| AIMSIntrauterine growth restriction (IUGR) is one of the common diagnoses in obstetrics, the perinatal morbidity and mortality of IUGR is 4 - 8 times higher than normal pregnancy. However, not all IUGR are intrauterine compromised fetuses, most of them without other complications have a quite good perinatal outcome. In order to avoid the unnecessary intervention to fetuses at no real risk, and also in order to intervene the fetuses at risk of intrauterine hypoxia timely and properly, it is important to find a good way to select the IUGR at risk of potential intrauterine hypoxia and intervene them in appropriate time.Umbilical artery blood flow velocimetry plays an important role in monitoring IUGR. IUGR with absent or reversed end - diastolic blood flow velocity in the umbilical artery indicates a fetus at a particular high risk of suffering death or morbidity. The choice of prompt abdominal delivery is then usually not controversial. In contrast, IUGR fetuses having only a slightly or moderately increased umbilical vascular resistance, with forward diastolic flow maintained are not at a high risk and half of them can be delivered vaginally. However, there is no general consensus on when and how to deliver IUGR fetuses having only a slightly or moderately increased umbilical vascular resistance.Oxytocin Challenge Test ( OCT) has been regarded as a good method to e-valuate the placental function. However, OCT has a rather high false positive rate (8 -57% ) , which limited OCTs clinical application. In order to decrease the false positive rate of OCT, we performed the OGT and umbilical artery blood flow velocimetry simultaneously, and we investigated fetal middle cerebral blood flow and maternal uterine artery blood flow during OCT, and to observe the rela-tionship of fetal middle cerebral blood flow and maternal uterine artery blood flow change during OCT with OCT results and perinatal outcomes.MATERIAL AND METHODSI. Patients; 114 cases with suspected IUGR were selected from obstetrical outpatient clinic, Lund university, university hospital, Sweden from March, 1998 to July, 2002. Among them, 53 cases were increased umbilical vascular resistance but maintained forward diastolic flow, and 61 cases were normal umbilical blood flow. All the cases were singleton pregnancy without any pregnant complication; the gestational age was from 36 to 41 gestational weeks; the mean maternal age was 28. 6 years old.II. Methods;1. Selecting IUGR: We performed ultrasound imaging for every pregnant woman in 32 gestational weeks, and we estimated the fetal weight using the formula as follows; log10(EFW) = 1.35960.00386 ( AC FL) + 0.0064 ( HC ) +0.00061 (BPD AC) + 0.0424 (AC) + 0.174 (FL). (EFW = estimated fetal weight; AC = abdominal circumference; FL = femur length; HC= head circumference; BPD = biparietal diameter). If the EFW belowed the 10th percentile gestational age - corrected mean value, was defined as suspected IUGR.2. Oxytocin challenge test; The OCT was preceded by 30 minutes of basal electronic fetal heart rate monitoring with a standard cardiotocograph, externally recording fetal heart rate and uterine contractions at a paper speed of 1 cm/min. Oxytocin stimulation begun at an intravenous infusion rate of 6 mlu/h (5 units of oxytocin in 500 mL 5.5% glucose). The infusion rate was doubled every 10 minutes until 3 consecutive uterine contractions per 10 - minute window occurred repeatedly, and then maintained for at least 30 minutes, or until repetitive late decelerations occurred in OCT positive cases. The maximal infusion rate was set at 96 mL/h. The OCT was classified as negative or positive according to Freeman.3. Blood flow velocimetry:The umbilical artery flow velocity waveforms ( FVWs) were recorded from a free - floating part of the cord before OCT was started and during uterine contraction and relaxation during OCT. Analysing indicator was pulsatility index (PI).The MCA was identified by color Doppler ultrasound, as a major lateral branc...
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