The use of fetal echocardiography for predicting intrapartum fetal heart rate patterns in the post-term pregnancy.

One of the shortcomings of antepartum testing in the post-term pregnancy is that it does not identify the majority of fetuses who develop abnormal intrapartum fetal heart rate changes. The purpose of this study was to determine whether antenatal cardiovascular evaluation could aid in the identification of post-term fetuses at risk for intrapartum heart rate abnormalities. Seventy-five patients with a gestational age greater than 41 weeks underwent a non-stress test, amniotic fluid index and real-time assessment of the heart for the presence or absence of a pericardial effusion. M-mode measurements of the right ventricular inner dimension (RVID), left ventricular inner dimension (LVID), biventricular outer dimension (BVOD) and Doppler velocimetry of the umbilical artery (S/D) were performed. Group I (n = 32) had normal intrapartum heart rate tracings. Group II (n = 20) had abnormal intrapartum fetal heart rate tracings but did not undergo emergency delivery. Group III (n = 23) had abnormal intrapartum fetal heart rate tracings but underwent emergency delivery. When comparing Group I with Group II, the latter had significant differences for abnormal RVID, RVID/LVID ratio, and pericardial effusion. When comparing Groups I and III, there were significant differences for RVID, RVID/LVID ratio, pericardial effusion, BVOD, LVID and amniotic fluid index. Neither the non-stress test nor S/D predicted abnormal intrapartum fetal heart rate patterns. For prediction of abnormal intrapartum heart rate patterns, the sensitivities of the RVID (0.79), LVID (0.33), RVID/LVID ratio (0.72) and BVOD (0.63) were 1.7-4 times greater than the non-stress test (0.19) and the sensitivities of the RVID, RVID/LVID ratio and BVOD were 2 times greater than the amniotic fluid index (0.28). The positive (0.50-0.86) and negative (0.42-0.68) predictive values were similar for all groups. To predict emergency delivery associated with abnormal heart rate tracings, the sensitivities of the RVID (0.83), RVID/LVID ratio (0.70) and BVOD (0.65) were 2.5-3 times greater than the non-stress test (0.26) and 1.5 times greater than the amniotic fluid index (0.39). The positive (0.36-0.56) and negative (0.70-0.86) predictive values were similar. The presence of pericardial effusion had a higher sensitivity than the non-stress test and amniotic fluid index for predicting abnormal intrapartum heart rate patterns but not emergency delivery. Doppler velocimetry of the umbilical artery had a lower sensitivity than the non-stress test and amniotic fluid index for predicting intrapartum heart rate patterns as well as identifying the fetus needing emergency delivery. The results of this study would suggest that there is initially dilatation of the right ventricle which may be associated with abnormal intrapartum fetal heart rate patterns. However, when the left ventricle dilates, leading to cardiomegaly, there is a greater incidence of abnormal intrapartum fetal heart rate changes and associated emergency delivery. The amniotic fluid index appears to be a later finding for predicting abnormal intrapartum fetal heart rate changes.

The intrauterine probe electrode.

An intrauterine probe electrode was inserted into 100 laboring women and 366 bipolar electrode combinations were tested. A noise-cancelling technique was used with the final 28 subjects to remove competing maternal cardiac signals. Twenty-four (86%) had fetal heart rate tracings with sufficient technical quality to allow determination of the baseline fetal heart rate.

Fetal death following antepartum fetal heart rate testing: a review of 65 cases.

The nonstress test (NST) remains in widespread use for antepartum fetal surveillance. Our institutional experience with 14,028 patients and 38,645 tests over eight years reveals a fetal death rate of 2.6 per 1000 within seven days of a reactive NST. The autopsy findings of 53 fetal deaths are presented. The most common findings, in descending order of frequency, were meconium aspiration, perinatal infection, and abnormal umbilical cord position. These findings support changes we have made in our antepartum assessment protocols.

The nonlaboring transverse lie. A management dilemma.

During a one-year period, 29 patients at 37 weeks' gestation or later were referred to the breech version clinic at Los Angeles County/University of Southern California Medical Center and found to have sonographic evidence of a transverse lie. Because of the relative instability of the lie and the high probability of spontaneous conversion, the patients were not considered candidates for version and were returned to their referral agencies for subsequent prenatal care. The subsequent outcomes in these patients were reviewed. Twenty-four (83%) spontaneously converted to a longitudinal lie and presented in labor with either a vertex (15 [52%]) or breech (9 [31%]) presentation. The five (17%) remaining patients presented in labor with a persistent transverse lie. Overall, the cesarean section rate was 13 of 29, or 45%. The indications for cesarean section were breech presentation, eight (62%), and transverse lie, five (38%). Major complications included two prolapsed cords, one spontaneous uterine rupture and one neonatal death. Based on a review of our experience, it appears reasonable to consider external version in any patient with a persistent transverse lie around 39 weeks. The high rate of subsequent cesarean section and major morbidity associated with expectant management of these patients suggests that if version is unsuccessful, strong consideration should be given to elective cesarean section.

Antepartum fetal heart rate testing. XII. The effect of manual manipulation of the fetus on the nonstress test.

A prospective study of 790 patients was performed in order to examine the role of manual manipulation of the fetus in the nonstress test. The patients were assigned randomly to two groups based on the last two digits of their hospital number. The odd-numbered patients underwent manual manipulation of the fetus prior to the onset of the nonstress test; the even-numbered patients did not. There was no significant difference between the two groups with respect to the indications for testing and the total number of tests. There was no statistically significant difference between the two groups with respect to the ratio of reactive to nonreactive nonstress tests and the mean duration of testing. Simple manual manipulation of the fetus does not seem to change the outcome in antepartum fetal heart rate testing when the nonstress test is the primary one.

External cephalic version with tocolysis. Observations and continuing experience at the Los Angeles County/University of Southern California Medical Center.

We considered 113 consecutive patients for attempted external cephalic version with tocolysis (ECV-T) after 37 weeks' gestation. We randomized the first patients to the control group (no ECV-T attempted, 23 patients) or the study group (ECV-T attempted, 25 patients). Nine patients were excluded, and ECV-T was then considered for 88 patients, with a success rate of 77% for the 104 total attempts. Six patients were lost to follow-up. In the successful ECV-T group, 71 of 75 patients (95%) presented the vertex in labor, while 4 patients (5%) reverted to breech. Uterine exploration at delivery revealed uterine anomalies in three of the patients who reverted. The cesarean rate was 25% in the successful-ECV-T group and 87% in the failed-ECV-T group. In the initial group, four patients (18%) spontaneously converted to cephalic presentations after 37 weeks. None of the failed-ECV-T patients spontaneously converted to cephalic presentations. The cesarean rate for the control and failed-ECV-T patients presenting the breech intrapartum was 88%. Complications included transient fetal bradycardia in 37 patients (36%), evidence of fetomaternal bleeding (positive Kleihauer-Betke test) in 2 patients (2%) and one fetal demise three weeks following successful ECV-T and diagnosed at the onset of labor. We lowered the cesarean section rate for breech presentation in labor with the selective application of ECV-T late in gestation. We consider this technique to be a powerful addition to our armamentarium for managing the term breech presentation.

Observations of fetal heart rate characteristics related to external cephalic version and tocolysis.

External cephalic version performed in conjunction with tocolysis in the term breech presentation has been found to decrease the number of breech presentations at delivery and thus reduce the number of cesarean sections for breech presentation. However, information regarding the fetal heart rate (FHR) patterns associated with version is limited. In an attempt to broaden our understanding of the FHR changes that occur in association with version, the FHR tracings of 141 patients who had undergone version were analyzed. Approximately 39% of the fetuses exhibited changes in FHR characteristics during and/or after attempted version. These FHR changes were primarily manifested as bradycardias and/or decelerations. However, some of the fetuses (less than 5%) demonstrated a tachycardia or sine wave pattern. All of these FHR changes were transient and bore no apparent relationship to the subsequent outcome of the fetus. In addition to these FHR alterations, the incidence of diminished FHR variability (less than or equal to 5 bpm) was significantly higher after version than before version (p less than 0.01). The decline in FHR variability lasted 15 +/- 12 minutes. While this decline in variability appeared to be related to the success or failure of the version, the decreased variability observed after version was found to be unrelated to the tocolytic agent used and to the subsequent fetal outcome. In summary, alterations in FHR activity were frequent during the version process. All were transient and most responded to cessation of manipulation. Subsequent fetal outcome was apparently unrelated to the observed FHR alterations. Nonetheless, continuous fetal monitoring during and after the version is recommended.

Effect of antepartum glucocorticoid administration upon neonatal respiratory distress syndrome and perinatal infection.

A double-blind, randomized study comparing the antepartum use of betamethasone (12 mg), methylprednisolone (125 mg), and hydrocortisone (250 mg) was performed to evaluate effect on neonatal respiratory distress syndrome and perinatal infection. Of 144 mothers and 149 infants entered, 92 mothers and 97 infants were available for analysis. The betamethasone-treated group had a significantly reduced incidence of severe respiratory distress syndrome (4%) compared with the control group (26%; p = 0.038); this effect was confined to patients who received at least two doses. No similar effect was found in the methylprednisolone or hydrocortisone groups. Neonatal infection and neonatal mortality rate were not affected by glucocorticoid use. Maternal infection was significantly increased in hydrocortisone-treated patients who were delivered vaginally compared with control patients (all patients: 50% versus 9.5%, p less than 0.05; with ruptured membranes: 63% versus 15%, p = 0.04). No similar increase in maternal infection was found with betamethasone or methylprednisolone use.

Fetal hiccups: an associated fetal heart rate pattern.

Fetal hiccups are commonly diagnosed during the antepartum period, and they have a tendency to recur. The reflex of hiccuping is similar to that of gasping, except hiccuping efforts are made against a closed airway. An episode of intrapartum hiccups was confirmed via real-time ultrasound scanning during monitoring with a direct fetal scalp electrode. A neonatal heart rate pattern during hiccuping is also included. Distinctive fetal and neonatal heart rate patterns were observed during the hiccuping episode. It is speculated that the fetal heart rate pattern seen with hiccups may resemble that of fetal gasping.

Maternal and fetal response to alphaprodine during labor. A preliminary study.

Alphaprodine is a synthetic narcotic, structurally similar to meperidine. Respiratory depression has been reported as a not-infrequent side effect when larger doses of alphaprodine were used, particularly intravenously. In this study, the maternal respiratory rate and tissue pO2 and pCO2 were determined in patients receiving alphaprodine, 0.4 mg/kg of prepregnancy weight, for first-stage analgesia. Statistically significant falls in maternal tcpO2 and increases in tcpCO2 were observed. The baseline fetal heart rate decreased significantly 20 minutes after the injection (139 to 132 bpm). There was no increase in abnormal fetal heart rate patterns. The variability of the baseline fetal heart rate was unchanged until 25 minutes following alphaprodine administration, when a significant reduction occurred. The changes seen in the parameters monitored in this study were not associated with any clinically adverse effects on the mother or fetus.

Antepartum fetal heart rate testing. V. The nonstress test--an outpatient approach.

A total of 567 tests were performed in a 1 year period on 399 patients in an outpatient clinic setting to test the feasibility of an office approach to antepartum heart rate testing. Of these tests, 510 were reactive and 57 were nonreactive (NR); 15 NR tests had associated spontaneous CST's; 39 NR tests and one reactive test with an equivocal spontaneous CST were repeated in 2 to 4 hours; 30 tests were reactive and nine tests remained NR. An oxytocin-induced CST was needed to clarify fetal status in only nine of 607 tests. With this approach, the NST may be quite appropriate for office use.