Joseph M. Miller

Bacterial colonization of amniotic fluid from intact fetal membranes

Abstract Except in rare instances, intact membranes have been considered to be a barrier to infection of amniotic fluid. Amniotic fluid was collected from 45 selected patients by amniocentesis or needle amniotomy prior to or duing labor, or by needle aspiration at the time of cesarean section. Fluid was cultured and examined directly by Gram stain. Among 14 patients who were not in labor, only one had growth of bacteria from broth culture [ 10 2 CFU/ml), five grew in broth only, and 13 were negative. Of the 13 patients with positive cultures of >10 2 CFU/ml, eight patients had clinical chorioamnionitis; five patients were afebrile and clinically asymptomatic, except that premature labor occurred in three of these patients. Of the amniotic fluid cultures with >10 2 CFU/ml, six contained only aerobes, five contained only anaerobes, and two contained mixed aerotolerance types. Aerobic bacteria included Haemophilus influenzae, Pseudomonas aeruginosa, Klebsiella pneumoniae, Listeria monocytogenes , group B β-hemolytic streptococci, and coagulase-negative staphylococci. Anaerobic organisms isolated included Fusobacterium nucleatum (on three occasions), Bacteroides corrodens, Bacteroides ochraceus, Bacteroides bivius , and Peptostreptococcus micros . Bacteria and leukocytes observed by oil immersion microscopy on direct Gram stain of unspun amniotic fluid were significantly associated with culture of >10 2 CFU/ml. Also, the presence of bacteria on Gram stain and >10 2 CFU/ml from culture were significantly associated with the presence of clinical chorioamnionitis. These data demonstrated a wider spectrum of bacteria capable of colonizing amniotic fluid in the presence of intact membranes than was previously appreciated, indicating that direct Gram stain in addition to culture can provide valuable diagnostic information.

Bacterial colonization of amniotic fluid in the presence of ruptured membranes

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.

Premature labor and premature rupture of the membranes

Abstract The effects of prolonged rupture of membranes upon the outcome of the mother and the fetus remain a problem in obstetrics. In an attempt to correlate the time interval between premature rupture of the membranes (PROM) and the onset of labor prior to term and maternal and perinatal outcome, a retrospective study was done in patients admitted to the Duke University Medical Center during the 5 year interval 1971 to 1975. Of these patients, 184 had premature labor prior to the rupture of membranes and 151 had PROM. A total of 335 pregnant patients who bore infants weighing from 1,000 to 2,500 grams were studied. Only infants of appropriate weight for their gestational age at birth and without apparent fetal malformations were included in the study. The time interval between rupture of membranes and onset of labor and delivery ranged from 0 hours to 4 weeks. All the patients were divided into three groups according to birth weight. For each group with PROM, the length of time of rupture of membranes prior to labor was compared with the development of neonatal respiratory distress syndrome (RDS) and maternal and neonatal infections. Infants from mothers with premature labor only were used as a reference group. Statistically, the data demonstrated a decrease in RDS in infants weighing from 1,000 to 1,500 grams with an increase in duration of rupture of membranes. This incidence of RDS was not altered when birth weight was above 1,500 grams. The development of fetal pulmonary maturity and the effect of time in relationship to the development of maternal and fetal infections and a possible time for delivery following PROM are discussed.

Renal disease in pregnancy.

Renal disease in pregnancy may be progressive but only rarely. The problems encountered that create maternal and fetal morbidity and mortality relate to the development of superimposed preeclampsia and renal failure. Diagnosis is important to differentiate the cause of renal pathology so that appropriate treatment can be undertaken. The use of medications in renal disease in the presence of hypertension is controversial; however, adequate therapy should be given if indicated. Most cases of renal disease in pregnancy do not require termination; however, counseling concerning pregnancy is needed initially or subsequently.

Rh isoimmunization: A 24 year experience at Duke University Medical Center

A retrospective analysis was made of Rh-sensitized patients delivered of their babies at Duke University Medical Center during a 24 year period. Records of 202 obstetric patients representing 280 sensitized pregnancies from a pool of 39,910 deliveries were analyzed for past obstetric history, blood group information, antibody determinations, amniocentesis data, and details of the pregnancy and delivery. The medical records of the corresponding infants were analyzed for their neonatal course. A severity index (SI) was devised to classify the degree of severity of the erythroblastosis fetalis. A significant correlation between SI and the delta OD450 of amniotic fluid, umbilical cord hematocrit, and bilirubin was noted. The evaluation of amniotic fluid delta OD450 is considered to be the cornerstone of clinical management. Twenty-nine patients had initial Liley zone 1 determinations which decreased to delta OD450 = 0.000; however, only 10 of 29 (34.5%) of the infants were unaffected, and 13 of 29 (44.8%) had mild sensitization, four of 29 (13.8%) had moderate sensitization, and two of 29 (6.9%) had severe sensitization. The previously held concept of critical titer as a guide for initiating amniocentesis is challenged, and the recommendation is made that amniocentesis for amniotic fluid determination should be undertaken in any patient with a positive indirect Coombs titer.

Comparison of dynamic image and pulsed Doppler ultrasonography for the diagnosis of the small-for-gestational-age fetus

OBJECTIVEnBecause poor fetal growth is a significant cause of perinatal morbidity and mortality, a prospective study was undertaken to evaluate the ability of real-time ultrasonography and Doppler velocimetry to detect the small-for-gestational-age fetus.nnnSTUDY DESIGNnA prospective study of 136 women at risk for fetal growth abnormalities was conducted. Patients were delivered within 3 weeks and had live-born, nonanomalous, singleton infants. The relative estimated fetal weight (estimated fetal weight divided by the median birth weight for gestational age) and the systolic/diastolic ratio were measured and compared with receiver-operator characteristic curves. In this method the area under the curve is the index of performance.nnnRESULTSnForty-six infants were small for gestational age. Although both relative estimated fetal weight (area under the curve = 0.923) and systolic/diastolic ratio (area under the curve = 0.837) were significantly associated with the small for gestational age fetus, the former was more strongly correlated, p = 0.021.nnnCONCLUSIONnRelative estimated weight is more sensitive and specific and should be the preferred parameter when gestational age is known.

The startle test revisited

OBJECTIVE: Our purpose was to the compare fetal heart reaction to external physical stimulation with the nonstress test (NST).STUDY DESIGN: This prospective study evaluates documentation of fetal heart rate accelerations by two methods. The standard NST was performed prior to the ultrasound evaluation. The NST results were unavailable to the ultrasonographer. M-mode ultrasound was used initially to detect a stable heart rate. Then the ultrasound transducer was used to stimulate fetal movement by indenting the uterus over the fetal small parts. A second fetal heart rate was determined within 15 seconds after stimulation.RESULTS: A total of 194 patients underwent 235 studies. The patient population included four sets of twins. When the NST was reactive, 151/216 had an ultrasound startle response of ≥15 beats per minute; however, all nonreactive NSTs were associated with an ultrasound response of 14 beats per minute or less (p<0.001). A receiver-operating characteristic curve comparing the ultrasound fetal response to the startle with the NST identified the area under the curve to be 0.948, consistent with high specificity and sensitivity.CONCLUSION: The fetal heart rate response to external stimulation identifies 67% of patients with a reactive NST.

Comparison of Morbidity in Cesarean Section Hysterectomy Versus Cesarean Section Tubal Ligation

This study was undertaken to compare the morbidity of cesarean section hysterectomy (C-HYST) and cesarean section bilateral tubal ligation (C-BTL) in a nonemergency or elective environment. Charts were reviewed for patients who underwent elective C-HYST or elective C-BTL before the onset of labor, without the use of antibiotics. Demographics, maternal morbidity, operative difficulties and postoperative complications were compared. Statistically significant differences in patient demographics include a higher maternal age in the C-HYST group than for those in the C-BTL group (31.0 +/- 5.8 versus 27.7 +/- 5.4 years; p = 0.002). C-BTL patients had higher gestational ages (39.4 +/- 1.6 versus 38.7 +/- 1.3 years; p = 0.0017). The C-HYST group had a higher estimated blood loss (1,201 +/- 472 versus 718 +/- 364 milliliters; p = 0.001), change in hematocrit level (6.0 +/- 4.4 percent versus 4.5 +/- 3.4 percent; p = 0.013) and operating time (115 +/- 37 versus 74 +/- 26 minutes; p = 0.0001). Blood transfusion was similar in both groups. Febrile morbidity was higher in the C-BTL group (68.0 percent versus 50.0 percent; p = 0.01). Endometritis was the significant determinant of febrile morbidity for the C-BTL group (41.7%) and cuff cellulitis in the C-HYST group (25.6 percent). Intraoperative and postoperative complications between the two groups were rare and not statistically different. Clinical morbidity for C-HYST is not significantly different than C-BTL. Elective C-HYST may be used in place of C-BTL when indications for hysterectomy are present.

Acute Bacterial Diarrhea and Bacterial Food Poisoning

Acute diarrheal disease caused by bacteria, along with food poisoning of bacterial etiology, is a major cause of morbidity throughout the world. Of particular interest in developing countries is the infant and child mortality associated with these gastrointestinal syndromes. However, even in the United States, acute diarrheal disease ranks second only to the common cold as a cause of absence from work. Therefore, the obstetrician should be familiar with some of the more common and more serious of these syndromes, since the pregnant patient will often present with such a malady.

Choriocarcinoma Following Term Pregnancy

Two hundred and sixty-five patients with malignant trophoblastic disease were admitted to the Southeastern Trophoblastic Disease Center at Duke University Medical Center between July 1966 and June 1976. Of these 265 patients, 20 had choriocarcinoma following a term gestation with a survival rate of 60% as compared to 95% survival rate for the remaining 245 patients. Previously described risk factors of initial human chorionic gonadotropin (hCG) titer of>100,000 IU/24 hr urine, duration of symptoms for more than 4 months, significant prior unsuccessful chemotherapy or cerebral or hepatic metastases identified the “poor prognosis” group. Post-term gestation “poor prognosis” patients had a significantly lower cure rate (47%), than other patients with “poor prognosis” for gestational trophoblastic disease (75%; P<0.05). Post-term gestation choriocarcinoma has a propensity for more extensive metastatic spread and would appear to be less responsive to conventional chemotherapy, which may be due to an altered immune response in these patients. This suggests that an antecedent term pregnancy should be added to the previously described high-risk factors for patients with malignant trophoblastic disease.