Fetal Pulmonary Artery Acceleration/Ejection Ratio for Transient Tachypnea of the Newborn in Uncomplicated Term Small for Gestational Age Fetuses.

OBJECTIVE

Transient tachypnea of the newborn (TTN) is the leading cause of neonatal morbidity in preterm deliveries and has been reported in term small-for-gestational-age (SGA) fetuses; therefore, determination of fetal lung maturity before delivery is extremely important. Our present study aimed to evaluate the ratio of fetal pulmonary artery acceleration time to ejection time (At/Et) in uncomplicated term SGA fetuses and whether this ratio changes with TTN.

STUDY DESIGN

One hundred seventy-five pregnant women with uncomplicated pregnancies who delivered after 37 gestational weeks were included in this cross-sectional study. Participants were divided by birth weight percentiles into SGA (n = 86) and healthy control groups (n = 89). All participants underwent ultrasound examination to determine fetal pulmonary artery At/Et. After delivery, the neonates were grouped according to diagnosis of TTN (i.e., TTN-positive SGA group [n = 14], TTN-negative SGA group [n = 72], and TTN-negative control group [n = 86]), and the fetal pulmonary artery At/Et was compared between the two.

RESULTS

Maternal demographic characterizes were similar between groups. At/Et was 0.309 ± 0.181 in the SGA group and 0.348 ± 0.213 in the control group and was significantly lower in the SGA group. At/Et was 0.290 ± 0.007 in the TTN-positive SGA group, 0.313 ± 0.017 in the TTN-negative SGA group, and 0.351 ± 0.186 in the TTN-negative control group, a significant difference. Additionally fetal pulmonary artery At/Et was found to be inverse correlated with TTN. (-0,464 P = 0.000). The cut-off value of 0.298 provided optimal specificity of 93.0 % and sensitivity of 81.0 % for subsequent diagnosis of TTN in term SGA newborns in the neonatal period.

CONCLUSION

The risk for TTN increases in uncomplicated term SGA fetuses. The fetal pulmonary artery At/Et appears to be a noninvasive useful method by which to predict TTN in these fetuses.