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Biomedical subjects

R K Laros

Publications and source records attributed to R K Laros.

At least 19 recordsLinked to original sources

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.

Breech Presentation

The cost of teaching residents outpatient obstetrics and gynecology in a university medical center.

OBJECTIVE: To quantify the cost of teaching residents ambulatory obstetrics and gynecology, expressed as the difference in revenue generated between a faculty physician practicing as a private practitioner and a faculty physician serving as a resident supervisor. METHOD: Outpatient revenue generated by faculty generalists and residents was analyzed. The net gain in revenue was calculated per half-day session for faculty and residents by subtracting contractual allowances and expenses from gross patient charges. Net revenue gain per half-day clinical session per year for a faculty member practicing as a private practitioner was compared with that of a faculty member functioning as a supervisor. The net gain for the faculty supervisor was based on the revenue generated by the residents supervised. RESULTS: The faculty member serving as a private practitioner generated a net gain per session per year of $23,947. The faculty member acting as supervisor for two residents per session generated a net gain or loss per session per year of -$9678, -$972, and $15,542 for first-, second-, and third-year residents, respectively. The cost of teaching, expressed as the difference in the net gain of a faculty member as private practitioner and the net gain of a faculty member as supervisor, for first-, second-, and third-year residents was $33,625, $24,919, and $8405, respectively, per session per year. CONCLUSION: This analysis shows that first-year residents are an expense to the practice site, second-year residents are close to breaking even, and third-year residents begin to generate a net gain.

Ambulatory Care

Vaginal delivery from the persistent occiput posterior position. Influence on maternal and neonatal morbidity.

We performed a retrospective study of 564 vaginal occiput posterior (OP) deliveries to investigate the influence of this position on maternal and fetal morbidity. The cases were compared to 1,068 controls matched for race, parity and delivery method. The OP group had a higher incidence of severe perineal laceration and episiotomy than the occiput anterior (OA) group. Within the OP group, operative delivery was associated with a higher incidence of severe perineal laceration, vaginal laceration and episiotomy than was spontaneous delivery. Similarly, the OP group delivered by forceps had a higher incidence of severe perineal lacerations, vaginal lacerations and episiotomy than those delivered by vacuum extraction. Mediolateral episiotomy was associated with a lower incidence of severe perineal lacerations than median episiotomy during delivery from the OP position. The infants delivered from the OP position had a higher incidence of Erb's and facial nerve palsy than did those delivered from the OA position. All these injuries occurred following forceps delivery. Vaginal delivery from the persistent OP position is associated with increased maternal morbidity, and operative vaginal delivery from this position is associated with increased neonatal morbidity.

Delivery, Obstetric

Neonatal morbidity according to gestational age and birth weight from five tertiary care centers in the United States, 1983 through 1986.

OBJECTIVES: This study details the incidence, by gestational age and birth weight, of specific neonatal morbidities in singleton neonates without major congenital anomalies. STUDY DESIGN: Data were prospectively collected on all deliveries at five tertiary centers in the United States during the years 1983 through 1986. Pregnancies were meticulously dated and the gestational ages of the neonates at delivery were confirmed by Dubowitz score. RESULTS: The incidence of respiratory distress syndrome gradually decreases with increasing gestational age until 36 weeks. A marked decrease in the incidence of necrotizing enterocolitis, patent ductus arteriosus, intraventricular hemorrhage, and sepsis occurs after 32 completed weeks. The number of days of mechanical ventilation for respiratory distress syndrome and newborn stay in the tertiary care facility also were significantly reduced after 32 weeks. CONCLUSIONS: The incidence of both respiratory distress syndrome and patent ductus arteriosus is markedly decreased by both increasing gestational age and birth weight. The incidence of grade III and IV intraventricular hemorrhage, necrotizing enterocolitis, and sepsis virtually vanishes after 34 weeks. These data relating neonatal morbidities to gestational age are important to the obstetrician in the critical decision regarding the timing of delivery and to the parents, who can benefit from a realistic prediction of the neonatal course.

Academic Medical Centers

Cost-benefit analysis of autologous blood donation in obstetrics.

OBJECTIVE: To determine whether there are predictors of peripartum transfusion, other than placenta previa, that identify a population of pregnant women whose risk of transfusion is high enough to justify antepartum autologous blood donation. METHODS: Using an established perinatal data base, we studied 14,267 consecutive term deliveries without placenta previa. Univariate and multivariate analyses were performed to assess ten predictors of peripartum transfusion that might reasonably be detected in the antepartum period. Costs were calculated for a hypothetical autologous blood donation program to prevent transfusion-related infection. RESULTS: Red-cell transfusion was used in 150 deliveries (1.1%). A total of 424 units was transfused (2.9 per 100 deliveries). Four risk factors were significantly (P less than .05) predictive of peripartum red-cell transfusion: preeclampsia (adjusted odds ratio 3.69), multiple gestation (2.82), elective cesarean (1.71), and nulliparity (1.51). Controlling for these, there was no association between transfusion and previous postpartum hemorrhage, previous cesarean with trial of labor, prior abortions, induction of labor, or ethnic group. A hypothetical antepartum blood donation program restricted to patients with three or more risk factors would cost $32,800-130,700 per case to prevent transfusion-related hepatitis and $26,000,000-78,000,000 per case to prevent human immunodeficiency virus infection. CONCLUSION: In obstetric patients without placenta previa, the need for peripartum red-cell transfusion cannot be predicted with sufficient accuracy to justify the costs of antepartum autologous blood donation.

Blood Transfusion, Autologous

Maternal and neonatal outcomes after oxytocin augmentation in patients undergoing a trial of labor after prior cesarean delivery.

OBJECTIVE: To study the safety of oxytocin augmentation in patients having abnormal labors after a prior cesarean delivery. METHODS: We retrospectively analyzed a case series of women undergoing a trial of labor after a previous cesarean delivery from the University of California San Francisco perinatal data base. Women whose labors were augmented with oxytocin were compared to women with labor abnormalities managed without the use of oxytocin. A wide range of maternal and neonatal outcomes was compared. Only vertex singleton term deliveries were studied. RESULTS: From 1975-1990 there were 504 trials of labor, of which 185 (37%) had labor abnormalities; 62 of these 185 (34%) were augmented with oxytocin. Fifty-eight percent of the trials of labor ended in vaginal delivery. In patients since 1982, 73% delivered vaginally. Forty-six (74%) of augmented patients delivered vaginally. There were no maternal deaths, uterine ruptures, or hysterectomies. Estimated blood loss was slightly greater among augmented patients after controlling for mode of delivery (P < .05), but only by 50-100 mL on average. There was no difference in the need for maternal transfusion. Fetal trauma and fetal scalp blood sampling occurred more frequently (P < .05) in the augmented labors, but only in the subgroup delivered by cesarean. No increased risk was demonstrated by a comparison between patients receiving oxytocin and epidural anesthesia and patients with labor abnormalities receiving neither. CONCLUSION: Retrospective analysis supports the use of oxytocin and epidural anesthesia to augment abnormal trials of labor after prior cesarean.

Anesthesia, Epidural

Outcome of very-low-birth-weight infants exposed to beta-sympathomimetics in utero.

In this study we examined neonatal and early childhood outcomes after intrauterine exposure to beta-sympathomimetic agents on infants with birth weights less than or equal to 1500 gm. The hospital courses and anthropomorphic, developmental, and neurologic development of 201 infants exposed to one or more beta-sympathomimetic agents (isoxsuprine, 33; ritodrine, 70; terbutaline, 43; combination, 55) were analyzed and compared with those of 130 control infants of similar birth weight. One hundred and seventy-seven infants had follow-up to 1 year of age, 101 to age 3, and 58 to age 4. When treatments consisting of a single beta-sympathomimetic or no treatment were compared, there were no statistically significant overall differences found in growth and development or in most of the short-term measures of infant well-being. However, significant overall differences with no evidence of confounding by time-related effects were found for the following; mortality, none greater than terbutaline; maximum positive inspiratory pressure when respiratory distress syndrome was present, none greater than terbutaline; neonatal trauma, terbutaline greater than ritodrine. Other differences were found in conjunction with evidence of time-related confounding, or within specific time intervals. It should be noted that these differences are not necessarily due to effects of the different treatments, as the data are observational.

Female

Obstetric complications with GDM. Effects of maternal weight.

Obstetric complications recorded prospectively were assessed retrospectively in 150 women with gestational diabetes mellitus (GDM) and 305 control subjects matched for age, parity, and ethnicity. Intensive diet therapy and self-monitoring of capillary blood glucose were used to obtain postprandial euglycemia; 22% of GDM subjects required insulin. GDM and control subjects were grouped by body mass index to detect any influence of maternal prepregnancy weight on outcome. Polyhydramnios, preterm labor, and pyelonephritis were not more frequent in GDM, but hypertension without proteinuria (7.3 vs. 3.3%) and preeclampsia (8 vs. 3.9%) were more frequent in GDM. The frequency of hypertensive complications in GDM was not totally attributable to being overweight. Abnormalities of labor, birth trauma, and fetal macrosomia were not more common in GDM; 6.7% of the infants of mothers with GDM weighed greater than 4200 g at birth compared with 3.6% of control infants (NS), and 10% were large for gestational age and sex compared with 6.6% of control infants (NS). Despite this, cesarean delivery was more common in GDM (35.3 vs. 22%, P less than 0.01), mostly due to significantly more cesarean births without labor.

Birth Weight

Maternal hydration increases amniotic fluid index.

Although adequate amniotic fluid (AF) volume is considered an important aspect of fetal well-being, the etiology of decreased AF volume is not well understood. A randomized blinded trial was designed to examine our hypothesis that maternal hydration would increase the AF index in women with low AF indexes. Women seen in our testing centers were randomized into control or hydration groups. The control group was instructed to drink their normal amount of fluid; the hydration group was instructed to drink 2 L of water, in addition to their usual amount of fluid, 2-4 hours before the post-treatment AF index. The women returned for the post-treatment AF index the same or following day. The mean post-treatment AF index was significantly greater in the hydration group (6.3 versus 5.1; P less than .01), as was the mean change in AF index (post-treatment AF index--pre-treatment AF index: 1.5 versus 0.31; P less than .01). These findings suggest that maternal oral hydration increases AF volume in women with decreased fluid levels.

Amniotic Fluid

Factors associated with postpartum hemorrhage with vaginal birth.

A case-control study was performed to study risk factors for postpartum hemorrhage. Cases of hemorrhage were defined by a hematocrit decrease of 10 points or more between admission and post-delivery or by the need for red-cell transfusion. Patients with antenatal bleeding were excluded. Among 9598 vaginal deliveries, postpartum hemorrhage occurred in 374 cases (3.9%). Three controls were matched to each case and multiple logistic regression was used to control for covariance among predictor variables. Factors having a significant association with hemorrhage were prolonged third stage of labor (adjusted odds ratio 7.56), preeclampsia (odds ratio 5.02), mediolateral episiotomy (4.67), previous postpartum hemorrhage (3.55), twins (3.31), arrest of descent (2.91), soft-tissue lacerations (2.05), augmented labor (1.66), forceps or vacuum delivery (1.66), Asian (1.73) or Hispanic (1.66) ethnicity, midline episiotomy (1.58), and nulliparity (1.45). These data may help predict postpartum hemorrhage and may be useful in counseling patients about the advisability of home delivery, intravenous access in labor, or autologous blood donation.

Case-Control Studies

Factors associated with hemorrhage in cesarean deliveries.

A case-control study was performed to study risk factors for hemorrhage in cesarean deliveries. Hemorrhage was defined by a pre- to post-delivery hematocrit decrease of 10 points or more or by the need for red-cell transfusion. Patients with antenatal bleeding were excluded. Among 3052 cesarean deliveries, hemorrhage occurred in 196 cases (6.4%). Three controls were matched to each case and multiple logistic regression was used to control for covariance among predictor variables. Factors having a significant association with hemorrhage were: general anesthesia (adjusted odds ratio 2.94), amnionitis (odds ratio 2.69), preeclampsia (2.18), protracted active phase of labor (2.40), second-stage arrest (1.90), and Hispanic ethnicity (1.82). After adjustment for these variables, a classic uterine incision had a small but significant association (odds ratio 1.06) with hemorrhage. Previous cesarean, parity, gestational age, and several other factors had no association with hemorrhage. These data allow one to anticipate hemorrhage in patients at risk and may be useful in planning appropriate use of blood bank resources, including antepartum autologous blood donation.

Blood Loss, Surgical

Prolonged third stage of labor: morbidity and risk factors.

Although retained placenta is a major cause of postpartum hemorrhage, there is no general agreement regarding when manual placental extraction is indicated to prevent hemorrhage. We sought to determine the following: 1) what duration of the third stage of labor is abnormal, 2) what duration is associated with complications, and 3) what antecedent conditions are associated with prolonged third stage. We studied 12,979 consecutive, singleton vaginal deliveries over an 11-year period. Third-stage duration had a log-normal distribution, with a geometric mean of 6.8 minutes, a median of 6 minutes, and an interquartile range of 4-10 minutes. A third stage of 30 minutes or longer occurred in 3.3% of the deliveries. The incidence of postpartum hemorrhage, transfusion, and D&C remained constant in third stages less than 30 minutes, then rose progressively, reaching a plateau at 75 minutes. The increase in these complications after 30 minutes was observed with both spontaneously delivered and manually extracted placentas. In a logistic regression analysis, factors significantly associated with prolonged third stage included: preterm delivery (odds ratio 3.81), delivery in a labor bed (odds ratio 2.17), preeclampsia (odds ratio 1.76), augmented labor (odds ratio 1.47), and nulliparity (odds ratio 1.45). Because there was no increase in hemorrhage until the third stage exceeded 30 minutes, we suggest that in the absence of bleeding, manual placental extraction is not indicated until 30 minutes have elapsed.

Female

Neonatal and maternal outcome in low-pelvic and midpelvic operative deliveries.

A retrospective analysis of low-pelvic and midpelvic operative deliveries (according to the new definitions by the American College of Obstetricians and Gynecologists, 1989) matched with cesarean section deliveries of similar station was undertaken. In all vaginally delivered groups there was significantly decreased maternal morbidity, maternal hospital stay, and estimated blood loss. In the midpelvic deliveries, there was a significant increase in the frequency of neonatal resuscitation and an increase in base deficit for the umbilical artery. In both the midforceps and low-forceps groups, there was a significant increase of neonates with cord arterial pH less than 7.10, and an increase of base deficit, even when cases of fetal distress were eliminated. The midforceps group also had an increased rate of admission to the intensive care nursery and an increase in the risk of significant birth trauma. In considering a midforceps or midvacuum operative delivery, the potential associated risks to the neonate must be balanced against the benefits to the mother.

Birth Injuries

Risk factors for third-degree and fourth-degree perineal lacerations in forceps and vacuum deliveries.

Third- and fourth-degree perineal lacerations occur frequently during operative vaginal deliveries. To identify risk factors for lacerations, 2832 consecutive forceps and vacuum extraction deliveries were analyzed. Third- and fourth-degree lacerations occurred in 30% of deliveries. Multiple logistic regression was used to control for intercorrelation between potential risk factors. Factors associated with increased risk for third- and fourth-degree lacerations were midline episiotomy, nulliparity, second-stage arrest, occipitoposterior position, low or mid station, use of forceps instead of vacuum, use of local anesthesia, and Asian race. When these factors were controlled, there was no effect of birth weight, faculty versus resident operator, gestational age, abnormalities of first-stage labor, or several other factors. Prevention of perineal lacerations requires that the operator identify the patient at risk. Possible options for management of high-risk patients include use of mediolateral episiotomy or no episiotomy, use of vacuum extraction instead of forceps, and use of conduction anesthesia.

Anesthesia, Obstetrical

Müllerian duct anomalies: MR imaging evaluation.

Twenty-nine patients underwent magnetic resonance (MR) imaging for investigation of müllerian duct anomalies (MDAs). The anomalies evaluated were uterine agenesis (n = 2), uterine hypoplasia (n = 5), unicornuate uterus (n = 5), uterus didelphys (n = 5), bicornuate uterus (n = 10), and septate uterus (n = 2). The MR imaging interpretation was correlated with results of laparotomy (n = 18), hysterosalpingography (HSG) (n = 5), laparoscopy (n = 2), hysteroscopy (n = 1), HSG and laparotomy (n = 2), and HSG and laparoscopy (n = 1). MR imaging enabled correct classification of the anomaly in each patient and identification of coincidental gynecologic disease in 10 patients (34%). MR imaging results influenced clinical treatment in six (24%) of 25 patients referred prospectively. Of particular value was the ability to characterize septal tissue (myometrium versus fibrous tissue), identify the patients in whom the septum of bicornuate uteri had both fibrous and myometrial components, and establish that suspected adnexal lesions were actually components of obstructed MDAs.

Adult

Evaluation of a risk-scoring system for prediction of preterm labor.

A scoring system was used prospectively to screen 7329 patients for risk of preterm labor over a 6-year period. When 15.8% of patients (1156 of 7329) were scored as high risk, sensitivity was 42.4% (multiparas, 55.2%, nulliparas, 29.8%) and positive predictive value was 22.8%. The incidence of preterm labor increased with increasing risk score; gestational age at delivery was negatively correlated with risk score. Analysis of individual factors revealed that more than half were not of predictive value in the population under investigation. A simplification of the system, defining 12 of the factors as major (high risk) and six as minor (2 or more indicates high risk) yielded a high risk group of 14.1%, sensitivity of 41.0%, and positive predictive value of 24.6%. Thus, although risk scoring does predict a substantial proportion of patients with preterm labor, its sensitivity is less than ideal. No advantage was gained with a larger and more complex system. Planning for preterm birth prevention programs should include recognition of the limitations of risk scoring, consideration of simplified systems, and investigation of additional biochemical or biophysical screening methods.

Female

Characteristics of normal labor.

The length of the first and second stages of labor was evaluated in 6991 women with singleton gestations at 37-42 weeks with vertex presentation. All patients delivered spontaneously without the use of oxytocin. Four study groups were created based on parity and whether conduction anesthesia was used. The mean lengths and limits (95th percentile) for the first stage of labor, respectively, were as follows: nulliparas: no anesthesia--8.1 and 16.6 hours, conduction anesthesia--10.2 and 19.0 hours; multiparas: no anesthesia--5.7 and 12.5 hours, conduction anesthesia--7.4 and 14.9 hours. Similar data for the second stage were as follows: nulliparas: no anesthesia--54 and 132 minutes, conduction anesthesia--79 and 185 minutes; multiparas: no anesthesia--19 and 61 minutes, conduction anesthesia--45 and 131 minutes. These statistical parameters are useful for defining when a labor becomes abnormal and intervention should be considered.

Anesthesia, Conduction