Underestimation of gestational age by conventional crown-rump length dating curves.

Inaccuracies in gestational age assignment based on published crown-rump length data were noted in patients with known ovulation dates. In this study, we tested the hypothesis that crown-rump length data derived from pregnancies with known ovulation dates differ from those of menstrually timed pregnancies. Seventy-two previously infertile women with known dates of ovulation had crown-rump length measurements from 35-79 days postovulation. We transformed the data to menstrual age (gestational age) by adding 14 days to the date of ovulation and compared our crown-rump length values with those of two previous reports. At corresponding crown-rump length values, the gestational ages from our data differed from those in the previous studies. We suggest using crown-rump length dating curves based on ovulation-timed pregnancies because crown-rump length data derived from menstrually dated pregnancies underestimate true gestational age.

Sonographic diagnosis of congenital heart disease: comparison between the four-chamber view and multiple cardiac views.

OBJECTIVE: To report our experience in the detection of congenital heart disease using both the four-chamber view of the heart as part of the standard obstetric ultrasound examination and multiple cardiac views as part of the detailed targeted examination. METHODS: All admissions to Children's Memorial Hospital of Northwestern University Medical Center with the diagnosis of congenital heart disease between June 1988 and April 1992 were identified (N = 1947). These admissions were matched to deliveries (N = 19,321) that occurred at Prentice Women's Hospital during the same period; of these, 10,004 had at least one obstetric ultrasound examination. All fetuses were scanned either with the standard obstetric ultrasound type of examination, featuring only the four-chamber view of the heart, or by the detailed targeted imaging type of study, featuring multiple cardiac views. The type of examination performed was based on the specific request of the attending obstetrician or gynecologist. RESULTS: Thirty-three neonates who had at least one obstetric ultrasound examination were treated for congenital heart disease. An additional five pregnancies were terminated secondary to serious fetal heart defects. When only the four-chamber view was visualized, 11 of 33 fetuses (33.3%) with confirmed congenital heart disease were detected. CONCLUSIONS: Assessment of the outflow tracts is crucial for detection of many forms of congenital heart disease. However, before this is accepted as the standard of care, both the obstetric and radiologic communities should develop their skills in cardiac imaging. Only then can this sophisticated type of cardiac examination be offered to pregnant women.

The Northwestern University Twin Study. XV: Rationales for a standard of care in compromised twin pregnancies.

Current antenatal technologies have improved the obstetrician's ability to assess fetal well-being as well as to diagnose fetal compromise. These technologies have given rise to very difficult ethical issues in the management of compromised twin pregnancies: for example, a choice must be made between putting a healthy twin at risk due to preterm delivery for the sake of a compromised cotwin or of allowing the compromised twin to die in order to buy time for the healthy twin. Though each case is unique, good medical practice requires a standard of care by which consistent patient management can be proposed. In the pluralistic environment of Northwestern Memorial Hospital, our staff has favored a standard of care based on patient autonomy. This approach demands: 1) a practitioner who offers a thorough explanation of the diagnosis and possible treatment approaches; 2) time for the patient and her partner to assimilate this information and test treatment options against their personal value system; 3) a third, but disinterested, party to facilitate patient understanding and value clarification; 4) a practitioner either willing to support the patient's decisions or refer her to another practitioner who will.

Vaginal birth after cesarean section for arrest of labor: is success determined by maximum cervical dilatation during the prior labor?

The charts of 229 patients who attempted a vaginal birth after a cesarean section were reviewed. A total of 103 patients had a prior cesarean section for either failure to progress or cephalopelvic disproportion. On the basis of the maximum cervical dilatation in the prior labor, the patients were categorized into three groups: 0 to 5 cm, 6 to 9 cm, and 10 cm. The success rates for vaginal delivery of 61%, 80%, and 69%, respectively, were not significantly different among groups (p = 0.31). When arrest of labor was not the indication for primary cesarean section, 78% of the patients were subsequently delivered of their infants vaginally. This was not significantly different from the 70% overall success rate achieved by the group with failure to progress or cephalopelvic disproportion (p = 0.17). Similarly, when the success rate for a trial of labor was plotted against neonatal birth weight, the trends were comparable in the groups with and without failure to progress or cephalopelvic disproportion. These data suggest that patients with a prior cesarean section for arrest of labor are good candidates for a trial of labor and that the cervical dilatation previously reached does not determine the likelihood of success.

Factors that influence route of delivery--active versus traditional labor management.

OBJECTIVE: Our purpose was to compare maternal and fetal factors that influence the route of delivery with active management of labor and a traditional labor management protocol. STUDY DESIGN: Data were collected prospectively on 346 consecutive patients receiving active management of labor and 354 patients who were managed traditionally. Within each group demographic and labor characteristics of patients undergoing cesarean section were compared with those of patients having vaginal deliveries by means of the Student t test, chi 2 analysis, and stepwise logistic regression. RESULTS: With both active management of labor and traditional labor management success in achieving vaginal delivery was related to the station of the fetal vertex at admission, the need for oxytocin augmentation of labor, the uterine response to oxytocin, the use of epidural anesthesia, and the development of chorioamnionitis. By means of multiple logistic regression analysis maternal age, height, payor status, and birth weight were also identified as risk factors for cesarean section with traditional labor management but not with active management of labor. CONCLUSIONS: Differences were identified in risk factors for cesarean section between active management and traditional labor management. Active management of labor may diminish or eliminate some patient characteristics as risk factors for cesarean birth.

The efficacy of oral terbutaline after intravenous tocolysis.

OBJECTIVE: Our purpose was to investigate in a prospective, randomized study the efficacy of oral terbutaline after successful intravenous tocolysis in reducing preterm birth. STUDY DESIGN: Patients between 28 and 35 weeks' gestation with uterine contractions and change in cervical examination were treated with intravenous magnesium sulfate for 12 to 24 hours. After successful tocolysis patients were approached for study participation and randomized to receive either oral terbutaline or no therapy. The dose of terbutaline was individualized to achieve a maternal pulse > 100 beats/min, and terbutaline was continued until 36 completed weeks of gestation. Recurrent preterm labor (contractions with change in cervical examination) for either group was treated with intravenous magnesium sulfate, and subsequent treatment was based on the previous randomization. RESULTS: Fifty-five patients were enrolled (28 terbutaline, 27 no oral tocolytic). No difference was found between groups with respect to time gained (4.0 +/- 2.7 vs 4.6 +/- 3.1 weeks, p = 0.412), gestational age at delivery (35.6 +/- 2.7 vs 36.1 +/- 2.4 weeks, p = 0.562), > or = 37 weeks at delivery (nine vs 13, p = 0.291), recurrent preterm labor (10 vs four, p = 0.104), recurrent uterine contractions alone (five vs eight, p = 0.527), birth weight (2616 +/- 633 gm vs 2645 +/- 599 gm, p = 0.785), special care nursery admissions (eight vs six, p = 0.759), or neonatal respiratory distress syndrome (three vs two, p = 0.965). CONCLUSION: The use of oral terbutaline after successful parenteral tocolysis failed to reduce the rate of preterm birth.

Cesarean section rates in low-risk private patients managed by certified nurse-midwives and obstetricians.

This study was designed to assess the impact of selected medical interventions during labor upon cesarean section rates by comparing the maternal and neonatal outcomes of obstetrician- and nurse-midwife-managed low-risk private patients. All patients who delivered at Prentice Women's Hospital in Chicago, Illinois, from January 1, 1987 through December 31, 1990 were evaluated for low-risk criteria to be included in the study. During that time, the nurse-midwives delivered 573 patients and the obstetricians delivered 12,077 patients. Patients with fetal and maternal complications known to increase the cesarean section rate were eliminated from both groups. Eight percent of the nurse-midwife patients and 32% of the physician patients were eliminated, leaving 529 nurse-midwife patients and 8,266 physician patients. These patients were compared for race, parity, age, and birth weight. Information was collected from a perinatal data base and hospital computerized statistics. The rates of cesarean section, administration of oxytocin, analgesia, anesthesia, and infant outcome data were compared by chi-square analysis. Multiple logistic regression analysis was used to assess factors that predicted cesarean section. Nurse-midwife-managed patients had a significantly lower rate of cesarean section (8.5% versus 12.9%; P < .005) and operative vaginal delivery (5.3% versus 17%, P = .0001) than the physician-managed patients. Epidural anesthesia and oxytocin for induction and augmentation were used significantly more frequently in the physician-managed patients. Both interventions were associated with an increased rate of cesarean section. Fetal outcomes in the two groups were not statistically different. Women cared for by nurse-midwives had a lower cesarean section rate, fewer interventions, and equally good maternal and infant outcomes when compared with those cared for by physicians.

Severe acidosis and subsequent neurologic status.

To examine the relationship between severe acidosis at birth and evidence of subsequent neurologic dysfunction, a 4-year review was performed encompassing 15,528 neonates. One hundred forty-two (0.91%) of these neonates had an umbilical cord arterial pH less than or equal to 7.05 with a base deficit greater than or equal to mEq/L. Neurologic assessments found 101 of 110 term neonates (91.8%) and 17 of 32 preterm neonates (53.1%) with severe acidosis to be free of neurologic deficits at the time of hospital discharge. Follow-up developmental evaluation data were available for 7 of 9 term neonates and 8 of 15 preterm neonates with abnormal examinations. Although 5 term and 6 preterm infants demonstrated mild developmental delays or mild tone abnormalities in the first year of life, none exhibited a major motor or cognitive abnormality at 12 to 24 months of age. Consequently, acidosis in umbilical cord blood, even when severe, is a poor predictor of subsequent neurologic dysfunction.

Prediction of fetoplacental blood volume in isoimmunized pregnancy.

Direct intravascular fetal transfusion under ultrasound guidance allows precise evaluation of both fetal anemia and adequacy of therapy. In addition, the change in hematocrit after transfusion may be used to estimate the circulatory fetoplacental blood volume. In this study we present the estimates of fetoplacental blood volume calculated at the time of intravascular fetal transfusions. Between March 1986 and March 1988, 60 intravascular fetal transfusions were performed in 20 patients. The 56 procedures in which fetal hematocrits were obtained both before and after transfusion were analyzed. The mean fetoplacental blood volume before transfusion was 94.0 ml/kg. Furthermore, the fetoplacental blood volume per kilogram fetal weight decreased with advancing gestation. These estimates of fetoplacental blood volume and changes relative to gestational age may be useful in the treatment of the severely isoimmunized fetus. Reliance on the more recently generated fetoplacental blood volumes may allow more accurate predictions of transfusion volumes and estimation of the hematocrit after transfusion.

Factors contributing to the increased cesarean birth rate in older parturient women.

OBJECTIVE: Our purpose was to determine factors contributing to the increased use of cesarean section in patients > or = 35 years old. STUDY DESIGN: Data were collected prospectively on nulliparous patients in spontaneous labor with term, singleton pregnancies and vertex presentations. Criteria for the diagnosis of labor were standardized: regular, painful uterine contractions at least once every 5 minutes in the presence of either complete cervical effacement or spontaneous rupture of membranes. The labors of women > or = 35 years old (n = 74) were compared with those of women 20 to 29 years old (n = 275). RESULTS: The cesarean section rate was significantly greater for patients > or = 35 years old (21.6% vs 10.2%, odds ratio 2.4, 95% confidence interval 1.2 to 5.1). Mean birth weights were similar in the two groups, but when birth weight was > or = 3600 gm patients > or = 35 years old were more likely to be delivered by cesarean section (36.7% vs 12.2%, odds ratio 4.0, 95% confidence interval 1.4 to 11.9). There were no differences between the two age groups in physician factors that could explain the disparate rates of cesarean delivery. Indeed, of patients delivered vaginally the older parturients received oxytocin for longer duration (6.4 +/- 2.6 vs 5.0 +/- 3.1 hours, p < 0.05) and at higher maximum doses (12.4 +/- 6.1 vs 9.8 +/- 6.2 mU, p < 0.05). After controlling for potentially confounding variables with multiple logistic regression analysis, maternal age (R = 0.125, p < 0.005), birth weight (R = 0.196, p < 0.001), the need for oxytocin (R = 0.210, p < 0.001), and epidural anesthesia (R = 0.195, p < 0.001) were found to be independently associated with the increased rate of cesarean section. CONCLUSION: We could not identify any controllable physician factors affecting the rate of cesarean section in patients > or = 35 years old. The increased oxytocin requirements and the incidence of dystocia with birth weight > or = 3600 gm suggest that maternal and fetal characteristics contribute to the increased frequency of cesarean section in older parturients.

Northwestern University Twin Study X: Outcome of twin gestations complicated by gestational diabetes mellitus.

Existing data concerning the effect of gestational diabetes on perinatal outcome in twin pregnancies is scant. We hypothesized that altered carbohydrate metabolism would worsen perinatal outcome in twin gestation in a manner similar to singleton gestation. Thirteen twin pregnancies complicated by gestational diabetes mellitus were matched by gestational age at delivery to 13 twin pregnancies unaffected by gestational diabetes. Comparing infants of diabetic mothers to infants of control mothers, there was a trend of greater likelihood of respiratory distress syndrome, hyperbilirubinemia, and prolonged neonatal intensive care nursery admissions. Our experience suggests that altered carbohydrate metabolism in multiple gestations increases the potential for neonatal morbidity.

Absence of hyperinsulinemia in isoimmunized fetuses treated with intravascular transfusion.

We serially sampled blood from fetuses of five severely isoimmunized pregnancies at the time of each intrauterine intravascular transfusion and at birth. We were unable to demonstrate either an elevation in the plasma insulin/glucose ratio or a relationship between the insulin/glucose ratio and hemoglobin concentration at any time period. Plasma total glutathione concentration, however, decreased dramatically from the initial to the second transfusion (323 +/- 114 to 43 +/- 9 ng/ml; t = -5.06, p less than 0.01). We speculate that intrauterine transfusion may modify or prevent the previously reported fetal pancreatic beta-cell hyperplasia and hyperinsulinemia associated with isoimmunization by decreasing red blood cell hemolysis and thereby circulating glutathione.

Cocaine use during pregnancy: adverse perinatal outcome.

Cocaine use has increased dramatically in the United States during the past decade. The life-threatening cardiovascular and central nervous system complications of cocaine have been well documented; however, few studies have examined the risks of cocaine use during pregnancy. In this report the perinatal outcome data of 70 women receiving care at the Perinatal Center for Chemical Dependence of Northwestern University, whose pregnancies were complicated by cocaine abuse, were compared with those of matched control subjects. The use of cocaine during pregnancy was associated with lower gestational age at delivery, an increase in preterm labor and delivery, lower birth weights, and delivery of small for gestational age infants.