Lung Growth and Intrapulmonary Circulation in Fetuses With Anhydramnios Due to Severe Renal Anomalies Treated With Serial Amnioinfusions

Objective: To evaluate changes in fetal lung size/volume and intrapulmonary circulation after serial amnioinfusions (AMI) in fetuses with early anhydramnios. Methods: Ten fetuses with anhydramnios due to renal agenesis (n = 4) or renal dysplasia (n = 6) were treated with serial AMIs. Before AMI, the following ultrasound parameters were obtained: fetal lung area, total lung volume (TLV), O/E LHR, thorax circumference (TC), cardiothoracic ratio (CTR), and pulsatility index of the main intrapulmonary artery (IPA). Differences in lung biometrics between the first and last AMIs are reported. Results: One hundred thirty-nine (median n = 14, [7–22] per patient) AMIs were performed. All deliveries were at ≥ 29 + 6 weeks/days of gestation. There were increases in lung areas (Left (z-scores (z-sc)) −1.86/−0.35; p < 0.001, Right −2.09/−0.81; p = 0.002), and in O/E LHRs (Left 0.56/0.73; p = 0.04, Right 0.57/0.73; p = 0.009). TLV increased (z-sc 0.24/0.53; p = 0.7) and IPA decreased (z-sc 0.87/0.43; p = 0.051), but differences were not significant. No differences in TC (z-sc 0.57/0.56; p = 0.97) or CTR (0.58/0.58; p = 0.1) were documented. The distribution of all lung biometric parameters across pregnancy showed values below the expected mean for gestational age. Conclusions: Fetuses with early anhydramnios treated with serial amnioinfusions showed an increase in lung size; however, this increment was below the expected mean for gestational age.