The effect of labor on olfactory exposure learning within the first postnatal hour.

Thirty-one neonates delivered by cesarean section were exposed to an odor for 30 min shortly after birth. Fifteen births had uterine labor contractions before delivery; 16 were without contractions. All babies were later tested (median age = 80 hr) for their responses to the familiar exposure odor and a novel odor presented on either side of the face. Overall, the babies spent more time turned toward the exposure odor than toward the novel scent. Babies in the labor condition, but not those born without labor, displayed a significant preference for the exposure odor. Norepinephrine (NE) levels were higher in babies who oriented preferentially toward the exposure odor. Brief exposure immediately after birth is sufficient for the development of olfactory learning. Heightened learning by neonates from births with contractions may reflect locus coeruleus and NE activation. Olfactory learning may therefore be particularly efficient shortly after birth. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vaginal birth after cesarean section in twin gestation

OBJECTIVE: We report a 10-year experience with vaginal birth after cesarean section in women with twins. STUDY DESIGN: Data were gathered from labor and delivery records and maternal and neonatal hospital charts. Women with a vertical uterine scar, a previous uterine rupture, an unrepaired dehiscence, or obstetric contraindications to labor were excluded from a trial of labor. Full-thickness uterine defects requiring intervention were classified as ruptures; all others were classified as dehiscences. RESULTS: Between Jan. 1, 1985, and Dec. 31, 1994, at Los Angeles County/University of Southern California Women's Hospital, 210 women with previous cesarean births were delivered of twins. One hundred eighteen (56%) underwent repeat cesarean delivery without a trial of labor. Ninety-two (44%) undertook a trial of labor with no uterine ruptures and no increase in maternal or perinatal morbidity or mortality. CONCLUSIONS: In women with twins a trial of labor after a previous cesarean section is a safe and effective alternative to routine repeat cesarean delivery.     

Trial of labor in patients with a previous lower uterine vertical cesarean section

OBJECTIVE: Our purpose was to determine the efficacy and safety of a trial of labor in patients previously delivered at least once by a lower uterine vertical cesarean section. STUDY DESIGN: A retrospective review was performed at a single tertiary perinatal center, The University of Florida Health Science Center, Jacksonville. The medical records of all patients with a previous low vertical cesarean section who underwent a trial of labor during a 72-month period from January 1988 until December 1993 were reviewed. The medical records of the next two patients who did not have a prior uterine incision admitted to labor and delivery after the index case served as the controls. The duration and outcome of labor, including mode of delivery, maternal and perinatal morbidity, and birth trauma were evaluated. RESULTS: Of 77 patients with a previous low vertical cesarean incision, 11 (14.3%) had a repeat operation compared with 14 of 154 patients (9.0%) in the no previous cesarean section group (not significant). No differences were noted in the incidences of operative vaginal deliveries or prolonged duration of the first or second stages of labor, or in the rate or maximum dose of oxytocin infusion between the two groups. One patient in the previous cesarean section group had uterine rupture. The incidence of umbilical artery pH < or = 7.20 was similar. No difference in the number of infants with 1- or 5-minute Apgar scores < or = 7 was noted. CONCLUSION: A trial of labor in women with previous low vertical cesarean sections results in an acceptable rate of vaginal delivery and appears safe for both mother and fetus.     

Lung hyaluronan and water content in preterm and term rabbit pups exposed to oxygen or air

Rabbit pups were delivered by cesarean section 1 or 2 d before term, or vaginally around term, and then reared in room air or exposed to intermittent or continuous hyperoxia (> 85%) for up to 9 d. Pups were killed at different ages, and lung hyaluronan (HA; microgram/g of dry lung weight) and lung water content, measured as wet/dry lung weight, were determined. Compared with the day of birth, the lung HA concentration did not change significantly on succeeding days in pups kept in air delivered 2 d (-2 d) or 1 d (-1 d) before term, whereas the water content decreased significantly. Continuous exposure to hyperoxia resulted in a significantly raised lung HA concentration 6 d postterm in both -2 d and -1 d pups, and intermittent exposure to hyperoxia resulted in a significantly raised HA concentration 6 d postterm in -1 d pups, compared with the groups exposed to room air. These increases were accompanied by significantly elevated wet/dry lung weight ratios. Microscopic examination revealed significantly increased HA staining scores in alveoli, arterioles, and bronchioli in both hyperoxia-exposed groups of -2 d pups 6 d postterm, and nonsignificantly higher scores in -1 d and vaginally delivered pups of comparable age, compared with the scores at birth. The results indicate that oxygen exposure neonatally may result in an increase in lung HA accompanied by an increase in lung water content. The increase in lung HA concentration in our study may be an effect of oxygen free radicals or of oxygen-induced stimulation of inflammatory mediators.     

Factors that influence route of delivery--active versus traditional labor management

OBJECTIVE: Our purpose was to compare maternal and fetal factors that influence the route of delivery with active management of labor and a traditional labor management protocol. STUDY DESIGN: Data were collected prospectively on 346 consecutive patients receiving active management of labor and 354 patients who were managed traditionally. Within each group demographic and labor characteristics of patients undergoing cesarean section were compared with those of patients having vaginal deliveries by means of the Student t test, chi 2 analysis, and stepwise logistic regression. RESULTS: With both active management of labor and traditional labor management success in achieving vaginal delivery was related to the station of the fetal vertex at admission, the need for oxytocin augmentation of labor, the uterine response to oxytocin, the use of epidural anesthesia, and the development of chorioamnionitis. By means of multiple logistic regression analysis maternal age, height, payor status, and birth weight were also identified as risk factors for cesarean section with traditional labor management but not with active management of labor. CONCLUSIONS: Differences were identified in risk factors for cesarean section between active management and traditional labor management. Active management of labor may diminish or eliminate some patient characteristics as risk factors for cesarean birth.     

Effects of 5-HT3 receptor agonists on voluntary ethanol intake in rats maintained on a limited access procedure

Catecholamines are a class of neurotransmitters involved in central nervous system autonomic control. Both acute and chronic hypoxia create alterations in ventilation and blood pressure via catecholamine release, although the mechanisms of these alterations are unknown. The enzymes tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT) catalyze the rate-limiting step in the catecholamine pathway and production of epinephrine, respectively. Both have been colocalized with Fos protein in metabolic mapping studies of the O2-chemosensory pathway of adult and early postnatal rat. Thus, catecholamines are putative neurotransmitters in a subset of second and higher order respiratory neurons. To characterize the effects of prenatal hypoxia on subsequent TH and PNMT gene and protein expression, pregnant rats were placed in moderate hypoxia (10% O2) from gestational d 18 until birth. Northern and Western analyses of dorsal (catecholaminergic/adrenergic cell group 2) and ventral (catecholaminergic/adrenergic cell group 1) medullary tissue of postnatal (P) age P0, P3, P7, P10, and P14 pups were then done to examine changes in TH and PNMT mRNA and protein compared with normoxia-reared controls. Compared with controls, pups exposed to maternal hypoxia during pregnancy had lower levels of TH mRNA and protein at birth in dorsal medulla and higher levels of TH mRNA the first postnatal week in the ventral medulla. Pups that had been hypoxic in utero showed significantly lower levels of PNMT protein during the second postnatal week in dorsal medulla than did controls. Prenatal hypoxia-induced changes in levels of enzymes responsible for catecholamine synthesis may later be manifest as developmental deficiencies in neuronal function. This may compromise responses to acute hypoxic challenges during early postnatal life and contribute to autonomic nervous system disorders of the newborn such as apnea and sudden infant death syndrome.     

Maternal contributions to sensory experience in the fetal and newborn rat (Rattus norvegicus).

Using videographic analyses, maternal contributions to the sensory environment of the perinatal rat were identified and quantified by analyzing, from the offspring's perspective, the dam's activities during gestation, labor, and delivery. The observations indicate that pregnant females remain highly active during the final week of gestation, as compared with nonpregnant control animals. Exploratory movements, feeding, drinking, self-grooming, and other activities of the rat dam pitch, turn, accelerate, and expose fetuses to mechanical pressures. During parturition uterine contractions and maternal licking and handling provide vigorous tactile and vestibular stimuli to pups. Newly born pups are exposed to intense thermal stimulation, cooling rapidly to the temperature of the postnatal environment. Results suggest that fetal and newborn rats are exposed during development to a broad range of maternally produced stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cesarean birth: how to reduce the rate

The cesarean section rate, which approached 25%, has stabilized and started a modest decline. A stated United States national goal by the year 2000 is a rate of 15%. Suggested rates are 12% for primary and 3% for repeat cesarean sections. The major indications for cesarean section are prior cesarean delivery (8%), dystocia (7%), breech presentation (4%), fetal distress (2% to 3%), and others. The major areas of reduction must occur in the categories of prior cesarean delivery and dystocia. An expanded use of trial of labor and vaginal birth after a prior cesarean section will produce further reductions. Countries in Europe achieve > 50% vaginal birth after a prior cesarean section compared with 25% in the United States. A heightened awareness must occur regarding the decision to perform the first cesarean section. The residual impact, a scarred uterus, affects 12% to 14% of women seen for delivery. Even if 50% achieve a vaginal birth after a prior cesarean section, the national goals are unachievable. The obstetrician must consciously consider the impact of "once a cesarean, always a scar."     

The alpha-isoform of glycogen synthase kinase-3 from rabbit skeletal muscle is inactivated by p70 S6 kinase or MAP kinase-activated protein kinase-1 in vitro

OBJECTIVES: A major component of the increasing trend in cesarean sections in Western Australia is the rise in emergency cesarean sections in primiparous women. The aim of this study was to identify independent risk factors (particularly those known early in pregnancy) associated with operative delivery in low-risk primiparous women. METHODS: Retrospective multivariate logistic regression analyses of antenatal and perinatal data were conducted for all low-risk primiparous women entering labor spontaneously and giving birth in Western Australia in 1987 (n = 3641). RESULTS: Of the subjects, 58% had a spontaneous vaginal delivery, 8% had an emergency cesarean section, and 34% had an operative vaginal delivery. The significant independent risk factors for emergency cesarean section were older maternal age, shorter maternal height, heavier infant birthweight, and long labor. The risk factors for operative vaginal delivery were older maternal age, shorter maternal height, heavier infant birthweight, epidural anesthesia, labor/delivery complications, male infant, private patient status, and being married. CONCLUSIONS: This multivariate analysis confirms known risk factors for operative delivery in low-risk primiparous women and suggests that it may be possible to predict the likelihood of operative delivery for an individual woman by using knowledge of maternal age and height and assessment of infant birthweight.     

Management of term breech presentation: a protocol of external cephalic version and selective trial of labor

OBJECTIVE: The results of a program of external version and selective trial of labor for term breech presentation are reviewed. This is a follow-up to our 1987 report describing management of singleton, term breech presentations and expands our 16-year experience to 1180 cases. STUDY DESIGN: All term breech presentations cared for in 1985 through 1992 are reviewed and outcome contrasted with those predicted in our earlier report. During these 8 years a trial of external version was offered if a breech presentation was identified after 36 completed weeks' gestation and before active labor. The criteria for allowing a trial of labor are detailed. RESULTS: Four hundred sixty-four breech presentations were identified for review. Three hundred eighty-two (82%) were diagnosed before active labor. Of these, 344 (90%) underwent an attempt at external version, of which 174 (51%) were successful. The 290 breech presentations where version either was not attempted or was unsuccessful were stratified into three groups: cesarean section without labor (147), trial of labor with cesarean section (90), and trial of labor with vaginal delivery (53). The 174 cases where version was successful were stratified into two additional groups on the basis of the eventual route of delivery. Careful review of maternal and fetal variables indicates that a trial of labor in selected patients resulted in vaginal delivery in only 37% but was achieved without an increase in fetal or maternal mortality or morbidity. Surprisingly, 54 of the 174 cases where version was successful were ultimately delivered by cesarean section. This 31% rate of cesarean delivery is significantly higher than the 15% rate observed for all cases of term, singleton vertex presentation. A higher prevalence of cases complicated by failed progress in labor and failed induction contributed to the excess. CONCLUSION: External version is successful in 51% of cases of term breech presentation. With careful selection, cases where version has failed can be allowed to labor and be delivered vaginally. The incidence of cesarean section (31%) for those cases where version had been successful was surprisingly high, largely because of an increase in labor abnormalities and failed labor inductions.     

Vaginal birth after cesarean delivery: an admission scoring system

OBJECTIVE: To develop a scoring system to predict the likelihood of vaginal birth in patients undergoing a trial of labor after previous cesarean delivery using factors known at the time of hospital admission. METHODS: Trial of labor was attempted in 5022 patients who were assigned randomly to score derivation and score testing groups. Multivariate logistic regression modeling was used in the score derivation group to develop a predictive scoring system for vaginal birth. The scoring system was then applied to the testing group to evaluate its predictive ability. RESULTS: Five variables significantly affected the mode of birth and were incorporated into a weighted scoring system. Rates of successful vaginal birth after cesarean ranged from 49% in patients scoring 0-2 to 95% in patients scoring 8-10. Increasing score was associated linearly with increasing probability of vaginal birth after cesarean. CONCLUSION: Increasing scores correlate with increasing probability of vaginal birth after cesarean. The admission vaginal birth after cesarean scoring system may be useful in counseling patients regarding the option of vaginal birth or repeat cesarean delivery. This information could be particularly valuable for the patient who opts for trial of labor but has second thoughts about her mode of birth when labor begins.     

Suppression of CYP1A1 transcription by H2O2 is mediated by xenobiotic-response element

OBJECTIVE: To investigate the effect of amniotic fluid on prostaglandin synthesis and metabolism in the fetal membranes. DESIGN: A cell culture study of amnion and chorion obtained at elective cesarean section incubated with amniotic fluid collected following either spontaneous labor and delivery, or elective cesarean section. SUBJECTS: Forty-eight pregnant women at 3742 weeks gestation: 24 in spontaneous labor and 24 delivered by elective cesarean section. RESULTS: Significantly more PGE2 and PGF2alpha were produced by amnion and chorion treated with amniotic fluid from spontaneous labor compared with elective cesarean section. Spontaneous labor amniotic fluid favors PGE2 and PGFM production by amnion and chorion respectively; while elective section fluid stimulates PGE2 synthesis by both tissues (reflected as PGEM in chorion). Amniotic fluid, from either spontaneous labor or elective section, had no effect on the metabolism of exogenous PGE2 or PGF2alpha by chorion cells. CONCLUSION: Spontaneous labor is associated with the presence of a substance in amniotic fluid which facilitates prostaglandin synthesis in the fetal membranes, but which is without effect on prostaglandin metabolism.     

Cord blood erythropoietin in the presence and absence of labor in normal infants

To evaluate erythropoietin (Ep) levels in normal labor and cesarean section we studied the cord serum of 111 term pregnancies, divided into three groups: (i) those born by normal vaginal delivery (n = 69); (ii) those delivered vaginally from mothers who were smokers (n = 20); and (iii) those delivered by elective cesarean section (n = 22). The three groups did not differ in maternal age, gestational age, birthweight, infant sex and Apgar scores. No correlation was found between Ep and hematocrit in all three groups of normal terms studied. Although not statistically significant the lower mean Ep value observed in cesarean section compared with the values obtained from normal deliveries could suggest that the process of labor may be a cause of these differences.     

Pretransplant renal dysfunction predicts poorer outcome in liver transplantation

BACKGROUND: Numerous clinicians and researchers have expressed concern about the necessity and potential adverse consequences of many cesarean births in the United States. The purpose of this study was to explore college students' attitudes and beliefs about cesarean section. METHODS: One hundred two college students (66% women) completed a 20-item questionnaire that asked if they viewed cesarean delivery as a potentially negative experience, as a normal or acceptable method of childbirth, and as medically necessary, and asked about their beliefs concerning risk and prevention of cesarean birth. RESULTS: The number of "undecided" responses in the study was striking (7.8% to 69.6% across the 20 items). In general, women and men responded similarly, although women were significantly more likely than men to say they would be profoundly disappointed if their babies had to be delivered by cesarean section. Despite expressing cynicism about the cesarean birth rate (40% agreed that many unnecessary cesarean births occurred) and not viewing the procedure as a normal way of giving birth (47%), most respondents (over 70%) disagreed that giving birth by cesarean would be a negative experience or would make a woman feel like a failure. CONCLUSION: A high level of uncertainty exists about certain aspects of cesarean birth among young women and men, highlighting the need for information for prospective parents. Most college students did not view the cesarean birth experience as either potentially negative or normal. Future research should explore coverage of cesarean birth in childbirth education classes and the roles physicians, nurses, and midwives play in preparing expectant parents for the possibility of cesarean delivery.     

Trends in stimulation and induction of labor 1989-1995

Between 1989 and 1995 the rates for stimulation and induction of labor rose every year, representing a 48 and 77 percent, respectively, total rise over the time period. In 1995 the rate of stimulation was 161 per 1,000 live births and of induction 160. Two percent, or 74,167, of the 3,899,589 births in 1995 had both procedures performed. While rates of stimulation decline with advancing maternal age, the induction rates tend to be higher for older women. Rates for both procedures increased between 1989 and 1995 for both black and white women in all age categories. Women whose pregnancies have extended beyond the expected gestation of 37 weeks consistently had much higher rates of both stimulation and induction. Rates for both procedures rose for doctors of medicine (MD's), doctors of osteopathy (DO's) and certified nurse-midwives (CNM's). DO's had the greatest increases in both stimulation and induction rates. Declines in the cesarean section rate were greater for births that were stimulated or induced than for those without either of these procedures. The rates for stimulated or induced vaginal birth after cesarean (VBAC) were double those of VBACs without such procedures.     

Effects of warmth on newborn rats' motor activity and oral responsiveness to an artificial nipple.

Temperature is a powerful regulator of the behavior and physiology of newborn altricial animals. The effects of warmth on newborn rats' oral responsiveness to suckling stimuli and spontaneous motor activity in a thermoneutral environment were investigated. Newborn rat pups' oral grasp responses to an artificial nipple and overall motor activity were recorded for 18 min. Near-term pups were delivered by cesarean section so that their 1st experiences with suckling stimuli could be observed. Experimental pups were warmed for 15 s every 2 min; control pups were not warmed. Warmed pups grasped the nipple fewer times than the not-warmed pups. However, oral grasp durations became longer for the warmed pups but not for the not-warmed pups. Warmth increased pups' motor activity but only while the heat was applied. Warmth in a thermoneutral environment may promote longer nipple attachment during newborns' early feeding experiences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vaginal administration prostaglandin E2 in premature ruptured membranes at term with an unfavorable cervix

AIM OF THE STUDY: To compare immediate labor induction by vaginal prostaglandins to immediate labor induction by oxytocin or to expectant management in case of prelabor rupture of the membranes at term. MATERIAL AND METHODS: A meta-analysis of all randomized trials indexed in Medline or in the Cochrane Database of Systematic Reviews comparing labor induction by vaginal prostaglandins to labor induction by oxytocin or to expectant management. The statistical analysis was performed according to Peto and Yussuf's modified Mantel Haenszel method. The results were expressed as odds-ratios. RESULTS: Ten published studies meeting the above criteria were found. These trials included 1004 patients. When comparing labor induction by prostaglandins to expectant management, we observed a reduction of the admission-to-delivery interval, a decreased maternal and neonatal infection rate, without difference in the cesarean section rate. When comparing labor induction by vaginal prostaglandins to labor induction by oxytocin, a decreased cesarean section rate was observed without difference in maternal or neonatal infection rates. CONCLUSION: Immediate labor induction by vaginal prostaglandins provides better maternal and neonatal outcomes than labor induction by oxytocin or expectant management in case of prelabor rupture of the membranes at term.     

The relationship between shoe size and mode of delivery

This study investigates whether a woman with a small shoe size has a higher chance of being delivered by cesarean section. Data on shoe size and mode of delivery were collected by chart review and telephone survey from clients of a freestanding birth center. Purposive sampling was done to include all women transferred and delivered by cesarean section for CPD or FTP, and an equivalent number of women who had a normal spontaneous vaginal delivery. Data on twenty two first time mothers who were delivered by cesarean section and twenty three who delivered vaginally were compared. This study did not find any relationship between small shoe size and cesarean section delivery.     

Antibiotic prophylaxis in cesarean section

BACKGROUND: To investigate the guidelines for patient selection and drug regimens for application of antibiotic prophylaxis in relation to cesarean section in the maternity clinics in Denmark. METHODS: A questionnaire to all the Danish maternity clinics that perform cesarean section, concerning indications for application of antibiotic prophylaxis and antibiotic regimens to patients undergoing acute and elective cesarean section. RESULTS: All departments (n = 48) returned the questionnaire. Twenty departments (46%) provided written guidelines for antibiotic prophylaxis. Four departments (8%) used antibiotic prophylaxis to elective cesarean sections, 25 departments (52%) applied antibiotics to all emergency sections. In the presence of the rupture of membranes or prolongation of labor (> 12 hrs) 58% and 63% of the departments applied antibiotic prophylaxis, respectively. The most infrequent first choice drug was cefuroxim, employed by 27 departments (56%). Concerning timing, 21 departments (44%) applied antibiotics after cord clamping and 13 departments (27%) before incision. CONCLUSION: We propose a nation-wide prospective investigation on the rate of infections associated with cesarean section to set up rational guidelines for antibiotic prophylaxis.