Faculty Bibliography

In a prospective study of 62 patients undergoing cesarean section before the onset of labor a fetal biophysical profile assessment was performed within 3 hours before the cesarean section. The presence or absence of the individual fetal biophysical activities (fetal heart rate reactivity, fetal breathing movements, fetal body movements, and fetal tone) were correlated with umbilical cord blood gas and acid-base measurements (artery and vein). Fetuses with nonreactive nonstress test results or the absence of breathing had significantly lower cord artery pH, PO2 bicarbonate, and base excess measurements but not a significantly different PCO2 level as compared with fetuses that had these activities present. Fetuses with the absence of movements or tone had lower pH, PO2 bicarbonate, and base excess levels and higher PCO2 levels as compared with fetuses with the presence of movements or tone, respectively. These blood gas and acid-base differences were observed in both umbilical cord artery and vein. Subsequent analysis of the blood gas and acid-base measurements of the fetuses with compromised biophysical activities revealed that there are different levels of acidemia, hypoxemia, and hypercapnia at which the individual biophysical activities are compromised. These data suggest that the first manifestations of fetal hypoxemia and acidemia are nonreactive nonstress test results and loss of fetal breathing; in advanced acidemia, hypoxemia, and hypercapnia fetal movements and fetal tone are compromised.

The relationship between cord blood gases and infection outcome was determined in 53 consecutive patients with preterm premature rupture of the membranes who were delivered because of abnormal fetal biophysical assessment. Measures of infection outcome included the presence of clinical amnionitis, possible neonatal sepsis, and neonatal sepsis. Fetal acidosis at birth, as defined by cord arterial pH less than 7.20, was found in six fetuses; five of these developed neonatal sepsis and the other was born to a mother who had intrapartum clinical amnionitis. The mean cord blood pH (artery and vein) of fetuses with neonatal sepsis was significantly less than in fetuses with possible neonatal sepsis or no sepsis; however, two thirds (10 of 15) of the neonates with sepsis had normal acid-base status at birth. These data suggest that the fetal biophysical assessment becomes abnormal before the development of fetal acidosis. The possible mechanisms by which fetal infection diminishes fetal biophysical activities prior to the development of acidosis are discussed

Microscopic features of placentas from 539 consecutive preterm deliveries and 214 term deliveries were compared. The presence of either umbilical or chorionic vasculitis was identified in 38% of the cases at 22 to 28 weeks' gestation, in 32% of the cases at 29 to 32 weeks' gestation, in 13% of the cases at 33 to 36 weeks' gestation, and in 10% of the cases at term (p less than 0.0001). Decidual vascular abnormality was present in 70% of the cases at 22 to 28 weeks' gestation, in 35% of the cases at 29 to 32 weeks, in 29% of the cases at 33 to 36 weeks, and in 15% of the cases at term (p less than 0.0001). Chronic villitis was significantly more frequent in preterm deliveries without umbilical vasculitis than in those cases with umbilical vasculitis (17% vs 8%, p less than 0.05). Our data indicate that the placental lesions of umbilical-chorionic vasculitis, decidual vascular abnormality, and chronic villitis are related to preterm birth. Umbilical-chorionic vasculitis reflects acute ascending bacterial infection. Decidual vascular abnormality has been associated with maternal autoimmune or alloimmune disorders. Chronic villitis may indicate either congenital viral infection or maternal-fetal immunopathologic conditions. Both decidual vascular abnormality and chronic villitis may reflect the activation of inflammatory mechanisms capable of leading to preterm delivery

The relationships among umbilical artery velocimetry, fetal biophysical profile, and placental inflammation in 44 consecutive patients with preterm premature rupture of the membranes were determined. All patients were followed up with daily fetal biophysical profiles and systolic/diastolic ratios. After delivery, placental pathologic examination for histologic evidence of infection (umbilical vasculitis) was performed in all cases according to a standard protocol. The longitudinal trends of fetal biophysical profile scores and systolic/diastolic ratios were analyzed for patients with and without umbilical vasculitis. Analysis of the longitudinal trend during the period of 2 to 7 days before delivery showed that there were no differences of biophysical scores of systolic/diastolic ratios in either group. However, in the last examination, within 24 hours of delivery, patients with umbilical vasculitis had higher systolic/diastolic ratios and lower biophysical profile scores as compared with previous examinations. In addition, the biophysical profile score of the last examination 24 hours before delivery in patients with umbilical vasculitis was found to be significantly lower as compared with patients without umbilical vasculitis (mean +/- SD, 6.6 +/- 2.3 versus 8.2 +/- 2.4, respectively). These data suggest that subclinical stages of infection are associated with biophysical alterations of the fetoplacental unit (i.e., simultaneous decrease in fetal biophysical activities and increase in systolic/diastolic ratios). Daily umbilical artery systolic/diastolic ratios, in conjunction with biophysical profiles, may be useful to follow up patients with preterm premature rupture of the membranes

During a large statewide outbreak of fifth disease in Connecticut in 1988, 39 pregnant women were identified who had serologic evidence of recent human B19 parvovirus infection. The patients were followed up prospectively with targeted fetal ultrasonographic examinations to detect signs of fetal hydrops. Of these 39 pregnant women, 37 had healthy infants and two patients had miscarriages. None of the fetuses developed hydrops. We propose that pregnant women exposed to B19 parvovirus be tested for evidence of IgG and IgM B19-specific antibodies and that targeted fetal ultrasonography be considered when IgM antibodies are found. Percutaneous umbilical blood sampling and intrauterine transfusion can be considered in cases of B19 parvovirus-associated hydrops and anemia. The overall fetal loss rate in this prospective follow-up group was 5%.

Computer technology and the use of personal computers in obstetrics, particularly antepartum, and intrapartum fetal evaluation, are discussed. The future direction of computer technology in fetal assessment is also addressed.

Twenty-five discordant twin pairs were assessed ultrasonically in a longitudinal fashion and were compared with a group of 60 concordant twin pairs. The growth parameters of the larger fetus of the discordant pair did not differ significantly from the concordant twins, while the smaller of the discordant pair exhibited a slower rate of intrauterine growth as early as 23 to 24 weeks. We conclude that (1) twins who ultimately become discordant exhibit demonstrable differences as early as 23 to 24 weeks; (2) the smaller twin in a discordant pair has a much slower rate of growth between 33 to 37 weeks; and (3) using estimated fetal weight to predict concordancy and discordancy by Shepard's and Hadlock's tables are equally efficacious, although Hadlock's table can be used more often because biparietal diameter cannot be obtained as often as femur length.