Frank H. Boehm

Pregnancy-related Rupture of Arterial Aneurysms

Over 50 per cent of ruptured arterial aneurysms in women under the age of 40 are pregnancy-related. The hemodynamic and endocrine changes of pregnancy appear to be the cause of arterial alterations which may lead to new aneurysm formation and/or weakening of preexisting aneurysms. The most commonly reported arteries to have aneurysms rupture during pregnancy are the aorta, cerebral arteries, splenic artery, renal artery, coronary artery, and ovarian artery. In many instances, the rupture of an arterial aneurysm will initially simulate other less serious disease processes, thus delaying the correct diagnosis until a catastrophic event occurs. Early diagnosis and treatment of a ruptured arterial aneurysm are imperative in order to give optimal chances of survival to the mother and fetus.

In utero Repair of Myelomeningocele: A Comparison of Endoscopy and Hysterotomy

Objective: To compare endoscopic coverage of myelomeningocele with a maternal split-thickness skin graft in utero to definitive neurosurgical closure through a hysterotomy. Methods: Four fetuses with isolated myelomeningocele underwent endoscopic coverage of the defect with a maternal split-thickness skin graft in a CO2 environment at 22–24 weeks’ gestation. Subsequently, 4 fetuses underwent standard neurosurgical closure of their myelomeningoceles at 28–29 weeks’ gestation. Results: The mean operating time for the endoscopic procedures was 297 ± 69 min. Two fetal losses occurred as a result of chorioamnionitis and placental abruption, respectively. A third baby delivered at 28 weeks’ gestation after prolonged disruption of the membranes. The 2 survivors required standard closure of the myelomeningocele after delivery. The mean operating time for the hysterotomy procedures was 125 ± 8 min. No mortality occurred, and all the infants delivered between 33 and 36 weeks with well-healed myelomeningocele scars. At present, the functional levels of all infants approximate the anatomical levels of the lesions. Conclusion: With current technology, in utero repair of congenital myelomeningocele through a hysterotomy appears to be technically superior to procedures performed endoscopically.

Intrapartum management of category II fetal heart rate tracings: towards standardization of care

There is currently no standard national approach to the management of category II fetal heart rate (FHR) patterns, yet such patterns occur in the majority of fetuses in labor. Under such circumstances, it would be difficult to demonstrate the clinical efficacy of FHR monitoring even if this technique had immense intrinsic value, since there has never been a standard hypothesis to test dealing with interpretation and management of these abnormal patterns. We present an algorithm for the management of category II FHR patterns that reflects a synthesis of available evidence and current scientific thought. Use of this algorithm represents one way for the clinician to comply with the standard of care, and may enhance our overall ability to define the benefits of intrapartum FHR monitoring.

The effect of type of delivery upon neonatal outcome in premature twins

A retrospective study from January 1, 1976, through July 31, 1981, was performed to evaluate the relationship between type of delivery and perinatal morbidity and mortality in twins of birth weight less than 2,000 gm. Vaginally delivered second twins who weighed 601 to 999 gm had increased risk of neonatal mortality when compared to their siblings. Among twins who weighed 1,000 to 1,499 gm, vaginally delivered second twins had significantly lower Apgar score and increased risks of neonatal morbidity in comparison to their siblings, whereas second twins who were delivered by cesarean section had no difference in Apgar score or neonatal morbidity from those of their siblings. In twins who weighed 1,500 to 1,999 gm, a significant increase in neonatal complications in vaginally delivered second twins was not found, although the majority of neonatal complications did occur in vaginally delivered second twins. Cesarean section is proposed as the optimal route of delivery for all twins expected to have a birth weight less than 1,500 gm.

Induced abortion: A risk factor for placenta previa

A threefold increase in the incidence of placenta previa, from one in 318 deliveries (0.3%) in 1972-1974 to one in 109 deliveries (0.9%) in the twelve-month period ending June 30, 1980, was noted at Vanderbilt University Hospital. Two large groups of patients not present in 1972-1974 were found to be responsible for this increased incidence of placenta previa: one-way maternal transports and women who had had induced first trimester abortions. The frequency of maternal transports having placenta previa was 3.3% (p less than 0.0001), and the frequency of placenta previa in women after an induced first trimester abortion was 3.8% (p less than 0.0001). When correction for maternal transports was made, the endogenous induced first trimester abortion population had a frequency of placenta previa of 2.1% (p less than 0.004), whereas the remainder of the endogenous population had an incidence of placenta previa similar to that found in the years 1972-1974. Induced first trimester abortion is seen as a significant factor predisposing to placenta previa.

Solubilization and identification of human placental endothelin receptor.

Endothelin-1 (ET-1) receptor was identified on the membranes from human placenta and 66% of original binding activity in the membranes was solubilized with 0.75% (w/v) CHAPS. Binding studies of the solubilized membranes using 125I-ET-1 indicated the presence of a single class of high-affinity binding sites with an apparent Kd of 760 pM and a Bmax of 1.8 pmol/mg of protein. The binding was inhibited by addition of unlabeled ET-1 and ET-3 in dose dependent manner. The Ki values of solubilized membranes were 84 pM for ET-1 and 250 pM for ET-3, whereas particulate membranes had weaker affinities (Ki = 410 pM for ET-1, 2500 pM for ET-3). Calcium channel blockers such as nicardipine, verapamil and diltiazem did not affect the binding of 125I-ET-1. Affinity labeling of the particulate and solubilized membranes with CHAPS revealed a specific binding protein with a Mr of 32,000.

The nonstress test: An evaluation of 1,000 patients

In November, 1978, the fetal heart rate nonstress test (NST) was instituted as the primary screening procedure for the evaluation of fetal well-being at Vanderbilt University Hospital. The results of the first 1,000 patients tested are presented. The stillborn rate within 8 days of a reactive NST was 6.4 per 1,000, with the stillbiths occurring either in patients with diabetes mellitus or with intrauterine growth retardation (IUGR). A review of other series in which both the total indications for nonstressed testing and the risk groups in which stillbirths occurred within 7 days of an NST reveals that patients with diabetes mellitus (p less than 0.025) and patients with IUGR (p less than 0.01) are at greater risk for stillbirth within 7 days of an NST. Weekly nonstress testing, effective in preventing stillbirths in most risk groups, is not adequate in patients with diabetes mellitus or IUGR.

Reassessment of White's classification and Pedersen's prognostically bad signs of diabetic pregnancies in insulin-dependent diabetic pregnancies

The classification systems developed over 20 years ago by White and Pedersen identified diabetic pregnancies at increased risk for perinatal mortality. To assess whether these same criteria would currently be valid, 199 diabetic pregnancies with deliveries from 1977 to 1983 were reviewed. Perinatal mortality rates for Whites Classes B gestational (n = 72), B (n = 27), C (n = 67), and D + F + R (n = 33) were 2.9%, 11.1%, 14.9%, and 21.1%, respectively (p less than 0.05). Whites classes were also predictive of pulmonary morbidity (12.5%, 18.5%, 22.4%, and 42.4%, respectively). The presence of one or more of the prognostically bad signs of pregnancy (n = 76) increased the perinatal mortality rate to 17.1% versus 7.3% among insulin-dependent diabetic pregnancies without prognostically bad signs (p less than 0.05). The presence of any prognostically bad signs of pregnancy was also predictive of pulmonary morbidity in general (31.6% versus 16.3%, respectively) and hyaline membrane disease in particular (13.2% versus 4.1%, respectively). Thus with use of modern obstetric management and medical care of the pregnant diabetic patient, both Whites classification and Pedersens prognostically bad signs of pregnancy continue to be predictive of perinatal mortality.

Pre term premature rupture of membranes: Detection of infection

This prospective study was designed to determine the value of a daily modified biophysical profile in detecting infection in patients with preterm premature rupture of the membranes who were managed expectantly. Ninety-nine patients received daily nonstress tests and biophysical profile scores. Results of the last predelivery study were related to subsequent development of amnionitis or fetal sepsis. Infection was present in 16 patients. When the biophysical profile score was 0/8, infection was uniformly present. When fetal breathing was absent (biophysical profile score, less than or equal to 4/8) and nonstress test was nonreactive, infection was present in 75% of cases (sensitivity, 75%; specificity, 95%). Because a nonreactive nonstress test could be secondary to prematurity instead of infection, these results were analyzed over time. Those who initially had a reactive nonstress test that subsequently became nonreactive were more likely to be infected. We conclude that a daily biophysical profile score and nonstress test can detect infection and propose delivery of patients with a biophysical profile score of 0/8 and nonreactive nonstress test. Patients with absent fetal breathing and a nonstress test that changes from reactive to nonreactive also should be considered for delivery. Absent fetal breathing with a reactive nonstress test or a consistently nonreactive nonstress test should have further testing to rule out infection.

Increased risk of endometritis and wound infection after cesarean section in insulin-dependent diabetic women

To determine if diabetic women have an increased risk for post-cesarean section endometritis and/or wound infection, all insulin-requiring diabetic women who were delivered by cesarean section between 1977 and 1981 were compared with a group of nondiabetic patients delivered by cesarean section. Patients were divided into low-risk or high-risk groups on the basis of labor and ruptured membranes. Compared with control subjects, diabetic patients were at significantly greater risk for postoperative infectious morbidity. Among diabetic patients, risk for postoperative infections was independent of Whites classification of diabetes and gestational age at delivery. The increased rate of infection among the diabetic patients suggests that prophylactic antibiotics might be efficacious for insulin-requiring diabetic patients undergoing cesarean section.