A non-invasive method to rule out transient tachypnea of the newborn (TTN): fetal pulmonary artery acceleration to ejection time ratio.

ABSTRACT

OBJECTIVE: To investigate whether fetal pulmonary artery acceleration to ejection time (PATET) ratio can predict or rule out subsequent diagnosis of transient tachypnea of the newborn (TTN). METHODS: This prospective cohort study included 105 pregnant women in labor, who met the inclusion criteria. Eighteen of these women were removed from the study cohort, because of an inability to acquire sufficient Doppler waveforms and a longer duration of deliveries. According to subsequent diagnosis of TTN in the neonate, the two groups were constituted, TTN+ and TTN-. RESULTS: There were no statistically significant differences between the groups regarding maternal obstetric and demographic features. The neonatal intensive care unit (NICU) submission rate was significantly higher in the TTN+ group (100%, 17%, P<0.0001, respectively). Regarding the fetal pulmonary artery Doppler findings, PATET ratio in the TTN+ group was significantly lower than the TTN- group (0.307 vs. 0.389, P<0.0001, respectively). The PATET ratio and diagnosis of TTN were inversely correlated (r=-0.41, P<0.001), even if adjusted for birth weight, gestational age and fetal gender (r=0.42, P=0.0021). The cut-off value of 0.319 provided 82.7% specificity, 83.3% sensitivity, 96% negative predictive value and 41.6% positive predictive value. Additionally intraobserver ICC for PATET was found to be 0.86. CONCLUSION: The fetal PATET ratio seems to serve as a promising tool to rule out subsequent diagnosis of TTN.