Objective: To establish the normal parameters of fetal lung development at different gestational ages and to study their correlation with gestational age, thereby providing clinicians with a noninvasive method for assessing fetal lung maturity.
Methods: Two hundred eight cases with pregnancy of 22 to 39 weeks plus 6 days were divided into 18 groups according to gestational age. Ultrasound Doppler was used to measure the relevant parameters of fetal pulmonary development, including right pulmonary left and right diameter, right pulmonary upper and lower diameter, right pulmonary anterior and posterior diameter, right pulmonary area, thoracic area, inner diameter of fetal main pulmonary artery, and Doppler velocity curve parameters of main pulmonary artery: systolic acceleration time (AT), ejection time (ET), AT/ET.
Results: This study establishes normal parameters of lung development at different gestational weeks, draws scatter plots, correlation, and regression analysis of fetal main pulmonary artery AT, ET, AT/ET, and gestational weeks; selects the optimal equation; and analyzes the correlation among right pulmonary left and right diameter, right pulmonary upper and lower diameter, right pulmonary anterior and posterior diameter, right lung diameter, right lung area, thoracic area, and gestational weeks; and draw growth curve. The diameter of main pulmonary artery, AT, and AT/ET increased with the increase of gestational age and were positively correlated with gestational age (r = 0.948, 0.875, 0.810; P = 0.012). Ejection time had no correlation with gestational weeks. There were significant differences in the diameter of main pulmonary artery, AT, AT/ET between different gestational weeks (F = 240.67, 41.137, 23.067; P = 0.024); left and right diameter of right lung, anterior and posterior diameter of right lung, upper and lower diameter of right lung, chest area and right lung area were positively correlated with gestational weeks, and there were significant differences between different gestational weeks (F = 190.85, 105.74, 34.97, 172.33, 35.33, P = 0.018).
Conclusions: Ultrasound Doppler can be used as a noninvasive detecting equipment to evaluate the growth of fetal lung, thus providing a basis for the evaluation of fetal lung maturity.