Correlation between Progesterone as a Treatment of Preterm Labor and Changes in Fetal Pulmonary Artery Doppler

Abstract Background: Progesterone is a crucial drug that is utilized for both preventing and treating preterm birth (PTB). The sonographic echogenicity of the fetal lung changes in an anticipated pattern throughout pregnancy. Fetal pulmonary artery indices have been evidenced to be correlated with proceeding fetal gestational age and assessing maturity of fetal lungs in amniotic fluid. Aim of Study: To explore the correlation between proges-terone as a treatment of preterm labor and changes in fetal pulmonary artery Doppler. Patients and Methods: This study was a prospective study that was conducted at obstetric and gynecology department of El-Sayed Galal Hospital of Al-Azhar University on 50 pregnant women with singleton pregnancies who presented with preterm labor pain at a gestational age of 28 to 34 weeks and treated with progesterone and 50 normal pregnant women at 37 weeks of gestation during the period from May 2020 to December 2020. Doppler Flow Velocity Waveforms study was done via pulsed-wave Doppler after real time color flow localization of pulmonary trunk. All Doppler indices were measured at 37 weeks of gestation. Results: Pulmonary artery At/Et ratio was lower in cases who developed preterm labor pain and received progesterone compared with control cases but without significant difference (mean: 0.332±0.066 versus mean: 0.341±0.014) (p=0.069). Moreover, pulsatility index (PI) was nearly similar in both studied groups (p=0.09). The mean resistance index (RI) was lower in the control group than that in patients groups but statistically significant difference (p=0.119). In addition, there was no statistically difference in the mean of PSV & S/D ratio in control group compared to patients group (p=0.562 & 0.467 respectively). There was statistically significant difference between the patients who had adverse neonatal outcome and those who hadn't in both group I and group II regarding all Doppler indices. In the studied subjects the mean Pulmonary artery At/Et had significant positive correlation with age (p=0.004). Also, it had significantly negative correlation with NICU more than 2 weeks, RDS, PI, and RI (p < 0.05). ROC curve showed the optimum cutoff for Pulmonary artery At/Et was 0.31 for detecting adverse outcome in patients group with sensitivity 92.9% and specificity 91.7%; an area under the ROC curve (AUROC) 0.975 (95% CI: 0.939-1.000) (p < 0.001).
Also, in control group ROC curve analysis showed that Pulmonary artery At/Et was significant for predicting outcome of pregnancy (p=0.004) at a cut off value 0.315 with sensitivity of 100% and specificity of 90.1 % and an area under the ROC curve (AUROC) 0.938 (95% CI: 0.868-1.000). Conclusion: Administration of vaginal progesterone for the prevention of preterm, although having beneficial role in prolongation of pregnancy time, nevertheless it may have adverse events on fetal circulation especially decreasing At/ET ratio, Thus increasing cases at risk for RDS development. Also, we can introduce fetal PA At/Et as noninvasive accurate method for neonatal RDS prediction in at risk- preterm cases who administer progesterone as prophylaxis.