Impending macrosomia: will induction of labour modify the risk of caesarean delivery?

OBJECTIVE: To compare the annual incidence rates of caesarean delivery between induction of labour and expectant management in the setting of macrosomia. DESIGN: This is a retrospective cohort study. SETTING: Deliveries in the USA in 2003. POPULATION: Singleton births of macrosomic neonates to low-risk nulliparous women at 39 weeks of gestation and beyond. METHODS: Women who had induction of labour at 39 weeks of gestation with a neonatal birthweight of 4000 ± 125 g (3875-4125 g) were compared with women who delivered (either induced or spontaneous labour) at 40, 41 or 42 weeks (i.e. expectant management), assuming an intrauterine fetal weight gain of 200 g per additional week of gestation. Similar comparisons were made at 40 and 41 weeks of gestation. Chi-square test and multivariable logistic regression analysis were used for statistical comparison. MAIN OUTCOME MEASURES: Method of delivery, 5-minute Apgar scores, neonatal injury. RESULTS: There were 132,112 women meeting the study criteria. In women whose labours were induced at 39 weeks and who delivered a neonate with a birthweight of 4000 ± 125 g, the frequency of caesarean was lower compared with women who delivered at a later gestational age (35.2% versus 40.9%; adjusted OR 1.25, 95% CI 1.17-1.33). This trend was maintained at both 40 weeks (36.1% versus 42.6%; adjusted OR 1.31, 95% CI 1.23-1.40) and 41 weeks (38.9% versus 41.8%; adjusted OR 1.16, 95% CI 1.06-1.28) of gestation. CONCLUSIONS: In the setting of known birthweight, it appears that induction of labour may reduce the risk of caesarean delivery. Future research should concentrate on clinical and radiological methods to better estimate birthweight to facilitate improved clinical care. These findings deserve examination in a large, prospective, randomised trial.

Outcomes associated with cesarean section versus vaginal breech delivery at a university hospital.

OBJECTIVE: To determine whether vaginal breech delivery is associated with increased morbidity in term breech singletons using strict selection criteria. This study encompasses our previous studies (in 1987 and 1995) and extends our experience to 21 years. STUDY DESIGN: Retrospective cohort study from 1980 to 2001 including term, non-anomalous singleton breech deliveries selected by strict criteria. Univariable and multivariable analyses were performed for neonatal and maternal outcomes. RESULTS: Five hundred and eleven women underwent cesarean section and 214 a trial of labor. We found greater overall maternal morbidity in the cesarean section group (odds ratio (OR) 1.89, 95% confidence interval (CI)=1.34-2.65). In the vaginal delivery group, neonates were more likely to have had >1 day of mechanical ventilation (OR 10.0, 95% CI=1.56-63.9). No maternal deaths occurred and no neonatal deaths or seizures occurred. CONCLUSION: Given our findings, offering a trial of vaginal breech delivery to well-counseled strictly selected patients remains an appropriate option.

Maternal and neonatal outcomes after uterine rupture in labor.

OBJECTIVE: There is significant controversy about the risks related to attempted vaginal birth after cesarean and the implications for informed consent of the patient. Recent data suggest that women who deliver in hospitals with high attempted vaginal birth after cesarean rates are more likely to experience successful vaginal birth after cesarean, as well as uterine ruptures. We conducted a study to evaluate maternal and neonatal morbidity and mortality after uterine rupture at a tertiary care center. STUDY DESIGN: We performed a retrospective chart review of cases of uterine rupture from 1976 to 1998. All women who had a history of uterine rupture were identified with International Classification of Diseases, Ninth Revision, identifiers with hospital discharge data cross-referenced with a separate obstetric database. We abstracted demographic information, fetal heart rate patterns, maternal pain and bleeding patterns, umbilical cord gas values, and Apgar scores from the medical record. Outcome variables were uterine rupture events and major and minor maternal and neonatal complications. RESULTS: During the study period there were 38,027 deliveries. The attempted vaginal birth after cesarean rate was 61.3%, of which 65.3% were successful. We identified 21 cases of uterine rupture or scar dehiscence. Seventeen women had prior cesarean deliveries (10 with primary low transverse cesarean delivery, 3 with unknown scars, 1 with classic cesarean delivery, 2 with two prior cesarean deliveries, and 1 with four prior cesarean deliveries). Of the 4 women who had no history of previous uterine surgery, one had a bicornuate uterus whereas the others had no factors increasing the risk for uterine rupture. We confirmed uterine rupture and scar dehiscence in 19 women. Specific details were not available for 2 patients. Uterine rupture or scar dehiscence was clinically suspected in 16 women with 3 cases identified at delivery or after delivery. Sixteen women had symptoms of increased abdominal pain, vaginal bleeding, or altered hemodynamic status. There were 2 patients who required hysterectomies and 3 women who received blood transfusions; there were no maternal deaths related to uterine rupture. The fetal heart rate pattern in 13 cases showed bradycardia and repetitive variable or late decelerations. Thirteen neonates had umbilical artery pH >7.0. Two cases of fetal or neonatal death occurred, one in a 23-week-old fetus whose mother had presented to an outlying hospital and the second in a 25-week-old fetus with Potter's syndrome. All live-born infants were without evidence of neurologic abnormalities at the time of discharge. CONCLUSION: Our data confirm the relatively small risk of uterine rupture during vaginal birth after cesarean that has been demonstrated in previous studies. In an institution that has in-house obstetric, anesthesia, and surgical staff in which close monitoring of fetal and maternal well-being is available, uterine rupture does not result in major maternal morbidity and mortality or in neonatal mortality.

Maternal and fetal outcomes in pregnancies affected by von Willebrand disease type 2.

We report a case series that lends support for both the maternal and neonatal safety of vaginal delivery in pregnancies complicated by heritable von Willebrand disease types 2A and 2B. With proper hematologic support, a cesarean delivery may be indicated only for obstetric reasons.

Incidence of persistent birth injury in macrosomic infants: association with mode of delivery.

OBJECTIVE: Our purpose was to determine the incidence of birth injury in a cohort of macrosomic infants (birth weight >4000 gm) and analyze the association between persistent injury and delivery method. STUDY DESIGN: Deliveries of 2924 macrosomic infants were reviewed. Outcomes were compared with those of 16,711 infants with birth weights between 3000 and 3999 gm. RESULTS: Macrosomic infants had a sixfold increase in significant injury relative to controls (relative risk 6.7,95% confidence interval 6.5 to 6.9). Risk of trauma correlated with delivery mode: forceps were associated with a fourfold risk of clinically persistent findings compared with spontaneous vaginal delivery or cesarean section. However, the overall incidence of persistent cases remained low (0.3%); a policy of elective cesarean section for macrosomia would necessitate 148 to 258 cesarean sections to prevent a single persistent injury. Avoidance of operative vaginal delivery would require 50 to 99 cesarean sections per injury prevented. CONCLUSIONS: These findings support a trial of labor and judicious operative vaginal delivery for macrosomic infants.

Hyperreactio luteinalis differentiated from severe ovarian hyperstimulation syndrome in a spontaneously conceived pregnancy.

The clinical presentation of hyperreactio luteinalis can mimic ovarian hyperstimulation. Historically, though, the former most often leads to unnecessary surgery whereas the latter is treated supportively. We present a case of a 32-year-old woman who was initially seen with markedly enlarged multicystic ovaries, ascites, and pleural effusions in the tenth week of a spontaneously conceived gestation. Despite a noniatrogenic cause, the patient received supportive management, as would be given with ovarian hyperstimulation syndrome. Making the distinction between hyperreactio luteinalis and ovarian hyperstimulation syndrome has important consequences for diagnosis and management.

Umbilical cord blood acid-base state: what is normal?

OBJECTIVE: Umbilical cord blood gases and acid-base data from vigorous neonates were examined to determine normal values and ranges. STUDY DESIGN: The University of California, San Francisco, Perinatal Data Base was used to retrieve information from deliveries between 1977 and 1993. Newborns with 5-minute Apgar scores > or = 7 were selected because it is generally accepted that a vigorous newborn has not had substantial intrapartum asphyxia lasting until delivery. RESULTS: Full blood gas and obstetric data were available for 16,060 newborns. Of these, 15,073 (94%) had a 5-minute Apgar score > or = 7. The median umbilical artery values, with 2.5th percentile values in parenthesis, were pH 7.26 (7.10), PCO2 52 mm Hg (74), base excess -4 mEq x L(-1) (-11), and PO2 177 mm Hg (6). Although the distributions were skewed, the mean +/- 2 SDs were similar to these values. Data for these babies were further analyzed by method of delivery, gestational age, presentation, and presence of thick meconium. Although the means were significantly different in all groups, the differences between groups were relatively small. CONCLUSION: A wide range of acid-base values were found in babies with normal Apgar scores, defining the "physiologic acidemia" of the normal vigorous newborn.

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.

Thalassemia in pregnancy.

The responsibility of the obstetrician is to identify during the first trimester women who are carriers for thalassemia. When she has been identified, the father of the baby should be screened and if he is also a carrier, the couple should be offered prenatal diagnosis. In the majority of cases, prenatal diagnosis can identify the homozygous fetus, thus allowing the family a choice in continuing the pregnancy.

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.

Mode of delivery in pregnancies complicated by preeclampsia with very low birth weight infants.

The aims of this study were to examine data from an institution at which the goal has been to pursue vaginal delivery in patients with a preterm gestation and preeclampsia and to test the hypothesis that labor does not increase the risk of poor outcome for the preterm infant of a mother with preeclampsia. An analysis of all singleton infants born live who weighed 1500 gm or less and who were born to mothers with preeclampsia or eclampsia from 1975 to 1990 was undertaken. The infants who were delivered by cesarean section without labor and with a reassuring fetal assessment were compared with the infants who went through labor. Of 116 women with singleton pregnancies with preeclampsia and an infant who weighed 1500 gm or less, 54.3% were delivered by cesarean section without labor, 31.0% because of nonreassuring fetal assessment and 23.3% (group 1) because of other indications. Of the patients allowed to labor (group 2), 47.2% had cesarean sections because of fetal intolerance of labor and 32.1% were delivered vaginally. Of the patients who were delivered vaginally, 75% had an unfavorable Bishop's score at the outset of the induction. There was no significant difference between groups 1 and 2 for a number of immediate and long-term outcome variables except for a lower incidence of respiratory distress syndrome in the infants who went through labor. On the basis of these limited data a trial of labor should be considered in carefully selected women with preeclampsia who have very-low-birth-weight infants.

Three consecutive pregnancies in a patient with glycogen storage disease type IA (von Gierke's disease).

Glycogen storage disease type IA is associated with metabolic abnormalities that can compromise fetal outcome. Normal outcome can be achieved by maintaining euglycemia throughout gestation. We report three consecutive pregnancies in a patient with glycogen storage disease type IA. The patient, a 35-year-old woman, has been maintained on a regimen of nightly nasogastric or cornstarch feedings for the past 12 years with improving metabolic control, reduced liver size, and no progression of multiple hepatic adenomas. On confirmation of each pregnancy, early in the first trimester nightly feeding was changed from cornstarch ingestion to Polycose by nasogastric intubation, with good metabolic control. During the last trimester of each pregnancy metabolic control showed further improvement, with lowering of lactate, urate, and triglyceride levels. During the first pregnancy unexpected fetal death occurred at 33 weeks. During the last two pregnancies, the patient was admitted at 33 and 34 weeks, respectively, for closer supervision of metabolic status and fetal monitoring. She underwent a cesarean section at 35 weeks 4 days of gestation and was delivered of a girl. She underwent a repeat cesarean section at 35 weeks 2 days for the subsequent gestation and was delivered of a boy. Both infants are healthy and appear to be unaffected by von Gierke's disease. Hepatic adenomas did not enlarge during the pregnancies. Meticulous management resulted in normal pregnancy outcomes in two consecutive gestations. Rapid fetal growth late in the third trimester may require particularly careful supervision to maintain euglycemia.

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.

Pregnancy outcome in nulliparous women aged 35 or older.

OBJECTIVE: Our objective was to test the hypothesis that pregnancies beyond 20 weeks in women aged 35 or older are high-risk pregnancies. STUDY DESIGN: Pregnancies of 857 women aged 35 and older were compared with pregnancies of 1597 women aged 20 to 29 with respect to pregnancy complications and outcome. All women received prenatal care and were delivered at our institution. Data were collected prospectively and stored in a data base. The chi 2 test was used to identify trends in individual variables and outcomes. Logistic regression analysis was used to examine the relationship between maternal age and delivery by cesarean section. RESULTS: Women aged 35 or older had cesarean deliveries twice as often as women 20 to 29 years old. This statistically significant difference was not accounted for by the modestly higher rates of fetal distress, placenta previa, multiple gestation, abnormal labor, or malpresentation found in the older group. Cord blood gas values and 5-minute Apgar scores did not differ between the two groups. There was no difference in neonatal morbidity or mortality. CONCLUSIONS: Women of 35 or older are more likely than those in their 20s to have cesarean deliveries. The excess rate of cesarean section is only partially accounted for by gestational complications.

Active-phase arrest in labor: predictors of cesarean delivery in a nulliparous population.

OBJECTIVE: To identify clinical variables associated with cesarean delivery for active-phase arrest with hypotonic labor. METHODS: We reviewed all deliveries at our institution from September 1975 through March 1989. Data were collected from medical records and a computerized data base. Nulliparas with active-phase arrest were identified and those with hypotonic labor (defined as less than 180 Montevideo units) were selected. The clinical characteristics of each parturient were examined. A linear logistic regression analysis was used to examine the incidence of cesarean delivery as a function of clinical variables. RESULTS: The incidence of active-phase arrest was 4.9%, and hypotonic forces were diagnosed in 81% of the cases managed with an intrauterine pressure catheter. Despite the consistent use of oxytocin in hypotonic labor, the cesarean rate was 60%. Four factors correlated with cesarean delivery in this setting: estimated fetal weight, station at the time of arrest, duration of ruptured membranes, and year of delivery. CONCLUSIONS: After an active-phase arrest, cesarean delivery increased when there was suspected cephalopelvic disproportion. In addition, we observed a strong correlation between cesarean delivery and the year of delivery, which suggests a change in physician behavior over time, independent of all other risk factors for cesarean.

Supportive nurse-midwife care is associated with a reduced incidence of cesarean section.

OBJECTIVE: Our purpose was to examine whether care by a certified nurse-midwife, including personal labor support, was associated with a reduced risk of cesarean delivery. STUDY DESIGN: A retrospective cohort study comparing 3551 physician-managed patients with 1056 certified nurse-midwife-managed patients in a university hospital with a mixed socioeconomic and ethnic population was performed. Regression analysis was used to estimate the risk of labor abnormalities, diagnosis of fetal distress, and cesarean delivery in patients delivered by a certified nurse-midwife vs a physician and to control for maternal age, race, parity, fetal size, and delivery year. Subjects included were women having at least five prenatal visits who were delivered of term, singleton, liveborn infants without congenital anomalies with occiput presentation. RESULTS: Odds ratio for cesarean section for women delivered by certified nurse-midwives versus those delivered by physicians was 0.71 (95% confidence interval 0.55, 0.91). Midwifery care was associated with a lower risk of abnormal labor (adjusted odds ratio 0.70, 95% confidence interval 0.60, 0.83) and diagnosis of fetal distress (adjusted odds ratio 0.50, 95% confidence interval 0.32, 0.77). CONCLUSION: This work demonstrates that labor abnormalities and diagnosis of fetal distress are less frequent in patients cared for by nurse-midwives, and there is an association with a lower incidence of cesarean section.

Maternal and neonatal outcomes after prolonged latent phase.

OBJECTIVE: To examine the association of prolonged latent phase with cesarean risk, subsequent labor abnormalities, and other adverse maternal and neonatal outcomes. METHODS: Patients with prolonged latent phase were compared to patients with normal latent phase. We studied 10,979 singleton vertex deliveries of at least 37 weeks' gestation. Patients with risk factors for adverse outcome known before labor were excluded from the analysis. RESULTS: Seven hundred thirteen patients (6.5%) had prolonged latent phase. Subsequent labor abnormalities were more frequent among patients with prolonged latent phase (42.9 versus 16.3%; P < .05), as was cesarean delivery (24.4 versus 6.9%; P < .05). Need for neonatal resuscitation, thick meconium, maternal fever, low 5-minute Apgar score, intensive care nursery admission, lengthened maternal and newborn hospital stays, and higher estimated blood loss were all significantly more frequent in patients with prolonged latent phase after controlling for mode of delivery. Multivariate linear logistic regression models were created to determine whether these risks actually reflected the prolonged latent phase. The first model controlled for other labor abnormalities, parity, epidural use, and macrosomia and showed prolonged latent phase to be associated with an increased risk for cesarean delivery (relative risk [RR] 1.65, 95% confidence interval [CI] 1.32-2.06). The second model controlled for other labor abnormalities, postdates, thick meconium, mode of delivery, and prolonged rupture of membranes and showed that both the need for newborn resuscitation and 5-minute Apgar scores less than 7 were significantly more frequent in association with a prolonged latent phase (RR 1.37 and 1.97, 95% CI 1.15-1.64 and 1.23-3.16, respectively). CONCLUSIONS: Prolonged latent phase is independently associated with an increased incidence of subsequent labor abnormalities, need for cesarean delivery, depressed Apgar scores, and need for newborn resuscitation. The presence of prolonged latent phase should alert the clinician to an increased risk for further problems during the labor.

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.

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.