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PubMed1979

Human fetal breathing activity during electively induced labor at term.

Human fetal breathing movements were measured during the first stage of electively induced labor in 20 healthy term pregnancies. Fetuses made breathing movements 25.6% of the time during a 1 hour control period and breathing decreased significantly to 8.3% during latent-phase labor and further decreased to 0.8% during active labor (P less than 0.001). Patterns of increased fetal breathing activity accompanied by increased gross fetal body movements and increased fetal heart rate variability for periods of 20 to 60 minutes out of every 1.0 to 1.5 hours were observed, and the intermittent patterns of increased body movement and heart rate variability continued throughout the first stage of labor despite the decrease in fetal breathing activity during latent- and active-phase labor. It will be important to account for rest activity patterns when interpreting variability of heart rate during labor. The absence of fetal breathing activity during electively induced labor at term is not a clinical indicator of fetal ill health.

Anesthesia, Epidural↗
PubMed1983

Perinatal heart rate variability and circulatory adaptation in association with normal labor and after elective cesarean section.

Heart rate variability and basal hemodynamic parameters were studied in connection with 20 normal deliveries and after 16 elective cesarean sections. Eight of the cesarean sections were performed with the use of maternal barbiturate anesthesia and eight with the use of epidural blockade. The interval index describing the long-term variability and the differential index describing the short-term variability of the heart rate were measured continuously from 10-minute samples of a direct fetal electrocardiogram and a neonatal electrocardiogram of the infants by a microprocessor-based system. In association with normal labor, significant increases in both indices of variability were observed during the second stage of labor and during the first 2 hours of extrauterine life. After elective cesarean section both indices of neonatal heart rate variability remained significantly lower than those after normal labor. However, a significant increase was observed in the differential index of the infants delivered with the use of epidural blockade. During the neonatal period, simultaneous recordings of basal heart rate, systolic and diastolic blood pressures, and rectal and heel temperatures were made at 10-minute intervals. The basal neonatal heart rate was significantly higher in both cesarean section subgroups compared with that after normal labor. A significant decrease in basal neonatal heart rate during the second hour of life was observed after normal labor and after cesarean section with the use of epidural blockade. Systolic blood pressures in newborn infants delivered with the use of maternal epidural blockade were equal to those after normal labor, but higher than those after cesarean section with barbiturate anesthesia. Newborn infants after elective cesarean section had significantly lower diastolic blood pressures than infants delivered normally, but there was no difference in the diastolic blood pressures between the two cesarean section subgroups. The infants delivered vaginally had lower heel temperatures than those delivered abdominally. According to the present study, the neonatal circulatory adaptation after elective cesarean section is different from that after normal delivery; however, the neonatal hemodynamics after cesarean section with epidural blockade more closely resemble the situation after normal labor.

Anesthesia, Obstetrical↗
PubMed1989

Newborn lymphocyte subpopulations: the influence of labor.

Cord blood mononuclear cell subsets were enumerated in 31 neonates delivered after maternal labor, in 25 neonates delivered by cesarean section without preceding labor, and in 60 healthy adults. In neonates born with and without preceding labor percentages of CD3 cells were lower than those in adults (63% and 60% as opposed to 83% in adults). However, the absolute numbers of CD3 cells were significantly greater in newborn infants delivered without preceding labor (3.287 +/- 1.451 cells per microliter) than in both neonates born after labor (2.660 +/- 800 cells per microliter) and in adults (2.189 +/- 807 cells per microliter). The increase in CD3 cells in infants delivered without preceding labor reflects increased numbers of CD4-positive cells. This increase in the absolute number of T lymphocytes and CD4 (helper) lymphocytes was significant (p less than 0.02). These data indicate that labor-related stress significantly decreases the total number of neonatal T lymphocytes and the CD4 (helper) T-cell subpopulation in cord blood.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1990

The role of fetal membranes in regulating production, transport, and metabolism of prostaglandin E2 during labor.

The level of prostaglandin E2, a potent stimulator of myometrial contractions, increases in amniotic fluid during labor. We tested whether amniotic prostaglandin E2 crosses the reflected fetal membranes to the myometrium during labor. Disks of amnion, chorion-decidua, and amnion chorion-decidua from 10 term pregnancies before labor and nine vaginal deliveries after normal spontaneous labor were incubated in two-sided perfusion chambers in the absence or presence of 1 mumol/L indomethacin, or in the presence of a bolus of prostaglandin E2 and radiolabeled prostaglandin E2 added to the fetal chamber. Net amniotic prostaglandin E2 increased significantly (p = 0.003) after labor. However, there was no significant difference in prostaglandin E2 concentrations on the maternal side of amnion chorion-decidua between labor conditions. High-pressure liquid chromatography identified the transport of intact tritiated prostaglandin E2 across amnion but not across chorion-decidua or amnion chorion-decidua in which prostaglandin E2 was completely metabolized. Because of 15-hydroxyprostaglandin dehydrogenase activity in chorion, we suggest that amniotic prostaglandin E2 transport to the myometrium is impaired. Thus the increase in prostaglandin E2 production that occurs in amnion tissue after labor commences does not result in an increase in prostaglandin E2 concentration on the myometrial side of the fetal membranes in the in vitro preparation.

Adult↗
PubMed1990

The prevalence of substance abuse in patients with suspected preterm labor.

Premature labor is a recognized complication of substance abuse in pregnancy. However, the prevalence of substance abuse in patients first seen with symptoms of preterm labor and who deny use of illicit drugs is unknown. Between July 1, 1988, and December 15, 1988, 141 patients first seen at Northwestern Memorial Hospital in suspected preterm labor and a comparison group of 108 uncomplicated laboring term patients had urine toxicology screening performed to detect substance abuse. Positive urine toxicology screenings were found in 24 of 141 (17.0%) patients with suspected preterm labor and in 3 of 108 (2.8%) patients in the comparison group. The most common substance identified was cocaine (14/24 and 1/3, respectively). Of those patients in suspected preterm labor, 22 of 86 (25.6%) clinic patients had positive urine toxicology screenings as did 2 of 55 (3.6%) private patients. On the basis of our observations, we recommend that patients admitted in possible preterm labor be encouraged to submit to screening for substance abuse so that appropriate counseling and prenatal and neonatal care become available for these high-risk patients.

Adolescent↗
PubMed1992

Decrease in annexin I messenger ribonucleic acid expression in human amnion with labor.

OBJECTIVE: Annexins are a superfamily of proteins that are thought to inhibit phospholipase A2 activity and hence inhibit prostaglandin production. The purpose of this study was to test the hypothesis that annexin I concentration in human amnion is reduced with labor and that this reduction is mediated by a decrease in annexin I messenger ribonucleic acid expression. STUDY DESIGN: Amnion and choriodecidua were collected from term singleton pregnancies, eight after spontaneous vaginal delivery and eight from elective cesarean section without labor. Annexin I protein was quantitated by Western blotting. Ribonucleic acid was isolated from amnion, and then annexin I messenger ribonucleic acid was identified by Northern hybridization and quantitated by slot blotting. RESULTS: Annexin I (35 kd) was identified in amnion tissue. The concentration in the group undergoing labor (320 +/- 45 integrated optical density units, mean +/- SE) was significantly reduced (p < 0.05) compared with that in the group not undergoing labor (635 +/- 65 units). The size of the annexin I messenger ribonucleic acid was approximately 1.8 kb. The mean integrated optical density for the labor group (840 +/- 139 units, mean +/- SE) was significantly reduced (p < 0.05) compared with that of the nonlabor group (1912 +/- 464 units). CONCLUSION: There is a significant decrease in annexin I messenger ribonucleic acid expression in human amnion with labor, corresponding to a significant decrease in annexin I protein concentration. This may contribute to the increased phospholipase A2 activity, arachidonic acid mobilization, and prostaglandin production at labor in humans.

Amnion↗
PubMed1993

Efficacy and safety of nifedipine versus magnesium sulfate in the management of preterm labor: a randomized study.

OBJECTIVE: Our purpose was to establish the efficacy and safety of nifedipine versus magnesium sulfate in arresting preterm labor and the efficacy of nifedipine versus terbutaline in preventing recurrent labor. STUDY DESIGN: Singleton pregnancies at < 34 weeks in preterm labor were randomized to either oral nifedipine or intravenous magnesium sulfate. In case of tocolysis failure ritodrine was added. After labor was arrested, the patients in the nifedipine group were maintained on oral nifedipine, and those in the magnesium sulfate group were treated with oral terbutaline until completing 34 weeks. RESULTS: Of 100 patients 80 were considered eligible, of whom 39 were randomized to the nifedipine group. Both groups were comparable in terms of a number of entry variables, including cervical examination, contraction frequency, and gestational age. Both drugs were equally effective in arresting labor and delaying delivery > 48 hours, 92% versus 93%. Both study groups had a similar incidence of side effects, although four (10%) of magnesium sulfate-treated patients required drug discontinuation because of severe symptoms. Nifedipine was as effective as terbutaline in preventing recurrent labor, 26% versus 24%, and in achieving a gestation > 34 weeks, 62% versus 68%. CONCLUSIONS: Oral nifedipine is as effective as magnesium sulfate and terbutaline in arresting and preventing idiopathic preterm labor.

Administration, Oral↗
PubMed1993

Do tocolytic agents stop preterm labor? A critical and comprehensive review of efficacy and safety.

OBJECTIVE: Our aim was to determine the efficacy and safety of tocolytic agents currently used to treat premature labor. STUDY DESIGN: We carried out a comprehensive review of tocolytic agents in the treatment of premature labor. Three hundred twenty-eight studies published between 1933 and 1992 were analyzed. RESULTS: An analysis of randomized, placebo-controlled, clinical trials showed that magnesium sulfate is not better than placebo in the treatment of premature labor. beta-Adrenergic receptor agonists effectively stop premature labor for only 24 to 48 hours. Calcium channel blockers and oxytocin antagonists inhibit uterine contractions, but their role in stopping labor is undefined. Prostaglandin inhibitors appear to be effective in treating premature labor and have few adverse side effects. CONCLUSIONS: The only tocolytic drugs that might be effective are the prostaglandin inhibitors. Tocolytic agents should be used only between 24 and 32 completed weeks of gestation. Magnesium sulfate should not be used to treat premature labor. Oxytocin antagonists should be used only in experimental clinical trials. Calcium channel blockers and beta-adrenergic receptor agonists inhibit uterine contractions but do not prolong gestation for longer than 48 hours.

Adrenergic beta-Agonists↗
PubMed1993

Oncofetal fibronectin in patients with false labor as a predictor of preterm delivery.

OBJECTIVE: Our objective was to determine whether fetal fibronectin is a discriminator for preterm labor and early delivery in women who have intact membranes and uterine activity. STUDY DESIGN: In our prospective study 28 women between 24 and 34 weeks' gestation with regular, persistent uterine contractions (> 10/hr) and intact membranes were assessed for presence of fetal fibronectin. A Dacron swab was applied to the external os for 10 seconds. The cervix was < or = 1 cm, and all patients were diagnosed as having false labor. The assay was performed by using monoclonal antibody FDC-6 to bind fetal fibronectin. RESULTS: Of the 28 patients with false labor, 14 had a positive fetal fibronectin, and all had preterm labor (specificity and positive predictive value 100%). Of these, nine delivered preterm, yielding a specificity and positive predictive value of 72% and 64%, respectively. Among the 14 women with a negative fetal fibronectin, only four developed preterm labor (sensitivity 78%, negative predictive value 71%). One patient delivered preterm at 34 weeks (sensitivity 90% and negative predictive value 93%). CONCLUSIONS: A positive fetal fibronectin in women who have false labor indicates a significant risk for preterm labor and early delivery. A negative fetal fibronectin is a reassuring sign.

Adult↗
PubMed1994

The effects of labor on maternal and fetal levels of insulin-like growth factor binding protein-1.

OBJECTIVE: Our purpose was to determine the effects of labor and fetal hypoxia on the levels of insulin-like growth factor binding protein-1 in the maternal and fetal circulation. STUDY DESIGN: Serum levels of insulin-like growth factor binding protein-1 were determined in maternal and umbilical blood at delivery in two groups. The first group included 43 vaginal deliveries and 23 elective cesarean sections. The second group consisted of 44 women; in 24 the liquor was meconium stained and in 20 it was clear. RESULTS: Levels of insulin-like growth factor binding protein-1 in the neonate were lower in deliveries occurring before onset of labor (p < 0.001), Mann-Whitney U test) and higher in cases with severe meconium staining (p = 0.01). There were no differences in maternal levels of insulin-like growth factor binding protein-1 between subjects in labor and not in labor or those with or without meconium staining. CONCLUSION: The process of labor leads to an increase in fetal levels of insulin-like growth factor binding protein-1. This increase may well be associated with the relative fetal stress that occurs during labor. This suggestion is supported by the finding of the highest levels in labors in which there was thick staining of the liquor.

Adolescent↗
PubMed1996

Clinical amnionitis and endometritis in patients with premature rupture of membranes: endocervical prostaglandin E2 gel versus oxytocin for induction of labor.

OBJECTIVE: To compare the rates of clinical amnionitis and endometritis in patients with premature rupture of membranes (PROM), using endocervical prostaglandin E2 (PGE2) gel for induction of labor versus immediate oxytocin induction of labor. METHODS: We randomized 118 patients to receive either endocervical 0.5 mg of PGE2 gel (study group) or immediate oxytocin induction of labor (control group). If labor was not established in the group receiving PGE2 gel in 24 hours, intravenous oxytocin was given in incremental doses. The rates of clinical amnionitis and endometritis in the two groups were analyzed. Also compared were hours of labor, duration of rupture of membranes and number of vaginal examinations. Student t test, chi 2, or Wilcoxon rank-sum test were used for statistical analysis, as appropriate. P < .05 was considered significant. RESULTS: The rates of clinical amnionitis were 5.3% in the PGE2 group and 8% in the control group. Endometritis developed in 1.7% of PGE2 patients and 3.2% of controls. These differences in maternal infection rates were not statistically significant. The two groups were comparable with respect to age, parity, and antepartum group B streptococcal colonization. No significant differences in hours of labor, duration of ruptured membranes, or vaginal examinations were observed. Neonatal outcome data (mean birth weight, Apgar scores at 1 and 5 minutes, Apgar score less than 7 at 5 minutes) were not statistically significant. CONCLUSION: Endocervical placement of 0.5 mg of PGE2 gel does not increase the incidence of clinical amnionitis and endometritis in patients with PROM at term when compared with immediate induction of labor with oxytocin.

Administration, Topical↗
PubMed2004

The effect of early epidural versus early intravenous analgesia use on labor progression: a natural experiment.

OBJECTIVE: The purpose of this study was to compare the effect of early epidural with the use of early intravenous analgesia on labor progression. STUDY DESIGN: We systematically selected singleton, nulliparous term pregnancies with a spontaneous labor and analgesia placement <or=4 cm who were delivered at a hospital where the rate of epidural analgesia in labor increased from 1% (before) to 84% (after) in 1 year (a natural experiment). In the before period (n=223 pregnancies), 98% of women used intravenous analgesia, and 2% of women used epidural analgesia. In the after period (n=278 pregnancies), 92% of women used epidural analgesia, and 8% of women used intravenous analgesia. The median duration of labor by each centimeter of cervical dilation was computed and used as a measurement of labor progression. RESULTS: After adjustment had been made for confounders, women in the after period had a slower labor progression only from 4 to 5 cm, compared with those women in the before period. Interestingly, the process of labor admission and epidural analgesia placement, rather than analgesia use per se, appeared to explain most of the slowdown. No significant difference in the rest of the active phase was observed between the 2 groups. CONCLUSION: Our data support recent American College of Obstetricians and Gynecologists guidelines that the restraining use of epidural analgesia at <4 cm of cervical dilation is unnecessary.

Adult↗
PubMed2004

Meperidine for dystocia during the first stage of labor: A randomized controlled trial.

OBJECTIVE: This study was undertaken to evaluate whether the administration of meperidine decreases the length of labor in patients with a diagnosis of dystocia during the first stage of labor. STUDY DESIGN: Women with term singleton pregnancies who received a diagnosis of dystocia and required an active management of labor were randomly assigned to receive either 100 mg of meperidine or placebo. The primary outcome measure was length of labor. RESULTS: Four hundred seven pregnant women were included. There were no significant statistical differences between meperidine and placebo groups in length of labor and operative delivery rates such as forceps and cesarean section by intention-to-treat analysis. Low Apgar scores, umbilical artery acidosis, and admission to neonatal care units were increased in the meperidine group. CONCLUSION: Because of the absence of any benefits in patients with dystocia in labor and the presence of harmful effects on neonatal outcomes, meperidine should not be used during labor for this specific indication.

Analgesics, Opioid↗
PubMed2005

Catastrophizing labor pain compromises later maternity adjustments.

OBJECTIVE: The purpose of this study was to evaluate the impact of labor pain intensity and labor pain catastrophizing on maternity blues and postpartum social functioning. STUDY DESIGN: Pain intensity and pain catastrophizing were assessed in 89 women in active labor before the administration of analgesia. Both these measures were assessed again retrospectively 2 days after delivery in 82 women who had a spontaneous vaginal delivery. Women also filled out the Edinburgh Postnatal Depression Scale. Six weeks later women completed the social functioning domain of the short form SF36 health survey. RESULTS: Pain catastrophizing during labor significantly predicted both maternity blues (P = .001) and postpartum social functioning (P = .001) when being controlled for maternal age and education, parity, type of analgesia, and labor pain intensity. Low level of education and younger age also contributed to the prediction of maternity blues and social functioning. CONCLUSION: Labor pain catastrophizing rather than labor pain intensity predicts postpartum maternal adjustments.

Adaptation, Psychological↗
PubMed2004

Active induction management of labor for diabetic pregnancies at term; mode of delivery and fetal outcome--a single center experience.

OBJECTIVES: To evaluate the mode of delivery in diabetic pregnancies at term following induction of labor with vaginal application of prostaglandin E2 (PGE2), and to identify possible predictors of successful vaginal delivery. PATIENTS AND METHODS: The study group consisted of 105 women with diabetic pregnancies at term admitted for induction of labor; 84 (80%) had gestational diabetes (GDM) and 21 (20%) type 1 diabetes. Findings were compared with women who underwent elective induction of labor (n=115), and women with normal spontaneous onset of labor (n=510). Women with previous cesarean section (CS) were excluded from both study and control groups. RESULTS: Maternal age and gravidity were significantly higher in the study group than the control groups (age: 31.4+/-5, 28+/-5.0 and 28.1+/-4.8 years, respectively; gravidity: 3.0+/-1.9, 2.5+/-1.6, and 2.1+/-1.4, respectively; P<0.001 for both) and gestational age and nulliparity rate were significantly lower (gestational age: 38.6+/-1.1, 40.2+/-1.3 and 39.3+/-2.7 weeks, respectively; nulliparity: 34.6, 45.2, 51.6%, respectively; P<0.002 for both). There were no between-group differences in the incidence of oligohydramnios, number of PGE2 applications used, birth weight, rate of non-reassuring fetal heart rate pattern leading to CS, and rate of low 5 min Apgar score (<7). The rate of CS in the study group (18.2%) was significantly higher than in the spontaneous labor group (9%) but similar to the elective induction group (14.8%). On stepwise analysis, only nulliparity (OR 4.56, 95% CI 1.11-18.67, P=0.035) was independently and significantly associated with increased risk of CS. Within the study group (R2=0.257, P=0.002), type 1 diabetes (OR 2.4, 95% CI 1.04-5.51) was independently and significantly associated with increased risk of CS. CONCLUSION: In diabetic pregnancies, induction of labor at term with vaginal PGE2 is successful in approximately 82% of patients, but yields a significantly higher CS rate compared to uncomplicated pregnancies. Nulliparity and diagnosis of type 1 diabetes are independently and significantly associated with increased risk of CS. CONDENSATION: In diabetic pregnancies, induction of labor at term is successful in 82% of patients, but yields higher CS rates compared to uncomplicated pregnancies.

Adult↗
PubMed2005

Relationship between beta-hCG levels in cervicovaginal secretions and labor.

OBJECTIVE: To determine whether levels of human beta-chorionic gonadotropin hormone (beta-hCG) in cervicovaginal secretions can predict the labor process. METHODS: A total of 150 women admitted in active labor to the urgent delivery unit of a university hospital were enrolled in a prospective study. The beta-hCG level of each woman's cervicovaginal secretions was measured by radioimmunoassay on admission; then, beta-hCG levels were compared between 2 groups of 35 women, one in whom labor progressed normally and another in whom augmentation of labor with oxytocin was required. RESULTS: There were significant differences in beta-hCG levels of cervicovaginal secretions between the spontaneous delivery group and the augmentation of labor group (130.72+/-64.51 mU/mL vs. 93.9+/-65.29 mU/mL) (P<0.05). A receiver-operating characteristic (ROC) curve analysis showed that the optimal cut-off value was 82 mU/mL, with a sensitivity of 66% and a specificity of 60%. CONCLUSION: beta-chorionic gonadotropin hormone levels were significantly higher in the cervicovaginal secretions of women whose labor was progressing normally than in those who required augmentation of labor.

Adult↗
PubMed2006

A survey of labor patient-controlled epidural anesthesia practice in California hospitals.

BACKGROUND: Patient-controlled epidural analgesia (PCEA) offers many advantages over continuous epidural infusions for labor analgesia including fewer physician interventions, improved analgesia and satisfaction, and reduced local anesthetic doses. However, anesthesiologists have been slow to adopt this technique, first described in 1988. No previous studies have evaluated specific labor patient-controlled epidural analgesia practices in the United States. The aim of this study was to determine labor epidural and patient-controlled epidural analgesia practices among California hospitals. METHODS: Following institutional review board exemption approval, an online survey was created using freeonlinesurveys.com. An anonymous survey was sent via e-mail to 230 California Society of Anesthesiologists' members chosen at random to represent their hospitals' labor analgesia practices. RESULTS: We received 133 replies from the 230 survey requests sent, a 58% response rate. The median labor epidural rate among the hospitals involved was 65% (range 0-95%). Overall, only 25% of California hospitals use patient-controlled epidural analgesia for analgesia in labor, with greater use among hospitals with dedicated obstetric anesthesia coverage and larger numbers of deliveries. Reasons given for not using patient-controlled epidural analgesia include cost, clinician preference, safety concerns and the inconvenience of change. CONCLUSIONS: Despite the potential advantages of patient-controlled epidural analgesia over continuous epidural infusions for labor analgesia, patient-controlled epidural analgesia has not been widely adopted in California hospitals. Education regarding this technique is needed to encourage its increased use.

Analgesia, Epidural↗
PubMed2005

Labor-associated regulation of prostaglandin E and F synthesis and action in the ovine amnion and cervix.

OBJECTIVE: Prostaglandins (PGs) are key regulators of cervical dilatation and membrane breakdown at the onset of labor. PG synthase and receptor expression has been previously documented in uterine tissues; however, mechanisms governing the changes occurring in the cervix and amnion are less well established. The aim of the current study was to determine the level of expression of PG synthetic enzymes and receptors in these tissues in association with induced labor in sheep. METHODS: Labor was induced in sheep at 135 days of gestation by continuous fetal dexamethasone infusion. Amnion and cervical tissue was obtained before and after labor for measurement of mRNA encoding enzymes (cytosolic phospholipase A2 [cPLA2], PGH synthase-2 [PGHS-2], PGF synthase [PGFS], and PGE synthase [PGES]) and receptors (FP and EP1-4) by real-time polymerase chain reaction (PCR). RESULTS: cPLA2 expression increased significantly in cervical tissue at labor onset, whereas expression of the other enzymes measured did not change. There was a marked rise in EP3 expression in the cervix, but abundance of this receptor was lower than EP2 and FP expression, which did not change. The amnion exhibited a labor-associated decrease in PGHS-2, PGFS, and FP mRNA expression. CONCLUSION: The regulation of PG synthesis and action occurring in the amnion and cervix in association with labor appear to differ markedly between the two tissues, indicating tissue-specific roles for PGs. The data support a role for increased PG synthesis and action in the cervix and suggest a decrease in PG production and action in the amnion, in sharp contrast to the pattern reported in human amnion.

Amnion↗