The Experimental Study On IUGR Diagnosis Of Fetal Rats By Heart Rate Variability Analysis

1 ObjectiveIUGR is the familiar syndrome in obstetrics and Ultrasonic examination is a usual method to diagnose it. But the method by Ultrasonic can not distinguish IUGR from SGA. There are a lots of information of growth and function about autonomic nervous system and the activity and balance and the modulation to heart of sympathetic nerve and vagus can be quantificationally evaluated by FHRV, so the analysis on fetal heart rate variability can be used to estimate the growth of ANS. Restricting feed and drinking on maternal rat was used to set up the IUGR model in the rats. Based on the animal model, the analysis methods of HRV was used to study the characters of FHRV in IUGR. We hope fetal heart rate variability can be applied as a new diagnostic method of IUGR. 2 Methods20 female SD rats was divided into two groups at random and each team was 10 rats. Control group was feed normally. Experimental group was feed by 40% according to Control group from the first gestation day and drinking from the 7th day(0.9ml/100g). Intrauterine embryonic ECG was record after anesthesia in the 20th gestation day. Time domain analysis method, power spectral analysis method and the fetal heart rate based variability analysis method were used to evaluate FHRV. After recording embryonic ECG, every index about growth was noted by taking embryonic. 30 placentas in every groups was studied in pathology by HE coloration.3 Results1. The weight of maternal rats in the control group was gradually increased in the whole pregnant period. The weight of maternal rats in the experiment group was declined distinctively before the 5th pregnant day and the trend of incline became slowly from 6-10 days' gestation. From the 11th day, the weight began to add gradually and the weight basically reach the level before pregnant. Until the 15th day, the weight didn't change. The weight in the experiment group always lighter than the control group(P<0.01).2. There were 121 embryos in the control group and the average weight of embryo was 3.017g. The number of embryo in the experiment group was 87 and the average weight was 2.013g, so the distinguish was notable(P<0.05). The weight of embryo and the placentas in the experiment group were lighter than these of the control group(P<0.01), so as the weight of brain and liver. The length of the embryo and the tail was shorter in the experiment group than that of the control group(P<0.01), but the percentage of IUGR and death were higher in the experiment group(P<0.01, P< 0.05).3. Macroscopic and histological observation was performed. The results showed that the placental weight and villous area ratio in the IUGR group were decreased than that of the control group(P<0.05). The placental coefficient was higher that of the control group, but there wasn't significant in statistics(P >0.05). The percentage of gore and hemorrhage in placenta were higher in the IUGR group than that of the control group(P<0.05).4. The ECG of was recorded while noting embryonic ECG and the embryonic ECG was recording over again after extirpating the heart of maternal rat. It proved that the electric action represented embryonic ECG.5. The index (SDNN, RMSSD, SDSD, PNN50) of time domain analysiswere all increased in the IUGR group than these of the control groups(P< 0.05). Power spectral analysis method was used. The results showed that TF, LF and HF were all higher in the IUGR group than these of the control groups(P<0.01). But after normalization, LF in the control groups became higher than that of the IUGR group. The apexes of LF and HF were inclined to left coordinate. The results of fetal heart rate based variability analysis showed the altitudes of FHRV were lower in the IUGR group than that of the control groups(P<0.05). Frequency of FHRV in the control groups was higher than that of the IUGR group, but the distinguish was inconspicuous(P >0.05). 4 Conclusions1. The animal model was set up successfully by restricting feed and drinking on maternal rat.2. The function and status of A...