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Objective: Oxidative stress occurs when the production of damaging free radicals and other oxidative molecules exceeds the capacity of the body's antioxidant defenses. Oxidative stress is implicated in diseases that are associated with prematurity (such as retinopathy, cerebral palsy, intraventricular hemorrhage, and necrotizing enterocolitis). Nonenzymatic antioxidant reserve is the first line of defense against free radicals. We hypothesized that an in utero redox imbalance because of stress would diminish the fetal antioxidant reserve. We tested aspects of this hypothesis by investigating whether the presence of labor or gestational age at delivery (term vs preterm) alters the maternal/fetal nonenzymatic antioxidant reserve peripartum., Study Design: Fetal redox consumption was calculated from the difference in the nonenzymatic antioxidant reserve that was measured in umbilical venous and arterial blood that was collected prospectively at delivery from 39 newborn infants. Eight women were delivered at term by elective cesarean delivery in the absence of labor; 31 women labored either at term (n = 20) or preterm (<37 weeks, n = 11). Maternal venous blood was collected on admission and within 1 hour of delivery. Nonenzymatic antioxidant reserve was measured in the plasma and red blood cells of each specimen by the quantitation of glutathione content (glutathione in red blood cell lysate) and the plasma total free radical-trapping antioxidant potential. Glutathione was measured with the use of a colorimetric assay and expressed in nanomoles per milligram of hemoglobin. The plasma total radical-trapping antioxidant potential was estimated with the use of a controlled, kinetic assay based on the time that was required to inhibit peroxyl-free radical generated under controlled conditions. The differences between both umbilical venous and umbilical arterial total radical-trapping antioxidant potential and glutathione were computed to estimate fetal nonenzymatic antioxidant reserve consumption. The differences between maternal total radical-trapping antioxidant potential and glutathione before and after delivery were computed to estimate maternal peripartal nonenzymatic antioxidant reserve consumption., Results: Fetal red blood cell glutathione content was significantly greater than maternal red blood cell glutathione content, independent of delivery route. The calculation of the fetal nonenzymatic antioxidant reserve consumption and maternal peripartal nonenzymatic antioxidant reserve consumption revealed that women who labored at term experienced an up-regulation in red blood cell glutathione content, while their fetuses had significantly lower red blood cell glutathione consumption. In contrast, there was consumption of plasma antioxidants in preterm fetuses, as illustrated by a doubling of the fetal nonenzymatic antioxidant reserve consumption (elective cesarean delivery in the absence of labor, 0.9 +/- 0.5 min/microL; term labor, 1.0 +/- 0.1 min/microL; preterm labor, 2.0 +/- 0.4 min/microL; one-way analysis of variance; P =.04). This was mostly due to a lower umbilical arterial total radical-trapping antioxidant potential in preterm versus term fetuses (umbilical arterial, 3.3 min/microL versus umbilical venous 5.4 min/microL; paired t test; P =.001; power, 0.98). Generally, maternal total radical-trapping antioxidant potential remained unchanged peripartum., Conclusion: Term labor triggers a compensatory up-regulation of nonenzymatic antioxidant reserve in the fetal red blood cell compartment that may act to protect against the relative hyperoxia that is experienced by the newborn infant at birth. In contrast, the decreased nonenzymatic antioxidant reserve in the fetal red blood cell and plasma compartments after preterm labor and delivery would enhance the vulnerability to free radical damage of the preterm neonate. These findings suggest that the two compartments of nonenzymatic antioxidant reserve have distinct physiologic roles in the peripartal defense against free radicals and that their development is, in some fashion, ontogenes, in some fashion, ontogenetically regulated.

Introduction: Low birthweight is a major determinant of infant mortality, as well as a contributor to infant and childhood morbidity. A key issue is how to reduce the incidence of low birthweight in the United States. One emerging factor is exposure to psychosocial stressors. In this research, we evaluated the association between exposure to psychosocial stressors and low birthweight in a population of urban, low-income pregnant women., Methods: Over 2,000 pregnant women 18 years of age and older were enrolled in this prospective study and recruited at their first prenatal care visit. We obtained information on maternal exposure to stressors. After the pregnancy, we abstracted clinical records of each woman enrolled in the study. Logistic regression was used to estimate the adjusted odds ratio for the association between stressor group membership and low birthweight, controlling for the effects of confounding factors., Results: In logistic regression analyses stratified by race, for African-American women, the following variables were significantly associated with low birthweight: smoking, hypertension, low prepregnancy weight, hospitalization during pregnancy, previous preterm birth, and exposure to stressors. For Caucasian women, significant predictors were: smoking, drug use, hospitalization during pregnancy, hypertension, and previous preterm birth. Exposure to stressors was also significantly associated with many clinical and behavioral risks for low birthweight., Conclusion: Our results suggest two potential mechanisms for an association between stressors and low birthweight. Exposure to stressors may be indirectly associated with low birthweight through a relationship with clinical and behavioral risks for low birthweight. Exposure to psychosocial stressors may also be directly associated with risk of low birthweight among African-American women.

The University of Maryland was the first program in the state to offer chorionic villus sampling (CVS). Since the program's beginning in 1984, 998 patients have been seen with successful sampling in 99.1 percent, using both transcervical and transabdominal approaches. The overall loss rate was quite low (2.3 percent), and no increased risk of birth defects was seen. These observations demonstrate that CVS provides a safe and accurate alternative to amniocentesis.

Fifteen patients were identified in a retrospective analysis of one institution's experience with the use of tocolysis in selected patients with an admission diagnosis of placenta previa or abruptio placentae. There were no fetal deaths after admission, and the two neonatal deaths were related to prematurity. Eight of the 15 patients receiving tocolysis had their pregnancies prolonged by 2 weeks or more, and there were no fetal or neonatal deaths in this group. Both neonatal deaths occurred in patients who underwent tocolysis but who gave birth within 1 day of admission. These data suggest the safety of tocolysis in preterm patients with the diagnosis of placenta previa or abruption who are bleeding. A prospective, randomized trial is required to evaluate whether tocolysis is superior to expectant management or to immediate delivery. The clinical difficulty in differentiating between these two diagnoses, despite liberal use of ultrasonography, is discussed.

The dehydroepiandrosterone loading test (DLT) has been used in a small population of normal and high-risk obstetric patients, to date, in an attempt to develop a dynamic test of placental function. In spite of its limited applications, it has shown reliability in discriminating, with statistical significance, between high-risk pregnancies that result in normally grown, undistressed infants, and high-risk pregnancies that result in infants showing signs of placental insufficiency. The present report expands the study population by presenting our data on 40 loading tests performed in 37 high-risk and normal obstetric patients. Results of 19 of these DLT's have been previously reported and are included herein for statistical analysis. The DLT utilizes an excess substrate load of dehydroepiandrosterone to assess the maximum capability of the placenta to convert it to estrogen. Although our previous report did not show false positive or negative results in the conversion rates, the present results (40 DLT's) found two (2 out of 17) false positives (12%) and two (2 out of 19) false negatives (11%). The highly significant correlation between DLT result and pregnancy outcome seen previously was preserved. In addition, the data of another five DLT's in four patients are presented. This group includes a pregnancy with a fetus with multiple congenital malformations, two patients with intrauterine fetal death, and a nonpregnant woman. The results are not included in the statistical analysis, but discussion of these results has interesting pathophysiologic implications.

This report complements the previously described preliminary clinical evaluation of the dehydroepiandrosterone (DHEA) loading test (DLT) by presenting the results of 65 DLTs in 59 patients. In patients whose fetuses were suspected of being intrauterine growth retarded, a DHEA to estrogen conversion rate constant less than or equal to 3.0 x 10(-3) min(-1) was associated with a birth weight below the tenth percentile in 60% of the pregnancies, whereas a conversion rate constant above this threshold was not associated with the same degree of growth retardation. The DLT continues to qualify as an accurate predictor of pregnancy outcome as judged by birth weight. Although it seems to be too cumbersome to serve as a screening technique, the DLT will permit evaluation of the efficacy of various pregnancy interventions directed toward improvement of the intrauterine environment, such as bed rest, tocolysis, or antihypertensive medication.

Creatinine phosphokinase and its isoenzymes (myocardial-specific MB and brain-specific BB) are elevated in the presence of specific tissue injury. The value of this serum marker as an objective indicator of perinatal asphyxia was studied. Forty-nine patients with gestational ages ranging from 36 to 42 weeks were prospectively studied. Patients who by interpretation of the fetal heart rate tracing alone were diagnosed as having fetal distress demonstrated significantly lower pH (p = 0.001) and base excess (p less than 0.0001) in umbilical venous blood. Umbilical venous cord MB (p less than 0.05) and BB (p less than 0.01) were increased in this group. Abnormal fetal heart rate patterns correlate well with acid-base abnormalities and elevated creatinine phosphokinase values. These tests may demonstrate more efficient and improved indicators of tissue injury and damage from perinatal asphyxia than clinical observation alone.

The fetoplacental unit of the ewe is capable of increasing the biosynthesis of estrogens following the exogenous administration of DHEA to the fetus. The maximum concentrations of estrogens appeared approximately 30 minutes after the administration of DHEA. Uterine blood flow in the pregnant ewe increased approximately 90 minutes after the maximum concentrations of estrogens were noted. The administration of DHEA to the nonpregnant, ovariectomized ewe did not elicit estrogen biosynthesis or changes in uterine blood flow. Isotope experiments in the pregnant ewe demonstrated the incorporation of DHEA into urinary estradiol.

The efficacy of magnesium sulfate was analyzed in relation to ritodrine hydrochloride. Patients presenting in preterm labor between 20 and 35 weeks' gestation were prospectively randomized. Tocolysis was achieved for more than 72 hours in 35 of 40 cases (88%) where magnesium sulfate was administered and 31 of 39 cases (79%) in which ritodrine hydrochloride was infused. Delay of greater than or equal to 7 days was achieved in 75% and 72% of cases, respectively. The mean dosage to achieve tocolysis was 4.5 gm/hr, in the magnesium sulfate group and 210.0 micrograms/hr in ritodrine hydrochloride-treated patients. The mean magnesium level to achieve tocolysis was 6.60 mg/dl. Side effects in the two groups were similar in number but less alarming in the magnesium sulfate group. Magnesium sulfate was found to be easy to administer and clinically efficacious. Its tocolytic action was found to be dose dependent and drug concentrations are easily determined. On the basis of this work and data from other investigators, magnesium sulfate should be used as the first line of tocolytic therapy with ritodrine hydrochloride as its pharmacologic backup.

Amniotic fluid (AF) was collected from 37 selected patients by amniocentesis, aspiration through a pressure catheter, or aspiration at the time of cesarean section. The unspun AF was examined directly by Gram stain for bacteria and white blood cells (WBC) and was cultured. Thirteen AF cultures were positive, defined as growth on primary plating media which corresponded to greater than 10(2) colony-forming units (CFU) per milliliter. Almost equal numbers of aerobic and anaerobic bacteria were isolated. The presence of bacteria, but not WBC, on Gram stain of AF correlated significantly with a positive culture, which indicated that microscopic examination of AF would usually predict the culture result. Growth of greater than 10(2) CFU/ml from AF was significantly associated with clinical chorioamnionitis, but colonization also was observed in five afebrile patients, four of whom were in premature labor. In patients delivered by cesarean section, bacteria on Gram stain and a positive culture from AF each were significantly correlated with postpartum endometritis.

The fetal heart rate acceleration response to an acoustic stimulation was compared to the traditional nonstress test in regard to pregnancy outcome, as reflected by the incidence of intrapartum fetal distress, meconium staining of the amniotic fluid, 1- and 5-minute Apgar scores, and perinatal mortality. Fetuses with spontaneous or sound-generated reactivity had comparably good outcomes with respect to all outcome measures investigated. Fetuses who lacked spontaneous or sound-stimulated reactivity had an increased risk for intrapartum fetal distress. The acoustic stimulation test is a safe and rapid test of fetoplacental sufficiency that appears to perform comparably to the nonstress test. The acoustic stimulation test significantly shortens total antepartum testing time and expense.

A dehydroepiandrosterone (DHEA) loading test (DLT) is described. The results of 19 DHEA loading tests in as many third-trimester obstetric patients are presented. Analysis involves inspection of the raw data and the application of the physiologic model of the DHEA to estrogen conversion system described in the preceding paper (Part I). The DLT results show that within the population studied, the conversion rate of DHEA to estrogens is lower in patients with placental insufficiency than in normal patients (N = 5, p = 0.002) or in patients with various complications of pregnancy who deliver normally grown, undistressed infants (N = 6, p = 0.001). Routine clinical application must await more extensive evaluation to preclude the existence of forms of placental insufficiency not detected by this means, or normal states resulting in "false-positive" tests. These initial clinical results are intended primarily to demonstrate the potential clinical applicability of the physiologic model described in Part I.

Two patients with acute fatty metamorphosis of the liver of pregnancy who survived are presented. Clinical and pathologic features, possible etiologic factors, and principles of treatment are discussed. Both patients subsequently were allowed to become pregnant again, both had uncomplicated second pregnancies without evidence of liver disease, and both delivered healthy babies.

We compared the findings from pelvic examination, preoperative ultrasound and surgery on 50 patients who underwent exploratory laparotomy for a pelvic mass at Tulane University Medical Center. Of the 50 cases, 34 (68%) were correctly diagnosed as a pelvic mass by both pelvic examination and ultrasonography. Ultrasound had nine false negatives (21%) and only one false positive (2%). Pelvic examination had 7 false positives (16%). There was no statistical difference by chi-square analysis in the accuracy between ultrasonography and pelvic examination in the detection or diagnosis of the masses. Ultrasound indicated pathology not associated with the suspected mass in ten patients; surgery confirmed pathology in five of them. More errors occurred on both pelvic examination and ultrasonography in obese patients than in nonobese ones: seven of the ten ultrasound errors occurred in obese patients, and five of the seven pelvic exam errors also occurred in obese patients. In the nine cases of false-negative ultrasound findings surgery was postponed, but all of them eventually underwent surgery because of a deteriorating clinical course. In our study pelvic ultrasonography was not beneficial in the management of patients with a known or suspected pelvic mass, but it was very accurate for confirmation of a mass.

A retrospective study of all inborn infants at 26 to 35 weeks' gestational age delivered from August, 1976, through July, 1977, was undertaken to determine the effects on the neonate of maternal isoxsuprine therapy for premature labor. Mothers of 43 infants received ISX within 48 hours of delivery and mothers of 107 received no ISX. Hypocalcemia, hypoglycemia, evidence of ileus, hypotension, and neonatal death were all significantly more common in infants whose mothers received ISX. Hypotension and death occurred predominantly in infants of 26 to 31 weeks' gestation and in infants whose mothers developed hypotension or tachycardia during ISX infusion. The frequency of hypotension and death decreased as the time interval from the loading dose of ISX to delivery increased.

A simple technique is presented for determining the volume of blood to be exchanged in an isovolumetric partial exchange transfusion in order to achieve a desired final hematocrit or desired final percentage of normal hemoglobin. Experience from 16 exchange transfusions in 10 obstetric patients is used to improve the estimate of specific blood volume and, hence, the accuracy of the technique. A detailed protocol for this simple outpatient procedure is presented.

The effects of cryosurgical treatment of the fetal ductus arteriosus (DA) on the structure and function of the neonatal DA are assessed for the first time. A cryosurgical probe, cooled with nitrous oxide, was used to freeze the wall of the DA in 5 fetal lambs. Six fetal lambs were used as control animals. After birth, all the cryosurgically treated lambs had a patent DA whereas all the control lambs had a closed DA. Only the cryosurgically treated group had these histologic findings: calcific deposits, necrosis, and focal ganglion cell necrosis in the outer one third to two thirds of the media with a decrease or loss of muscle cells and elastic fibers. This study suggests the feasibility of developing a cryosurgical approach for maintaining patency of the DA.

Seventy patients treated with isoxsuprine for premature labor were studied. In patients with intact membranes prolongation of pregnancy for more than 7 days occurred in 77% of women with 50% cervical effacement or less and 3 cm dilatation or less at the initiation of therapy, and in none with more than 50% effacement and more than 3 cm dilatation. Cervical effacement was the primary factor in determining success. Cord isoxsuprine concentrations averaged 90% of maternal concentrations at delivery. Maternal and cord isoxsuprine concentrations at delivery were inversely correlated with the drug-free interval before delivery. An interval of more than 5 hours was necessary to attain a cord concentration of less than 2 ng/ml, a level not associated with neonatal problems. Drug-free intervals of 2 hours or less usually resulted in cord isoxsuprine values of more than 10 ng/ml, levels that are associated with severe neonatal problems. Seventy-seven percent of infants with cord isoxsuprine concentrations of more than 2 ng/ml and 91% with values of more than 10 ng/ml were delivered of mothers with more than 3 cm dilatation or more than 50% effacement at the initiation or reinstitution of intravenous therapy. Most severe neonatal problems are preventable if patients are selected carefully.

A physiologic model of the dynamics of fetoplacental unit dehydroepiandrosterone (HDEA) to estrogen conversion is presented. A mathematical representation of this model is included. The model is used in Part II to determine the rate constant of DHEA to estrogen conversion and to successfully identify those fetuses in jeopardy from placental insufficiency within the population studied. This presentation permits critical comprehension of the model without extensive mathematical background.

Acute carbon monoxide poisoning occurred in pregnancy. An acute treatment plan involving hyperbaric oxygen administration was employed in place of the more traditional passive approaches usually used during pregnancy. This treatment plan may help circumvent the potentially lethal effect of this gas.

Placenta accreta is a rare complication of pregnancy. Traditional therapy has centered upon total abdominal hysterectomy to prevent serious hemorrhagic and infectious sequelae. Conservative management, however, may preserve reproductive function without jeopardizing maternal welfare.