Predictors of repeat cesarean delivery after trial of labor: do any exist?

BACKGROUND: We evaluated the predictive value of risk factors for repeat cesarean delivery identified in retrospective studies. STUDY DESIGN: We identified 175 consecutive patients who underwent trial of labor (TOL) and compared detailed admission, intrapartum, and postpartum characteristics of those who required repeat cesarean delivery with those who had vaginal births. We calculated relative risks, positive predictive values, and sensitivities for potentially predictive admission characteristics. We also performed multiple logistic regression and classification analyses. RESULTS: Ninety-five percent of eligible patients underwent a TOL, and 85 percent of them delivered vaginally. Patients who had labor induced and patients with high fetal station on admission were significantly more likely to require repeat cesarean section (relative risk [RR]=2.9 and 2.1; 95 percent confidence interval [CI]=1.5 to 5.3, 1.1 to 4.2, respectively), but even these patients had high rates of vaginal birth (67 percent and 75 percent, respectively). A subgroup of patients who underwent labor induction and had large fetuses (estimated weight 3,800 g or more) had a 75 percent risk of cesarean delivery (RR=2.5, 95 percent CI=0.9 to 7.5). Multivariate models using different combinations of admission characteristics could not correctly identify which patients would require repeat cesarean delivery. CONCLUSIONS: Admission characteristics with statistically significant risk ratios have low predictive values because of the extremely low rate of repeat cesarean delivery in this population. A larger series is needed to study TOL outcomes in patients with large fetuses who are being induced. We conclude that until risk factors with high predictive value for repeat cesarean delivery are identified, all eligible patients should be encouraged to undergo a TOL.

Maternal hepatitis B screening at a private hospital.

A prospective study was performed to determine whether the Centers for Disease Control risk factors are reliable predictors of the hepatitis B surface antigen (HBsAg) carrier state in the obstetric population at a large private hospital in Cincinnati. During the 12-month study period, 5,877 patients delivered at the hospital. The patients were screened for HBsAg either prenatally or on presentation in labor. Questionnaires were administered after arrival at the hospital to assess for historical risk factors. An overall 0.0925% incidence of HBsAg seropositivity was discovered. All patients who were HBsAg positive had identifiable risk factors.

Use of magnetic resonance imaging in the diagnosis of cortical blindness in pregnancy.

Magnetic resonance imaging (MRI) may be helpful in the assessment of eclampsia and preeclampsia with central nervous system symptomatology such as cortical blindness. We describe a rare case of complete binocular blindness postpartum with no other neurologic deficits, in which MRI abnormalities were undetected on computed tomography. The better soft-tissue discrimination of MRI may visualize important but subtle lesions which ultimately may help to explain the underlying pathophysiologic mechanism in such cases.

Cecal volvulus in pregnancy.

Cecal volvulus in pregnancy is an uncommon complication. A case is reported of a 28-year-old white female, gravida 2, para 1, who presented at 36 weeks' gestation with flu-like symptoms accompanied by regular uterine contractions every 3 minutes; she underwent repeat cesarean section without incident. The patient did well until the second postoperative day, when she developed obstructive bowel symptoms and underwent emergency laparotomy. Operative findings revealed cecal volvulus with partial malrotation of the small bowel, absence of the ligament of Treitz, agenesis of the left kidney, and a redundant sigmoid colon. Medical and surgical management of this case, as well as a general description of the symptoms of cecal volvulus, is discussed. Early diagnosis and operation are essential to avoid the high morbidity and mortality associated with this disease.

Significance of phosphatidylglycerol in amniotic fluid in complicated pregnancies.

In normal pregnancy lecithin/sphingomyelin ratios correlate with gestational age. In complicated pregnancies biochemical maturation of fetal lung may be accelerated or delayed, depending upon maternal, fetal, or placental conditions. Surfactant contains other phospholipids besides lecithin, including phosphatidylglycerol (PG), the second major component of mature surfactant. Ninety phospholipid patterns in amniotic fluid were studied by two-dimensional thin-layer chromatography. In uncomplicated pregnancies PG was absent until 37 weeks' gestation, then increased there after. In complicated pregnancies (pre-eclampsia, diabetes Classes D, F, and R, premature rupture of membranes) PG was identified before 35 (as early as 29 weeks' gestation. These results verify accelerated lung maturation in certain complicated pregnancies. No newborn infant developed respiratory distress syndrome in the presence of PG.

Antepartum fetal heart rate testing. I. Evolution of the nonstress test.

On May 1, 1975, at Women's Hospital, Los Angeles County--University of Southern California Medical Center, a new antepartum fetal heart rate (AFHRT) protocol was put into clinical use. This included the widely used contraction stress test (CST) and a new concept of nonstress testing (NST). The NST was based on FHR response associated with fetal movements and was categorized as reactive (normal) or nonreactive (abnormal). The nonreactive fetus was then evaluated with a CST if not contraindicated. During the 24 months, May 1, 1975 to April 30, 1977, a total of 2,422 NST's were done in 1,169 patients with 1,547 (64 per cent) reactive and 829 (35 per cent) nonreactive. CST was done 939 times, with 851 (90.6 per cent) negative, 29 (3 per cent) positive, 13 (1.4 per cent) equivocal, and 46 (5.0 per cent) unsatisfactory. There were ten (3.3 per cent) perinatal deaths within one week of a negative CST, five (1.0 per cent) within one week of a reactive NST, and two (8.7 per cent) with a positive CST. A reactive NST was as predictive of good outcome as was a negative CST. Analysis of the nonreactive NST showed that two or more accelerations were not associated with abnormal CST's. Also, some nonreactive fetuses became reactive with oxytocin and had good outcome. These observations were utilized in the development of a newer, shorter NST which allows for fetal stimulation in an attempt to further define fetal well-being.

Antepartum fetal heart rate testing. II. Intrapartum fetal heart rate observation and newborn outcome following a positive contraction stress test.

The positive contraction stress test (CST) has been looked upon as a predictor of fetal compromise. On this basis, some reports advise routine cesarean delivery on the assumption that the compromised fetus should not tolerate labor. Other authors advocate selective cesarean delivery, based on obstetrical factors such as the inducibility of the cervix and the practicality of fetal monitoring. Finally, an attempted trial of labor may be allowed on the basis of occurrence of fetal heart rate acceleration with fetal movement, or "reactivity." The occurrence of "false positive" tests is not infrequent (20 to 45 per cent). The definition of such is unclear and little quantitative information regarding intrapartum performance is available. In this series of 27 patients, a trial of labor was undertaken in 20. Vaginal delivery occurred in 11 (55 per cent) and cesarean section in nine (45 per cent). Fetal heart rate abnormalities thought to indicate "distress" occurred in five patients (25 per cent). The "positive" window or repetitive late deceleration as equivalent to the positive CST was seen in only three patients during labor. A trial of labor should be attempted in the face of a positive CST whenever obstetric factors are favorable and careful intrapartum monitoring can be performed.

Antepartum fetal heart rate testing: the nonstress test.

Antepartum assessment of fetal well being relies heavily on the observation of RHR. Fetal stress testing was introduced in the early 1970's in an attempt to define the fetus at risk. The stress factor most widely used has been uterine contractions, which isolate the fetus from its oxygen supply, and in the compromised fetus would be anticipated to provoke late decelerations in the FHR. Although the contraction stress test or "oxytocin challenge test" is useful in evaluating fetal condition, it is time consuming, not easily quantitatable or repeatable, and many times difficult to interpret. An attractive alternate approach of antepartum FHR testing (AFHRT) is the "nonstress" test. The positive experience of European investigators has led to interest in this method of fetal assessment in North America. Investigation from the literature contrasting the "stress" versus "nonstress" methods is discussed and observations derived from 2 year experience at LAC/USC Medical Center are presented. A protocol for AFHRT currently being evaluated clinically is presented.

Fetal demise following negative contraction stress tests.

The contraction stress test (CST) has become widely used to assess antepartum fetal well-being over the past 5 years. A summary of 14 reports in the literature revealed seven fetal deaths in 1739 patients within 1 week of a negative CST, an incidence of 0.4%. This prompted an investigation of our results for comparison. During the period January 1, 1975, to February 28, 1977, 746 patients underwent 1119 CSTs. Seven fetal deaths occurred in 680 patients within 1 week of a negative CST, an incidence of 1.0%. Although maternal conditions associated with fetal demise within 1 week of a negative CST include diabetes mellitus, prolonged pregnancy, chronic hypertension, and pre-eclampsia, fetal death in most instances resulted from factors other than uteroplacental insufficiency (UPI). Conditions commonly associated with fetal demise following a negative CST were umbilical cord accidents, severe congenital anomalies, and abruptio placentae. The low incidence of fetal death after a negative CST supports continued use of the CST in evaluation of high-risk pregnancies.