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Measuring reference value of tracheal cross-sectional area in fetuses between 22 and 32 weeks with ultrasound to study changes of fetal tracheal cross-sectional area with gestational age.
From October 2016 to April 2017 three hundred and thirty pregnant women were enrolled in the Third Affiliated Hospital of Sun Yat-sen University. The pregnant women aged 19-45 years old, average age 27±5 years. The fetuses were between 22 and 32 weeks. These fetuses were divided into 11 groups. Inclusion criteria: (1)pregnant women have no drinking and smoking history, (2)pregnant women have no hypertension, diabetes, severe arrhythmia, autoimmune disease, hyperthyroidism or congenital heart disease,(3)The fetus checked by 3D ultrasound of prenatal examination to exclude structural abnormalities and arrhythmias, (4)checked the early and Mid Down's screening and noninvasive detection of DNA or amniocentesis to exclude related abnormal chromosome. GE Voluson 730 color Doppler ultrasonic diagnostic apparatus were used, convex array probe, frequency 4-8MHz, HITACHI-ALOKA F75 color Doppler ultrasonic diagnostic apparatus were used, convex array probe, frequency 3-6MHz. According to the 2011 fetal echocardiography guidelines of American Society of Echocardiography, showed the three vascular plane, obtained the cross section of the trachea, measured cross-sectional area of the trachea in ventricular systole. Data were analyzed by SPSS17.0 statistical software, all data were expressed as mean±standard deviation.
All the fetal tracheal cross-sectional area as follows: 22-22+6: 3±1mm2, 23-23+6: 3±1mm2, 24-24+6: 4±1mm2, 25-25+6: 5±1mm2, 26-26+6: 5±2mm2, 27-27+6: 5±2mm2, 28-28+6: 6±2mm2, 29-29+6: 6±3mm2, 30-30+6: 7±3mm2, 31-31+6: 8±2mm2, 32-32+6: 8±2mm2.
This study found that fetal tracheal cross-sectional area increased linearly correlated with gestational age. The results of this study can help for further studies of tracheal compression in fetus with congenital isolated vascular ring. It also can provide literature base to judge prognosis of fetuses with congenital isolated vascular ring after birth.