Linda A. Goodrum

Pneumonia in pregnancy

Pneumonia occurs in the pregnant population with a frequency equal to that in the general population. However, its course is often more virulent, and mortality rates from certain pathogens may be high. The pregnant woman is more susceptible to injury to the respiratory tract due to a number of factors. These include alterations in the immune system which involve cell-mediated immunity and mechanical and anatomical changes involving the chest and abdominal cavities. The cumulative effect is decreased tolerance of hypoxia and acute changes in pulmonary mechanics. The spectrum of pathogens is similar to that for nonpregnant individuals, and the management of pneumonia in pregnancy does not differ in general from the nonpregnant state. However, careful attention should be paid to the fetoplacental unit with delivery generally indicated for obstetric purposes only. Issues that also need to be addressed include effects of certain infections, medications, fever, and hypoxia on the developing fetus.

Effect of nitric oxide and carbon monoxide on uterine contractility during human and rat pregnancy

OBJECTIVE We sought to study the effects of authentic nitric oxide and carbon monoxide on the contractile activity of pregnant human and rat myometrium. STUDY DESIGN Strips were prepared from uterine biopsy specimens of 10 pregnant, nonlaboring women at term gestation undergoing cesarean delivery. In addition, rings were prepared from the uteri of pregnant rats at midterm (day 14) and at term (day 22) gestation (n = 10-12). The tissues were mounted in organ chambers filled with Krebs-Henseleit solution continuously aerated with 5% carbon dioxide in air (37 degrees C, pH approximately 7.4) for isometric tension recording. The effects of nitric oxide and carbon monoxide gases on spontaneous contractile activity were studied. Responses to hemin (hemoxygenase substrate), which produces endogenous carbon monoxide, were also examined. Responses to nitric oxide and carbon monoxide were also studied in aortic and tail artery rings from pregnant rats after contraction with phenylephrine. RESULTS Nitric oxide significantly inhibited contractility of human myometrium at term (area under the concentration-response curve, 145.36 +/- 30.02 vs 40.56 +/- 22.81 in controls; P <.05) and rat myometrium at midterm gestation (264.23 +/- 47.86 vs 121.82 +/- 23.50; P <.05) but not at term. No statistically significant inhibition was induced in human or rat myometrium by carbon monoxide, whereas hemin significantly attenuated contractility in human myometrium at term and in rat myometrium at midterm gestation (P <. 05). Nitric oxide, carbon monoxide, and hemin relaxed aortic and tail artery rings. CONCLUSIONS Authentic nitric oxide inhibits rat uterine contractile activity at midterm gestation but not at term. However, nitric oxide inhibits human myometrium activity at term. Authentic carbon monoxide does not appear to modulate uterine contractility, whereas hemin may have some inhibitory properties.

Conference report: Complex clinical, legal, and ethical issues of pregnant and postpartum women as subjects in clinical trials

BACKGROUND The Office of the Vice President for Research and School of Nursing of the University of Texas Medical Branch convened a multidisciplinary conference to address the national problem of underrepresentation of pregnant women in clinical trials. METHODS Conference participants reviewed pertinent issues through lectures and panel discussions. RESULTS More funded studies are needed to specifically examine pharmacokinetic, physiological, and pharmacological interactions in the pregnant woman. Legal, ethical, and financial issues need to be better delineated, and more focus is needed on specific diseases with particular import for pregnant women and their fetuses. CONCLUSIONS This paper provides a report on the conference and the powerful consensus statements developed by the participants.

Effects of Intravascular Transfusion for Red Cell Alloimmunization on Fetal Arterial Blood Pressure

OBJECTIVE To evaluate the effects of intravascular transfusion (IVT) on the fetal umbilical arterial pressure (UAP) in pregnancies complicated by red cell alloimmunization. STUDY DESIGN UAP and amniotic fluid pressures (AFP) were measured immediately before and after IVT. Mean UAP was calculated by computing 1/3 (systolic blood pressure - diastolic blood pressure) + diastolic blood pressure. The fractional increase in fetoplacental blood volume with transfusion was calculated by dividing the net volume of blood transfused by the sum of the net volume transfused and the fetoplacental volume based on the estimated fetal weight by ultrasound. Statistical techniques included paired t-test, and the Pearson product correlation. Significance was defined as p < 0.05. RESULTS The fetal umbilical artery was punctured during a total of 27 procedures in 21 patients. Pre- and posttransfusion mean UAPs were recorded in 16 of these procedures. Mean UAP increased from 34.0 +/- 14.2 mm Hg pretransfusion to 38.6 +/- 12.8 mm Hg posttransfusion (p = 0.34). There was no correlation between the fractional change in fetoplacental blood volume and the calculated difference between pre- and posttransfusion blood pressure. Bradycardia occurred during 5 procedures (31.2%). Fetal demise occurred after 2 procedures (12.5%). CONCLUSION IVT appears to have a minimal effect on the fetal UAP. Fetal bradycardia occurs in a significant percentage of these cases.

The Effect of Intrauterine Transfusion on Fetal Bilirubin in Red Cell Alloimmunization

Objective To evaluate the change in fetal serum bilirubin levels in response to intrauterine transfusion for red cell alloimmunization. Methods The records of 37 patients who underwent more than one intrauterine transfusion were reviewed. The following indices were extracted: pre- and post-transfusion fetal hematocrit, total and direct serum bilirubin, reticulocyte count, Kleihauer-Betke test results, volumes of intravascular and intraperitoneal transfusions, and the source used for transfusion. The data were compared for interval 1 (transfusion 1 to 2) and interval 2 (transfusion 2 to 3). The rates of change in bilirubin, reticulocyte count, and percent fetal cells on the Kleihauer-Betke test were defined as the differences between the initial values of one transfusion and the initial values of the next transfusion divided by the number of days between transfusions. Analysis of variance, sign-rank test, and linear regression analysis were used when appropriate. P < .05 was significant. Results The median number of intrauterine transfusions for each patient was 3 (range 2–8). Gestational ages ranged from 22 to 37 weeks. Total bilirubin remained above the 97.5 percentile for gestational age in all but five patients. There was a significant decrease in reticulocyte count and fetal cells on the Kleihauer-Betke test, and an increase in hematocrit with serial intrauterine transfusions. Bilirubin increased significantly after the first intrauterine transfusion (3.9 versus 5.0 mg/dL) and remained elevated thereafter. Conclusion Fetal total serum bilirubin remains elevated with repeated intrauterine transfusions in fetal alloimmunization. Total bilirubin should not be used to evaluate fetal hematologic responses to the transfusions.

Fluorescence probe for cervical examination during various reproductive states

These studies represent further investigations that have been done utilizing the fluorescence from pyridinoline, one of the major crosslinks of type I and III collagen, to evaluate cervical connective tissue changes during various female reproductive periods. Based on our previous studies, a prototype instrument has been constructed. The instrument was specifically designed for the purpose of vaginal examination of cervical connective tissue by measuring light induced fluorescence directly from the surface of the external os of the cervix. The studies were carried out on nonpregnant rats, rats during gestation at different periods, rats at different times during postpartum, and rats during preterm birth after being treated with antiprogesterone drugs. A study has also been done on humans during pregnancy and postpartum. The results parallel previous investigations that have used various invasive methods to analyze cervical extensibility, cervical collagen content and collagenase. In consideration of the important role of the collagen fibers and their turnover in the process of cervical function during pregnancy (softening or ripening at term), this method could be a useful tool for evaluating treatment strategies of the cervix. Moreover, the instrument could serve as a device for the non-invasive estimation of cervical status in the clinic and the diagnosis of the changes in the cervix during the preparation for labor.