reports agreed in only 25 instances (27%). On the day of labor onset, significantly more women had an objective assessment (32%) (P less than or equal to .01). Patients subjectively identified labor onset 10.6 +/- 6.7 hours after objective monitoring indicated increased uterine activity, and when subjectively identified, both cervical dilatation (4.9 +/- 2.5 cm) and effacement (85 +/- 30%) were significantly advanced (P less than or equal to .001) compared with the admission examination (1.1 +/- 1.2 cm; 20 +/- 30%).(ABSTRACT TRUNCATED AT 250 WORDS)     

0.8 mm控释地诺前列酮栓用于足月胎膜早破促宫颈成熟的多中心研究

目的 探讨0.8 mm控释地诺前列酮栓(其他名称:欣普贝生)用于足月胎膜早破促宫颈成熟的安全性及有效性.方法 采用多中心、前瞻性研究方法,选择孕足月、单胎、头位,宫颈Bishop评分<6分、无严重合并症及引产禁忌证、胎儿情况正常的足月胎膜早破产妇100例为观察组,选择同期条件相同、具备引产指征的180例胎膜完整产妇作为对照组.在无菌操作下,将0.8 mm控释地诺前列酮阴道栓剂1枚横向置于产妇的阴道后穹隆深部,药物放置后产妇卧床2 h.记录两组产妇药物放置至宫缩开始、临产及分娩的时间;药物平均放置时间;胎心率异常、羊水粪染、子宫过度刺激情况及其他不良反应;分娩方式、产程时间、产后出血量及新生儿情况.结果 两组共280例产妇中,26例置药后24 h未临产(9.3%,26/280),其中观察组3例,对照组23例;观察组24 h内临产率为97.0%(97/100),明显高于对照组的87.2%(157/180),两组比较,差异有统计学意义(P<0.01).观察组73例阴道分娩(75.3%,73/97),24例剖宫产分娩(24.7%,24/97);对照组107例阴道分娩(68.2%,107/157),50例剖宫产分娩(31.8%,50/157),两组阴道分娩及剖宫产率比较,差异均无统计学意义(P>0.05).两组药物放置至宫缩开始时间、药物平均放置时间、总产程时间比较,差异也无统计学意义(P>0.05).观察组宫缩过频发生率为11.3%(11/97),对照组为19.1%(30/157),两组比较,差异无统计学意义(x2=2.673,P>0.05);两组均无新生儿窒息发生.结论 0.8 mm控释地诺前列酮栓用于足月胎膜早破促宫颈成熟安全、有效,但用药期间应加强监护.     

感染相关早产的防治

羊膜腔感染是感染相关早产的重要影响因素。羊膜腔感染后炎症引起子宫收缩或伴胎膜早破,导致早产;炎症同时引起胎儿缺氧和死胎。早产儿感染后可发生呼吸窘迫综合征、缺氧缺血性脑病和脑瘫。本文对感染相关早产的发病机制和防治策略进行阐述。     

What have we learned about uterine contractions and preterm birth? The HUAM Prediction Study

Measurement of uterine contraction frequency has been employed as a screening test to identify women with increased risk of preterm birth, and as an aid in the early diagnosis of preterm labor. The National Institute of Child Health and Human Development Maternal-Fetal Medicine Units (NICHD MFMU) Network performed a prospective, blinded observational study of uterine contraction frequency to detect and predict preterm labor and birth, respectively. The goal of the study was to assess the sensitivity, specificity, and positive and negative predictive value of various measures of uterine contraction frequency. Data collected from 306 women revealed that contraction frequency was significantly greater in women who would ultimately deliver before rather than after 35 weeks' gestation. However, both sensitivity and positive predictive value of any measure of contraction frequency to predict preterm birth were poor. Contraction frequency did not increase significantly within 1 or 2 weeks of an episode of preterm labor. These results serve to explain the absence of an association between contraction-based surveillance and preterm birth in randomized trials conducted in women at risk of preterm birth.     

The Preterm Prediction Study: prediction of preterm premature rupture of membranes through clinical findings and ancillary testing. The National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network

OBJECTIVE: Our objective was to determine the relative importance of demographic characteristics, clinical risk factors, and ancillary screening tests in the prediction of preterm birth as a result of premature rupture of membranes. STUDY DESIGN: A total of 2929 women were evaluated in 10 centers at 23 to 24 weeks' gestation. Demographic and clinical characteristics were ascertained. Cervicovaginal fetal fibronectin and bacterial vaginosis were evaluated. Cervical length was measured by vaginal ultrasonography. Patients were evaluated for spontaneous preterm birth caused by preterm premature rupture of membranes at <37 and <35 weeks' gestation. Multivariate analyses were performed separately for nulliparous women and multiparous women. RESULTS: Premature rupture of membranes at <37 weeks' gestation complicated 4.5% of pregnancies, accounting for 32.6% of preterm births. Univariate analysis revealed low body mass index, pulmonary disease, contractions within 2 weeks, short cervix (相似文献   

Occupational fatigue and preterm premature rupture of membranes. National Institute of Child Health and Human Development Maternal-Fetal Medicine, Units Network

OBJECTIVE: The aim of this study was to prospectively determine the relationship between occupational fatigue and spontaneous preterm delivery segregated into the etiologically distinct categories of spontaneous preterm labor, preterm premature rupture of membranes, and indicated preterm delivery. STUDY DESIGN: A total of 2929 women with singleton pregnancies at 22 to 24 weeks' gestation were enrolled in a multicenter (10 sites) Preterm Prediction Study. Patients reported the number of hours worked per week and answered specific questions designed to determine the following 5 sources of occupational fatigue described by Mamelle et al: posture, work with industrial machines, physical exertion, mental stress, and environmental stress. Fatigue was quantified (0-5 index) according to the number of these sources positively reported. Simple and Mantel-Haenszel chi2 tests were used to test the univariate association and hypothesis of a linear trend between sources of occupational fatigue and spontaneous preterm delivery. Covariables were considered by multivariate logistic regression analysis. Women who did not work outside the home were considered separately from those who worked but did not report any sources of occupational fatigue. RESULTS: Each source of occupational fatigue was independently associated with a significantly increased risk of preterm premature rupture of membranes among nulliparous women but not among multiparous women. The risk of preterm premature rupture of membranes increased (P = .002) with an increasing number of sources of occupational fatigue-not working outside the home, 2.1%; working but not reporting fatigue, 3.7%; working with 1 source of fatigue, 3.2%; working with 2 sources of fatigue, 5.2%; working with 3 sources of fatigue, 5.1%; and working with 4 or 5 sources of fatigue, 7.4%. There was also a significant relationship (P = .01) between preterm premature rupture of membranes and an increasing number of hours worked per week among nulliparous women. Neither spontaneous preterm labor nor indicated preterm delivery was significantly associated with occupational fatigue among either nulliparous or multiparous women. CONCLUSION: The occupational fatigue index of Mamelle et al discriminated a group of nulliparous women at increased risk for preterm premature rupture of membranes. The relationship between preterm premature rupture of membranes and occupational fatigue or hours worked may provide guidelines according to which nulliparous women and their employers can be advised.     

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.     

Programmed cell death (apoptosis) as a possible pathway to metalloproteinase activation and fetal membrane degradation in premature rupture of membranes

OBJECTIVE: Increased matrix metalloproteinase 2 expression and activity are associated with premature rupture of fetal membranes. A proapoptotic protein produced in response to deoxyribonucleic acid fragmentation, p53, can bind to the matrix metalloproteinase 2 gene promoter and cause increased gene expression. It promotes apoptosis by inducing the expression of the proapoptotic bax gene and inhibiting the antiapoptotic bcl-2 gene. This study was undertaken to investigate the expression pattern of apoptotic elements in pregnancy complications that may cause increased expression of the gene for matrix metalloproteinase 2. STUDY DESIGN: Amniochorial membranes were collected from the following groups of women: (1) women with premature rupture of fetal membranes, (2) women with preterm labor and intact membranes, and (3) women with term labor after vaginal delivery. Deoxyribonucleic acid fragmentation was tested with ligation-mediated polymerase chain reaction and the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyribonucleoside triphosphate end-labeling assay. Matrix metalloproteinase 2, p53, bcl-2, and bax gene expression patterns were studied with quantitative competitive polymerase chain reaction. Statistical analysis was performed with the Tukey-Kramer multiple comparison test. RESULTS: Quantitative competitive polymerase chain reaction documented a 10-fold increase in the expression of the gene for matrix metalloproteinase 2 in premature rupture of fetal membranes with respect to term and preterm labor. This induction coincided with an increase in the expressions of the proapoptotic genes p53 and bax and a drop in the expression of the antiapoptotic gene bcl-2. Ligation-mediated polymerase chain reaction revealed deoxyribonucleic acid fragmentation in specimens from premature rupture of fetal membranes and not in those from preterm labor or labor at term. Histochemical analysis documented fragmented deoxyribonucleic acid in chorionic and amniotic cells. CONCLUSION: This study suggests that apoptosis is associated with premature rupture of fetal membranes. Deoxyribonucleic acid fragmentation, associated with elevations in the levels of the two proapoptotic gene products evaluated (p53 and bax ) and a drop in the level of the antiapoptotic bcl-2, was seen in premature rupture of the fetal membranes. Induction of matrix metalloproteinase 2 may be a function of p53 gene expression increase in premature rupture of fetal membranes.     

Intraamniotic infection and the onset of labor in preterm premature rupture of the membranes

The purpose of this study was to examine the relationship between intraamniotic infection and the onset of labor in patients with preterm premature rupture of the membranes. Two hundred and thirty consecutive patients were admitted with premature rupture of the membranes to Yale-New Haven Hospital from January 1985 to July 1987. Amniotic fluid was retrieved by amniocentesis from 96% (221/230). Sixty-one patients were in labor on admission (27.6%, 61/221) and 39% of them (24/61) had a positive amniotic fluid culture. Patients in labor on admission were more likely to have a positive amniotic fluid culture than those who were not in labor on admission (24/61 versus 41/160, p = 0.049). Of the 160-patients who were not in labor on admission, 81 subsequently went into spontaneous labor; microbiologic information at the time of labor was known in 48 of these patients (59.2%). Seventy-five percent (36/48) of these patients had a positive amniotic fluid culture. The incidence of intraamniotic infection in quiescent women who subsequently went into labor was higher than that of patients admitted in active labor (75% versus 39%, p = 0.0004). These results provide a basis for the clinical impression that the onset of labor in women with preterm premature rupture of the membranes is associated with a subclinical intraamniotic infection. The mechanisms responsible for the onset of labor in women without an intraamniotic infection may be associated with an extraamniotic infection (e.g., deciduitis) or a noninfectious process.     

Abnormality of calcium channel inhibitor released from fetal membranes in preterm labor

OBJECTIVE: This study was undertaken to test the hypothesis that an inhibitor of uterine contractions acting at the level of the dihydropyridine receptor of the uterine L -type uterine calcium channel is released in greater amounts from fetal membranes before term than at term. STUDY DESIGN: Endogenous calcium channel inhibitor activity was generated with standardized 25-cm2 surface area fetal membrane samples from the following 4 categories of women: preterm in labor, preterm not in labor, term in labor, and term not in labor. The amount of inhibitor in each membrane category was quantified by means of a competitive binding assay. Inhibition of uterine contractions induced by Bay K 8644 (an L -type calcium channel agonist) was used as another test of endogenous calcium channel inhibitor activity released from fetal membranes of all 4 groups of patients. RESULTS: Endogenous calcium channel inhibitor activity was most variable but present in the greatest amount in fetal membranes of women who were preterm not in labor followed by those in women at term not in labor and at term in labor. Fetal membranes from women in preterm labor had the least amount of measured endogenous calcium channel inhibitor activity. Consistent with the competitive binding assay, endogenous calcium channel inhibitor activity from fetal membranes from women who were preterm not in labor, at term not in labor, and at term in labor inhibited Bay K 8644-induced uterine contractions. Fetal membranes from women in preterm labor did not inhibit Bay K 8644-induced contractions. Endogenous calcium channel inhibitor activity was present in the chorion, the decidua, and the placenta, with little activity in the amnion. CONCLUSION: The down-regulation of endogenous calcium channel inhibitor activity with advancing gestation is consistent with a potential role for this inhibitor in maintaining uterine quiescence and in regulating the transition into labor. One possible cause of idiopathic preterm labor may be an abnormally low amount of endogenous calcium channel inhibitor activity in fetal membranes.     

Rupture of the preterm uterus in the nonlaboring woman: a report of 3 cases

BACKGROUND: Uterine rupture in a laboring patient is a well-known pregnancy complication. There is a paucity of information regarding uterine rupture at a preterm gestational age in a nonlaboring patient. CASE: Three women experienced spontaneous uterine rupture at a preterm gestational age prior to the onset of labor. All women presented with a primary complaint of abdominal pain that was nonfocal and had been noted over hours to days. In no case was a common risk factor for uterine rupture present. On initial evaluation, no woman appeared hemodynamically unstable, and all fetuses had a reassuring status. In all cases, rapid deterioration of maternal and/or fetal status resulted in emergency delivery. CONCLUSION: Uterine rupture at a preterm gestational age in a nonlaboring woman may present with nonspecific findings and be associated with rapid maternal and fetal decompensation. Awareness of this complication is necessary if maternal and fetal outcomes are to be optimized.     

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.     

Detection of preterm labor by ambulatory monitoring of uterine activity: a preliminary report

Effective tocolytic therapy depends on the ability to make an early diagnosis of preterm labor. This study was designed to assess whether daily ambulatory home monitoring of uterine activity could facilitate early diagnosis of preterm labor. Of 76 patients at high risk for preterm labor who used daily ambulatory tocodynamometry, approximately half developed preterm labor. Evaluation when the diagnosis of preterm labor was first established has shown that in 8% of the patients the cervix was dilated more than 2 cm, shortened to less than 0.5 cm in 23%, and the fetal membranes were intact in all subjects. The same evaluation in 76 nonrandom contemporary controls matched for risk factors, maternal age, and parity has shown that more than 50% had a cervix dilated more than 2 cm, 38% had a cervix shorter than 0.5 cm, and 24% had rupture of the fetal membranes. Ultimately, 88% of the monitored patients and 59% of controls delivered at term. Comparisons between these groups indicate that intermittent home tocodynamometry may indeed be useful in making the early diagnosis of preterm labor.     

Relationship of measured external tocodynamometry with measured internal uterine activity.

The use of home uterine activity monitoring for patients at high risk for preterm labor and delivery has become common in clinical perinatology. The ability of the monitoring devices to detect accurately uterine contractions in early pregnancy has not previously been reported. Ten women in labor between 20 and 35 weeks' gestation underwent simultaneous monitoring of uterine activity with a guard-ring tocodynamometer and an intrauterine pressure monitor. When compared with internal monitoring, the external monitor detected 90.8% of uterine contractions with a specificity for uterine quiescence of 98.1%. The predictive value of external monitoring was 97.3% for detecting uterine contractions and 93.6% for recording the absence of uterine contractions. The contractions detected externally were similar in duration: mean 63.7 +/- 23.0 seconds for internal monitoring and 62.2 +/- 22.6 seconds for external monitoring (p greater than 0.05). The intensity of contractions detected externally was less than internally measured contractions, mean difference, 19.7 +/- 15.9 mmHg (p less than 0.001). External tocodynamometry using this guarding tocodynamometer reliably distinguishes between uterine contractions and uterine quiescence in preterm pregnancies but does not adequately measure the intensity of contractions.     

Fetal breathing as a predictor of infection in premature rupture of the membranes

The value of the presence or absence of fetal breathing in predicting infection was determined by a retrospective analysis of 130 patients with premature rupture of the membranes and no clinical signs of infection or labor. The last ultrasound examination performed within 48 hours of delivery was used for comparison to infection outcome, as reflected by the development of clinical amnionitis, possible neonatal sepsis, and neonatal sepsis. The sensitivity and specificity of fetal breathing in predicting infection in patients with premature rupture of the membranes were 91.6 and 64.8%, respectively. These data suggest that the presence of fetal breathing is a good predictor of noninfection outcome (negative predictive value 95.3%), whereas its absence does not necessarily indicate impending infection (positive predictive value 50%).     

Antenatal uterine activity monitoring of women at increased risk of preterm labour.

The aim of the study was to investigate the usefulness of antenatal uterine activity monitoring in the management of women at increased risk of preterm labour on the basis of a past history of preterm birth or mid-trimester abortion. Uterine activity was recorded every 2 weeks between 20 and 28 weeks gestation. Activity was considered to be increased if pressure changes > 15 mmHg were detected. Fifty-eight women had uterine activity monitoring. Of them, 39 had normal uterine activity. Nineteen women had increased activity and they were randomized to either a study group (9) where the findings were revealed to the clinicians caring for them or a control group (10) where the findings were not revealed. There was no standard regimen of management for the study group except that additional uterine activity monitoring was performed to provide feed back to the clinicians about their interventions. The sensitivity, specificity, positive predictive value and negative predictive value of uterine activity monitoring for preterm births and for preterm births before 32 weeks were disappointing. Uterine activity monitoring was not useful for predicting births prior to 32 weeks; most of these were preceded by prelabour rupture of the membranes. The pregnancy outcome of women with increased uterine activity was not better if clinicians were aware of that increased activity than if they were not.