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.

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.

Therapeutic amenorrhea in hematologic disorders.

PIP: The feasibility of medical control of and prevention of uterine bleeding secondary to hematologic disease by the induction of prolonged amenorrhea with steroids was investigated. 29 patients were treated during a 30-month period. Mean age was 25.7 years and mean parity was 1.8. Acute lukemia and immune thrombocytopenic purpura were the most frequently primary diseases. Chronic lukemia, chronic renal disease, and aplastic anemia were also diagnosed. In 23 women menorrhagia had an unfavorable effect on the primary illness and in 14 it was present when treatment began. All platelet counts were very low. 3 drug regimens were used: 1) norethynodrel + mestranol, 2) depomedroxyprogesterone acetate (DMPA), and 3) DMPA + conjugated estrogens. Significant breakthrough bleeding occurred in 7 patients (24%) and was not related to the degree of thrombocytopenia. Average length of treatment was 15.3 weeks. During the study 18 patients died of their primary disease. Treatment was discontinued in 7 because of improvement in the primary disease. In 4 treatment is being continued. As DMPA is released slowly, in 10 urgent cases iv conjugated estrogens were given until bleeding was controlled or medroxyprogesterone acetate was given orally for a few days. Results show the feasibility of this method of producing therapeutic amenorrhea in the management of a variety of hematologic diseases. Fluid retention was more frequent with high estrogen dosage.^ieng

Implications of metric conversion.

The international scientific community is rapidly achieving conversion to the metric system, and the Système International (SI system) has been chosen for use by health scientists. Because the United States remains 1 of only 4 countries not now using part or all of the SI system, there is now a systematic effort toward rapid conversion. Although most of the SI system is not controversial, several SI units are highly so. Examples include joules instead of calories, pascals instead of millimeters of mercury, and moles per liter instead of milligrams per 100 milliliters. Obstetrician-gynecologists need to be familiar with the SI units and to voice their feelings about the various controversial units. There are decisions still to be made, and the time for discussion and advice is now.

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.

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.

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.

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.

Pathophysiology of disseminated intravascular coagulation in saline-induced abortion.

Our previous studies suggested that disseminated intravascular coagulation (DIC) may be a sequel to saline-induced abortion. A hypothetical mechanism for the DIC is that hypertonic saline produces cellular disruption in the products of conception with the release of thromboplastic substances into the amniotic fluid. These substances, in turn, diffuse through the damaged membranes into the maternal circulation. To examine this hypothesis we obtained samples of amniotic fluid (AF) from 5 patients just prior to and at 1 hour, 6 hours, and 24 hours after intraamniotic instillation of hypertonic saline. The procoagulant and thromboplastic properties of the various AF specimens were quantitated using the prothrombin time (PT), partial thromboplastin time (PTT), and activated clotting time (ACT) as in vitro test systems. The results indicate that a change in the procoagulant and/or thromboplastic activity of AF following saline instillation is not afactor in the pathophysiology of DIC associated with saline abortion.

Female sterilization. II. A comparison of methods.

An analysis was made of 1757 female sterilization procedures performed over a 5 1/2-year period. The majority of these were accomplished by one of 8 technics: puerperal abdominal tubal ligation (TL), cesarean section plus TL, hysterotomy plus TL, interval abdominal TL, colpotomy TL, laparoscopic TL, vaginal hysterectomy, and abdominal hysterectomy. The various technics have been compared with respect to 55 variables. The procedures having the shortest hospital stay, lowest morbidity, lowest blood loss, and shortest operating time were interval laparoscopic TL, colpotomy TO, and puerperal abdominal TL. The more major procedures were attended by significantly more morbidity and longer hospitalization and should be used only when specific indications justify the increased cost and risk.

PIP: A retrospective analysis of 1757 female sterilization procedures over a 5 1/2-year period from July 1, 1965 through June 30, 1970 is presented. Almost all of the procedures were performed by either puerperal abdominal tubal ligation (TL), colpotomy TL, laparoscopic TL, interval abdominal TL, cesarean section with TL, hysterotomy with TL, vaginal hysterectomy, or abdominal hysterectomy. Operative complications were present in 90 cases, the most common of which was excessive blood loss (67 cases). Laparoscopic TL appeared to be an excellent method, given its low morbidity (8.4%), low blood loss, and short operating time and hospitalization. Colpotomy TL and puerperal abdominal TL also had favorably low incidences of morbidity and blood loss. The incidence of morbidity and length of hospitalization were considerably greater for the more major sterilization procedures. Several variables related to risk, cost, and gynecological and psychological health should be considered by the surgeon before electing a sterilization procedure.

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.

California North Coast Preterm Birth Prevention project.

A demonstration project aimed at reducing the incidence of preterm birth in a rural population of Northern California was conducted using risk assessment, patient education, and education for providers as interventions. We compared 1914 preintervention deliveries with 7382 births during the intervention period. Although the percentage of preterm labor patients eligible for tocolysis was 34% greater during the intervention period than during the preintervention period, and the percentage of preterm labor patients who achieved term gestation was 53% greater in the intervention period, the overall rate of spontaneous preterm delivery in the population did not differ significantly in the two periods.

Puerperal tubal ligation morbidity, histology and bacteriology.

PIP: To assess the relationship of morbidity to the time interval between delivery and puerperal tubal ligation, 76 women were studied after receiving a tubal ligation. The women were divided into 4 subgroups relating to the time interval of the tubal ligation after delivery from 12-108 hours. Morbidity was defined as (1) puerperal morbidity: a temperature of 100.4 degrees F which occurs on any 2 of the first 10 post-partum days, and (2) other morbidity: a temperature of greater than 100 degrees F on any 1 of the first 10 post-partum days. Endometrial and tubal specimens were taken and tested for the presence of bacteria. In addition, tubal specimens were tested for salpingitis, edema, and perivascular infiltrate. There was no correlation between the time interval and post-operative morbidity. Positive endometrial cultures were found in 39.5% of the patients involved, and positive tubal cultures in 28.9%, which showed no correlation with time delay. There was significantly less histologic salpingitis in cases done within 36 hours after delivery. There was a correlation between salpingitis and positive tubal cultures. Post-operative morbidity did not correlate with either abnormal tubal histology or positive tubal cultures.^ieng

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.

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.

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.

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.

Suppurative salpingitis after laparoscopic tubal cauterization.

PIP: 3 case reports of suppurative salpingitis after laparoscopic tubal cauterization taken from a series of over 1800 such operations at the University of Michigan Medical Center are presented and examined for similar clinical characteristics that may suggest a common pathogenesis. In each case an intrauterine device was present until the time of surgery and in each case a uterine curettage had been done. The delay between the operation and the onset of the salpingitis symptoms ranged from 4-8 days. Pelvic surgery was necessary in 2 cases but high dosages of multiple antibiotics corrected the condition in the third patient. Though only 3 cases are involved, the presence of the IUD must be suspected as a possible cause of the infection, since these devices have caused similar physiologic reactions under other conditions. Removal of the IUD several weeks before tubal cauterization or prophylactic antibiotic treatment should be considered in patients with an IUD in situ undergoing this operation.^ieng

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.