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At least 19 recordsLinked to original sources
PubMed1990

Pregnancy outcome in women with labor-onset hypertension. Similar outcome between labor-onset hypertension and preeclampsia.

Labor-onset hypertension is a poorly documented category, and there is scanty information concerning the outcome of pregnancy in this condition. A retrospective study was performed to compare the pregnancy outcome of 36 patients with labor-onset hypertension (group A) with 36 patients with classical preeclampsia diagnosed before labor (group B) who were matched for parity and age. There was no difference in age, past history of hypertensive pregnancies or family history of hypertension between the two groups. The need for intrapartum hypertensive and anticonvulsant treatment as well as the outcome of pregnancy were similar in both groups. The only significant difference was that group A patients had lower maximum and booking systolic and diastolic pressures. The results indicate that labor-onset hypertension represents a late manifestation of the preeclampsia process, because these patients had lower blood pressure in pregnancy and would not be identified until intrapartum elevation of blood pressure satisfied the diagnostic criteria of preeclampsia.

Apgar Score↗
PubMed1990

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)

Cardiotocography↗
PubMed1989

Purification and characterization of a uterine phospholipase inhibitor that loses activity after labor onset in women.

Gravidin, a protein that inhibits release of arachidonic acid from human decidual cells, was purified from amniotic fluid. The protein has a molecular weight of 58 to 60 kilodaltons, an isoelectric point of 8.4, and physical characteristics that are indistinguishable from those of inhibitor II previously described. Activity was determined in a dispersed decidual cell system that released arachidonic acid in response to either histamine or calcium ionophore and in a cell-free assay of phospholipase A2. Protein purified from incubates of chorion obtained after the onset of labor was significantly less active than that from chorion obtained before the onset of labor.

Chorion↗
PubMed1998

Reduction of serum citrulline levels in women at term toward the day of labor onset.

OBJECTIVE: To test the hypothesis that labor onset could be the result of a reduced release of nitric oxide (NO). STUDY DESIGN: Out of 91 consecutive healthy nulliparous women at term serum citrulline (Cit) and arginine (Arg) levels were measured at least twice in 37 subjects, by the means of HPLC with fluorometric detection. Twenty cases underwent a spontaneous onset of labor (group A) while in 17 cases labor was induced (group B) because of pregnancy prolongation or amniotic fluid reduction. RESULTS: Cit and Arg levels were unaffected by the gestational age. In group A, Cit levels undergo a progressive decrease toward the day of labor (from 32.9+/-4.7 microM/L the day - 18,-5 to 27.7+/-7.8 the day -4,0; p=0.012) whilst they remained stable in group B (from 33.3+/-7.7 to 34.2+/-9.2). No significant changes were observed in Arg levels. Cit/Arg ratio remained stable in group A whereas it showed a trend to increase in group B. CONCLUSION: These data indirectly suggest a reduced release of NO toward term. This phenomenon could play a permissive role in the spontaneous onset of labor of healthy nulliparous women.

Arginine↗
PubMed1987

Circadian incidence of labor onset hour in preterm birth and chorioamnionitis.

Normal labor begins most frequently between midnight and 2 AM, presumably because of an unidentified circadian labor-activating mechanism. We used records of the Collaborative Perinatal Project to determine whether such a circadian mechanism is present with intrauterine growth retardation (IUGR) or preterm birth, and whether chorioamnionitis is associated with alternative patterns. In the absence of chorioamnionitis, both preterm births and term births with IUGR demonstrated nocturnal labor onset distributions like those of control term deliveries, which had a peak incidence at 1:45 AM and an amplitude of 35%. With chorioamnionitis, in contrast, there was a different circadian distribution of term labor onset hour, with a peak at 7:45 PM and a 32% amplitude. A similar trend was found among preterm births. These data suggest the presence of the normal nocturnal labor-activating mechanism in both growth-retarded term deliveries and a defined subset of preterm deliveries. Chorioamnionitis appears to be associated with a prominent, unidentified alternative labor-activating mechanism that is maximal in the evening.

Chorioamnionitis↗
PubMed1980

[Prediction of labor onset and difficulty by the multivariate analysis (author's transl)].

Based on the multivariate analysis, we analysed the weekly change of the antepartum cervical ripe (consistency, effacement, dilatation, position) and the station, then predict the labor onset and difficulty retrospectively. 1) According to longterm observation of the internal examination of 210 primipara, in third trimester, the ripe type increased, and the unripe type decreased are found. Because of the intermediate type increased and unmovable in incidence relatively, so based on the former scoring method of mere addition of scores, it appears ineffective to predict the labor onset. 2) We studied primipara 385 and multipara 434 from 6 weeks before labor. Based on the multiple regression analysis, we could predict the labor onset. The predict value is higher in multipara than primipara, on the primipara, 78.2% antepartum 6 weeks, 82.2% 4 weeks, 92.6% 2 weeks, and on the multipara 84.6%, 82.2%, 96.2% respectively. 3) Based on the method of Mahalanobis' generalized distance, we could predict the labor difficulty in the primipara and multipara. Accuracy of abnormal prediction are 77.1% at 4 weeks formula, 77.2% at 2 weeks formula on primipara; 69.0%, 69.2% respectively on multipara. Accuracy of normal prediction 53.3%, 56.9% on primipara; 30.9% (4 weeks formula) on multipara are found. The abnormal prediction is better than the normal prediction. This method can early predict the labor onset and difficulty than the former scoring method of mere additional scores.

Analysis of Variance↗
PubMed2001

Reduced binding of progesterone receptor to its nuclear response element after human labor onset.

OBJECTIVE: There is indirect evidence of decreased progesterone-activated transcription after human labor onset. Binding of the progesterone receptor to its response element is a prerequisite of progesterone-activated transcription. We established an assay to investigate whether there is reduced binding of progesterone receptor to its nuclear response element after, compared with before, labor onset. STUDY DESIGN: The binding of progesterone receptor from the decidua to its nuclear response element was measured in gel shift assays. Tissues from 52 patients who were term, preterm, in labor, and not in labor were compared. RESULTS: A 9-fold decrease in progesterone receptor binding to its response element was observed in tissues obtained after, compared with before, the onset of labor (P = .0008). In both preterm and term not-in-labor tissues, binding was higher than for in-labor tissues (P = .0172 for preterm; P = .0147 for term, Mann-Whitney U test). CONCLUSION: These findings provide a mechanism for the effective withdrawal of progesterone in human parturition.

Cell Nucleus↗
PubMed1986

[Anatomical and physiological bases of labor onset].

The induction of labor involves a series of complex mechanisms, the control of which is only partially explained in humans. It is accepted today that the maturing of the uterine cervix is independent of the onset of uterine contractions. These two phenomena are regulated by a complex system where prostaglandins play a key role.

Female↗
PubMed1995

Prostaglandin endoperoxide-H synthase-1 and -2 messenger ribonucleic acid levels in human amnion with spontaneous labor onset.

Increased prostaglandin (PG) production within the uterine compartment has a pivotal role in the processes leading to labor onset in women. Two PG endoperoxide-H synthase (PGHS) isoenzymes have been identified in a number of cell types. PGHS-1 is constitutively expressed in most cases, whereas PGHS-2 expression is rapidly induced by several agonists. The aims of this study were to determine the levels of PGHS-1 and PGHS-2 expression before and after spontaneous labor (SL) onset in the amnion and to assess the contribution of PGHS-1 and PGHS-2 to enzyme activity. We established and validated ribonuclease protection assays to quantify PGHS-1 and PGHS-2 messenger ribonucleic acid (mRNA) levels in the amnion. PGHS enzyme activity was measured with an established assay. The antisense RNA probes used in the protection assays were generated using human PGHS-1 and PGHS-2 complementary DNAs. These probes specifically detected the 2.8-kilobase mRNA of PGHS-1 and the 4.8-kilobase mRNA of PGHS-2 in amnion RNA samples on Northern blots. We measured mRNA levels in amnion from patients after SL at term and from patients not in labor undergoing elective cesarean section (CS) at term. PGHS-2 mRNA levels were markedly higher after SL compared to levels in CS amnion [5.18 +/- 1.08 (n = 16) and 2.27 +/- 0.50 (n = 15), densitometric units, respectively; P < 0.02], whereas there was no difference in PGHS-1 mRNA levels after labor compared with CS samples. PGHS-2 mRNA levels were also positively correlated with PGHS enzyme activity in 4 separate assays with a total of 25 patients (r = 0.65-0.88; P < 0.05). There was no correlation between PGHS-1 mRNA levels and enzyme activity. We conclude that PGHS-2 mRNA is present in human amnion; its levels are elevated after SL onset, and they are correlated with enzyme activity. The stimulation of PGHS activity at labor onset probably involves increased expression of PGHS-2. The expression of PGHS-1 does not change in association with labor in human amnion.

Amnion↗
PubMed2000

Interleukin 8 expression in human myometrium: changes in relation to labor onset and with gestational age.

PROBLEM: Preterm labor remains the major cause of perinatal mortality and morbidity in normally formed babies. The mechanisms involved in the onset of preterm labor are poorly understood, mainly because the mechanisms initiating term labor remain ill-defined. METHOD OF STUDY: Human myometrial samples were collected at cesarean delivery from preterm (26-36 weeks gestation) and term (37-41 weeks) women. Women at term were either non-laboring or laboring. The expressions of interleukin-8 (IL-8) mRNA and protein were measured by reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. RESULTS: The expression of both IL-8 mRNA and protein significantly increased in the term laboring group, compared with either the term non-laboring or preterm groups. Levels of IL-8 expression did not alter with advancing gestational age. CONCLUSIONS: The increased expression of IL-8 in laboring myometria at term supports the hypothesis that up-regulation of IL-8 has a role in the initiation of labor in association with an influx of neutrophils and the release of their collagenolytic enzymes into uterine tissues.

Enzyme-Linked Immunosorbent Assay↗