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At least 307 records · Page 17Linked to original sources
PubMed1999

Predictors of cesarean delivery after prelabor rupture of membranes at term.

OBJECTIVE: To identify the significant predictors of cesarean delivery after prelabor rupture of membranes (PROM) at term. METHODS: In a multicenter study involving 72 institutions in six countries, 5041 women were randomized to induction of labor with oxytocin or prostaglandins or to expectant management. We did univariate and multivariate logistic regression analyses to determine the statistically significant independent predictors of cesarean delivery (P < .05). RESULTS: The following variables were found to be significantly associated with cesarean delivery: delivery in Israel, versus Canada (odds ratio [OR] 0.34); delivery in Australia, versus Canada (OR 1.93); nulliparity (OR 2.81); labor lasting more than 12 hours, versus less than 6 hours (OR 2.78); labor lasting 6-12 hours, versus less than 6 hours (OR 1.66); previous cesarean delivery (OR 2.75); epidural anesthesia (OR 2.66); clinical chorioamnionitis (OR 2.42); internal fetal heart rate monitoring (OR 2.19); birth weight of at least 4000 g (OR 2.07); use of oxytocin (OR 1.97); maternal age of at least 35 years (OR 1.44); latent period of at least 12 hours (OR 1.41); and meconium staining (OR 1.41). CONCLUSION: Strong predictors of cesarean delivery after PROM at term were country of birth, nulliparity, long labor, previous cesarean delivery, and epidural anesthesia.

Adult↗
PubMed1979

Serum levels of progesterone, 5 alpha-dihydroprogesterone and hydroxy-5 alpha-pregnanones in the prepartum and postpartum equine.

Blood samples were collected from eight mares for ten days before and two days following parturition. Progesterone, 5 alpha-dihydroprogesterone and hydroxy-5 alpha-pregnanones were extracted from serum, separated by Sephadex LH-20 column chromatography and quantitated by radioimmunoassay. Progesterone levels ranged from 8.5 to 4.1 ng/ml among mares with normal parturition and decreased to 1.2 ng/ml after parturition. One mare with a retained placenta maintained the prepartal levels of progesterone into the postpartum period. 5 alpha-dihydroprogesterone increased to a level of 133 ng/ml at 80 hrs before parturition and began decreasing and reached a level of 9.2 ng/ml in the postpartum period. Levels of hydroxy-5 alpha-pregnanones were variable with a high of 1690 ng/ml and declined to a postpartum level of 60 ng/ml. The timing of the decline varied among the mares. The possible source and significance of these progestins remain speculative.

20-alpha-Dihydroprogesterone↗
PubMed2001

Transcriptional regulation of prostaglandin-H-synthase-1 in the amnion-derived AV3 cell line.

Prostaglandin-H-synthase-1 (PGHS-1), while constitutively expressed in most tissues, increases in abundance in human gestational membranes at term. This suggests that PGHS-1 may be up-regulated in preparation for labor, and thus might be a key determinant in timing labor onset. We conducted transient transfection experiments in amnion-derived AV3 cells utilizing pPGHS1CAT to identify substances that might regulate PGHS-1 expression in amnion. Transforming growth factor-beta (1 ng/ml) and 15-deoxy-delta(12,14) prostaglandin J2 (1 microM) significantly (P < 0.05) (33% and 44% respectively) increased PGHS-1 promoter activity. The activity decreased significantly (P < 0.05) in response to interleukin-1 (IL-1)beta (1 ng/ml) (45%), tumor necrosis factor (TNF)-alpha (50 ng/ml) (34%), epidermal growth factor (10 ng/ml) (54%), phorbol myristate acetate (10 nM) (70%), IL-4 (10 ng/ml) (50%), IL-8 (100 ng/ml) (72%) and Activin A (25 ng/ml) (32%). Whether this degree of change in promoter activity leads to physiologically relevant alterations in the amounts of PGHS-1 present in cells remains to be determined.

Amnion↗
PubMed1975

Induction of term labor with intravenous prostaglandin F2alpha (a comparison of two dosage schedules).

The efficacy of intravenous Prostaglandin F2alpha (PGF2alpha) infusion for induction of labor in two different dosage schedules was studied in 90 women between 36 and 43 weeks of gestation. The rate of PGF2alpha infusion was increased at four-hour intervals in 36 women in the low dosage group and every hour in 54 women in the high dosage group, never exceeding an infusion rate of 20 mug/min. in either group. Labor was successfully induced in approximately 90% of the patients in each group. There was no statistically significant difference in the mean induction-delivery interval between the two groups at the 5 percent level. Intravenous PGF2alpha was found to be effective and safe for both mother and infant in the dosage schedules used in this study for induction of labor.

Adolescent↗
PubMed1976

Mechanism for increased production of prostaglandins in labour.

It is proposed that uterine hypoxia, beginning initially with the uterine contractions in late pregnancy, leads to the increased formation of free fatty acids. The liberated fatty acids are then used to form prostaglandins and they can also act on mitochondria to release calcium. The released calcium can directly activate contractile proteins and/or can further stimulate phospholipase A (active at neutral pH) and thereby reinforce the progressive production of prostaglandins.

Calcium↗
PubMed1998

Production of prostanoids via increased cyclo-oxygenase-2 expression in human amnion cells in response to low molecular weight hyaluronic acid fragment.

Increased concentrations of hyaluronic acid (HA) have been found in serum and at uterine cervix at term. In its native form, HA exists as a high molecular weight (MW) polymer, but during parturition a lower MW HA fragment accumulates. The aim of this study was to investigate the regulatory mechanisms responsible for increased amnion prostanoid production and cyclo-oxygenase (COX) expression in response to HA. Human term amnion cells in culture were exposed to native HA polymer (MW 2.2x106) and its fragment (MW 3.5x104). We have determined levels of prostanoids, prostaglandins E2 and F2alpha, in conditioned media using specific immunoassays. Expression of COX-1 and COX-2 was examined with Western blot. Results were analyzed for statistical significance with Mann-Whitney U-test. Human amnion cells treated with HA fragment (100 nmol/l) produced significantly more PGE2 (2.3+/-0.21 (mean+/-S.D.) pg/106 cells/24 h) than controls (0.34+/-0.03) or high MW HA-treated cells (1.2+/-0.21). Protein levels of COX-2, but not COX-1, were substantially increased in amnion cells treated with HA fragment. HA fragment-mediated prostanoid production is markedly diminished by pretreatment with indomethacin. Our results indicate that HA fragment, rather than physiologic native HA polymer, induces amnion cell-derived prostanoid production via increased COX-2 expression. COX-2-mediated prostanoid production is likely a key physiologic event in HA fragment-mediated cervical ripening and the labor onset.

Amnion↗
PubMed2000

The onset of human labor: current theories.

Innovative research has led to marked improvement in medical knowledge. Advances in technology have allowed us to attain a clearer understanding of many physiologic processes. Despite these impressive gains in knowledge, the cause of the initiation of the process of human labor remains unclear. Potential factors include changes in hormonal levels of estrogen and progesterone, increased production of prostaglandins, and elevation of levels of corticotropin-releasing hormone, as well as increased sensitivity of the myometrium to endogenous oxytocin. It is most likely that interactions between these factors play an essential role in the process of labor, but the precise mechanism of onset still eludes us.

Journal Article↗
PubMedDate not supplied

Am I in labor?

Explore the source record for details and available documents.

Adult↗
PubMed2000

Prenatal depiction of angioarchitecture of an aneurysm of the vein of Galen with three-dimensional color power angiography.

A fetus with a large supratentorial cyst and cardiomegaly was encountered at 33 weeks of gestation. The cyst appeared as an aneurysmal, fluid-filled structure extending posteriorly with a finger-like appendage. Using color flow mapping, we disclosed rapid in-and-out blood flow with marked turbulence within the cyst. For evaluation of its blood supply and venous drainage of the vascular malformation, a three-dimensional reconstruction of the power Doppler image was conducted. The results revealed that the vascular malformation was supplied by a small contralateral aneurysm from the branches of Willis' circle, draining posteriorly into an abnormal falcine sinus and then into the superior sagittal sinus. No other fetal abnormality such as hydrocephalus or hydrops was discovered. The prenatal diagnosis of an aneurysm of the vein of Galen was made on the basis of the gray-scale, color Doppler findings, and also the angioarchitecture obtained by three-dimensional power Doppler imaging. The woman was admitted at 37 weeks of gestation due to labor onset and delivered the baby via the vaginal route without complication. Postnatal angiography and magnetic resonance imaging confirmed the diagnosis of an aneurysm of the vein of Galen, and the angioarchitecture depicted it before birth. We suggest that three-dimensional power Doppler ultrasonography may assist in the diagnosis of an aneurysm of the vein of Galen, and precisely delineate the complicated corresponding vasculature. This may guide postnatal management and predict the prognosis more accurately.

Adult↗
PubMed1989

Phospholipases in the control of human parturition.

Prostaglandins play a key role in human labor in that prostaglandins can cause abortion or labor and prostaglandin antagonists can inhibit preterm labor. However, the factors determining prostaglandin synthesis and release in human pregnancy are uncertain. An increase in the synthesis of prostaglandins at the start of labor could result from either increased release of free arachidonic acid or removal of constraint on prostaglandin H synthase activity, or both. The points in the biosynthetic pathway of prostaglandins at which control could be exerted physiologically are examined, with emphasis on the phospholipases.

Annexins↗
PubMed1989

Influence of premature rupture of membranes on induction of labor and plasma 13,14-dihydro-15-keto-prostaglandin F2 alpha and oxytocin levels in patients with unripe cervix.

Rupture of membranes at term, whether spontaneous or artificial, causes rapid and sustained increase in prostaglandin F2 alpha (PGF2 alpha) metabolite (PGFM) levels and is associated with augmentation of uterine contractions. To investigate why premature rupture of membranes (PROM) often fails to initiate uterine contractions, we measured plasma concentrations of PGFM and oxytocin (OT) in patients with PROM near term. Serial blood samples were taken before and after PROM as well as before and after local PGE2 gel application for cervical ripening. For comparison, patients with similar criteria with intact membranes were also studied, as were patients in spontaneous labor at term with and without spontaneous rupture of membranes. PROM was always associated with an initial, marked increase in plasma PGFM. Whether or not this increased PGF2 alpha production was maintained was related to the cervical status at the time of PROM. In patients with unripe cervix PGFM levels returned to initial levels within 2 hours and no contractions were elicited; when the cervix was 3 cm or more dilated, PGFM levels remained high and contractions began within 1 to 3 hours. PROM had no significant effect on plasma OT levels. When PGE2 gel was applied to ripen the cervix, PGFM levels increased moderately within 30 minutes in all patients regardless of the status of the membranes. In patients with intact membranes the concentration of PGFM in plasma declined to initial levels within 4 hours, whereas in patients with PROM, PGFM levels remained increased throughout the study period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1980

Early detection of abnormal labor using the Friedman labor graph.

Early recognition and appropriate management of abnormal labor can reduce perinatal mortality and morbidity and lower the cesarean section rate. A simple labor graph devised over 25 years ago and later modified makes labor abnormalities easy to detect; the two main divisions of labor, the latent and active phases, are easily recognized. A prolonged latent phase has no serious effects on mother or fetus, but protraction and arrest disorders of the active phase--eg, protracted cervical dilatation, arrest or failure of descent of the presenting part--may have a deleterious effect. Common causes of a prolonged latent phase include false labor and inappropriate use of analgesia and anesthesia. Fetopelvic disproportion and fetal malposition are common causes of disorders of the active phase.

Adolescent↗
PubMed2003

Electrical impedance measurements: an objective measure of prelabor cervical change.

OBJECTIVE: To investigate the use of electrical impedance measurements of the pregnant cervix as an objective measure of cervical favorability (Bishop score > or = 5). METHODS: A prospective study of 86 women, investigating electrical impedance measurements of the pregnant cervix at the time of induction of labor. Transfer electrical impedance measurements were made by placing a tetrapolar pencil probe of 8 mm in diameter on the surface of the cervix. A Bishop score was determined simultaneously. RESULTS: A mean resistivity (standard error of the mean) of 7.03 (6.01-8.04) omega(m) was measured for the unfavorable group and 5.34 (4.61-6.07) omega(m) for the favorable group. This was a statistically significant difference (p = 0.016). CONCLUSION: We highlight the ability of this safe, painless technique to differentiate the favorable from the unfavorable cervix at induction of labor.

Adolescent↗
PubMed2001

A comparison of intermittent vaginal administration of two different doses of misoprostol suppositories with continuous dinoprostone for cervical ripening and labor induction.

PURPOSE: To compare the efficacy of a vaginal insert administering continuous dinoprostone with vaginal suppositories containing two different doses of misoprostol for cervical ripening and induction of labor. STUDY DESIGN: In this prospective, randomized, double-blinded study, 118 patients with indications for induction of labor and an unfavorable Bishop score were randomly assigned to receive either continuous dinoprostone, misoprostol 35-microg suppositories, or misoprostol 50-microg suppositories. RESULTS: No significant differences were noted among the three groups in the change of Bishop score, induction of active labor or the time from initial treatment to delivery. Active labor occurred in roughly two-thirds of the patients in an average of about 5.7-6.7 h regardless of treatment assignment. When the two misoprostol groups were combined, a shorter interval from insertion to vaginal delivery was observed in the nulliparous women receiving misoprostol than those receiving continuous dinoprostone (21.3 vs. 27.2 h, p = 0.019). Except for the significantly lower incidence of tachysystole observed in the combined misoprostol group (3.8% vs. 15.4%, p = 0.036), there were no other significant differences between the groups in mode of delivery or in adverse maternal, fetal, or neonatal effects. CONCLUSION: Misoprostol suppositories appeared to be as effective and safe as continuous dinoprostone in inducing cervical ripening in this sample.

Administration, Intravaginal↗
PubMed2004

Actigraphic recordings of activity-rest rhythms of neonates born by different delivery modes.

Activity-rest behavior of 20 neonates born vaginally, 18 neonates born by medically planned Cesarean section (C-section), and 19 neonates born by medically required C-section after labor onset (all born in the thirty-seventh to forty-second week of gestation) was monitored for six successive days starting in the first week of life. Actigraphy was used to record and show time patterns of activity and rest in neonates by using small wristwatch-like Actiwatch actometers. Nursing/feeding times were recorded by using the actometers' integrated event marker button. Recordings in both C-section groups were performed in the hospital; for neonates born vaginally and for some born by C-section, recordings were carried out in the hospital and in their homes. In addition to the actigraphic recordings, a standardized diary was kept regularly. To assess periodic characteristics, frequency components of activity-rest behavior were analyzed using fast Fourier transformation. Amount of sleep time during daytime, nighttime, and 24 h, as well as sleep bouts during the daytime and nighttime, were compared. The majority of vaginally born neonates showed a distinct circadian frequency in their spectra. In contrast, both groups of neonates born by C-section showed significantly less distinct circadian frequencies in their spectra. All three groups showed a significant difference in amount of nighttime sleep vs. daytime sleep, with more sleep at nighttime. There were no differences in the amount of nighttime sleep, daytime sleep, and sleep time during 24 h between the groups born by different delivery modes.

Activity Cycles↗
PubMed1999

Virus levels in untreated African infants infected with human immunodeficiency virus type 1.

In developed areas, human immunodeficiency virus (HIV)-infected infants have high virus levels and rapidly progress to death. HIV levels were assessed in 1994-1997 in untreated infants in Malawi by analysis of dried blood spots tested by nucleic acid silica-bound amplification. Of 24 umbilical cord blood (CB)-positive samples, 83% had >10,000 copies/mL. The median virus level was 78,000 copies/mL. First positive sample median levels were 355,000 copies/mL among 52 perinatally infected infants and 130,000 copies/mL among 43 infants infected by breast-feeding. Virus levels were stable, and initial levels predicted levels 1 year after infection (P=.005), at which time levels did not significantly differ among in utero, perinatally, or postnatally infected infants. Thus, neither age at infection nor route of infection significantly influenced HIV levels measured 1 year after infection. Most (87%) CB-positive infants were infected before labor onset, since virus levels greatly exceeded those expected in their mothers.

Adult↗