Hospital surgical volume-outcome relationship in caesarean hysterectomy for placenta accreta spectrum.

OBJECTIVE: To examine the association between hospital surgical volume of caesarean hysterectomy and surgical morbidity in women with placenta accreta spectrum (PAS). DESIGN: Population-based retrospective cohort study. SETTING: National Inpatient Sample, January 2016 to December 2018. POPULATION: Six thousand and ten women with PAS who underwent caesarean hysterectomy in 738 centres. METHODS: (1) Comprehensive modelling for relative hospital surgical volume cut-point selection, (2) multinomial regression analysis for characterising hospital surgical volume, and (3) binary logistic regression analysis to examine the volume-outcome relationship. MAIN OUTCOME MEASURES: Surgical morbidity (haemorrhage, coagulopathy, shock, urinary tract injury, and death). RESULTS: The majority of centres had five surgeries over the 3-year period (468 centres, 63.4%) and were grouped as the low-volume group. Surgical morbidity decreased after a relative hospital surgical volume of 25 cases (24 centres, 3.3%) was reached, grouped as the high-volume group. The remaining centres were grouped as the mid-volume group (246 centres, 33.3%). In multivariable analysis, women in the high-volume group were more likely to be Black, have lower median household income, medical comorbidity, previous caesarean delivery, placenta praevia or placenta percreta, and to have undergone surgeries at large urban teaching hospitals compared with those in the low-volume group (all, P < 0.05). After controlling for patient demographics, hospital characteristics and pregnancy factors, performance of caesarean hysterectomy at high-volume centres was associated with a 22% decreased risk of surgical complications compared with surgery at the low-volume centres (adjusted odds ratio 0.78, 95% CI 0.64-0.94). CONCLUSION: Caesarean hysterectomy for PAS is a rare surgical procedure. Higher hospital surgical volume may be associated with improved surgical outcome in PAS. TWEETABLE ABSTRACT: Higher hospital caesarean hysterectomy volume may be associated with improved surgical outcome in PAS.

Pre-pregnancy weight and excess weight gain are risk factors for macrosomia in women with gestational diabetes.

OBJECTIVE: To determine whether women with gestational diabetes mellitus (GDM) whose weight gain exceeded the 2009 Institute of Medicine (IOM) recommendations were more likely to have macrosomia. STUDY DESIGN: Retrospective cohort study of the association of weight gain in women with Class A1 GDM, with term (≥37 weeks) singleton liveborns and macrosomia (birthweight ≥4000 g). Multivariate logistic regression models were used to adjust for covariates and test for interactions. RESULT: Of 1502 women studied, pre-pregnancy body mass index (BMI) categories were: normal (39.6%), overweight (28.5%) and obese (31.9%). The mean (±standard deviation ) weight gain (lbs) for these groups was: 27.6±10.9, 24.2±13.0 and 18.8±16.3 (P<0.0001), whereas the occurrence of macrosomia was 7.4, 11.4 and 19.0%, respectively. Women with an obese BMI were twice as likely to have a macrosomic infant compared with women in the normal BMI group (odds ratio, OR 2.0; 95% CI 1.4-3.0; P=0.0005). Independently, women who exceeded the IOM guidelines were three times more likely to have a macrosomic infant (OR 3.0, 95% CI 2.2-4.2, P<0.0001). CONCLUSION: Maternal pre-pregnancy weight and weight gain during pregnancy appear to be significant and independent risk factors for macrosomia in women with GDM.

Brachial plexus palsy: an in utero injury?

Acquired brachial plexus injury historically has been linked with excessive lateral traction applied to the fetal head, usually in association with shoulder dystocia. Recent reports in the obstetric literature, however, have suggested that in utero forces may underlie a significant portion of these injuries. Brachial plexus palsies may therefore precede the delivery itself and may occur independent of the actions of the accoucheur. Thus we propose that the long-held notions of a traction-mediated pathophysiologic mechanism for all brachial plexus injuries warrant critical reappraisal.

Obstetric maneuvers for shoulder dystocia and associated fetal morbidity.

OBJECTIVE: We sought to determine the fetal injury rate associated with shoulder dystocia and to determine whether there is a higher rate of brachial plexus injury or bone fracture when fetal manipulation techniques are required for delivery. STUDY DESIGN: A retrospective review of 285 cases of shoulder dystocia that occurred between January 1991 and December 1995 was performed. The type, sequence, and combination of obstetric maneuvers used to relieve the shoulder dystocia were noted. These cases were divided into two groups, as follows: (1) those resolved with McRoberts' maneuver, suprapubic pressure, or proctoepisiotomy or a combination of these and (2) those that required the addition of direct fetal manipulative maneuvers (Woods, posterior arm, or Zavanelli). Fetal injury was defined as the occurrence of brachial plexus palsy, clavicular fracture, humeral fracture, or fetal death caused by asphyxial complications. RESULTS: The fetal injury rate was 24.9% (71/285), including 48 (16.8%) brachial plexus palsies, 27 (9.5%) clavicular fractures, and 12 (4.2%) humeral fractures. Sixteen infants had both nerve injury and bone fracture. Four (8.9%) brachial plexus palsies had documented persistence at 1 year of follow-up. One neonatal death occurred at age 3 months after an episode of hypoxic ischemic encephalopathy. The incidence of bone fracture was not higher when direct fetal manipulation was required: 21 of 127 (16.5%) versus 18 of 158 (11.4%), p = 0.21. The incidence of brachial plexus palsy was also similar in both groups (27/127 vs 21/158, p = 0.1). CONCLUSIONS: Direct fetal manipulation techniques used to alleviate shoulder dystocia are not associated with an increased rate of bone fracture or brachial plexus injury.

Permanent Erb's palsy: a lack of a relationship with obstetrical risk factors.

Our objective was to investigate the association between permanent Erb's palsy and the presence of historic obstetrical risk factors. Cases of documented permanent Erb's palsy from our national registry of children with Erb's palsy were extracted and analyzed for the purpose of this descriptive study. Maternal and neonatal records were reviewed for demographic data, prenatal care, labor characteristics, delivery outcome, and long-term follow-up. Sixty-three infants with permanent Erb's palsy were identified. Seventeen (27.0%) mothers were nulliparous. Mean +/- SD (range) gestational age at delivery and birthweight were 39.9 weeks +/- 1.3 (37-43) and 4501 g +/- 625 (3352-6905), respectively. Maternal and perinatal characteristics of these cases were (n [%]): nondiabetic-56 (89%); weight gain <40 lb-48 (76%); normal labor-57 (91%); 2nd stage <2.0 hr-54 (86%); midpelvic procedure-13 (21%); and shoulder dystocia-59 (94%). There were no statistically significant differences between patients with birthweight >4500 g (n = 26 [41%]) and those with birthweight < or =4500 g (n = 37 [59%]). These data suggest that historic risk factors for neonatal brachial plexus injury may not be associated with permanent Erb's palsy.

Spontaneous vaginal delivery: a risk factor for Erb's palsy?

OBJECTIVE: Our purpose was to determine whether Erb's palsies occurring in the absence of shoulder dystocia differ from those occurring after shoulder dystocia. STUDY DESIGN: We compared the time course of resolution and incidence of persistent injury at 1 year of age in 17 cases of Erb's palsy without shoulder dystocia and 23 cases associated with shoulder dystocia. RESULTS: The rate of persistence at 1 year was significantly higher in those Erb's cases without identified shoulder dystocia, 7 of 17 (41.2%) versus 2 of 23 (8.7%), p = 0.04. These cases of Erb's palsies also took longer to resolve (6.4 +/- 0.9 vs 2.6 +/- 0.7 months, p = 0.002), had a higher rate of associated clavicular fracture (12 of 17 vs 5 of 23, p = 0.006), and were more likely to occur in the posterior arm (10 of 15 vs 4 of 21, p = 0.009). CONCLUSIONS: Erb's palsy occurring without shoulder dystocia may be a qualitatively different injury than that occurring with shoulder dystocia.

Symphyseal separation and transient femoral neuropathy associated with the McRoberts' maneuver.

Many authors have recommended the McRoberts' maneuver as the initial technique in the management of shoulder dystocia. There have been, however, no reported adverse maternal outcomes associated with this technique. We report a case of symphyseal separation and transient femoral neuropathy associated with the McRoberts' maneuver. An overly exaggerated lithotomy position and thigh abduction stretches the articular surfaces of the symphysis pubis and places increased pressure on the femoral nerve by the overlying inguinal ligament.

Brachial plexus palsy associated with cesarean section: an in utero injury?

OBJECTIVE: Brachial plexus injury may be unrelated to manipulations performed at the time of delivery, occurring in the absence of shoulder dystocia and in the posterior arm of infants with anterior shoulder dystocia. To further support the hypothesis that some of these nerve injuries appear to be of intrauterine origin, we present a series of brachial plexus palsies associated with atraumatic cesarean delivery among fetuses presenting in the vertex position. STUDY DESIGN: We performed a computerized search of all deliveries from 1991 to 1995 for the discharge diagnoses of brachial plexus injury and cesarean section. Inclusion criteria included cephalic presentation at the time of delivery and the absence of traumatic delivery. RESULTS: We noted six cases of Erb's palsy, with four palsies in the anterior shoulder and two in the posterior arm. Among those five patients undergoing cesarean section because of labor abnormalities, two had uterine cavity abnormalities whereas one had a prolonged second stage of labor. One brachial plexus palsy occurred in the absence of active labor. All nerve injuries were persistent at age 1 year. CONCLUSIONS: Brachial plexus palsy can be associated with cesarean delivery. Such palsies appear to be of intrauterine origin and are more likely to persist.

The accuracy of intrapartum ultrasonographic fetal weight estimation in diabetic pregnancies.

OBJECTIVE: Our purpose was to compare the accuracy of ultrasonographic fetal weight estimation in pregnant diabetic women with that of matched nondiabetic controls. STUDY DESIGN: We performed a case-control study of pregnant patients who underwent ultrasonographic fetal weight estimation within 3 days of delivery. The study group consisted of pregnant diabetic women and nondiabetic controls matched for maternal body mass index and neonatal birth weight. Fetal weight estimates were calculated with use of Hadlock's and Shepard's formulas. The difference between ultrasonographic fetal weight estimation and actual birth weight (absolute percent error) was analyzed with respect to maternal diabetic status and actual birth weight. RESULTS: A total of 450 patients were studied (225 patients in each group). The mean (+/- SD) gestational age at delivery was 39.0 +/- 1.5 weeks versus 39.9 +/- 1.7 weeks for the diabetic and nondiabetic patients, respectively. There was no statistically significant difference between the two groups with respect to the mean (+/- SD) time interval between the ultrasonographic examination and delivery (0.9 +/- 1.8 days vs 0.8 +/- 2.1 days) or the mean (+/- SD) absolute percent error (9.0% +/- 7.1% vs 8.4% +/- 6.3%). The mean (+/- SD) absolute percent error of fetal weight estimates among subjects with macrosomic fetuses (birth weight > or = 4500 gm) was significantly greater than that observed in fetuses with birth weights < 4500 gm (12.6% +/- 8.4% vs 8.4% +/- 6.5, p = 0.001). This difference was observed irrespective of maternal diabetic status. CONCLUSION: When matched for maternal body mass index and birth weight, the accuracy of ultrasonographic fetal weight estimation was similar among diabetic and nondiabetic women. Birth weights > or = 4500 gm rather than maternal diabetes seem to be associated with less accurate ultrasonographic fetal weight estimates.

Ultrasonographic fetal cardiac measurement in isoimmunized pregnancies.

OBJECTIVE: To investigate the predictive value of the ultrasonographically measured fetal biventricular outer dimension (BVOD) in diastole in detecting neonatal anemia in pregnancies complicated by isoimmunization. STUDY DESIGN: The records of all patients evaluated for isoimmunization in pregnancy from January 1992 to December 1994 were reviewed retrospectively. The fetal BVOD had been measured with real-time-directed M-mode fetal echocardiography. The BVOD measurement was plotted on a nomogram (with reference to biparietal diameter) and a percentile value determined graphically from the nomogram. Neonatal outcome was obtained prospectively and by chart review. RESULTS: Sixty-three singleton fetuses from the study period who met entry criteria were identified. Anti-D sensitization represented 66% of cases of isoimmunization. Twenty (32%) fetuses required subsequent neonatal transfusion, and 43 (68%) did not. Seventeen fetuses (27%) had BVOD measurements greater than the 95th percentile, and 10 (59%) required subsequent transfusion. Infants in this group also had significantly lower hematocrits at birth (37.7 +/- 13.0% vs. 46.6 +/- 9.0%) and prolonged neonatal intensive care unit stay (10.7 +/- 10.0 vs. 4.7 +/- 3.6 days), respectively, when compared to patients with a BVOD measurement less than the 95th percentile. A BVOD 95th percentile threshold had a sensitivity, specificity and positive predictive value of 50%, 84% and 59%, respectively, in predicting the need for neonatal transfusion. CONCLUSION: In patients with isoimmunization, a BVOD measurement in the 95th percentile or greater was associated with a relatively high likelihood of neonatal anemia and transfusion. Although the measurement is not sufficiently sensitive to be used as a single parameter in predicting neonatal compromise in these patients, it can be a useful, noninvasive adjunct to the management of isoimmunized pregnancies.

The McRoberts' maneuver for the alleviation of shoulder dystocia: how successful is it?

OBJECTIVE: Our purpose was to determine the rate of success of the McRoberts' maneuver as the initial treatment for shoulder dystocia and to compare the rate of maternal and neonatal morbidity with those cases of shoulder dystocia requiring additional obstetric maneuvers. A secondary goal was to assess those factors associated with successful McRoberts' maneuvers. STUDY DESIGN: A retrospective review of shoulder dystocia cases occurring between 1991 and 1994 was performed. The identified cases were divided into two groups on the basis of the maneuvers used to relieve the shoulder dystocia. The first group comprised cases in which the McRoberts' maneuver was used as the sole treatment and the second group consisted of cases in which additional maneuvers were subsequently used. Exclusion criteria included lack of documentation concerning the maneuvers used or cases in which the McRoberts' maneuver was not the initial technique used. The two groups were compared with respect to various antepartum, intrapartum, and neonatal characteristics. RESULTS: During the study period we identified 250 cases of shoulder dystocia among 44,072 vaginal deliveries, for an incidence of 0.57%. Of these, 236 cases (94%) fulfilled entry criteria. The McRoberts' position alone successfully alleviated the shoulder dystocia in 98 cases (42%). In the group of cases where the McRoberts' maneuver was the sole maneuver used, there were significantly lower mean birth weights (p = 0.008), shorter durations of the active phase of labor (p = 0.009), and shorter second stages (p < 0.0001). In the group of cases that required additional maneuvers to relieve the shoulder dystocia, there was a trend toward an increased incidence of postpartum hemorrhage and brachial plexus injury (p = 0.07). CONCLUSIONS: These data suggest that the McRoberts' maneuver is associated with a significant degree of success in relieving shoulder dystocia and may be associated with decreased morbidity compared with other maneuvers. On the basis of these findings, we recommend the McRoberts' maneuver as the initial technique for disimpaction of the anterior shoulder.

Permanent Erb palsy: a traction-related injury?

Historically, the primary risk factor attributed to brachial plexus injury during birth has been excessive traction applied at delivery to an entrapped anterior shoulder. However, recent evidence has suggested that not all cases of brachial plexus palsy are attributable to traction. We have encountered several cases of permanent Erb palsy associated with birth that were not attributable to traction applied at delivery. We reviewed cases of neonates with documented permanent Erb palsy that occurred either in the absence of shoulder dystocia or in the neonate's posterior arm in the presence of anterior shoulder dystocia. We identified four cases that occurred in the absence of shoulder dystocia and four cases that occurred in the posterior arm of infants with anterior shoulder dystocia. These data further support the notion that the etiology of permanent brachial plexus palsy associated with birth may not be related to traction.

Radiologic studies in acute fatty liver of pregnancy. A review of the literature and 19 new cases.

OBJECTIVE: Radiologic findings thought to be characteristic of acute fatty liver of pregnancy have been described in a limited number of cases. We describe wide experience with liver imaging of this disease. STUDY DESIGN: A retrospective review was performed on charts from 1982 to 1994 to identify those patients with acute fatty liver of pregnancy who had radiologic studies. RESULTS: Twenty-eight patients with acute fatty liver of pregnancy were identified, for an incidence of 1/6,692 births. Nineteen patients underwent at least one imaging study, and seven had more than one. Findings consistent with fatty infiltration of the liver are found in 3/11 patients with ultrasound, 5/10 with computed tomography (CT) and 0/5 with magnetic resonance imaging (MRI). Three patients with normal ultrasound scans subsequently had evidence of fatty filtration on CT scan. CONCLUSION: Detection of fat in the liver of patients with acute fatty liver of pregnancy with current imaging techniques is limited and did not contribute to the management of patients in this series. Further studies are necessary to define to role of MRI--in particular, spectroscopy.

Intrahepatic cholestasis of pregnancy: perinatal outcome associated with expectant management.

OBJECTIVE: Our goal was to compare the pregnancy outcomes of patients with intrahepatic cholestasis of pregnancy managed expectantly with antepartum testing with those of other patients who were followed up with a similar testing scheme. STUDY DESIGN: Cases of intrahepatic cholestasis of pregnancy monitored with antepartum testing at our institution over a 7-year period were reviewed. Their pregnancy outcomes were compared with those of control patients followed up with the same testing scheme for a history of stillbirth. Both groups had at least weekly nonstress tests and amniotic fluid assessment until spontaneous labor or delivery for standard obstetric indications RESULTS: Seventy-nine patients were analyzed in each group. The two groups did not differ with respect to the mean gestational age at delivery (38.5 vs 38.8 weeks), birth weight (3216 vs 3277 gm) or incidence of preterm delivery (14% vs 7.6%). Abnormal antepartum testing prompting delivery was more common in the control group (25% vs 7.6%, p < 0.05). The risk of meconium passage was higher in the cholestasis group (44.3% vs 7.6%, p < 0.05). Two antepartum fetal deaths occurred in the cholestasis group at 36 to 37 weeks' gestation within 5 days of normal results of antepartum testing. Thick meconium and appropriate birth weight were noted in both infants. No gross anomalies were found in either infant. CONCLUSION: Intrahepatic cholestasis of pregnancy is associated with adverse perinatal outcome not predicted by conventional fetal surveillance.

Clinical significance of prenatal ultrasonographic intestinal dilatation in fetuses with gastroschisis.

OBJECTIVE: Our purpose was to evaluate the clinical significance of intestinal dilatation detected by prenatal ultrasonographic examination in fetuses with gastroschisis. STUDY DESIGN: A retrospective chart review was performed of all patients cared for at Los Angeles County/University of Southern California Women's and Children's Hospital with the prenatal diagnosis of gastroschisis over a 7-year period (1988 through 1995). Patients were divided into two groups on the basis of the presence or absence of ultrasonographically measured fetal bowel diameter of > or = 17 mm. Neonatal outcomes of the two groups were compared. RESULTS: Twenty-one patients met the entry criteria during the study period. Fetuses with maximal bowel diameter of > or = 17 mm did not have a longer time to full oral feeding, a longer initial hospital stay, or a greater need for bowel resection when compared with fetuses with a bowel diameter < 17 mm. Two newborns underwent bowel resection because of intestinal atresia. Prenatal ultrasonographic examination failed to show significant bowel dilatation in either infant. CONCLUSION: Our data suggest that prenatal evidence of intestinal dilatation in fetuses with gastroschisis does not predict immediate neonatal outcome. Thus this finding is not an appropriate indication for preterm delivery in the absence of other evidence of fetal compromise.

The nonreactive nonstress test: predictive value for neonatal anemia in the isoimmunized pregnancy.

OBJECTIVE: To assess the value of the fetal nonstress test (NST) in predicting neonatal transfusion in pregnancies complicated by red cell isoimmunization. METHODS: We retrospectively reviewed the records of all patients evaluated for isoimmunization in pregnancy for the period January 1992 to December 1994. In addition to prenatal care, serial ultrasonography, and invasive testing when indicated, patients had NSTs two times per week. Nonstress tests were interpreted as either reactive or nonreactive using standard criteria. Results of the last NST before delivery were analyzed. Neonatal outcome data were obtained prospectively and by chart review. RESULTS: Sixty patients with isoimmunization were identified during the study period. Fifty-one patients (85%) had reactive NSTs until delivery, and nine (15%) had nonreactive NSTs that prompted delivery. Twelve of 51 (23.5%) patients with reactive NSTs and seven of nine (77.8%) patients with nonreactive NSTs required neonatal transfusion (P = .003, odds ratio 11.4 [95% confidence interval (CI) 1.7-120.2]). The mean (standard error of the mean; range) hematocrit (%) at birth was 38.9 (3.0; 21.3-52.0) in patients with reactive NSTs and 28.3 (3.8; 14.5-45.0) in those with nonreactive NSTs (P < .05). A nonreactive NST had a 77.8% positive predictive value (95% CI 49.0-100) in identifying the need for neonatal transfusion. CONCLUSION: These findings indicate that a nonreactive NST is predictive of subsequent neonatal transfusion in patients with isoimmunization. The antepartum fetal NST is a useful adjunct in the management of isoimmunized pregnancies.

Prognostic significance of antenatally detected fetal pyelectasis.

In order to evaluate the prognostic significance of ultrasonographically detected fetal pyelectasis, a retrospective review was performed of patients evaluated for fetal pyelectasis over a 24-month period. From 84 patients a total of 98 fetal kidneys with pyelectasis were identified. Fetal pyelectasis was more common in the left kidney and in males. Postpartum evaluation revealed 48 (57.1%) neonates with hydronephrosis. Among these, mean (SD; range) values of antenatal fetal pyelectasis were 17.0 mm (8.4; 5-26) before 33 weeks and 16.9 mm (8.5; 5-34) after 33 weeks in the left kidney and 15.4 mm (3.3; 10-24) and 17.1 mm (5.1; 5-36), respectively, in the right kidney. Thirteen infants (15.4%) with hydronephrosis required surgical pyeloplasties (mean age 6 months; range 3-18 months). It was found, from a receiver-operating characteristic curve, that fetal pyelectasis of 8 mm was 91% sensitive and 72% specific in predicting subsequent hydronephrosis. Use of a threshold of 5 mm yielded a sensitivity of 100% and a specificity of 24%. On the basis of these findings, we recommend that women with ultrasonographically detected antenatal fetal pyelectasis of > or = 5 mm at any gestational age have follow-up ultrasound examinations and detailed postnatal evaluation.

Clinical role of amnio-infusion.

Amnio-infusion is a simple, yet beneficial, technique for improving pregnancy outcome. Antepartum amnio-infusion has been shown to be beneficial as an aid to enhancing ultrasonographic fetal imaging and may have a role in the administration of antibiotic therapy or the prevention of pulmonary hypoplasia. There are considerable data to support the intrapartum use of amnio-infusion in the presence of oligohydramnios, variable decelerations or meconium. Numerous prospective clinical trials have shown a significant benefit of amnio-infusion in reducing the rate of emergency caesarean section for fetal distress and complications related to meconium when used for these indications. Additional research is needed to clarify further its intrapartum role in patients with premature rupture of membranes or chorio-amnionitis.

Systemic vascular resistance index determined by thoracic electrical bioimpedance predicts the risk for maternal hypotension during regional anesthesia for cesarean delivery.

OBJECTIVE: Our purpose was to evaluate the predictive value of the baseline systemic vascular resistance index for the development of maternal hypotension during regional anesthesia for cesarean delivery. STUDY DESIGN: Patients receiving a standardized spinal or epidural anesthetic for nonemergency cesarean delivery were studied prospectively. Hemodynamic data were obtained noninvasively with an NCCOM-3 cardiac output monitor (Bomed Medical Manufacturing, Irvine, Calif.), which uses thoracic electrical bioimpedance to estimate stroke volume and cardiac output. Measurements obtained were indexed to body surface area. The systemic vascular resistance index was calculated from mean arterial pressure and thoracic electrical bioimpedance-derived cardiac index. Hemodynamic data obtained were analyzed to identify statistically significant predictors of maternal hypotension. RESULTS: Maternal hypotension occurred in 24 of 42 (57%) patients studied. The incidence of hypotension did not differ between the types of anesthesia: spinal 17 of 274 (62%) versus epidural 7 of 15 (47%, p=0.48). The mean interval to the onset of hypotension was 12.2 minutes (SD 2.2 minutes, range 2 to 24 minutes). Mean (SD) baseline maternal systolic blood pressure was higher in patients who had hypotension (145 torr [4]) than those who did not (129 torr [4], p=0.01). The mean (SD) baseline systemic vascular resistance index was higher in patients who had hypotension (633 [SD 36] dyne . cm . sec-5/m2) than those who did not (454 [SD 29] dyne . cm . sec-5/m2; p =0.001). With receiver-operator characteristic curves, a baseline systemic vascular resistance index of 500 had a sensitivity of 83%, a specificity of 78%, a positive predictive value of 83%, and a negative predictive value of 78% for maternal hypotension (odds ratio 17.5, 95% confidence interval 3.1 to 109.4). A baseline systolic blood pressure of 140 torr had a sensitivity and specificity of 42% and 72%, respectively (odds ratio 1.9, 95% confidence interval 0.4 to 8.8). CONCLUSIONS: Baseline systemic vascular resistance index obtained by noninvasive cardiac output monitoring with thoracic electrical bioimpedance and systolic blood pressure are useful to predict the risk for maternal hypotension with regional anesthesia. Patients with increased baseline systemic vascular resistance index or systolic blood pressure are at increased risk for hypotension.

Amnioinfusion in women with previous cesarean births: a preliminary report.

OBJECTIVE: Our purpose was to evaluate the use of intrapartum amnioinfusion in women undergoing a trial of labor after a previous cesarean delivery. STUDY DESIGN: Labor and delivery records of women undergoing intrapartum amnioinfusion over a 1-year period were reviewed retrospectively. Neonatal data were obtained by chart review. RESULTS: During the study period 936 women underwent intrapartum amnioinfusion for the following indications: oligohydramnios (76.6%), meconium-stained amniotic fluid (12.8%),and variable decelerations (7.5%). Among these, 122 (13%) had previous cesarean births. Seventy-one (58.2%) women were delivered vaginally; the remaining 51 (41.8%) were delivered by repeat cesarean. Among women undergoing intrapartum amnioinfusion there were no statistically significant differences (p<0.05) between those with previous cesarean births and those with unscarred uteri with respect to the following: cesarean section for fetal distress (1.6% vs 1.4%), meconium aspiration (0% vs 0.9%), or low 5-minute Apgar scores (2.5% vs 0.9%). There were no perinatal or maternal deaths in either group. One uterine rupture occurred in a woman with one previous cesarean birth. CONCLUSIONS: Amnioinfusion appears to be an acceptable procedure in women with previous cesarean births. The incidence of uterine rupture (0.8%) noted was similar to the 10-year institutional rate at Los Angeles County-University of Southern California Women's Hospital (0.7%).