Kirk A. Keegan

A randomized trial of ritodrine tocolysis versus expectant management in patients with premature rupture of membranes at 25 to 30 weeks of gestation

Expectant management was compared with similar management plus ritodrine tocolysis in a randomized controlled trial in patients with premature rupture of membranes at 25 to 30 weeks of gestation. In the tocolysis group intravenously administered ritodrine was instituted at the onset of labor and then changed to the oral form if successful. Tocolysis was discontinued or not instituted after 31 weeks of gestation. Seventy-nine patients were randomized over a 4-year period, 39 in the tocolysis group and 40 in the expectant group. Twenty-three patients in the tocolysis group actually received ritodrine. No difference between the two groups was demonstrated in the interval between premature rupture of membranes and delivery or in reaching 32 weeks of gestation. No statistical difference was seen in maternal morbidity. Birth weights and gestational ages at delivery were similar between the two groups as were the incidences of neonatal morbidities caused by prematurity and infection and in the duration of neonatal hospital stays. Despite being conducted in those gestational ages in which prolongation of pregnancy might be expected to be of most benefit, no difference could be demonstrated with the addition of tocolytic therapy over expectant management alone.

Interdelivery interval and the success of vaginal birth after cesarean delivery

OBJECTIVE To determine whether a short interdelivery interval is associated with decreased rate of successful vaginal birth after cesarean (VBAC). METHODS A retrospective cohort study from January 1, 1997, to December 31, 2000, was conducted. Patients with previous cesarean delivery who attempted VBAC were identified. The analysis was limited to patients at term with one prior cesarean. The interdelivery interval was calculated in months between the index pregnancy and prior cesarean delivery. RESULTS A total of 1516 subjects who attempted VBAC were identified among 24,162 deliveries, with complete data available in 1185 cases. The VBAC success rate was 79.0% for patients with an interdelivery interval less than 19 months compared with 85.5% for patients with an interval delivery greater than or equal to 19 months (P = .12). For patients whose labors were induced, interdelivery intervals of less than 19 months were associated with a decreased rate of VBAC success when compared with longer intervals (P < .01). Sufficient power (β = .95) existed to detect a 64% difference between the groups (&agr; = .05). No significant difference was detected in women who underwent spontaneous labor (P = .98). There was no difference in the rate of symptomatic uterine rupture (P = 1.00). CONCLUSION Interdelivery intervals of less than 19 months were associated with a decreased rate of VBAC success in patients who underwent induction, a difference not found in those with spontaneous labor.

Quantitation of uterine activity preceding preterm, term, and postterm labor

To assess uterine activity before labor in patients delivering preterm, at term, and postterm, the maximum spontaneous contraction frequency per 10-minute window during the initial portion of antepartum fetal heart rate monitoring was analyzed. Patients with multiple gestation, third trimester bleeding, polyhydramnios, or premature rupture of membranes and those already diagnosed with preterm labor were eliminated from the study. Of the 2446 remaining patients (7247 antepartum fetal heart rate tests) who went into spontaneous labor, 237 did so before 37 completed weeks of gestation, 1077 entered labor at term (38 to 42 completed weeks), and 1132 did so after 42 weeks. There was a significant increase in maximum uterine activity per 10-minute window from 30 to 44 weeks of gestation (average 4.7% per week; r = 0.97, p less than 0.0001). When compared with patients delivering spontaneously at term, average maximum uterine activity per 10-minute window was greatest in the preterm labor group (p less than 0.05) and least in the postterm labor group (p less than 0.05). These differences were present for several weeks preceding the onset of spontaneous labor. All three groups showed a surge of uterine activity during the 3 days before the onset of spontaneous labor.

The “dangerous multipara”: Fact or fiction?

OBJECTIVE Our purpose was to compare the intrapartum complication incidence among grand multiparous women with that of age-matched control multiparous women. STUDY DESIGN A total of 382 grand multiparous women (para > or = 5) were compared with 382 age-matched control subjects (para 2 to 4), all delivering between July 1989 and September 1991. Intrapartum complications classically associated with grand multiparity (abruptio placentae, dysfunctional labor, fetal malpresentation, postpartum hemorrhage, and shoulder dystocia) were compared. RESULT Both groups had comparable antepartum complications and gestational ages at delivery. The overall intrapartum complication incidence for grand multiparous women was 33% (127/382 patients), not significantly different from that of the control multiparous women, 27% (103/382). Grand multiparity was associated with an increased incidence of macrosomia (16% vs 11%) and a decreased incidence of operative delivery (14% vs 21%). Macrosomia increased the incidence of intrapartum complications from 31% to 46% (p < 0.03) in the grand multiparous patients, and a trend was observed in the multiparous patients, from 26% to 37%. However, when properly controlled, this was noted to be a confounding variable and was not related to parity. CONCLUSIONS In a largely Hispanic population grand multiparous patients do not have an increased incidence of intrapartum complications.

Obstetric characteristics and fetal heart rate patterns of infants who convulse during the newborn period

Seizure activity in the immediate neonatal period has been shown to correlate with long-term neurological handicap. The perinatal course of 34 term and 32 preterm infants who developed seizure activity in the neonatal period was compared to that of 66 matched control infants without neonatal seizure activity. The incidence of antenatal complications and abnormal fetal heart rate patterns and the percentages of abnormal labor, operative delivery, and low Apgar scores were significantly greater in the study infants than in the control infants. Earlier onset of seizure activity was seen in term versus preterm infants and term infants with abnormal versus normal fetal heart rate patterns. Management decisions regarding intervention or nonintervention based on fetal heart rate patterns were deemed appropriate in 31 of 34 term infants, yet short- and long-term neurological sequelae were significant.

Activation of intrinsic coagulation pathway in pre-eclampsia

Disseminated intravascular coagulation, thrombocytopenia, consumption of factors VIII and II, and antithrombin deficiency have been previously demonstrated in pre-eclampsia. However, the precise mechanism responsible for initiation of disseminated intravascular coagulation has not been elucidated. The present study documents activation of the intrinsic coagulation pathway in a patient with severe pre-eclampsia. The studies revealed marked reductions of plasma coagulant activities of all intrinsic pathway factors, i.e., XII, XI, IX, and VIII. In addition, the ratio of plasma factor XII activity to antigen concentration was markedly abnormal, and plasma high-molecular-weight kininogen concentration was diminished. It is suggested that activation of the intrinsic coagulation pathway may be operative in the genesis of disseminated intravascular coagulation in pre-eclampsia.

Use of fetal scalp hematocrit in the diagnosis of severe hemorrhage from vasa previa

Described in a case in which a timely diagnosis of severe fetal anemia from bleeding vasa previa was made with the aid of a fetal scalp hematocrit. This technique can be used in patients in labor when bleeding vasa previa is suspected, and scalp sampling is feasible.

A prospective evaluation of nipple stimulation techniques for contraction stress testing

Nipple stimulation techniques for achieving a contraction stress test were evaluated prospectively in 1271 nipple stimulation contraction stress tests in 753 patients. Success was unrelated to parity, gestational age, or warm, moist towels but was related to the presence of spontaneous prestimulation contractions. Various stimulation techniques were equally successful in achieving a completed test in the presence of prestimulation contractions; however, continuous stimulation was more successful when contractions were absent. Hyperstimulation test results occurred in 21.5% of attempts and increased to 28.8% when bilateral, continuous stimulation was performed.

Effects of norepinephrine on lung fluid flow rate in the chronically catheterized fetal lamb

The influence of norepinephrine on lung fluid flow rate was studied in seven chronically catheterized fetal lambs. Lung fluid was collected through a catheter inserted into the fetal trachea. In six experiments, continuous saline solution infusion for 1 hour followed by equivolumnar norepinephrine (3.0 micrograms/min) for 1 hour via the fetal jugular vein was carried out. In three additional experiments (two fetuses), a 3.0 mg intravenous bolus of propranolol was administered before norepinephrine infusion. Saline solution infusion did not influence the lung fluid flow rate or fetal biophysical and biochemical parameters. Norepinephrine increased fetal blood pressure by 22% and decreased lung fluid flow by 45% from control values. Lung fluid flow rate recovered within 2 hours after the end of the norepinephrine infusion. Pretreatment with propranolol did not alter the results. In addition to previous reports that demonstrated beta-sympathomimetic agonist-enhanced reabsorption of lung fluid from fetal alveolar epithelial cells, our present results suggest that a reduction in fetal lung fluid secretion may be implemented as well through stimulation of alpha-sympathomimetic receptor sites in the pulmonary vasculature.