The effect of ephedrine upon uterine artery blood flow velocity in the pregnant guinea pig subjected to terbutaline infusion and acute hemorrhage

The purpose of the present study was to determine the effect of intravenously administered ephedrine upon uterine artery blood flow velocity (UBFV) in the gravid guinea pig subjected to terbutaline infusion and acute hemorrhage. Ephedrine, 1.0 mg/kg, was administered intravenously to ten chronically instrumented pregnant guinea pigs near term, before and after intravenous infusion of terbutaline and acute hemorrhage. Before terbutaline and hemorrhage, ephedrine increased maternal mean arterial pressure (MMAP) by 30 +/- 1% (P = .0001) and 17 +/- 1% (P = .0001) at 30 s and at 1 min after injection, respectively; UBFV was decreased by 10 +/- 4% (P less than .01) and 14 +/- 4% (P less than .01) at 1 min and at 90 s after injection, respectively. Infusion of terbutaline (1.5-6.0 ug X kg-1 X min-1) increased maternal heart rate (MHR) by 22 +/- 1% (P = .0001), decreased MMAP by 13 +/- 2% (P = .0001), and decreased UBFV by 24 +/- 3% (P = .0001). During hypotension resulting from acute hemorrhage, ephedrine, 1.0 mg/kg, was superior to placebo in restoring MMAP and UBFV toward the prebleed values. The authors concluded that ephedrine, 1.0 mg/kg, results in a small, transient decrease in UBFV in the normotensive gravid guinea pig. However, ephedrine aids restoration of UBFV in the gravid guinea pig rendered hypotensive by acute hemorrhage during terbutaline infusion.

Abnormal pregnancy sonogram: selective indication for fetal karyotype

The inability to make a definitive diagnosis in the fetus with a sonographically identified abnormality often results in parental and physician uncertainty. An antenatal chromosome evaluation could resolve this uncertainty. Forty-one fetuses with an abnormal ultrasound examination were tested for karyotypic abnormality using a variety of specimens. Nearly one-third (13 of 41) of these fetuses had various chromosome abnormalities. There were only seven survivors in this series, underscoring the often poor prognosis when a significant ultrasound defect is detected antenatally. Knowledge of the fetal chromosome constitution in the setting of an abnormal ultrasound has important epidemiologic, cost-benefit, counseling, and pregnancy management implications.

Diagnosis and treatment of twin to twin transfusion in the mid-second trimester of pregnancy

Acute hydramnios in the second trimester of pregnancy associated with twin to twin transfusion is a rare and usually disastrous complication. Few infants survive the neonatal period. We report a case of acute hydramnios prior to 20 weeks of gestation secondary to twin to twin transfusion documented by fetal blood samples obtained using cordocentesis. Selective fetacide was performed using a new procedure after a pericardial effusion had failed. The hydramnios resolved and the surviving co-twin was delivered at term.

Sacrococcygeal teratoma

The definition, natural history and prognosis of sacrococcygeal teratoma (SCT) are reviewed. Two cases of SCT are presented in detail. Both were diagnosed well before delivery and required intensive perinatal management. Both babies survived intact after removal of 30-50% of total body mass. Case selection for antenatal therapy remains a problem. Prospects for antenatal therapy are reviewed.

Effect of intravenous epinephrine on uterine artery blood flow velocity in the pregnant guinea pig

The purpose of the present study was to determine the effect of intravenously administered epinephrine on the maternal cardiovascular response and uterine artery blood flow velocity (UBFV) in the pregnant guinea pig. Epinephrine (0.2, 0.5, and 1.0 micrograms/kg) and lidocaine (0.4 mg/kg, with and without 0.2 micrograms/kg of epinephrine) were administered intravenously to seven chronically instrumented pregnant guinea pigs near term. Lidocaine without epinephrine did not significantly alter maternal heart rate (MHR), maternal mean arterial pressure (MMAP), or UBFV. Epinephrine, with and without lidocaine, resulted in a transient decrease in MHR. Further, epinephrine, with and without lidocaine, resulted in significant elevations in MMAP and significant, dose-related reductions in UBFV. Mean (+/- SEM) UBFV was 72 +/- 4%, 56 +/- 4%, and 40 +/- 5% of baseline at 30 s after administration of epinephrine, 0.2, 0.5, and 1.0 micrograms/kg, respectively. It is concluded that these small intravenous boluses of epinephrine result in significant, although transient, reductions in UBFV in the pregnant guinea pig.

The obstetric patient and disseminated intravascular coagulation

Disseminated intravascular coagulation remains a major problem for the practicing obstetrician. The various etiologies, the pathophysiology, and suggested therapeutic regimens are reviewed.

The relationship between capillary and venous glucose concentration during pregnancy

Previous attempts to construct capillary equivalents of venous glucose values for prognostic purposes have failed. We examined the relationship between capillary and venous glucose concentration during pregnancy in 258 women who had samples taken at four different time intervals in relation to two different standardized meals. Capillary glucose concentration was determined with the Chemstrips bG and an Accu-Chek reflectance colorimeter and venous plasma glucose concentration was measured by the hexose kinase technique on an AutoAnalyzer. The capillary: venous relationship was constant over time for a given meal but the magnitude of the difference was affected by time. The capillary: venous relationship differed significantly between the two standard meals. The findings indicate that meal size and sampling time must be controlled for when one is attempting to construct capillary equivalents for venous derived norms. The failure of previous studies to control for these variables may explain their inability to construct useful capillary equivalents for venous glucose values. Our findings also indicate that attainment of venous norms with capillary specimens represent, in reality, tighter control.

Cost efficacy of routine screening for diabetes in pregnancy: 1-h versus 2-h specimen

Undetected gestational diabetes mellitus (GDM) is associated with a two- to fivefold increase in perinatal morbidity and mortality. Widespread screening of the obstetric population (resulting in identification and treatment) should reduce these rates. Seven hundred ninety-eight women were examined during a 13-mo period of universal glucose challenge testing (GCT). A total of 2.8% of the population had an abnormal oral glucose tolerance test (OGTT). Thirty percent of those with an abnormal OGTT were less than 25 yr old. The specificity of a 1-h GCT (50-g carbohydrate load) using a threshold of either 140 or 150 mg/dl was compared with that of a 2-h specimen using a threshold of 118 mg/dl to determine whether the cost of screening could be reduced. One- and 2-h specimens were obtained in 347 of these women. A 34% reduction in the number of follow-up OGTTs required would have been achieved if a 2-h specimen had been used as the index instead of a 1-h specimen (P less than .05). As a result, the (direct and indirect) cost per patient identified with GDM would have declined 23.5%--from $866 to $662. No comment concerning the actual false-negative rate of either the 1- or 2-h GCT can be made because only select women underwent an OGTT. To assess the validity of the 2-h threshold, an OGTT was performed in an additional 190 women if either the 1- or 2-h screen was abnormal. The results were confirmatory: the 2-h screen would have reduced the cost per case identified by 32% in this small group. Screening on the basis of past medical history clearly lacked sensitivity and cost efficacy in comparison with the GCT and should be abandoned as a practice.

Chronic measurement, using a Doppler probe, of uterine artery flow in the gravid guinea-pig

A chronic animal model is described which permits for the first time the continuous measurement of uterine artery blood flow velocity in the pregnant guinea-pig by using a miniaturized Doppler flow probe. Preliminary validation revealed that alterations in actual blood flow are directly and proportionally related to the change in the Doppler shift (r = 0.984) from 0 to 100 ml/h. The velocity signal baseline was as stable as that of systemic blood pressure. Depending upon the individual animal's flow velocity, a deviation of 2-5% from baseline was statistically significant. With experience, greater than 90% of preparations were successful and a 30-day interval was often available for study. Uterine artery flow velocity increased steadily between 45 and 55 days of gestation. Instrumentation did not result in fetal growth retardation. A reduction in flow velocity occurred during general anaesthesia using ketamine and the antianxietal xylazine. In agreement with the reports of other investigators using a different model, both hydralazine and angiotensin II increased uterine blood velocity and adrenaline reduced it.

Comparison of cefotetan and cefoxitin as prophylaxis in cesarean section

A study comparing the efficacy of cefotetan versus cefoxitin for prophylaxis in patients undergoing cesarean section was carried out at the University of Iowa. After institutional review, 36 subjects who met the study criteria and agreed to participate were entered into the study; of these, 29 were evaluable for efficacy. Twenty subjects received a single 2 gm dose of cefotetan, and nine subjects received three 2 gm doses each of cefoxitin. Both antibiotics were administered intravenously at the time the umbilical cord was clamped. The subsequent doses of cefoxitin were given intravenously at four and eight hours after the initial dose. Clinical and bacteriologic responses were evaluated; there were no statistically significant differences between the two groups, and both antibiotics provided effective prophylaxis against infection. It appears that cefotetan is a satisfactory antibiotic choice for cesarean section prophylaxis. Further, in this small study it appears that a single dose of cefotetan is as effective as three doses of cefoxitin. This implies that cefotetan would not only decrease administration time and supplies but would decrease the cost to the patient while maintaining very acceptable infection rates.

Ultrasonic fetal weight prediction: role of head circumference and femur length

The accurate sonographic estimate of fetal weight is helpful in those instances when the fetal weight estimate might alter clinical management. Most sonographic weight predicting formulas have been based predominantly on measurements from the term fetus and then applied to the preterm fetus. Yet, the morphology of the preterm and term fetus differs considerably. The authors have examined the predictive accuracy of three published sonographic formulas in 69 preterm fetuses scanned within 48 hours of delivery. The mean birth weight was 1396 g. Thirty-nine of the infants were less than 1500 g. Sixty-two percent were products of pregnancies complicated by premature rupture of membranes. The results were compared with new equations derived from combinations of head and abdominal circumferences, biparietal diameter, and femur length obtained from the first 33 fetuses and then tested on the remaining 36. Whereas each formula correlated highly with birth weight, the selected new formula was more accurate than the published formulas by each criteria examined. In contrast to the latter, the mean error (actual minus predicted weight) of most new equations did not significantly differ from zero when tested prospectively. In addition, it appeared that the accuracy of two new formulas not incorporating femur length could be further enhanced in the group of fetuses whose femur length differed from the mean by at least 2 standard deviations by multiplying the predicted weight by the ratio of actual to mean femur length. The authors conclude that the use of head circumference and femur length coupled with a population restricted to the preterm fetus enhances the accuracy of sonographic weight predictions.

Diagnosis of septic pelvic thrombophlebitis by measurement of fibrinopeptide A

Septic pelvic thrombophlebitis is an uncommon but potentially life-threatening complication of puerperal endometritis. The lack of specific physical findings necessitates a diagnosis based by exclusion on the patient's response to anticoagulation. Fibrinopeptide A (FPA) is the first peptide cleaved from fibrinogen during thrombin-mediated fibrin generation. Because of its short half-life, FPA accurately reflects the level of ongoing fibrin generation. In a preliminary study of 40 puerperal patients, FPA successfully differentiated puerperal fever secondary to endometritis or abscess from fever responsive to a heparin trial. The mean FPA level in patients presumed to have septic pelvic thrombophlebitis was 23.8 ng/ml as opposed to 7 ng/ml in patients with endometritis. No patient with septic pelvic thrombophlebitis as diagnosed by her response to a heparin trial had a level of FPA less than 14 ng/ml. There was no overlap of FPA levels between patients with endometritis or abscess and septic pelvic thrombophlebitis. The data suggest further prospective evaluation of FPA for the diagnosis of septic pelvic thrombophlebitis is warranted.

A hypothetical model suggesting suboptimal intrauterine growth in infants delivered preterm

Infants delivered preterm often reflect accelerated maturation. The present study examines the occurrence of suboptimal intrauterine growth in infants delivered preterm by comparing their birth weights to the weights sonographically predicted for in utero fetuses at similar gestational ages but who ultimately deliver at term. Two weight-predicting formulas based on different sonographic parameters were used. In the fifth, tenth, and 50th percentiles of birth weight, the predicted weights were persistently and significantly greater than the actual birth weights between 24 and 31 weeks' gestation. The results of this model support the concept that the growth of infants delivered prematurely has been suboptimal. The authors hypothesize that preterm delivery may be in some instances another manifestation of the same underlying stress that hastens pulmonary and neurologic maturity.

Antithrombin III activity in women with hypertension during pregnancy

Antithrombin III activity was measured prospectively in 127 pregnant women within four weeks of delivery, and the results were tabulated with respect to the clinical diagnosis of their hypertensive disorder. Plasma antithrombin III activity was significantly lower than controls in women with preeclampsia and in women with chronic hypertension and superimposed preeclampsia (P less than .001). In contrast, women with chronic hypertension alone had antithrombin III activities similar to controls. Based on discriminant analysis, an antithrombin III activity of less than 70% was selected as indicative of the preeclampsia-eclampsia syndrome. The sensitivity and specificity of plasma antithrombin III for preeclampsia was 76 and 91%, respectively. Importantly, an antithrombin III activity in excess of 70% accurately predicted the absence of preeclampsia in 89% of study patients. Although gestational ages at delivery were similar in preeclamptic women with antithrombin III activity above and below 70%, women with antithrombin III activity above 70% delivered larger infants and experienced less fetal distress during labor. These findings suggest antithrombin III measurement may be useful in the management of hypertensive pregnant patients who are unresponsive to bedrest.

Platelet activation in preeclampsia

Platelet activation was assessed in hospitalized third-trimester patients with preeclampsia (n = 11) or chronic hypertension with superimposed preeclampsia (n = 11) and in healthy outpatient pregnant controls (n = 10) by measuring plasma beta-thromboglobulin, platelet factor 4, the platelet aggregate ratio, and the amount of collagen required to produce half-maximal aggregation velocity (Kd). Only plasma beta-thromboglobulin levels differed significantly between patients with preeclampsia (50.1 +/- 37.9; p less than 0.05) or chronic hypertension with superimposed preeclampsia (47.6 +/- 16.3; p less than 0.01) and the control subjects (22.5 +/- 11.3). beta-Thromboglobulin values in patients with preeclampsia, but not chronic hypertension with superimposed preeclampsia, correlated directly with 24-hour urinary protein loss (r = 0.93, p less than 0.001) and serum creatinine levels (r = 0.62, p less than 0.05) and inversely with creatinine clearance (r = 0.60, p = 0.05). We conclude that (1) beta-thromboglobulin is elevated in patients with preeclampsia or chronic hypertension with superimposed preeclampsia, (2) the normal platelet aggregate ratio and the Kd indicate that the increase in beta-thromboglobulin is not due to an intrinsic change in platelet responsiveness, and (3) the elevation of beta-thromboglobulin in patients with either preeclampsia or chronic hypertension with superimposed preeclampsia appears to be secondary to platelet consumption in the microvasculature, although in patients with preeclampsia altered renal function may be contributory.

Fibrin generation in normal pregnancy

Both clinical and laboratory findings suggest that pregnancy constitutes a hypercoagulable condition; yet none of the observed laboratory changes are specific for thrombosis. An essential step involves thrombin-mediated fibrin generation. In the process, fibrinopeptide A (FPA) is cleaved from fibrinogen. Using a radioimmune assay, FPA was determined prospectively in a longitudinal and cross-sectional fashion. Fibrinopeptide A increased significantly over control by the end of the first trimester, from 1.3 ng/ml to 2.8 ng/ml. It continued to increase until 30 to 32 weeks' gestation and then plateaued at 4.3 to 4.7 ng/ml. In the immediate postpartum period, FPA remains elevated. In conclusion, thrombin generation as reflected in FPA production is increased throughout pregnancy, thus confirming a hypercoagulable milieu.

Control of preeclamptic hypertension by ketanserin, a new serotonin receptor antagonist

We investigated the effect of peripheral serotonin receptor blockade on preeclamptic hypertension in 20 postpartum patients by the use of ketanserin, a serotonin receptor antagonist. In a study consisting of a double-blind crossover with placebo, parenteral ketanserin significantly reduced blood pressure from 167/105 to 126/71 mm Hg compared to a decline from 157/98 to 150/91 mm Hg for the placebo (p less than 0.001). All patients became hypertensive again following infusion, although no abrupt rebound in pressure occurred. Side effects were minimal. The results demonstrate that preeclamptic hypertension can be controlled by ketanserin and suggest that serotonin may have a role in the modulation of preeclampsia.

Fibrin generation during the diabetic pregnancy

Fibrin catabolism was measured during the pregnancy of insulin-dependent diabetic women in both a longitudinal and cross sectional fashion. Samples of maternal peripheral venous blood were obtained in 20 pregnant diabetic women between 26 and 38 weeks' gestational age. Fibrinopeptide A, the first peptide cleaved from fibrinogen during thrombin-mediated catabolism, was measured by radioimmunoassay. Intra-assay and interassay variation for fibrinopeptide A in this laboratory were 2% and 4% respectively. Antithrombin III activity was determined by the method of Odegaard. The patients ranged from 23 to 36 years. Overall blood glucose control was good as reflected in near-normal HbA1 fasting plasma glucose values. The mean HbA1 +/- 1 standard deviation was 7.1% +/- 1.2%. The mean fasting plasma glucose concentration was 101.9 mg% +/- 21.5 mg%. Mean FPA for the diabetic women exceeded control values at each gestational period. Significant differences were found in four of the seven intervals. While the highest FPA was noted in a patient with advanced diabetic vasculopathy, exclusion of this patient did not alter the overall findings. The findings were striking and suggest the need for a prospective study designed to account for White's classification of diabetes and the degree of glucose control. Because complications of the diabetic pregnancy include an increased risk of hypertension in the mother and sudden, unexplained fetal loss, two complications associated with abnormal clotting, the increase in fibrin catabolism in patients in tight metabolic control would suggest that events other than glucose regulation impact upon fibrin catabolism and possibly pregnancy outcome in the diabetic mother.

A modified activated partial thromboplastin time with the use of amniotic fluid. Preliminary report of a new technique for detection of fetal lung maturity

The need for a simple, accurate, rapidly performed fetal lung maturity test remains unfilled despite the large number of methods available. In a preliminary prospective study, the amniotic fluid activated partial thromboplastin time (PTT) appeared to be encouraging. The false mature rate in an at-risk patient population was 0.80%, and the false immature rate was 61%. The false mature rates for the lecitin/sphingomyelin ratio and absorbance 650 in the same patients were 0% and 0.63%, respectively, whereas the false immature rates were 81.8% and 91.3%. Since both the amniotic fluid activated PTT and absorbance 650 can be readily performed in the smallest hospital, the accuracy of the combination was explored. Combining the amniotic fluid activated PTT with a mature absorbance 650 reduced the false immature rate to 30.7%. Th amniotic fluid activated PTT is a rapid, accurate, economical test that is unaffected by gross blood or meconium contaminants.

Plasma antithrombin III activity: an aid in the diagnosis of preeclampsia-eclampsia

Plasma antithrombin III (AT III) activity was examined retrospectively in patients with preeclampsia-eclampsia, chronic hypertension, and chronic hypertension with superimposed preeclampsia-eclampsia. Levels of AT III were greater than 1 SD below normal pregnant control in each case of preeclampsia-eclampsia syndrome. The degree of reduction in plasma AT III activity was correlated with the severity of disease. AT III activity was within normal limits in patients with chronic hypertension. AT III activity dropped prior to the appearance of clinically evident disease in three patients who were followed from an early gestational age. In no instance was low plasma AT III activity associated with normal pregnancy. Coincidental disease, including pyelonephritis and a viral syndrome, were associated with markedly decreased levels of plasma AT III activity in otherwise normal pregnancies. Plasma AT III activity may be valuable as a tool in diagnosing preeclampsia-eclampsia, as a screening test for preclinical preeclampsia-eclampsia, and as an indicator of severity of disease.

Sonographic abdominal circumference: dynamic versus static imaging

The ultrasonic abdominal circumference (AC) measurement is one of the essential parameters used for assessment of fetal status. Whereas the AC was traditionally derived by static equipment, dynamic scanners are presently used for that purpose. In this study, the AC values obtained by two gray-scale ultrasonic imaging modalities (static and dynamic) were compared; the differences between the mean AC measurements were not statistically significant. Additionally, when the outline of the AC in a fetus near term was larger than the sonic field displayed by dynamic equipment, the partially incomplete boundary could be "filled in" without affecting the accuracy of the result.

Plasma antithrombin III activity in normal pregnancy

The incidence of thromboembolic phenomena increases in pregnancy. Antithrombin III has been implicated as a possible etiologic factor for the increase of thromboembolic phenomena in women receiving exogenous estrogens. In a study of normal obstetric, postpartum, and oral contraceptive patients, no significant change in antithrombin III activity could be detected in a plasma-based assay within and among these groups. It is hypothesized that a decrease in antithrombin III activity is not a cause of increased thromboembolic phenomena during normal pregnancy and oral contraceptive use.