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An evaluation of pain and "fitness" during labor and its acceptability to women.

BACKGROUND: Labor experiences involve many dimensions that change during labor but are rarely measured contemporaneously and longitudinally. We examined pain and "fitness" aspects of women's labor experience and assessed the acceptability to participants. METHODS: Thirty nulliparas and 20 multiparas in term labor indicated pain and fitness every 45 minutes in contraction-free intervals on visual analog scales from 0 to 10. Fitness implied both physical and psychological strength. Data were analyzed cross-sectionally and longitudinally, with adjustment for analgesia and time dependency. Women received feedback and evaluated their participation on the first day postpartum. RESULTS: Measurements of pain and fitness ranged from 2 to 22 per woman (mean +/- SD: 7.4 +/- 4.4). Pain scores showed various patterns, mostly increasing from 1.4 (+/- 1.9) at the first to 6.6 (+/- 3.8) at the last measurement in nulliparas and from 1.3 (+/- 2.1) to 6.2 (+/- 4.0) in multiparas. One half of the women declined steadily in fitness throughout labor, occasionally after a slight increase early on. Multiparas entered labor more fit (5.9 +/- 3.0) than nulliparas (3.9 +/- 2.7), but showed a sharper decline so that the difference leveled out just before birth. Although fitness at any one time did not reflect pain levels, fitness and pain were inversely related, especially in nulliparas (p = 0.003). Analgesia affected pain scores but affected fitness only a little. Women's responses were mainly positive, especially in appreciating the feedback. Nevertheless, 32 percent of women skipped one or more measurements, often toward the end or when too close to a contraction. CONCLUSIONS: Pain and "fitness" are two distinctly different dimensions of labor experience. Repeated longitudinal measurements of elements of well-being are clearly feasible and acceptable to laboring women. They may be useful to assess how labor events and interventions affect women's well-being.

Cross-Sectional Studies↗

Evidence for 5-hydroxyeicosatetraenoic acid (5-HETE) and leukotriene C4(LTC4) in the onset of labor.

UNLABELLED: Arachidonic acid is metabolized by cyclooxygenase leading to prostaglandins (PG), and by lipoxygenases leading to hydroxyeicosatetraenoic acids (HETE) and leukotrienes (LT). PGs are potent uterine constrictors. 5-HETE and LTC4 also stimulate uterine contractions, but their role in labor is not known. To estimate the activities of these pathways before parturition and their relationship to uterine contractility, amniotic fluid (AF) concentrations of 5-HETE, LTC4 and PGF2 alpha were determined in 5 chronically catheterized rhesus monkeys. Uterine contractility was continually assessed by changes in AF pressure. RESULTS: AF concentrations at the time of intrauterine surgery were 4.4 +/- 0.8 ng/ml for 5-HETE and 2.5 +/- 0.7 ng/ml for LTC4. PGF2 alpha levels were nondetectable. Indomethacin infusion into the mother, although effective in suppressing PGF2 alpha levels, did not prevent the onset of premature labor and vaginal delivery in 2 animals. PGF2 alpha did not increase in 1 monkey with term labor. Approximately 1 week before delivery, 5-HETE and LTC4 concentrations increased sharply in all animals in association with a nocturnal pattern of labor contractions. Peak AF concentrations during labor were 5-HETE: 40 +/- 8 ng/ml, LTC4: 20 +/- 4 ng/ml, and PGF2 alpha: 5.4 +/- 2.1 ng/ml. COMMENT: LTC4 and 5-HETE stimulate uterine contractility in vitro, and probably act in concert with PGF and PGE to stimulate uterine contractions during parturition. HETEs may also act as a signal to recruit white blood cells to the uterus and to activate them, there to augment PG and LT production and act as a first line of defense against any infection that might enter the uterus from the vagina during or after delivery. CONCLUSIONS: 1) 5-HETE and LTC4, but not PGF2 alpha, are associated with uterine contractility after preterm intrauterine surgery. Surprisingly, AF PGF2 alpha levels were nondetectable for 1 to 2 weeks after surgery. 2) 5-HETE and LTC4 are present in higher concentrations than PGF2 alpha in AF. 3) 5-HETE, LTC4 and PGF2 alpha all increase with the onset of labor. AF concentrations of 5-HETE and LTC4 are significantly higher than PGF2 alpha before and during term and preterm labor. 4) Labor can occur with suppressed PGF2 alpha levels, but with increasing 5-HETE and LTC4 levels. 5) These data suggest that 5-HETE and LTC4 are important components of the parturitional process, and they challenge the dogma that PGs are the universal mediators of labor.

Amniotic Fluid↗

Active management of labor: a cost analysis of a randomized controlled trial.

OBJECTIVE: To compare the costs of a protocol of active management of labor with those of traditional labor management. DESIGN: Cost analysis of a randomized controlled trial. METHODS: From August 1992 to April 1996, we randomly allocated 405 women whose infants were delivered at the University of New Mexico Health Sciences Center, Albuquerque, to an active management of labor protocol that had substantially reduced the duration of labor or a control protocol. We calculated the average cost for each delivery, using both actual costs and charges. RESULTS: The average cost for women assigned to the active management protocol was $2,480.79 compared with an average cost of $2,528.61 for women in the control group (P = 0.55). For women whose infant was delivered by cesarean section, the average cost was $4,771.54 for active management of labor and $4,468.89 for the control protocol (P = 0.16). Spontaneous vaginal deliveries cost an average of $27.00 more for actively managed patients compared with the cost for the control protocol. CONCLUSIONS: The reduced duration of labor by active management did not translate into significant cost savings. Overall, an average cost saving of only $47.91, or 2%, was achieved for labors that were actively managed. This reduction in cost was due to a decrease in the rate of cesarean sections in women whose labor was actively managed and not to a decreased duration of labor.

Costs and Cost Analysis↗

Prognostic value of change in amniotic fluid color during labor.

OBJECTIVE: Evidence of meconium-stained amniotic fluid (AF) during labor suggests implementation of close monitoring of fetal well-being. We have investigated whether the presence of meconium in the AF on admission for labor is as important a predictor of neonatal outcome as a change in AF color during labor. METHODS: AF characteristics on admission for labor at term (37-42 weeks) and their changes during labor were recorded in all singleton pregnancies during an 8-year period (1992-1999). Excluded were stillbirths on admission, congenital anomalies, and elective cesarean sections. The presence of meconium and its consistency (light or thick) were documented on admission by inspection with transcervical amnioscopy in women with intact membranes or in the vaginal pool in those with ruptured membranes. Changes in AF color or consistency during labor were recorded and correlated with the obstetric and neonatal outcome. Statistical analysis utilized chi(2) for trend, with p < 0.05 considered significant. RESULTS: 19,090 women were admitted in labor at term during the study period and fulfilled the study inclusion criteria and had amniotic fluid evaluation available. The appearance of meconium or worsening in thickness of meconium during labor was associated with higher rates of Apgar scores <7 at 5 min (clear AF on admission and at delivery 0.6%; light or thick meconium on admission and no change at delivery 0.8%; clear AF on admission and light or thick meconium at delivery 3.2%, and light meconium on admission and thick meconium at delivery 2.5%; p < 0.001) and umbilical artery pH <7.10 (the respective rates in the four groups were 1.7, 1.8, 3.6, and 3.8%; p < 0.001). CONCLUSION: The appearance or thickening of meconium during labor has a greater predictive ability for depressed neonates than the presence of meconium on admission.

Adult↗

Stimulation of surfactant production by oxytocin-induced labor in the rabbit.

The respiratory distress syndrome is believed to be due to insufficient surfactant. It is known that there is a greater incidence of the respiratory distress syndrome among infants delivered by cesarean section before labor than among those delivered after labor at the same gestational age. The purpose of this study was to determine the effect of labor on the production of pulmonary surfactant. We measured the phospholipid content of lung lavage in newborn rabbits delivered by cesarean section before labor at 29, 30, and 31 (full-term) days gestation and after oxytocin-induced labor at 31 days. We also measured the activities of pulmonary cholinephosphate cytidylyltransferase and choline-phosphotransferase, enzymes involved in the de novo synthesis of phosphatidylcholine, the major component of surfactant. There was a two- to fourfold increase in the amount of lung lavage phospholipid during the first 6 h after birth. This was not dependent upon gestational age at delivery. There was a further two- to fourfold increase in the next 18 h which was, however, dependent upon gestational age. Labor increased the amount of lavage phospholipid from rabbits delivered at full term by 132%, 177%, and 50% at 3, 6, and 24 h after birth, respectively. There was a postnatal increase in the activity of cholinephosphate cytidylyltransferase. This was almost linear with time during the first 12 h, by which time essentially adult values were attained. Choline-phosphate cytidylyltransferase was not affected by labor. There was also a postnatal increase in the activity of cholinephosphotransferase but this was stimulated 86%, 59%, and 21% by labor at 0, 1, and 24 h after birth, respectively. These studies suggest that labor stimulates both the synthesis and secretion of surfactant in the immediate postnatal period and thus may be an important factor in the prevention of the respiratory distress syndrome of the newborn.

Animals↗

Amniotic fluid interleukin 6 in preterm labor. Association with infection.

To evaluate whether IL-6 participates in the host response to intrauterine infection, we studied IL-6 bioactivity and isoforms in amniotic fluid (AF). Two different assays for IL-6 were used: the hepatocyte stimulating factor assay (in Hep3B2 cells) and the SDS-PAGE/immunoblot assay. IL-6 determinations were performed in 205 AF samples. Samples were obtained from patients in the midtrimester of pregnancy (n = 25), at term with no labor (n = 31), at term in active labor (n = 40), and from patients in preterm labor (n = 109). Higher AF IL-6 levels were observed in women in preterm labor with intraamniotic infection than in women in preterm labor without intraamniotic infection (median = 375 ng/ml, range = 30-5000 ng/ml vs. median = 1.5 ng/ml, range = 0-500, respectively, P less than 0.0001). The 23-25- and 28-30-kD IL-6 species could be readily detected in SDS-PAGE immunoblots performed directly on 10-microliters aliquots of AF from patients with intraamniotic infection. Among women in preterm labor with culture-negative AF, those who failed to respond to subsequent tocolytic treatment had higher AF IL-6 concentrations than those who responded to therapy (median = 50 ng/ml vs. median = 1.2 ng/ml, respectively, P less than 0.05). Only low levels of IL-6 were detected in AF obtained from normal women in the midtrimester and third trimester of pregnancy. Decidual tissue explants obtained from the placentas of women undergoing elective cesarean section at term without labor (n = 11) produced IL-6 in response to bacterial endotoxin. In a pilot study, AF IL-6 was determined in 56 consecutive women admitted with preterm labor. All patients (n = 10) with elevated AF IL-6 (cutoff = 46 ng/ml) delivered a premature neonate. 4 of these 10 patients had positive AF cultures for microorganisms. These studies implicate IL-6 in the host response to intrauterine infection and suggest that evaluation of AF IL-6 levels may have diagnostic and prognostic value in the management of women in preterm labor.

Adult↗

Women's views of the preterm labor experience.

This study used a naturalistic approach to describe the childbearing woman's views of her preterm labor and delivery experience. Specifically, the aim was to identify how women describe, interpret, and manage preterm labor and subsequent preterm or term delivery. The views of 20 women who were hospitalized for preterm labor (before 37 weeks) were documented with semistructured, tape-recorded, in-depth interviews during their hospitalization for preterm labor and after delivery. Qualitative data analysis focused on the process of becoming a preterm labor patient and on living with a diagnosis of preterm labor. Women either waited for a period of time before seeking care or sought care immediately for the symptoms they were experiencing. Women interpreted the experience by identifying causes of preterm labor and by worrying about the outcome for the baby. Managing preterm labor required extensive, moderate, or limited changes in their lives. Women who delivered at term appeared to have more tangible help than those who delivered preterm. A better understanding of women's preterm labor experiences will provide clues to nurses on how to improve the care they provide.

Adolescent↗

Prostaglandin endoperoxide-H synthase (PGHS) activity and immunoreactive PGHS-1 and PGHS-2 levels in human amnion throughout gestation, at term, and during labor.

Prostaglandins (PGs) are of primary importance in the initiation and maintenance of labor in women. A major intrauterine source of prostaglandins is the amnion, which synthesizes increased amounts of PGE2 at term labor. Because PG endoperoxide-H synthase (PGHS) catalyzes the rate-limiting step of PG synthesis from arachidonic acid, we investigated the changes in amniotic PGHS specific activity during gestation and at term and preterm labor. Also, we determined the level of immunoreactive PGHS protein in the amnion to evaluate the mechanisms by which PGHS activity may be regulated. PGHS specific activity, measured at the amount of PGE2 produced by amnion microsomes under optimal conditions, was 18.2 +/- 3.7 pg PGE2/micrograms protein.min (mean +/- SE; n = 19) at term (37-42 weeks gestation) before the spontaneous onset of labor. PGHS specific activity was significantly higher after spontaneous term labor (38.9 +/- 6.0 pg PGE2/micrograms protein.min; n = 19; P < 0.05). Amnion samples from preterm (< 36 weeks gestation) nonlaboring patients contained low levels of PGHS specific activity (5.9 +/- 1.8 pg PGE2/micrograms protein.min; n = 9), which increased significantly with spontaneous preterm labor (28.3 +/- 6.8 pg PGE2/micrograms protein.min; n = 10; P < 0.05). Longitudinal analysis of the data showed that PGHS specific activity was low in the first and second trimesters of gestation, but increased dramatically before labor onset at term. We detected PGHS protein in all microsomal samples, with an antiovine PGHS antibody recognizing both PGHS-1 and -2 isoforms of the enzyme. However, there was no correlation between PGHS specific activity and the amount of immunoreactive PGHS protein. Using an antibody specific for PGHS-2, we detected immunoreactive protein in only 9 of the 25 tissues examined and found no correlation between PGHS specific activity and the amount of PGHS-2 protein. These results suggest that 1) PGHS specific activity in the amnion increases sharply before the onset of labor at term; 2) further increases in specific activity occur during term and preterm labor; and 3) the specific activity of PGHS in the amnion is not related directly to the amount of immunoreactive enzyme protein.

Amnion↗

Glucose homeostasis during spontaneous labor in normal human pregnancy.

Using stable isotope, glucose turnover was measured in six normal pregnant women during the various stages of labor; during the latent (A1) and active (A2) phases of cervical dilatation, during fetal expulsion (B), and during placental expulsion (C). These data were compared to measurements made in five postpartum women. Pancreatic hormones and cortisol were also measured. In four other normal women undergoing spontaneous labor, catecholamines and free fatty acids were measured. Plasma glucose increased throughout labor from 4.0 +/- 0.2 (A1) to 5.5 +/- 0.5 mmol/L (C) (P < 0.01), compared to 4.7 +/- 0.1 in the postpartum women. Glucose utilization and production were increased throughout labor at 33.4 +/- 3.1 and 32.8 +/- 3.1 mumol/kg min, respectively, compared to 8.2 +/- 0.9 in postpartum women. Glucose metabolic clearance was also increased to 7.5 +/- 0.8 mL/kg.min compared to that in nonpregnant women (1.8 +/- 0.3). Plasma insulin remained at 59 +/- 5 pmol/L during stages A1, A2, and B, but increased to 115 +/- 15 pmol/L during stage C. Plasma glucagon was increased throughout labor at 127 +/- 7 pg/mL, compared to 90 +/- 4 pg/mL in control postpartum women. Plasma cortisol increased during labor from 921 +/- 136 to 2018 +/- 160 nmol/L, compared to 645 +/- 355 during the postpartum period. Epinephrine and norepinephrine also increased during labor from 218 +/- 132 pmol/L and 1.09 +/- 0.16 nmol/L to 1119 +/- 158 and 3.61 +/- 1.04, respectively. It is concluded that labor is associated with a marked increase in glucose utilization and production. These findings suggest that muscle contraction (uterus and skeletal) independent of insulin is a major regulator of glucose utilization during labor. Furthermore, the increase in hepatic glucose production could be favored by an increase in glucagon, catecholamines, and cortisol.

Fatty Acids, Nonesterified↗

Expression of nitric oxide synthase isoforms in the human placenta is not altered by labor.

Nitric oxide has various biological activities including smooth muscle relaxation, anti-inflammatory activity, anti-coagulatory activity. As the human placenta is known to express nitric oxide synthases, this study investigated the possible effect of labor on the expression of endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) in human placental tissues at term. Both eNOS and iNOS mRNA expression in placental tissues in labor were significantly higher than those in the amnion, chorion laeve, decidua vera and myometrium. The eNOS mRNA and protein expressions in placental tissues in labor (n = 12) were 1.6023 +/- 0.1652 (eNOS/GAPDH, mean +/- SEM) and 12.8 +/- 1.3 arbitrary units (AU), respectively, which were similar to those not in labor (n = 10), 1.5806 +/- 0.2042 (eNOS/GAPDH) and 11.4 +/- 1.8 AU. The iNOS mRNA and protein expressions in the placental tissues in labor were 1.2831 +/- 0.2436 (iNOS/GAPDH) and 10.7 +/- 2.1 AU respectively, similar to those not in labor, 1.9254 +/- 0.8004 (iNOS/GAPDH) and 13.3 +/- 1.8 AU. The guanosine 3',5'-cyclic monophosphate (cGMP) concentration in the placental tissues in labor was 23.6 +/- 1.4 fmol/g wet tissue, similar to that not in labor, 26.1 +/- 2.0 fmol/g wet tissue. These findings suggest that nitric oxide production in the human placenta is maintained during labor.

Cyclic GMP↗

Glucose and insulin requirements during labor and delivery: the case for normoglycemia in pregnancies complicated by diabetes.

OBJECTIVE: To present protocols for maintaining normoglycemia during labor and delivery in order to achieve optimal outcomes of pregnancy in women with diabetes. RESULTS: Labor has a glucose-lowering effect. In the case of women with insulin-requiring gestational diabetes, no additional insulin is needed with the onset of labor; sufficient glucose should be infused to keep such women from becoming ketotic from the pronged period of starvation. Likewise, protocols derived from glucose-controlled insulin infusion studies reveal that women with type 1 diabetes require no more subcutaneously administered insulin on the morning of an induction of labor or at the onset of spontaneous labor. The intravenously administered solutions should be started with isotonic saline or electrolyte solutions. As soon as active labor is achieved, the solutions should be switched to a glucose-containing fluid and administered at a rate of 2.55 mg/kg per minute. CONCLUSION: Labor is a form of exercise and thus obviates the insulin requirement in women with all types of diabetes, but it also necessitates an eightfold increase in glucose substrate in order to prevent maternal hypoglycemia and ketosis. The literature presents clear evidence that neonatal hypoglycemia is directly related to maternal hyperglycemia during labor and delivery. Thus, protocols for maintaining normoglycemia during labor and delivery are necessary to achieve optimal results.

Animals↗

[Risk factors for preterm labor].

OBJECTIVES: Most studies investigating preterm risk factors include medically induced preterm labor due to fetal or maternal complications and do not distinguish preterm labor from preterm premature rupture of membranes. Thus, the objective of this study was to determine the proportion of the three types of preterm birth and identify risk factors for spontaneous preterm labor in a sample of pregnant women who delivered at two level III units. STUDY DESIGN: From January to October 1996, we interviewed 385 women with live preterm newborns and, as controls, 357 mothers of term newborns. Preterm births were classified as preterm labor, preterm premature rupture of membranes and iathrogenic preterm. Independent associations between maternal sociodemographic, constitutional, nutritional and obstetric characteristics and preterm labor were identified using logistic regression analysis. RESULTS: In this sample of preterm births, 29% corresponded to preterm labor, 49% to preterm premature rupture of the membranes and 22% were iathrogenic preterm. The identified risk factors for preterm labor were multiple gestation, no paid work during pregnancy, less than six prenatal care visits, arm circumference less than 26 cm and previous preterm or low birth-weight. Gestational bleeding during the first or third trimester was significantly associated with preterm labor. CONCLUSIONS: As previously recognized, multiple gestation, prior preterm or low birthweight and gestational bleeding are established risk factors for preterm labor. However, prenatal care, maternal work and nutritional status have also been revealed as important issues in preterm risk, deserving special interest since they are susceptible to preventive intervention.

Adult↗

[Delivery of large baby after cesarean section: role of trial of labor. Apropos of 355 cases].

OBJECTIVE: Our goal is to determine whether a trial of labor in women with suspected fetal macrosomia would be a valuable alternative to elective repeat cesarean. MATERIAL: and methods: Based on retrospective analysis of 355 women with previous cesarean section who delivered macrosomic infants (> or =4,000g), we tried to determine the impact of fetal weight on a trial of labor. The outcomes of trial of labor with fetal macrosomia were compared on the one hand to those of elective repeat cesarean and on the other hand to those of trial of labor with normal birth weight (<4,000g). RESULTS: The trial of labor was conducted in 297 cases (83,7%), and had led to vaginal birth in 189 cases (63,6%). There were 4 uterine ruptures (1,3%) and 8 uterine dehiscences (2,7%) among the women who underwent a trial of labor. In this group, there were 4 perinatal deaths (1,3%) related in one case to uterine rupture, and 2 brachial plexus injuries related to shoulder dystocia after vaginal birth. Perinatal and maternal outcomes of trial of labor were similar to those of elective repeat cesarean. A trial of labor was more associated with scar separations and lower success rate if the infant weighed 4,000g or more. CONCLUSIONS: It appears that the use of trial of labor for delivery of large baby with prior cesarean section was associated with lower success rate and the maternal and fetal risks could be increased. However, carefully others controlled studies are necessary to establish the appropriate management in this setting.

Birth Injuries↗

Induction of labor.

The goal of induction of labor is to achieve vaginal delivery by stimulating uterine contractions before the spontaneous onset of labor. According to the National Center for Health Statistics, the overall rate of induction of labor in the United States has increased from 90 per 1,000 live births in 1989 to 184 per 1,000 live births in 1997 (I). Generally, induction of labor has merit as a therapeutic option when the benefits of expeditious delivery outweigh the risks of continuing the pregnancy. The benefits of labor induction must be weighed against the potential maternal or fetal risks associated with this procedure. The purpose of this bulletin is to review current methods for cervical ripening and induction of labor and to summarize the effectiveness of these approaches based on appropriately conducted outcomes-based research. These practice guidelines classify the indications for and contraindications to induction of labor, describe the various agents used for cervical ripening, cite methods used to induce labor, and outline the requirements for the safe clinical use of the various methods of inducing labor.

Female↗

[Patient's preferences concerning the course of labor].

OBJECTIVE: Much concern is being focused on the improvement of perinatal care standards in recent time. Not only the safety of woman and newborn, but also the comfort and individual preferences should to be considered. The aim of this study was to assess of expectations and requirements of the delivering women in relation to the course of labor and usage of the most common procedures in clinical practice. MATERIAL AND METHODS: 47 women who delivered in Obstetrical Word in Puck were questionnaire. Mean gestational age was 39 +/- 1.5 hbd. 47% of women were nulliparous, 53% were multiparous. The following variables were analyzed: the presence of medical staff and family at delivery, possibility of the delivery position choice, use of auxiliary devices, a friendly atmosphere during delivery, use of analgesia and labor induction, episiotomy and ante-partum preparation, cesarean section on request, attendance to labor school. Mann-Whitney, Pearson and Yule tests were used for statistical analysis. RESULTS: 25% of women, mainly younger gravidae, attended the labor school. The midwife was considered the most important person at delivery. The presence of family member(s) was important for highly-educated women. The possibility to choose the delivery position and to walk during the 1st stage of labor was important for 73% of respondents. The majority of women who had attended the labor school avoided the horizontal position. Over 60% of patients accepted the usage of labor induction. A vast majority of women were against antepartum perineal shaving and episiotomy. Better-educated women preferred water delivery. 69% of the studied women would like to listen to the music at the delivery room. Cesarean section on request was supported by 11% of women. CONCLUSIONS: The tendency to promote modern delivery methods and active participation in labor leading is noticed. The significant influence of labor school on women's knowledge and their preferences was found.

Adolescent↗

Maternal serum interleukin-6, interleukin-8, tumor necrosis factor-alpha and interferon-gamma in preterm labor.

BACKGROUND: To find out whether preterm labor is associated with raised maternal serum concentrations of interleukin (IL)-6, IL-8, tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) and whether the measurement of these cytokines can be used to detect early intrauterine infection in preterm labor. METHODS: Cross-sectional study: 77 women in preterm labor, 47 controls of healthy preterm women not in labor and 19 women in term labor. The serum cytokines levels were measured by enzyme-linked immunosorbent assay (ELISA). The newborns of women who were in labor were followed up for evidence of infection. Differences between groups were tested using analysis of variance, Student's t-test and chi2-test. RESULTS: There was no significant difference in the concentration of all the cytokines measured between the different groups. No statistical difference was found in the concentration of the cytokines between women in preterm labor with ruptured membranes and those with intact membranes. There was also no difference found in the concentration of cytokines between women whose newborns had positive bacterial culture and those with negative culture. There was a positive correlation between the concentrations of IL-6, IL-8 and TNF-alpha. CONCLUSION: Serum levels of interleukin-6, interleukin-8 and tumor necrosis factor-alpha were not increased in preterm labor compared to normal control women. There is doubt regarding the usefulness of maternal serum measurement of these cytokines for the detection of early fetal infection in preterm labor, but this needs further evaluation.

Adolescent↗

Amniotic fluid interleukin-1 in spontaneous labor at term.

The regulatory signals responsible for the increased biosynthesis of prostaglandins during parturition have not been established. Interleukin-1 (IL-1) is capable of stimulating prostaglandin production by intrauterine tissues and is an inflammation mediator. It has been postulated as a signal for the onset of labor in the setting of intrauterine infection. A study was designed to determine if spontaneous labor at term was associated with changes in IL-1 activity in amniotic fluid. Such fluid was retrieved from 41 women in labor and from 39 women who were not in labor at term. Immunodetectable IL-1 beta was present in 22 of the 41 women in labor but in only 8 of the 39 women without labor. IL-1-like bioactivity was not different between the two groups at a dilution of 1:4, but at dilutions of 1:12, 1:36 and 1:108, amniotic fluid from women in labor had significantly higher bioactivity than that from women not in labor. A significant correlation was found between the bioassay and immunoassay results. Our data show that inhibitors of IL-1 bioactivity are present in amniotic fluid and suggest that in a subset of laboring women at term, an inflammatory reaction may play a role in triggering the onset of parturition.

Amniotic Fluid↗

The relationship of maternal prenatal development to progress in labor and fetal-newborn health.

A study of 32 normal married primigravidas was conducted to determine the relationships among maternal psychological and physiological variables, subsequent progress in labor, and the health status of the fetus and neonate. At the onset of phase 2 of labor (3 cm of cervical dilatation), self-reported anxiety and endogenous plasma epinephrine were significantly correlated. With the deletion of subjects to control for the effect of medications, higher epinephrine levels were significantly associated with lower uterine contractile activity at the onset of phase 2 and with longer labor in phase 2 (3-10 cm of cervical dilatation). Psychological variables measured in pregnancy correlated significantly with the variables measured at the onset of phase 2 labor. Conflict concerning the acceptance of pregnancy showed the most significant relationships to the phase 2 labor variables, with correlations of 0.39 for anxiety, 0.59 for plasma epinephrine, -0.70 and -0.52 for the two adjacent Montevideo units, and 0.58 for duration of labor in phase 2. Conflict regarding the acceptance of pregnancy also correlated significantly with the newborns' 5 minute Apgar scores. Anxiety in labor and plasma epinephrine were significantly correlated with the fetal heart rate pattern during phase 2 of active labor. The fetal heart rate pattern was significantly correlated with newborns' Apgar scores at 1 and 5 minutes. The results of this study support the following hypotheses: conflicts in pregnancy are predictive of maternal anxiety and stress-related biochemical factors, and these variables are related to prolonged labor and to fetal-newborn depression.

Adult↗