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PubMed1997

[Average length of spontaneous labor in Chinese primigravidas].

OBJECTIVE: To determine if labor duration is affected by ethnicity, we measured the average length of normal spontaneous labor in recently immigrated Chinese primigravidas and compared our findings to reference primigravida populations of differing ethnicity. MATERIALS AND METHODS: In this descriptive, retrospective study of 1,006 recently immigrated low-risk Chinese primigravidas delivering singleton, vertex, term infants (37-42 weeks gestation, inclusively) without conduction anesthesia or oxytocin, the length of first-, second-, and third-stage labor, maternal age, gestational age, and infant weight was measured and compared to labor lengths previously reported for women of differing ethnicity. RESULTS: Mean first stage labor duration was 326 minutes (SD +/- 185 min, range 25-1640 min), mean second stage labor duration was 52 minutes (SD +/- 42 min, range 2-450 min), and a mean third stage labor duration was 4.6 min (SD +/- 4.5 min, range 1-62 min). Interquartile range (IQR)/median for first-, second-, and third-stage labor was 225 min/300 min, 50 min/40 min, and 3 min/3 min respectively. Weak correlations were observed between first- and second-stage labor lengths, and second- and third-stage labor lengths. Average birth weight was 3250 g (SD +/- 376 g, range 2280-4660 g). Chinese parturients showed a significantly shorter duration of first-stage (P < 0.0001) when compared to parity-matched patients of differing ethnicity. Second-stage labor in Chinese parturients was also shorter, but did not differ significantly (P = 0.185) from previously reported non-Asian controls. CONCLUSION: When compared to previously collected data from non-Chinese women, clinically significant differences in first-stage labor lengths were measured in our study population. While second-stage labor durations were also shorter, the difference was not significant. Labor management should be individualized to account for these differences, and previous reports attempting to show equivalency of labor progress regardless of ethnicity warrant reinterpretation given these findings.

Asian People↗

PubMed2003

Concentrations of serum total activin A and inhibin A in preterm and term labor patients: a cross-sectional study.

OBJECTIVE: To compare maternal serum levels of total activin A and inhibin A in preterm and term patients who are in labor or not in labor. METHODS: A cross-sectional study compared activin A and inhibin A in the following groups of patients: preterm and in labor (n = 65), preterm and not in labor (n = 96), term and in labor (n = 65), and term and not in labor (n = 65). Preterm was defined as 23-34 weeks' gestation and term as 37-42 weeks' gestation. Labor was defined as regular contractions with progressive cervical change or an initial examination revealing cervical dilation of 1-3 cm with 50% effacement or more. Follistatin levels were analyzed in a subset of 12 patients from each group. Analytes were measured by two-site enzyme-linked immunosorbent assays. RESULTS: Activin A levels were higher in the preterm labor group (median 1.38 multiples of the median [MoM], interquartile range [IQR] 1.01 MoM) compared with the preterm nonlabor group (median 1.0 MoM, IQR 0.78 MoM, P <.05) and in the term labor group (median 1.37 MoM, IQR 1.74 MoM) compared with the term nonlabor group (median 1.0 MoM, IQR 0.87 MoM, P <.05). Inhibin A levels were higher in the preterm labor group (median 1.27 MoM, IQR 0.73 MoM) compared with the preterm nonlabor group (median 1.0 MoM, IQR 0.58 MoM, P <.05). Post-hoc analysis of activin A and inhibin A elevations in the preterm labor group revealed a significant effect only during 31-34 weeks' gestation. The total activin A:follistatin ratio, an indirect measure of free activin A, was similar between labor and nonlabor gestational age-matched patient groups. CONCLUSIONS: Levels of total activin A and inhibin A were increased in patients during labor; however, based on the moderate degree and narrow gestational age range of the increased levels, these analytes are not likely to be clinically useful in predicting preterm labor.

Activins↗

PubMed2005

Anaphylatoxins in preterm and term labor.

OBJECTIVE: The complement system plays a central role in the first line of defense against invading pathogens, and its activation involves the release of potent pro-inflammatory mediators such as anaphylatoxins C3a, C4a and C5a. The aim of this study was to determine whether differences existed in maternal plasma anaphylatoxin concentrations between patients with term and preterm parturition. STUDY DESIGN: A cross-sectional study was designed to determine the plasma anaphylatoxin concentrations in 296 pregnant women in the following groups: 1) normal pregnancy between 20-36 6/7 weeks (n=64); 2) term not in labor (n=70); 3) term in labor (n=60); and 4) preterm labor with intact membranes (n=102). Women with preterm labor were classified into: a) term delivery (n=24); b) preterm delivery without intra-amniotic infection (IAI) (n=62); and c) preterm delivery with IAI (n=16). Concentrations of C3a, C4a and C5a were determined by ELISAs. Statistical analysis was conducted with non-parametric methods. RESULTS: 1) The median plasma C5a concentration was lower in women at term in labor than in those not in labor (P<0.001). In contrast, there were no differences in plasma C3a and C4a concentrations between the two groups (P>0.05). 2) Among patients with preterm labor, those with IAI had a higher median plasma C5a concentration than those without IAI and those who delivered at term (post-hoc tests P<0.001 and P=0.01, respectively). When comparing the preterm labor subgroups with normal pregnancy, only women with preterm delivery and IAI had a median plasma C5a concentration higher than that of normal pregnant women (Kruskal-Wallis P<0.001, post hoc test P<0.001). There was no difference in the plasma C4a concentration among patients with preterm labor. The median plasma C3a concentration in patients with preterm labor with IAI was higher than in those without IAI (Kruskal-Wallis P=0.01, and post-hoc test P=0.005). There was no difference in the plasma C3a concentrations between women with preterm labor who delivered at term and those with preterm delivery, with or without IAI. In addition, no differences were observed in the median plasma C3a concentration between women with normal pregnancy and those in each of the preterm labor subgroups. CONCLUSIONS: The maternal plasma concentration of anaphylatoxin C5a is increased in women with preterm labor and IAI, but not in spontaneous labor at term.

Adolescent↗

PubMed1999

Fetal Doppler hemodynamic changes in spontaneous versus prostaglandin E1-induced active labor.

BACKGROUND: To assess fetal hemodynamic changes before and during active labor, either spontaneous or prostaglandin E1 (PGE1)-induced labor. MATERIALS AND METHODS: This is a prospective longitudinal study and a cohort of 49 healthy women at 37-41+ weeks gestation without signs of fetal distress was investigated until in labor. One group of 23 healthy women had spontaneous active labor, the second group of 26 women was in active labor induced by an intra-cervical administration of PGE1 for elective induction. Blood flow waveform indices (S/D ratio, RI, PI) were assessed by pulsed Doppler ultrasonography from the umbilical artery (UA) and fetal middle cerebral artery (MCA) before and in labor. Both groups were compared for the waveform indices and perinatal outcome including duration of labor, meconium stain, baby sex, birthweight, UA blood gas measurements at delivery, Apgar's scores, prolonged nursery stay (> or =5 days), and NICU admission. RESULTS: Demographic data of the two groups were comparable. During spontaneous active labor, the S/D ratio and RI became significantly decreased in the UA (p<0.05) and the three wave-form indices were decreased more in the MCA (p<0.01, 0.005, 0.05, respectively) compared with those measured before labor. During PGE1-induced active labor, all the waveform indices were not significantly decreased in either the UA or the MCA. The occurrence of abnormal UA blood gas values was significantly more in the PGE1-induced group than in the spontaneous labor group (23.1% v.s. 4.3%; p<0.05). No other adverse perinatal outcomes were observed in either group. CONCLUSIONS: Decreasing impedance in both the UA and MCA during spontaneous labor is a physiological fetal adaptation to labor to prevent fetal cerebral hypoxia by maintaining adequate brain blood flow during normal parturition. This fetal adaptation phenomenon was not observed in the group of PGE1-induced labor with the result of a high incidence of abnormal UA blood gas values.

Adult↗

PubMed2001

A comparison of spontaneous labor with induced vaginal tablets prostaglandin E2 in grand multiparae.

OBJECTIVE: To compare the outcome of labor in grandmultiparous patients (para >5) who had induction of labor with prostaglandin E2 vaginal tablets with grandmultiparous patients in spontaneous labor, and to observe the complications during induction of labor. METHODS: A retrospective case control study was carried out at King Faisal Military Hospital, Khamis Mushayt between January 1993 through until December 1994. This included 64 grandmultiparous patients that were induced with prostaglandin E2 vaginal tablets. Ninety grandmultiparous patients who went into labor spontaneously served as controls. Maternal and fetal data extracted from their hospital record files included age, parity, indication for induction, Bishop score at induction, total dose of prostaglandin used and complications of induction of labor. Other information were length of labor, need for syntocinon augmentation, blood loss during the 3rd stage of labor, mode of delivery, birth weight, sex and Apgar score at 10 minutes. RESULTS: No serious complication of induction of labor such as rupture of the uterus was noted in the subjects studied. There were no significant differences when the mean age and parity of patients in the 2 groups were compared (P>0.05) but there was difference in the gestational age at delivery (p=0.00). There was no significant difference in the mean length of first and 2nd stages of labor. The cesarean section rate was 11% and 8% in the cases and controls, while the need for syntocinon augmentation was twice in the cases than controls, 27% vs 14%. These were not statistically significant. CONCLUSION: We conclude that induction of labor with prostaglandin E2 vaginal tablets may not have adverse effect on the outcome of labor compared with patients in spontaneous labor. It may be safe to use prostaglandin E2 vaginal tablets for induction of labor in the grand- multiparae. We recommend a randomized prospective trial to validate these observations.

Administration, Intravaginal↗

PubMedDate not supplied

A national survey of herbal preparation use by nurse-midwives for labor stimulation. Review of the literature and recommendations for practice.

To document the use of herbal preparations for cervical ripening, induction, and augmentation of labor by certified nurse-midwives (CNMs) and nurse-midwifery education programs, a national survey of 500 members of the American College of Nurse-Midwives was conducted. Forty eight nurse-midwifery education programs were also surveyed to determine whether they were formally or informally educating students in the use of herbal preparations for cervical ripening, induction, or augmentation of labor. The results of this study, a review of the literature, professional issues, and recommendations for clinical practice are presented in this article. Of 500 questionnaires mailed to ACNM members, 90 were returned from CNMs who used herbal preparations to stimulate labor and 82 were returned from CNMs who did not use herbal preparations to stimulate labor. Three questionnaires were excluded due to incomplete data or blank questionnaires. No significant differences were noted in relations to geographical region, midwifery education, or highest level of education between the CNM respondents who did and those who did not use alternative methods to stimulate labor. Of the CNMs who used herbal preparations to stimulate labor, 64% used blue cohosh, 45% used black cohosh, 63% used red raspberry leaf, 93% used castor oil, and 60% used evening primrose oil. CNMs who used herbal preparations to stimulate labor were younger (43 versus 45 years, P < .01) and more likely to deliver at home or in an in-hospital or out-of-hospital birthing center (P < .0006), than CNMs who never used herbal preparations to stimulate labor. The most cited reason for using herbal preparations to stimulate labor was that they are "natural," whereas the most common reason for not using herbal preparations was the lack of research or experience with the safety of these substances. Sixty-nine percent of CNMs who used herbal preparations to stimulate labor learned about using them from other CNMs, 4% from formal research publications, and none from their formal education programs. Although 78% of the CNMs who used herbal preparations to stimulate labor directly prescribed them and 70% indirectly suggested them to clients, only 22% had included them within their written practice protocols. Seventy-five percent of the CNMs who used herbal preparations to stimulate labor used them first or instead of pitocin. Twenty-one percent reported complications including precipitous labor, tetanic uterine contractions, nausea, and vomiting. Sixty-four percent of the nurse-midwifery education programs included instruction in the use of herbal preparations to stimulate labor in their formal curricula, and 92% included informal discussions on the use of herbal preparations. Evening primrose oil was the most common herbal preparation discussed in nurse-midwifery education programs. Castor oil was the most commonly used herbal preparation used by nurse-midwives in clinical practice.

Adult↗

PubMed1998

An early labor assessment program: a randomized, controlled trial.

BACKGROUND: Approximately 31 percent of cesarean deliveries in the United States and Canada are performed for dystocia. The aim of this study was to determine the effectiveness of early labor assessment to reduce cesarean birth rates for low-risk nulliparous women. METHODS: Two hundred and nine low-risk nulliparous women were randomly allocated to either the early labor assessment group or the direct admission to hospital group. Women in the early labor assessment group were evaluated and, if found to be in false or latent labor, were encouraged to go home or walk before admission to the labor unit. Those in the direct admission group were admitted to the labor unit without an assessment. Data were collected and analyzed about method of delivery, duration of labor, intrapartum interventions, and neonatal well-being. Women completed an evaluation of their experience in the early postpartum period. RESULTS: Significant decreases occurred in duration of labor, use of epidural analgesia for pain, and use of oxytocin to augment labor in the early labor assessment group. These women evaluated their labor and birth experience more positively than women in the direct admission group. No significant differences were found in the frequency of cesarean section or instrumental vaginal delivery for the two groups. CONCLUSIONS: Early labor assessment has the potential to reduce the number of women receiving oxytocin for augmentation, the rate of epidural analgesia for pain relief, and the duration of the active and second stages of labor, and to improve women's evaluations of their labor and birth experiences.

Adult↗

PubMed2001

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.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed2005

Labor progression and risk of cesarean delivery in electively induced nulliparas.

OBJECTIVE: To describe the pattern of labor progression and risk of cesarean delivery in women whose labor was electively induced. METHODS: We analyzed data on all low-risk, nulliparous women with an elective induction or spontaneous onset of labor between 37 + 0 and 40 + 6 weeks from January 2002 to March 2004 at a single institution. The median duration of labor by each centimeter of cervical dilation and the risk of cesarean delivery were computed for 143 women with preinduction cervical ripening and oxytocin induction, 286 women with oxytocin induction, and 1,771 women with a spontaneous onset of labor. An intracervical Foley catheter was used to ripen the cervix. RESULTS: Electively induced labor with cervical ripening had substantially slower latent and early active phases. After controlling for potential confounders, women who had an elective induction with cervical ripening had 3.5 times the risk of cesarean delivery during the first stage of labor (95% confidence interval 2.7-4.5), compared with those admitted in spontaneous labor. Elective induction without cervical ripening, on the other hand, was associated with a faster labor progression from 4 to 10 cm (266 compared with 358 minutes, P < .01) and did not increase the risk of cesarean delivery, compared with those in spontaneous labor. CONCLUSION: The pattern of labor progression differs substantially for women with an electively induced labor compared with those with spontaneous onset of labor. Furthermore, elective induction in nulliparous women with an unfavorable cervix has a high rate of labor arrest and a substantially increased risk of cesarean delivery. LEVEL OF EVIDENCE: II-2.

Adult↗

PubMedDate not supplied

How do expert labor nurses view their role?

OBJECTIVE: To examine how expert perinatal nurses in a nurse-managed labor model view their role in caring for mothers during labor and birth. DESIGN: Focus group methodology. Data were analyzed using inductive coding methods to gain understanding from the perspective of those providing the care. SETTING: Labor and birth units in four large Midwestern medical centers. PARTICIPANTS: Fifty-four expert labor nurses. INCLUSION CRITERIA: 5 years experience in nursing care during labor and birth in institutions where nurse-managed labor was the predominant practice model. RESULTS: Four common themes related to nursing roles were identified. These included knowing the labor process and the intuitive nature of nursing care provided by expert labor nurses based on years of experience, knowing the woman and letting her body guide labor, advocacy for laboring woman, and the autonomous nature of the nurse-managed labor model. CONCLUSIONS: Expert labor nurses developed a keen sense of intuitive knowledge based on their years of experience. They reported using hands-on high-touch supportive care techniques with the potential to affect labor and birth outcomes. Autonomy is perceived as a key component of practice within the nurse-managed labor model.

Anecdotes as Topic↗

PubMed1993

The accumulation of prostaglandins (PG) in amniotic fluid is an aftereffect of labor and not indicative of a role for PGE2 or PGF2 alpha in the initiation of human parturition.

The accumulation of prostaglandins (PGs) in amniotic fluid (AF) during labor is cited frequently as one line of evidence in support of a role for these eicosanoids in the initiation of human parturition. In this study, we evaluated an alternate possibility, viz. that PGs entering AF at parturition are produced as a sequela of labor-associated processes. During labor, the AF normally becomes separated into two compartments, viz. the forebag and the upper compartment, by the obstruction produced as the descending fetal presenting part is engaged in the maternal pelvis. We theorized that the PGs that enter AF are produced in traumatized tissues lining the forebag, which is formed as the result of labor-driven cervical dilatation. In addition, these traumatized tissues are exposed to and bathed by the vaginal fluid, which contains many potent stimuli of PG formation, viz. large numbers of microorganisms and bacterial toxins. AF was collected at term before labor (n = 50) and from the upper compartment during labor (n = 47) by transuterine amniocentesis, and AF was collected by direct needle aspiration of the forebag during labor (n = 143). PGF2 alpha, 13,14-dihydro-15-keto-PGF2 alpha (PGFM), and PGE2 were quantified by RIA. The concentrations (nanomoles per L mean +/- SEM) of PGs in AF of the forebag (PGF2 alpha, 85.6 +/- 10.6; PGFM, 20.8 +/- 2.58; PGE2, 26.9 +/- 2.73) were much greater than those in the AF before labor (PGF2 alpha, 0.56 +/- 0.05; PGFM, 0.9 +/- 0.08; PGE2, 5.89 +/- 1.13) or in AF of the upper compartment during labor (PGF2 alpha, 7.14 +/- 1.64; PGFM, 5.11 +/- 0.82; PGE2, 8.74 +/- 1.71). The concentrations of PGs in AF of the upper compartment during early labor (< or = 2.5-cm cervical dilatation) were no greater than those in AF before labor began. The concentration and total content of PGs in AF of the forebag increased as a function of cervical dilatation until delivery. At 3- to 5-cm cervical dilatation, the levels of PGs in AF of the upper compartment were greater than those before labor, but significantly less than those in AF of the forebag at the same stage of labor progress. After 3-5 cm, the levels of PGs in the upper compartment did not increase further. These findings indicate that PGF2 alpha, PGFM, and PGE2, which enter AF in increased amounts during parturition, are produced during, not before, labor in tissues (principally decidua) lining for forebag.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗

PubMed1990

Do primiparas and multiparas have realistic expectations of labor.

Expectations of labor and childbirth can affect the degree of in-labor pain or discomfort experienced by the mother. By ascertaining whether expectations of labor experience are realistic or not, women can be prepared during the antenatal period to cope better with labor pain. The purposes of this prospective study were to 1) determine if pregnant women had realistic expectations of the labor experience, 2) determine if women who expected to have more pain during labor actually experienced more pain, than those not expecting to experience so much pain, and 3) determine if attending midwives assessed in-labor pain as intense as the mothers did. Fifty primiparas, 88 multiparas, and 12 full-time employed midwives participated in the study. The Visual Analogue Scale (VAS) was used to rate the expected and actual in-labor experience. A 3-point rating scale was used by the midwives to rate in-labor pain. Neither primiparas nor multiparas were found to have realistic expectations of the labor experience. Mothers experienced more pain and discomfort than expected, and the multiparas anticipated their need for medication to be greater than what was actually needed. The mothers reported that they felt less lonely and received more support from personnel during labor than they had expected. Multiparas who expected to experience more pain reported more pain than those expecting to experience less pain in stages I and III of labor. There was no significant correlation between midwives' and mothers' rating of the intensity of in-labor pain during stage III of labor.

Adult↗

PubMed1986

Increased immunoreactive erythropoietin in cord plasma and neonatal bilirubin production in normal term infants after labor.

The purpose of this investigation was to compare immunoreactive erythropoietin levels in umbilical cord plasma and neonatal bilirubin production in infants born of normal women who delivered with or without labor. Two groups of term (38 to 42 weeks) singleton pregnancies were compared: 1) those delivered by repeat elective cesarean section without prior labor (N = 17), and 2) those delivered vaginally or by cesarean section after labor (N = 24). None of the infants was asphyxiated, and there was no difference in Apgar scores between the no-labor and labor groups. The cord plasma erythropoietin levels were lower in the infants of women who had repeat elective cesarean section without labor than in those whose mothers had labor before delivery (Wilcoxon rank sum test, P less than .025). The median erythropoietin for the no-labor group was 22.9 mU/mL compared with 38.8 mU/mL for the labor group. The pulmonary excretion rate of carbon monoxide (VeCO), an index of bilirubin production, for the no-labor group was 14.3 +/- 6.2 SD microL/kg per hour compared with 18.0 +/- 4.9 SD microL/kg per hour for the labor group (P less than .05). The hemoglobin concentration for the no-labor group was 16.0 +/- 1.5 SD g/dL compared with 17.7 +/- 2.2 SD g/dL for the labor group (P less than .05). The VeCO correlated with the hemoglobin concentration (N = 32, r = 0.37, P less than .05). The results of the present study suggest that labor is normally associated with increases in the cord plasma erythropoietin level.(ABSTRACT TRUNCATED AT 250 WORDS)

Bilirubin↗

PubMed2002

Risk factors and outcome of failure to progress during the first stage of labor: a population-based study.

BACKGROUND: One of the major indications for Cesarean section (CS) is failure of labor to progress. This study was aimed at defining obstetric risk factors for failure of labor to progress during the first stage, and to determine pregnancy outcome. METHODS: A population-based study comparing all singleton, vertex, term deliveries between the years 1988 and 1999 with an unscarred uterus, complicated with failure of labor to progress during the first stage with deliveries without non-progressive labor (NPL). Multiple logistic regression analysis was performed to investigate independent obstetric risk factors associated with failure of labor to progress during the first stage. RESULTS: Failure to progress during the first stage of labor complicated 1.3% (n = 1197) of all deliveries included in the study (n = 92 918), and resulted in CS. Independent risk factors for failure of labor to progress during the first stage, using a multivariable analysis, were premature rupture of membranes (PROM; OR = 3.8, 95% CI 3.2-4.5), nulliparity (OR = 3.8, 95% CI 3.3-4.3), labor induction (OR = 3.3, 95% CI 2.9-3.7), maternal age > 35 years (OR = 3.0, 95% CI 2.6-3.6), birth weight > 4 kg (OR = 2.2, 95% CI 1.8-2.7), hypertensive disorders (OR = 2.1, 95% CI 1.8-2.6), hydramnios (OR = 1.9, 95% CI 1.5-2.3), fertility treatment (OR = 1.8, 95% CI 1.4-2.4), epidural analgesia (OR = 1.6, 95% CI 1.4-1.8) and gestational diabetes (OR = 1.4, 95% CI 1.1-1.7). Although newborns delivered after failure of labor to progress during the first stage had significantly higher rates of Apgar scores lower than 7 at 1 and 5 min as compared with the controls (18.2% vs. 2.1%; P < 0.001 and 1.3% vs. 0.2%; P < 0.001, respectively), no significant differences were noted between the groups regarding perinatal mortality (0.3% vs. 0.4%; P = O.329). Maternal anemia and accordingly packed cells transfusion (47.4% vs. 22.8%; P < 0.001 and 5.6% vs. 1.0%; P < 0.001, respectively) were higher among pregnancies complicated with failure of labor to progress during the first stage as compared with the controls. CONCLUSIONS: Major risk factors for failure of labor to progress during the first stage were PROM, nulliparity, induction of labor and older maternal age. Indications for labor induction should be carefully evaluated in order to decrease the rate of operative deliveries.

Adolescent↗

PubMed1999

Role of oxytocin in the initiation of term and preterm labor in rats: changes in oxytocin receptor density and plasma oxytocin concentration and the effect of an oxytocin antagonist, L-366,509.

OBJECTIVE: Our purpose was to compare the functional roles of oxytocin in term and preterm labor in rats by both biochemical and pharmacologic means. STUDY DESIGN: We determined the myometrial oxytocin receptor density and the maternal plasma concentrations of oxytocin and progesterone on gestational days 18, 20, and 22 (morning) and at the onset of delivery (day 22 afternoon) in rats with labor at term and at the onset of delivery (day 20 afternoon) in rats in preterm labor induced by the combined use of bilateral ovariectomy and estradiol injection. We also evaluated the effects of an oxytocin antagonist, L-366,509, on the initiation of both term and preterm labor. RESULTS: The number of tritiated oxytocin binding sites in myometrial membranes rapidly increased on gestational day 22 (morning) in rats with term labor. Plasma progesterone level decreased in an inverse fashion. A rapid increase in circulating oxytocin concentration was observed at the onset of delivery in rats in labor at term. Both the plasma oxytocin concentration and the receptor density had the same values in rats with preterm labor as in rats with term labor. L-366,509 delayed the initiation of labor in rats with term and preterm labor in a dose-dependent manner. CONCLUSION: It is confirmed biochemically and pharmacologically that oxytocin plays an important role in the initiation of both term and preterm labor in rats. The oxytocin antagonist examined was able to delay term and preterm labor, so it might prove useful in clinical practice for the treatment of preterm labor.

Animals↗

PubMed2001

Trial of labor after 40 weeks' gestation in women with prior cesarean.

OBJECTIVE: To compare outcomes in women with prior cesareans delivering at or before 40 weeks' gestation with those delivering after 40 weeks. METHODS: We reviewed labor outcomes over 12 years at one institution for women with one prior cesarean and no other deliveries who had a trial of labor at term. We analyzed the rates of symptomatic uterine rupture and cesarean for term deliveries before or after 40 weeks and stratified for spontaneous and induced labor. Potential confounding by birth weight was controlled using logistic regression. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated. RESULTS: Of 2775 women with one prior scar and no other deliveries, 1504 delivered at or before 40 weeks and 1271 delivered after 40 weeks. For spontaneous labor, rupture rate at or before 40 weeks was 0.5% compared with 1.0% after 40 weeks (P =.2, adjusted OR 2.1, CI 0.7, 5.7). For induced labor, uterine rupture rates were 2.1% at or before 40 weeks and 2.6% after 40 weeks (P =.7, adjusted OR 1.1, CI 0.4, 3.4). For spontaneous labor, rate of cesareans during subsequent trials of labor at or before 40 weeks was 25% compared with 33.5% after 40 weeks (P =.001, adjusted OR 1.5, CI 1.2, 1.8). For induced labor, rate of cesareans during subsequent trials of labor at or before 40 weeks was 33.8% compared with 43% after 40 weeks (P =.03, adjusted OR 1.5, CI 1.1, 2.2). CONCLUSION: The risk of uterine rupture does not increase substantially after 40 weeks but is increased with induction of labor regardless of gestational age. Because spontaneous labor after 40 weeks is associated with a cesarean rate similar to that following induced labor before 40 weeks, awaiting spontaneous labor after 40 weeks does not decrease the likelihood of successful vaginal delivery.

Adult↗

PubMed2003

Myometrial thickness during human labor and immediately post partum.

OBJECTIVE: Morphologic studies suggest dramatic, asymmetric uterine growth during pregnancy that is caused by muscle cell hypertrophy. This growth is most marked at the fundus. Our objective was to evaluate sonographically the in vivo changes in myometrial thickness during active labor, second-stage labor, and after delivery. STUDY DESIGN: Abdominal ultrasound scans were performed on 52 term pregnant women to investigate the dynamic changes in myometrial thickness during the active and second stages of labor and immediately after delivery. Twenty-six women (mean +/- SEM gestational age, 39.09 +/- 0.3 weeks) were in active labor (cervical dilatation >4 cm with regular uterine contractions). An additional 26 nonlaboring women (gestational age, 39.8 +/- 0.2 weeks) provided control measurements. The myometrium was defined sonographically as the echo homogeneous layer between the serosa and the decidua. Myometrial thickness was measured at the low segment and mid anterior, fundal, and posterior uterine walls by the same observer. Myometrial thickness was also measured during uterine contractions and after artificial rupture of the amniotic membranes. All laboring women had uncomplicated labor patterns when studied and were delivered spontaneously. RESULTS: The myometrium was significantly thinner during active labor compared with nonlabor at each site studied: midanterior (mean [+/-SEM] myometrial thickness, 5.8 +/- 0.27 vs 8.83 +/- 0.51 mm; t test, P <.001), fundus (mean myometrial thickness, 6.78 +/- 0.32 vs 8.49 +/- 0.35 mm; P =.0015), and posterior (mean myometrial thickness, 6.22 +/- 0.34 vs 8.12 +/- 0.30 mm; P <.001). However, myometrial thickness did not differ among sites within the two groups. The thickness of the low segment was not affected by labor status (nonlabor, 4.68 +/- 0.48 vs labor, 4.66 +/- 0.37 mm; P =.97). Similarly, the myometrial thickness of the anterior uterine wall was unaffected by contractions (no contractions, 5.56 +/- 0.2 vs contractions, 5.68 +/- 0.22 mm; t test, P =.654). There was no change in myometrial thickness measured immediately before and after rupture of the amniotic membranes, despite a significant decrease of the amniotic fluid index. There was significant thickening of the anterior and fundal myometrium during the second stage of labor after the fetal head descended to +3 station by digital examination (anterior, 12.99 +/- 0.60 vs 5.8 +/- 0.27 mm; t test, P <.001; fundus, 10.61 +/- 1.63 vs 6.78 +/- 0.32 mm; t test, P =.04). Valsalva maneuver (pushing) during contractions did not affect myometrial thickness at the fundus (between contractions, 10.61 +/- 1.63 vs pushing, 10.76 +/- 1.95 mm; t test, P =.99). Immediately after delivery, the myometrial thickness at the placental insertion site was the thinnest. After completion of the third stage of labor, the uterine fundus remained significantly thinner than the anterior and posterior walls (fundus, 27.37 +/- 3.5 mm vs anterior, 40.94 +/- 3.5 vs posterior, 42.34 +/- 2.44; one-way analysis of variance, P =.02). CONCLUSION: There is significant and widespread thinning of the myometrium during active labor. Descent of the fetal head during the second stage of labor is associated with a significant relative thickening of the anterior and fundal myometrium. After delivery, the relationship reverses. These findings suggest the directionality of the expulsive force vectors (fundal dominance) is not determined by asymmetric myometrial growth but, rather, may be a function of increased "myometrial mass" that results from increased surface area at the fundus.

Adult↗

PubMed2003

Intrapartum ultrasound for the examination of the fetal head position in normal and obstructed labor.

OBJECTIVE: To assess the feasibility of transabdominal ultrasound for determining fetal head position in laboring women and compare it to digital examination, and to study ultrasonographically the rotation of the fetal head in normal and obstructed labor. DESIGN: This was an observational prospective study of 148 women in active labor. Ultrasound examinations were performed longitudinally in the first and second stages of labor. RESULTS: Assessment of the fetal head position by digital examination was not possible in 60.7% (122/201) of cases in the first stage and 30.8% (41/133) in the second stage of labor. Difficulty in assessing the position was more likely if the occiput was posterior in comparison to anterior and in the maternal right in comparison to the left side. In the second stage, it was three times more likely for the assessment not to be possible digitally if the occiput was posterior. In the cases when assessment by vaginal examination was possible, the correlation with ultrasound was average in the first stage (kappa = 0.59) and good in the second stage (kappa = 0.77). Overall fetal head position assessment by digital examination was accurate in 31.28% of the cases in the first stage and 65.7% of the cases in the second stage of labor. Rotation of the fetal head is highly unlikely when labor begins in the occipital anterior position. Persistent occipital posterior position developed through failure to rotate from an initial occipital posterior or transverse position. Duration of the first stage of labor was independently related to parity and position of the fetal spine at presentation, and duration of the second stage of labor was independently related to parity, birth weight, position of the fetal head at the beginning of the second stage, rotation and position of the head at delivery. CONCLUSION: Ultrasound assessment of the fetal head position in labor is feasible in a busy labor ward. Digital examination is less accurate than ultrasound, in particular in cases of obstructed labor when medical intervention is more likely to be needed. Ultrasound assessment may prove useful in the prediction and diagnosis of difficult and prolonged labor.

Adolescent↗