Epidural labor analgesia and the incidence of cesarean delivery for dystocia.

UNLABELLED: We performed this retrospective study to examine the changes in cesarean delivery rates associated with the establishment of a labor epidural service. In April 1993, St. Louis Regional Medical Center established an on-demand labor epidural service. We obtained demographic data for all patients and reviewed the operative records of all patients undergoing cesarean section who delivered 12 mo before and 16 mo after the start of the labor epidural service. We compared labor epidural rates and total and nulliparous dystocia cesarean delivery rates before and after the epidural service started and among patients who did and did not receive labor epidural analgesia when it was available. Included were 3195 patients who delivered before and 3733 patients who delivered after epidural analgesia became available. Labor epidural rates were 1.2% vs 29.4% for the Before group versus the After group (P < 0.001). Total (9.1% vs 9.7%) and nulliparous dystocia (5.7% vs 6.4%) cesarean delivery rates did not significantly change with the availability of epidural analgesia. However, the total (11.6% vs 8.8%; P = 0.009) and dystocia (8.0% vs 1.0%; P = 0.001) cesarean delivery rates were higher among patients who received epidural analgesia when it was available. We conclude that epidural labor analgesia is associated with, but does not cause, cesarean delivery for dystocia. IMPLICATIONS: Increased epidural analgesia use did not change the overall dystocia cesarean delivery rate, although dystocia was more common among women who chose an epidural analgesia. Consequently, limiting epidural availability will not affect cesarean delivery rates. The evidence does not support advising patients that epidural labor analgesia increases the risk of cesarean delivery.

Visual attention in children with prenatal cocaine exposure.

Previous studies have reported that developmental disruption of dopaminergic systems results in lateralized deficits in visual attention (Posner et al., 1991; Craft et al., 1992). Infants who were prenatally exposed to cocaine were hypothesized to have increased reaction times to targets in the right visual field on measures of visual attention compared with infants who were not exposed to cocaine. Seventeen children without prenatal exposure to cocaine and 14 children who were exposed to cocaine (age range from 8-40 months) completed a visual attention task, the Mental Development Index of the Bayley Scales of Infant Development, Second Edition; and the Preschool Language Scale, Third Edition. Cocaine-exposed children were slower to orient to stimuli in the right visual field after repeated trials, especially after attention was first cued to the left visual field. They were also less likely to orient to the right when given a choice. Results suggest that the left hemisphere visual attention system is disproportionately affected by prenatal exposure to cocaine.

The use of oxytocin.

Synthetic oxytocin offers a safe and effective means of producing regular uterine activity and has a fairly large therapeutic index; however, the mild antidiuretic and vasoactive properties of oxytocin increase the risk of water intoxication and hypotension. The issue of reduction in cesarean section rates through the use of an active management protocol is being studied actively in the United States and Canada at this time. The authors recommend infusion protocols for the augmentation and induction of labor that use low doses of dilute oxytocin, increased at intervals no more than 40 minutes. Pharmacokinetic and clinical studies support the use of oxytocin in the physiologic range as efficacious and prudent. The longer induction to delivery time demonstrated by some, but not all authors, in our opinion, is a reasonable alternative to avoidable uterine hyperstimulation with the potential for fetal and maternal injury. We advocate the use of the lowest dose necessary to produce adequate uterine contractility and cervical change.

Oxytocin to induce labor.

Oxytocin is a highly successful and safe agent for inducing labor and has a fairly large therapeutic index. It has, however, minimal, but not trivial, antidiuretic and vascular activity when used in large doses. Therefore, to induce labor, low-dose oxytocin dosing regimens that produce efficacious uterine activity and avoid side effects are recommended. Oxytocin should be used in the lowest possible doses necessary to effect a clinical response. Diligence must be exercised when monitoring labor and fetal well-being. Hofbauer, the first to use oxytocin to induce labor, said in 1927 that oxytocin, "with its power of producing regular, rhythmical and forcible uterine contractions, should be regarded as a most beneficent and valuable agent, which, however, should always be employed with care and a realisation of its limitations and dangers." His words remain valid today.

Neurosonographic abnormalities associated with maternal history of cocaine use in neonates of appropriate size for their gestational age.

PURPOSE: To determine whether increased incidence of neurosonographic abnormalities (predominantly of the basal ganglia and thalamus) in cocaine-exposed neonates who are small for their gestational age is attributable to the cocaine or to neonatal size. METHODS: Neonates whose sizes were appropriate for their gestational age with no evidence of hypoxia or respiratory distress were identified prospectively by a maternal history of cocaine use. Scans were performed within 72 hours of birth using a 7.5-MHz transducer following a standard protocol. The images were analyzed without access to patient information. Forty study neonates were compared with 34 control subjects who were appropriate in size for their gestational age, scanned using the same protocol. Comparisons were made using Fisher Exact Test, t test, and logistic regression. RESULTS: No control infant had neurosonographic abnormalities. In the study group, gestational age ranged from 27 to 41 weeks. Of the 40 study neonates, 14 (35%) had one neurosonographic abnormality; two had two abnormalities. The predominant lesion was focal echolucencies, mainly in the area of the basal ganglia (10 of 40, 25%). Other findings were caudate echogenicity (3 of 40, 7.5%), ventricular dilation (2 of 40, 5%) and one "moth-eaten" appearance of the thalamus. Lesions were more likely approaching term and were not related to prematurity or alcohol use. CONCLUSION: Apparently normal neonates with a maternal history of cocaine use are likely to have degenerative changes or focal infarctions in their basal ganglia attributable to cocaine. Neurosonography should be used to evaluate these neonates. The long-term significance of these lesions needs further evaluation.

How small is too small and how early is too early? A survey of American obstetricians specializing in high-risk pregnancies.

Four hundred and five Maternal-Fetal Medicine specialists were surveyed to determine their clinical opinions regarding intrapartum management of the severely preterm fetus requiring delivery. Intrapartum fetal heart rate monitoring was initiated at 23, 24, and 25 weeks' gestation by 10%, 43%, and 66% of respondents, respectively. Cesarean section was not performed at less than 24 weeks' gestation or less than 500 gm fetal weight. Ninety percent of respondents were willing to perform cesarean section for fetal distress or breech presentation at 26 weeks' gestation or 750 gm fetal weight. Delivery management prior to 26 weeks' gestation or for fetuses smaller than 750 gm was variable and appeared to be individualized. Due to inherent uncertainty regarding appropriate management and observed variability of response, we conclude that studies be performed to assess objectively safety and efficacy of cesarean section for fetal indications at less than 26 weeks' gestation or less than 750 gm estimated fetal weight.

A comparison of the effect of epidural, general, and no anesthesia on funic acid-base values by stage of labor and type of delivery.

The effect of epidural anesthesia on neonatal acid-base status, before, during, and after labor, was determined by review of funic blood-gas values from 142 women with normal term pregnancies and normal fetal heart rate patterns. Funic acid-base parameters were compared by type of anesthesia when stratified by mode of delivery (vaginal, cesarean section in the active phase of labor, or elective cesarean section). Use of epidural analgesia for vaginal delivery was associated with significantly longer labor, lower umbilical arterial pH, higher arterial PCO2 and arterial bicarbonate values. In women who had cesarean section in the active phase of labor, use of epidural anesthesia was associated with significantly lower arterial and venous PO2 values when compared with women who received general anesthesia. Patients who had elective cesarean section with epidural anesthesia had funic acid-base values similar to women who had general anesthesia. Epidural analgesia-anesthesia offers no clear advantage to the uncompromised term fetus.

Lack of relationship between glucose tolerance and complications of pregnancy in nondiabetic women.

Recent studies suggest that gestational diabetes mellitus (GDM) is underdiagnosed. To test this hypothesis, we examined the relationship of perinatal complications to glucose tolerance during the third trimester. Our population consisted of 287 women evaluated at approximately 28 wk gestation who had normal fasting (less than 5.9 mM) and 2-h (less than 9.2 mM plasma glucose) levels after a 100-g glucose load. Glycosylated hemoglobin and glycosylated plasma protein were also measured. Study subjects were stratified into three groups based on 2-h plasma glucose values: group 1 (n = 59) less than 5.6 mM, group 2 (n = 112) 5.6-6.0 mM, and group 3 (n = 116) 6.7-9.2 mM. There were statistically significant but low correlations (r less than 0.20) between 2-h plasma glucose levels and mother's age, body mass index, infant weights, and Apgar scores. There was a significant increasing trend in the proportion of overweight and obese women from groups 1 to 3 (P less than 0.02). There was also a significant trend toward higher birth weights (P = 0.013) and larger proportions of large for gestational age (LGA) babies (P = 0.02) from groups 1 to 3, and women with LGA infants showed higher fasting and 2-h plasma glucose levels than women with non-LGA infants (P = 0.032). However, there was no significant difference in perinatal complications or infant morbidity or mortality between groups. Percentage of glycosylated hemoglobin or glycosylated plasma protein did not differ between groups.(ABSTRACT TRUNCATED AT 250 WORDS)