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Biomedical subjects

K J Leveno

Publications and source records attributed to K J Leveno.

At least 19 recordsLinked to original sources

Amniotic fluid meconium: a fetal environmental hazard.

OBJECTIVE: To investigate the hypothesis that meconium aspiration syndrome, the major hazard of meconium during labor, may be associated with superimposed fetal acute acidemia. METHODS: Umbilical artery blood gases were measured in 7816 term pregnancies with meconium in the amniotic fluid (AF) and the results were correlated with intrapartum and neonatal outcomes. RESULTS: Sixty-nine (1%) infants developed meconium aspiration syndrome and 31 (45%) of these were in association with fetal acidemia at birth. Moreover, umbilical blood gas analysis and intrapartum events suggested that the fetal acidemia linked to meconium aspiration was an acute event rather than a long-duration process, which might be expected if meconium was itself a marker of an antecedent fetal asphyxial event. CONCLUSION: Meconium in the AF may be a fetal environmental hazard when acidemia supervenes rather than solely a marker of preexisting fetal compromise leading to the release of meconium.

Acid-Base Imbalance

Randomized investigation of antimicrobials for the prevention of preterm birth.

OBJECTIVE: Occult amniotic fluid infection has emerged as a possible cause of many heretofore unexplained preterm births. We sought to determine whether antimicrobial therapy is effective in preventing preterm delivery. STUDY DESIGN: A double-blind, placebo-controlled, randomized trial was conducted to study the efficacy of ampicillin-sulbactam and amoxicillin-clavulanic acid in women hospitalized for preterm labor between 24 and 34 weeks' gestation. During this investigation no tocolytics or steroids were used. RESULTS: Thirty-nine women with preterm labor received antimicrobial therapy and 39 received placebos. The mean gestational ages at study entry were 29.8 +/- 0.4 weeks (SEM) and 30.6 +/- 0.3 weeks in the antimicrobial and placebo groups, respectively (not significant). Similarly, the mean gestational ages at delivery were 34.2 +/- 0.7 and 34.1 +/- 0.6 weeks, respectively (not significant). Other index values of pregnancy outcome, for example, birth weight, neonatal morbidity, and prenatal death, were not significantly improved by antimicrobial therapy given to the mother in preterm labor. CONCLUSION: We find that antimicrobial therapy given to women in preterm labor is ineffective in the prevention of preterm birth.

Amoxicillin

A comparison of magnesium sulfate with phenytoin for the prevention of eclampsia.

BACKGROUND: Magnesium sulfate is used widely to prevent eclamptic seizures in pregnant women with hypertension, but few studies have compared the efficacy of magnesium sulfate with that of other drugs. Anticonvulsant prophylaxis with phenytoin for eclampsia has been recommended, but there are virtually no data to support its efficacy. Our objective was to compare magnesium sulfate with phenytoin in preventing seizures in hypertensive women during labor. METHODS: We randomly assigned women with hypertension who were admitted for delivery to receive either magnesium sulfate or phenytoin. The magnesium sulfate regimen consisted of a 10-g intramuscular loading dose followed by a maintenance dose of 5 g given intramuscularly every four hours. For women with severe preeclampsia, an additional 4-g loading dose was given intravenously. The phenytoin regimen included a 1000-mg loading dose infused over a period of 1 hour, followed by a 500-mg oral dose 10 hours later. With either regimen, anticonvulsant therapy was continued for 24 hours post partum. RESULTS: Ten of 1089 women randomly assigned to the phenytoin regimen had eclamptic convulsions, as compared with none of 1049 women randomly assigned to magnesium sulfate (P = 0.004). There were no significant differences in any risk factors for eclampsia between the two study groups. Maternal and infant outcomes were also similar in the two study groups. CONCLUSIONS: Magnesium sulfate is superior to phenytoin for the prevention of eclampsia in hypertensive pregnant women. These results validate the long-practiced use of magnesium sulfate in the prevention of eclampsia.

Adolescent

Genital herpes during pregnancy: no lesions, no cesarean.

OBJECTIVE: To determine the effects at our hospital of adoption of the 1988 guidelines recommended by ACOG for management of genital herpes infections during pregnancy. METHODS: Between 1984-1986, 96 pregnancies complicated by active genital herpes were delivered at Parkland Hospital. The outcome of these pregnancies were compared with 217 similar pregnancies managed after implementation of the 1988 ACOG herpes guidelines. RESULTS: Adoption of the 1988 ACOG herpes guidelines resulted in a 37% decrease in the use of cesarean delivery for women with genital herpes infections at our hospital. Most of this decrease was because the new guidelines eliminated the need for a confirmatory negative herpes culture before permitting vaginal delivery. No neonatal herpes infections occurred as a result of implementing the ACOG recommendations. CONCLUSION: The rate of cesarean delivery for women with genital herpes infections during pregnancy declined significantly at our hospital as a result of the adoption of ACOG herpes guidelines, and there were no neonatal consequences, such as increased incidence of neonatal herpes simplex virus infection.

Cesarean Section

Fetal acidemia associated with regional anesthesia for elective cesarean delivery.

OBJECTIVE: To determine the prevalence, magnitude, and type of fetal acidemia associated with contemporary obstetric anesthetic techniques. METHODS: Umbilical artery blood gases were obtained in 1601 singleton pregnancies delivered by elective cesarean. RESULTS: General anesthesia was used in 371 (23%) women, epidural in 286 (18%), combined spinal-epidural in 659 (41%), and spinal in 231 (14%). Approximately 18% of infants exposed to regional anesthetics had umbilical artery blood pH values 7.19 or less, 42 (3%) infants had pH values less than 7.10, and nine (1%) had values 6.99 or less. The incidence of fetal acidemia was greater in spinal and combined spinal-epidural procedures compared to epidural anesthetics. Fetal acidemia was predominantly respiratory in type because carbon dioxide pressure was abnormally increased when fetal acidemia was diagnosed. CONCLUSIONS: Regional anesthesia is associated with fetal acidemia, occasionally severe, and has features of an acute respiratory type of acidemia. Fetal acidemia is less frequent with epidural anesthesia compared to subarachnoid techniques.

Adult

Randomized comparison of general and regional anesthesia for cesarean delivery in pregnancies complicated by severe preeclampsia.

OBJECTIVE: To evaluate the maternal and fetal effects of three anesthetic methods used randomly in women with severe preeclampsia who required cesarean delivery. METHODS: Eighty women with severe preeclampsia, who were to be delivered by cesarean, were randomized to general (26 women), epidural (27), or combined spinal-epidural (27) anesthesia. The mean preoperative blood pressure (BP) was approximately 170/110 mmHg, and all women had proteinuria. Anesthetic and obstetric management included antihypertensive drug therapy and limited intravenous (IV) fluid and drug therapy. RESULTS: The mean gestational age at delivery was 34.8 weeks. All infants were born in good condition as assessed by Apgar scores and umbilical arterial blood gas determinations. Maternal hypotension resulting from regional anesthesia was managed without excessive IV fluid administration. Similarly, maternal BP was managed without severe hypertensive effects in women undergoing general anesthesia. There were no serious maternal or fetal complications attributable to any of the three anesthetic methods. CONCLUSION: General as well as regional anesthetic methods are equally acceptable for cesarean delivery in pregnancies complicated by severe preeclampsia if steps are taken to ensure a careful approach to either method.

Adult

Randomized trial of epidural versus intravenous analgesia during labor.

OBJECTIVE: To compare the effects of epidural analgesia with intravenous (IV) analgesia on the outcome of labor. METHODS: Thirteen hundred thirty women with uncomplicated term pregnancies and in spontaneous labor were randomized to be offered epidural bupivacaine-fentanyl or IV meperidine analgesia during labor. RESULTS: Comparison of the allocation groups by intent to treat revealed a significant association between epidural allocation and operative delivery for dystocia. However, only 65% of each randomization group accepted the allocated treatment. Four hundred thirty-seven women accepted and received meperidine as allocated, and they were compared with 432 women accepting epidural allocation. Significant associations resulted between epidural administration and prolongation of labor, increased rate of oxytocin administration, chorioamnionitis, low forceps, and cesarean delivery. Because of the high rate of noncompliance with treatment allocation, a multifactorial regression analysis was performed on the entire cohort, and a twofold relative risk of cesarean delivery persisted in association with epidural treatment. The impact of epidural treatment on cesarean delivery was significant for both nulliparous and parous women (risk ratios 2.55 and 3.81, respectively). Epidural analgesia provided significantly better pain relief in labor than did parenteral meperidine. CONCLUSION: Although labor epidural analgesia is superior to meperidine for pain relief, labor is prolonged, uterine infection is increased, and the number of operative deliveries are increased. A two- to fourfold increased risk of cesarean delivery is associated with epidural treatment in both nulliparous and parous women.

Adult

Obstetric clavicular fracture: the enigma of normal birth.

OBJECTIVE: To determine the main risk factors involved in neonatal clavicular fracture, the most common injury to the neonate. METHODS: Two hundred fifteen cases of clavicular fracture of 65,091 vaginal deliveries (0.4%) occurring between January 1983 and December 1988 were pair-matched with controls based on mode and date of delivery, race, and maternal age. Incidences, odds ratios, and stratified analysis were used to identify and control for confounding between risk factors. RESULTS: Shoulder dystocia, increasing birth weight, and increasing gestational age were identified as risk factors. Within the range of normal birth weights, there is a biologic gradient of increasing risk for clavicular fracture. Although shoulder dystocia is the strongest risk factor identified, the magnitude of its point estimate is probably affected to a large extent by differential ascertainment. The use of forceps, prolonged second stage of labor, and nulliparity status were not significantly associated with neonatal clavicular fracture. CONCLUSIONS: Neonatal clavicular fracture occurs commonly in an obstetric population. Obstetric clavicular fracture is an unpredictable, unavoidable complication of normal birth.

Adolescent

Intentional delivery versus expectant management with preterm ruptured membranes at 30-34 weeks' gestation.

OBJECTIVE: To determine maternal and neonatal outcomes in pregnancies complicated by preterm rupture of membranes (PROM) at 30-34 weeks' gestation. METHODS: A randomized controlled trial was conducted to study the benefits of expectant management in women hospitalized for PROM at 30-34 weeks' gestation. During this investigation, no tocolytics, corticosteroids, or prophylactic antibiotics were used. RESULTS: Sixty-eight women with PROM were managed expectantly and 61 were delivered intentionally. The mean gestational age at study entry was 31.7 weeks in both the expectant management and intentional delivery groups (P > .05). The mean gestational ages at delivery were similar (32.0 and 31.7 weeks, respectively). Other indices of pregnancy outcome (ie, birth weight, intraventricular hemorrhage, necrotizing enterocolitis, sepsis, respiratory distress syndrome, and perinatal death) were not significantly improved by expectant management. However, there was a significant increase in the incidence of chorioamnionitis and antepartum hospitalization in the women managed expectantly. CONCLUSION: There were no clinically significant neonatal advantages to expectant management of ruptured membranes at 30-34 weeks. Antepartum hospitalization was decreased by 2.5 days in those women randomized to intentional delivery.

Adult

Maternal youth and pregnancy outcomes: middle school versus high school age groups compared with women beyond the teen years.

OBJECTIVE: We sought to measure and compare pregnancy complications in middle school versus high school versus older maternal age groups. STUDY DESIGN: From January 1988 through December 31, 1991, maternal and infant data from 16,512 consecutive nulliparous women were collected and electronically stored. These women were divided into three study groups: middle school (11 to 15 years old), high school (16 to 19 years old), and women 20 to 22 years old at delivery. Statistical analysis included logistic regression to control for potentially confounding demographic variables. RESULTS: Middle school-aged mothers were disproportionately black (50% vs 36% Hispanic vs 14% white), and very low birth weight (4% vs. 2%, p = 0.003) was increased in these youthful mothers. First births to high school-aged mothers were not found to be compromised compared with those of women 20 to 22 years old, and, indeed, cesarean birth was less frequent in these women compared with those > or = 20 years old. CONCLUSIONS: We conclude that the health hazard associated with school-age pregnancy is predominantly prematurity and is increased only in middle school-aged mothers. High school-aged mothers do not experience excess medical complications of pregnancy compared with older women. We suggest that middle school pregnancy, particularly for inner-city teenagers, should be a special focus for pregnancy prevention and intervention.

Adolescent

A simplified phenytoin regimen for preeclampsia.

The objective of this study was to assess the feasibility of giving phenytoin to a group of mild preeclamptic women in a universal dosing scheme comparable to that typical of magnesium sulfate administration. Serum phenytoin levels were measured at regular intervals for 32 hours following a 1 g intravenous loading dose in 14 patients. A second group of 14 women received 500 mg orally to supplement the 1 g initial dose and had serum levels similarly measured. The resultant serum levels are described, and the effect of maternal weight analyzed. The average serum phenytoin level in the first 14 women given the 1 g loading dose fell to 10 micrograms/mL approximately 12 hours after treatment. Serum levels plateaued above this threshold in the 14 women given 500 mg of additional medication orally 10 hours after treatment initiation and were maintained for an additional 14 hours before decline was observed. The serum levels resulting from the initial 1 g loading dose were analyzed 8 hours after treatment initiation in the entire group of 28 women according to body weight, and a clinically significant effect of weight on serum level was observed only at the extremes of weight. We conclude that a universal dosing scheme comparable to that typically used for magnesium sulfate is feasible for phenytoin administration to preeclamptic women.

Female

Correlation of measured amniotic fluid volume and sonographic predictions of oligohydramnios.

OBJECTIVE: To compare the measured volume of amniotic fluid (AF) in term gestations to the volume predicted sonographically. METHODS: One hour before elective cesarean delivery, 40 women had sonographic measurement of the AF index and largest vertical pocket diameter. At surgery, a suction catheter was placed into a 1-cm uterine incision and a second catheter was used to aspirate AF from the operative field. Hemoglobin concentration was measured in the collected AF to determine the extent of blood contamination. RESULTS: The mean measured AF volume was 532 mL (range 40-1692). The correlation coefficient between AF index and AF volume was 0.744 (P < .001). A similar value (r = 0.755, P < .001) was observed for the largest vertical pocket measured with ultrasound. CONCLUSION: Sonographic measurements of the largest vertical pocket and the AF index have similar positive correlations with measured AF volumes at term. Current methods of estimating AF volume have low sensitivity for detecting oligohydramnios.

Amniotic Fluid

The economic advantages of measured change in health care: an example from obstetrics.

To evaluate the economic effects of an increased oxytocin dosage for labor stimulation at a large urban hospital, a cost analysis of a before and after cohort, analytic clinical trial was performed. Delivery outcomes for two different oxytocin dosages were evaluated from the perspective of provider and consumer costs attributable to the oxytocin regimen. The high-dose oxytocin regimen resulted in an estimated provider and consumer cost savings of approximately $350,000 per year. We conclude that a small change in health care, such as an increased infusion rate of a single drug, can have economic advantages.

Cost Savings

Meconium: a 1990s perspective on an old obstetric hazard.

OBJECTIVE: To quantify the current perinatal consequences associated with intrapartum detection of meconium in the amniotic fluid (AF). METHODS: We compared retrospectively the outcomes in 8136 term singleton cephalic pregnancies with meconium and 34,573 similar pregnancies with clear AF. RESULTS: Virtually all measures of adverse fetal-neonatal outcomes were significantly increased with meconium. For example, perinatal mortality increased from 0.3 per 1000 births with clear AF to 1.5 deaths per 1000 with meconium (P < .001). Most of these deaths resulted from meconium aspiration. Other unwanted outcomes also increased; eg, severe fetal acidemia at birth (umbilical artery blood pH 7.00 or less) increased from three per 1000 to seven per 1000 when meconium was diagnosed (P < .001). Delivery by cesarean also increased with meconium, from 7 to 14% (P < .001). CONCLUSION: Meconium in the AF is an obstetric hazard with small but significantly increased risks of adverse fetal-neonatal outcomes.

Adolescent

High-dose oxytocin: 20- versus 40-minute dosage interval.

OBJECTIVE: To determine whether an increase in the oxytocin dosing interval would decrease the incidence of uterine hyperstimulation. METHODS: This study included 1801 consecutive pregnancies receiving high-dose oxytocin. Oxytocin was used for labor augmentation in 1167 and induction in 634 women. Twenty- and 40-minute dosage intervals were compared. The study period was based on an 80% likelihood of detecting 5 and 10% differences in the cesarean and hyperstimulation rates, respectively. Statistics were analyzed with chi 2, Fisher, and Wilcoxon rank-sum tests where appropriate. Multivariate logistic regression and analysis of covariance were used to control for confounding demographic variables. RESULTS: Comparison of the 20- and 40-minute regimens for labor induction yielded no differences in the rates of cesarean delivery for dystocia (16 versus 19%) or fetal distress (5 versus 6%). The 20-minute regimen for augmentation was associated with a significant reduction in cesarean for dystocia (8 versus 12%; P = .05). The incidence of uterine hyperstimulation was greater with the 20-minute than the 40-minute regimen for induction (40 versus 31%; P = .02), but not for augmentation (31 versus 28%). Neonatal outcomes were unaffected by the dosage interval for both augmentation and induction. CONCLUSION: A 40-minute dosing interval for high-dose oxytocin offers no clear advantage over a 20-minute interval. Both regimens were safe and efficient, with no differences in perinatal outcome. The 20-minute interval was associated with fewer cesareans for dystocia when used for labor augmentation, whereas the 40-minute interval resulted in less hyperstimulation when used for labor induction.

Adult

The return of life-threatening puerperal sepsis caused by group A streptococci.

A dramatic decline in the prevalence of serious puerperal infection caused by group A beta-hemolytic streptococci has been observed throughout most of the twentieth century, and it is currently a very uncommon cause of maternal morbidity and mortality. We report on two term pregnancies complicated by profound multisystem organ failure caused by group A streptococcal puerperal sepsis. This report serves to highlight the apparent return of serious group A streptococcal puerperal sepsis and to emphasize the clinical implications and sequelae attributable to an old yet virulent enemy.

Adult

Acid-base significance of meconium discovered prior to labor.

Although the significance of meconium in the amniotic fluid diagnosed during labor remains problematic, there is little information regarding the significance of meconium discovered prior to labor. The present study consisted of 40 term pregnancies with meconium found at amniocentesis for lung maturity (n = 7) or elective cesarean section (n = 33) and 40 uncomplicated, control pregnancies with clear amniotic fluid at elective cesarean section. The mean umbilical artery (UA) blood pH was 7.26 in the meconium group and 7.28 in the control group. Overall, the frequency of fetal acidemia (UA pH < 7.20) was 15% (6 of 40) of the infants in the meconium group versus 8% (3 of 40) in the control group (p = 0.24). All nine of these infants had a respiratory acidosis defined as a UA blood pH less than 7.20 with normal bicarbonate and elevated carbon dioxide pressure. Importantly, none of the neonates had metabolic acidemia and all had uncomplicated hospital courses. All of the pregnancies reported were promptly delivered because of meconium and we therefore cannot recommend nonintervention when meconium is diagnosed in the antepartum period. Meconium discovered prior to labor is not necessarily a marker of immediate or chronic fetal compromise.

Acid-Base Equilibrium