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PubMed2002

Circulating erythroblasts in maternal blood are not elevated before onset of preterm labor.

OBJECTIVE: Preterm labor has recently been reported to be associated with an increased release of cell free fetal deoxyribonucleic acid (DNA) into the maternal circulation. We have previously observed increases in both fetal cell traffic and cell free fetal DNA in preeclamptic pregnancies. In this study, we investigated whether fetal cell traffic is also disturbed in pregnancies with preterm labor. METHODS: In a case-control study, we examined 47 pregnancies complicated by preterm contractions that occurred between 20 and 34 weeks' gestation and an equal number of matched controls. Erythroblasts were enriched for by magnetic cell sorting and enumerated. These values were then correlated with subsequent pregnancy outcome. RESULTS: In the study group 16 patients delivered prematurely (subgroup A). The other 31 (subgroup B) delivered at term, as did all those in the control group. No significant difference was noted in erythroblast numbers between either one of the subgroups and the controls. CONCLUSION: Contrary to the reported increased levels of free fetal DNA in maternal serum, erythroblasts in maternal blood are not elevated significantly in pregnancies with threatened premature labor or in those that deliver preterm.

Abortion, Threatened↗
PubMed1999

Delay of preterm delivery in sheep by omega-3 long-chain polyunsaturates.

A positive correlation has been shown between dietary intake of long-chain omega-3 fatty acids in late pregnancy and gestation length in pregnant women and experimental animals. To determine whether omega-3 fatty acids have an effect on preterm labor in sheep, a fish oil concentrate emulsion was continuously infused to six pregnant ewes from 124 days gestational age. At 125 days, betamethasone was administered to the fetus to produce preterm labor. Both the onset of labor and the time of delivery were delayed by the fish oil emulsion. Two of the omega-3-infused ewes reverted from contractions to nonlabor, an effect never previously observed for experimental glucocorticoid-induced preterm labor in sheep. Maternal plasma estradiol and maternal and fetal prostaglandin E2 rose in control ewes but not in those infused with omega-3 fatty acid. The ability of omega-3 fatty acids to delay premature delivery in sheep indicates their possible use as tocolytics in humans. Premature labor is the major cause of neonatal death and long-term disability, and these studies present information that may lead to a novel therapeutic regimen for the prevention of preterm delivery in human pregnancy.

Adrenocorticotropic Hormone↗
PubMed2006

Hypothetical role of prostaglandins in the onset of preterm labor after fetal surgery.

Preterm labor is one of the most important factors limiting the advancement of fetal surgery programs. While prostaglandins (PGs) have long been indicated as the key factor in the initiation of labor in humans, there is significant evidence showing that the chorionic membrane acts as a powerful barrier between the decidua/myometrium and amniotic PGs during normal pregnancy. After either open or endoscopic fetal surgery the imperfect, non-hermetical closure of the chorion permits leakage of PGs from the amnionic sac, allowing them to reach the decidua and myometrium. The surgical wound in the chorionic barrier could be the major factor involved in preterm labor and delivery after human fetal surgery.

Amniotic Fluid↗
PubMed1996

Immunmodulating cytokines induce term and preterm parturition.

The aim of our study was to investigate if cytokines, which are able to cause preterm delivery is case of intraamniotic infection, also participate in the mechanisms of normal term labor. Therefore we estimated cytokine concentrations in cercicovaginal secretions of 96 patients, divided into four different collectives. In collective A (women with spontaneous term labor) cytokine concentrations raised from a median level of 278 pg/ml for Il-1 beta and 263 pg/ml for Il-6 in early term labor to a median level of 3351 pg/ml for Il-1 beta and 39,442 pg/ml for Il-6 at complete cervical dilatation. TNF-alpha-exclusively appeared after spontaneous rupture of fetal membranes. In collective B and C (women with preterm rupture of fetal membranes) cytokine concentrations declined from a maximum level of 1425 pg/ml for TNF-alpha, 12,982 pg/ml for Il-1 beta and 29,727 pg/ml for Il-6 soon after preterm rupture of membranes to a minimum level of 93 pg/ml for TNF-alpha, 851 pg/ml for Il-1 beta and 780 pg/ml for Il-6 with remission of labor in case of successful tocolytic treatment. High concentrations reappeared with the onset of labor, unresponsive to tocolysis. In collective D (women with intact membranes) TNF-alpha was not detectable and Il-1 beta and II-6 appeared exclusively in the presence of labor. Our results suggest, that normal term labor may be controlled by biochemical processes, similar to infection-associated signal transduction, which is commonly accepted to induce preterm labor.

Cervix Uteri↗
PubMed2001

[Epidural analgesia and the rate of cesarean delivery].

OBJECTIVES: To assess the influence of epidural analgesia on the increased rate of cesarean delivery and to analyze associated factors. PATIENTS AND METHOD: Prospective study enrolling 1,714 women in labor to whom epidural analgesia was offered; 719 received epidural analgesia and 995 did not. We recorded age, weight, height, parity, gestational age, duration of labor, manner of onset of labor, delivery, birth weight, Apgar score and pH in the umbilical artery and vein. Student t, Hotteling's t2 and chi-squared tests were used to compare the results. Multiple logical regression analysis was used to determine the variable or variables having the most effect on the rate of cesarean delivery. RESULTS: Labor lasted longer in the group of women who received epidural analgesia than in those who did not (234 +/- 90 versus 181 +/- 43 minutes) and the epidural group had significantly higher rates of induced labor (50% versus 15%), instrument-assisted delivery (19% versus 5%) and cesarean delivery (21% versus 8%). Cesarean sections were more frequent among women whose labor was induced and in nulliparous women in both groups. Logical regression analysis showed that epidural analgesia was the most significant variable affecting delivery by cesarean section. The next most influential variable was induction of labor. Parity was not significantly related to delivery by cesarean. CONCLUSIONS: Epidural analgesia increased the likelihood of cesarean delivery in our study. The same factors that most often encourage women to accept epidural analgesia (induced labor, greater pain, prolonged labor, etc.) may predict increased likelihood of cesarean delivery.

Adult↗
PubMed1981

Initiation of human parturition. XII. Biosynthesis and metabolism of prostaglandins in human fetal membranes and uterine decidua.

Prostaglandin synthetase activity was assayed in homogenates prepared from human fetal membranes and uterine decidua tissues with [14C] arachidonic acid used as substrate. In amnion, chorion laeve, and decidua vera tissues obtained after the spontaneous onset of labor and vaginal delivery the mean specific activities of prostaglandin synthetase were respectively 1.47, 0.53, and 0.39 nmoles x hr-1 x gm-1 tissue; in these same tissues obtained at elective cesarean section before the onset of labor the mean specific activities of prostaglandin synthetase were respectively 0.61, 0.33, and 0.28. The specific activity of prostaglandin synthetase of amnion (but not chorion laeve or decidua vera) was significantly greater in samples obtained after labor than in those obtained before labor (p less than 0.02). Prostaglandin synthesis in amnion, chorion laeve, and decidua vera was inhibited by acetylsalicylic acid and by indomethacin. Prostaglandin E2 was formed in amnion and chorion laeve, whereas prostaglandin E2 and prostaglandin F2 alpha were formed in decidua vera. The activity of NAD+ -dependent 15-hydroxyprostaglandin dehydrogenase was also assayed and the specific activities of this enzyme in chorion laeve and decidua vera tissues obtained before and after labor were high, whereas 15-hydroxyprostaglandin dehydrogenase activity in amnion was low.

Amnion↗
PubMedDate not supplied

Induction of labor in patients with term premature rupture of membranes. Effect on perinatal outcome.

OBJECTIVE: To determine whether delayed induction of labor in patients with premature rupture of membranes (PROM) at term has beneficial effects on the mother or the infant. STUDY DESIGN: Retrospective analysis of our database revealed 576 patients >37 weeks of gestation with PROM, who delivered live-born infants without major congenital anomalies. We analyzed the frequencies of primary cesarean, neonatal intensive care unit (NICU) admissions, and oxytocin use by time since hospital admission and interval until onset of labor. RESULTS: NICU admission increased from 1.9% in <3 h between admission to onset of labor to 13.3% after >18 h. Admission-onset of labor interval, birth weight of <2,500 or >4,000 g and meconium were all more important determinants of NICU admission than gestational age, duration of labor, PROM, and ROM. Prolonged admission-onset of labor interval was associated with an increased risk of variable decelerations (p < 0.001). Primary cesarean rates increased progressively with longer intervals between admission and onset of labor. Stepwise discriminant function analysis revealed that labor duration, admission-onset of labor interval, gestational age, and birth weight of <2,500 g were all more important determinants of primary cesarean delivery than the durations of PROM or ROM. CONCLUSIONS: The increased frequencies of NICU admission, variable decelerations, and primary cesarean suggest that delayed labor induction after hospital admission was linked to worsened perinatal outcomes. These results may have been influenced by usually performing a single digital examination as part of initial evaluation of term patients who present with PROM. Based on our data, we suggest immediate induction for PROM at term, especially if digital examination has been performed.

Adult↗
PubMed1990

Oxytocin receptor in human fetal membranes at term and during labor.

Human fetal membranes, taken from 30 patients submitted to caesarean section during the final stages of gestation and labor, were examined in order to evaluate the presence and characteristics of the oxytocin receptor. The presence of oxytocin receptors in human fetal membranes, both in the amnion and in the chorion-decidua, was demonstrated in this study. The receptor binding to oxytocin showed a significant increase during early and advanced labor compared with before the onset of labor. When the pre-labor level was taken as the normalized form (control = 100) the increase with respect to the control (10 cases) for the amnion in early labor (2.27 times +/- 0.11, mean +/- SEM, P less than 0.001, 10 cases) and in advanced labor (2.53 times +/- 0.15, 10 cases, P less than 0.001) was highly significant. In the chorion-decidua the increase was 1.61 times +/- 0.09, P less than 0.001 in early labor and 1.66 times +/- 0.19, P less than 0.001 in advanced labor. Scatchard analysis showed a single receptor site for oxytocin in amnion and chorion decidua. The dissociation constant (Kd) did not change during the various stages of labor; the mean values found were 0.228 +/- 0.02 (mean +/- SEM) nM in the amnion and 0.193 +/- 0.03 nM in the chorion-decidua respectively. These findings suggest that human fetal membranes are target organs for oxytocin and that they might play a role in the onset of labor through an increase of receptor binding.

Amnion↗
PubMedDate not supplied

Station in early labor in nulliparous women at term.

Several authors of standard obstetric texts state that engagement occurs before the onset of labor in a majority of nulliparas at term, and failure of the fetal head to engage in early labor is a greater indicator for operative birth. A pilot clinical descriptive study was done at University Hospital, University of Medicine and Dentistry of New Jersey, in Newark to examine the birth outcomes of nulliparous women who arrived in early labor with an unengaged vertex presentation at term. For the study, 146 births were reviewed, and data from 101 vertex deliveries that met the study's criteria were compiled to test this hypothesis. The study results showed that in approximately 31% of the nulliparas, the fetal head was engaged. The incidence of the unengaged vertex in early labor in nulliparous women who met the study's criteria was found to be 69%. This factor alone did not predict birth outcome.

Adolescent↗
PubMed1997

C-reactive protein in uncomplicated parturients delivered by cesarean section.

BACKGROUND: The purpose of this study was to determine normal values and evaluate clinical variables associated with postoperative C-reactive protein serum concentration after uncomplicated abdominal delivery. METHODS: C-reactive protein serum concentrations were determined serially by a quantitative immunoturbidimetric assay in 479 clinically non-infected parturients undergoing uncomplicated Cesarean section, before operation and during the first week of puerperium. Associations between clinical variables and maximal postoperative C-reactive protein levels were examined by variance analysis. RESULTS: The preoperative values were significantly higher in parturients from whom samples were obtained after the onset of labor and/or rupture of the membranes (16 +/- 10 (s.d.) mg/l) compared with the preoperative values obtained from parturients operated with no labor and intact membranes (12 +/- 7 (s.d.) mg/l) (p < 0.0001). An overall significant increase was observed in C-reactive protein concentrations after delivery, peaking on the second postoperative day, compared with the preoperative values. In the parturients operated upon after the onset of labor or ruptured membranes, postoperative values were 24% higher up to the sixth postoperative day than in parturients operated upon with intact membranes and no labor. The onset of labor, duration of operation, the number of vaginal examinations and the duration of internal monitoring before operation were associated with the maximal postoperative C-reactive protein concentrations, but they explained only 9% of postoperative CRP level variation. CONCLUSIONS: The wide range of serum C-reactive protein concentrations during puerperium complicates its use as a simple marker in obstetric postoperative complications. However, after normal uncomplicated operative delivery, C-reactive protein concentrations rapidly decrease towards the baseline after the second to third postoperative day.

Adult↗
PubMed1984

[Changes in urinary adrenaline and noradrenaline and plasma cortisol concentrations during labor and delivery].

Urinary adrenaline and noradrenaline concentrations were determined at 38-41 wks of gestation, admission for the onset of labor, 4 hrs after admission and at the cervical dilatation of 8-10 cm, immediately after delivery and on the next morning. Both catecholamine concentrations rose remarkably at the dilatation of 8-10 cm and were found to be still high immediately after delivery. The rise in adrenaline concentrations was much greater than noradrenaline. On the morning after delivery, the adrenaline concentrations fell significantly but noradrenaline remained high. The time-course of urinary catecholamines was similar to that of plasma reported by others. Serum cortisol concentrations rose significantly during labor and delivery but returned to the concentrations of 38-41 wks of gestation by the next morning. The present time course of adrenaline, noradrenaline and cortisol levels in urine or serum during labor, delivery and puerperium suggests that these hypersecretion may be due to emotional, physical and painful stress, respectively, considering literatures.

Epinephrine↗
PubMedDate not supplied

Labor pain before elective cesarean section reduces neonatal respiratory distress.

Neonatal respiratory distress is a major complication of elective Cesarean section. To clarify the effect of preceding labor on the incidence of respiratory distress, we studied 45 term neonates who were born with labor and 85 term neonates who were born without labor. Transient tachypnea of the newborns accounted for the majority of respiratory distress in term neonates. Respiratory distress occurred less frequently in term neonates delivered after the onset of labor compared to those delivered before the onset of labor (11.1% vs. 31.8%, p < 0.002). Neonatal respiratory distress syndrome (RDS) occurred in 4 of 85 (4.7%) term neonates delivered before the onset of labor. In contrast, none of the 45 term neonates born after the onset of labor developed RDS (p = 0.02). Awaiting the onset of labor appears to be beneficial in preventing neonatal RDS for term neonates delivered by elective Cesarean section.

Adult↗