Browsing by Author "Alvarez, M. (57208770409)"

Objective: To evaluate maternal and fetal apolipoprotein A-I and B (Lp A-I and Lp B) concentrations in uncomplicated pregnancies across the second half of pregnancy. Study design: Paired (n = 55) maternal and fetal umbilical venous samples were obtained at diagnostic cordocenteses from 20 to 36 weeks. Levels of Lp A-I and Lp B were measured by turbimetric assay. Results: Maternal Lp B (r = 0.30; p = 0.03) but not Lp A-I (r = -0.02, p = 0.5) levels displayed a significant correlation with gestational age. Moreover, the ratio of Lp B to Lp A-I significantly increased across gestation in maternal plasma (r = 0.30; p = 0.04). Fetal Lp A-I and Lp B values did not correlate with gestational age, or maternal Lp A-I or Lp B levels. Moreover, no significant correlation was found between the ratio of fetal plasma Lp B to Lp A-I and gestational age. The mean (± SD) maternal plasma Lp A-I concentration was significantly higher than the corresponding mean fetal Lp A-I level [1.55 (0.48) versus 0.78 (0.5); p < 0.001]. Similarly, the mean maternal Lp B level was significantly higher than the corresponding fetal value [1.28 (0.33) versus 0.46 (0.30); p < 0.001]. Conclusion: Fetal Lp A-I and Lp B levels were significantly lower than maternal levels and did not correlate with gestational age.

This study was conducted to determine whether fetal blood sampling during the second trimester is associated with changes in circulating fetal beta-endorphin (BE) concentrations. We measured BE concentrations in 68 paired fetal and maternal blood samples obtained between 18 and 28 weeks' gestation. Patients were divided into a control group (n = 50), if the fetal blood samples were obtained by a single umbilical cord puncture, or multiple insertion group (n = 18), if multiple cord punctures were required to obtain a sample. The mean (± SE) fetal BE value for the multiple insertion group was significantly higher than BE levels from the control group (771.2 ± 79.2 pg/ml versus 107.1 ±11.7 pg/ml; p<0.001]. This elevation did not appear to be related to acidosis, since no differences in fetal umbilical pH were observed between the two groups. Fetal BE levels from the control but not from the multiple insertion group significantly correlated with maternal values (Spearman rank r = 0.59; p <0.001 vs r = -0.08; p <0.5). In neither group did fetal BE levels correlate with gestational age. These findings indicate that multiple cord punctures at the time of fetal blood sampling are associated with significant increases in BE release. Furthermore, although a maternal or placental contribution to steady state circulating fetal BE cannot be excluded, it would seem that the fetus itself is the primary source of elevated circulating BE levels following multiple cord punctures. © 1993, by Thieme Medical Publishers, Inc. All rights reserved.