Abnormal Uterine Artery Doppler Research Articles

Antenatal prediction of fetal pH in growth restricted fetuses using computer analysis of the fetal heart rate.

We tested the accuracy of a mathematical model based on computer analysis of the fetal heart rate tracing in predicting umbilical artery pH at birth. In a previous report based on data on 38 growth-restricted fetuses, the second-order polynomial regression equation, umbilical artery pH = 7.28 + 0.002 (duration of episodes of low variation in minutes) + 0.00009 (duration of episodes of low variation in minutes), was retrospectively found to be the best model for the prediction of umbilical artery pH at birth. In the present study, this formula was prospectively tested in 29 growth restricted fetuses between 26 and 37 weeks of gestation from pregnancies with abnormal uterine and/or umbilical artery Doppler velocimetry. Computer analysis of the fetal heart rate tracing of 1 hour duration was performed within 1.5-6 hours of cesarean birth prior to the onset of labor. Umbilical artery cord blood was collected at birth with pH determined within 5 minutes of collection. Acidemia was defined as umbilical artery pH < 7.20, preacidemia pH 7.20-7.25 and nonacidemia pH > 7.25. Then, the data on all 67 growth-restricted fetuses were pooled to generate a new formula that was retrospectively assessed against the entire group. Values are reported as median (range). In the 29 prospectively evaluated cases, there was no statistical difference between the predicted and actual umbilical artery pH at birth [7.28 (7.1-7.29) vs. 7.28 (7.18-7.37), P = 0.57]. The median difference between the paired predicted and actual umbilical artery pH values was -0.001 (-0.10-0.08). The difference between the predicted and actual umbilical artery pH was zero and within +/- 0.04 in 17% (5/29) and 76% (22/29) of the cases, respectively. When the data on the 67 growth-restricted fetuses were pooled together the formula did not change. There was no difference between the predicted and actual umbilical artery pH at birth when the formula was applied to all 67 growth-restricted fetuses [7.28 (7.08-7.29) vs. 7.27 (6.97-7.37), P = 0.41]. The median difference between the paired predicted and actual pH values was -0.001 (-0.12-0.12). The difference between the predicted and actual umbilical artery pH was zero and within +/- 0.04 in 15% (10/67) and 74% (49/67) of the cases, respectively. The accuracy of the formula in correctly categorizing the umbilical artery pH at birth was: acidemia 67% (8/12), preacidemia 28% (8/29) and nonacidemia 80% (37/46), P < 0.0001. A mathematical formula using the computer analysis index of duration of episodes of low variation reliably predicted umbilical artery pH at birth. This type of noninvasive monitoring may allow for the antepartum estimation and continuous tracking of fetal pH.

Prediction of Pre-Eclampsia by Abnormal Uterine Doppler Ultrasound and Modification by Aspirin

Objective To assess the effect of low dose aspirin on severe pre-eclampsia when given to women identified as high risk by abnormal uterine artery Doppler ultrasound. Design Women with abnormal uterine artery flow velocity waveforms were recruited to the CLASP trial at 24 weeks. Abnormal uterine artery waveforms, with a high resistance index or an early diastolic notch, were identified at the 18–22 week anomaly scan and confirmed at 24 weeks. Of those women with persistently abnormal waveforms, 63 agreed to enter the CLASP trial. Three women were lost to follow up and five did not comply. Thus, 60 were randomised: 29 to placebo and 31 to low dose aspirin (60 mg daily) and analysis by intention to treat is reported. Results There were nine cases (29%) of pre-eclampsia in the aspirin group and twelve (41%) in the placebo group (odds ratio (OR) 0.58, confidence interval (CI) 0.2–1.69, P = 0.32). Severe pre-eclampsia developed in four women in the aspirin group and eleven women in the placebo group (OR 0.24, CI 0.07–0.88, P = 0.03) and intrauterine growth retardation occurred in eight cases in the aspirin group and twelve in the placebo group (OR 0.49, CI 0.17–1.47). The mean birthweight and gestation at delivery were 2.69 kg and 38.5 weeks in the aspirin group and 2.38 kg and 37.4 weeks in the placebo group, neither of which were statistically significant using the unpaired t test; P = 0.09 and P = 0.23, respectively. Conclusions In high risk pregnancy low dose aspirin commenced at 24 weeks may reduce the incidence of severe pre-eclampsia.

The efficacy of individual computer heart rate indices in detecting acidemia at birth in growth-restricted fetuses

To determine the efficacy of individual fetal heart rate (FHR) indices, as determined by computer analysis of the FHR tracing, in detecting fetal acidemia at birth in growth-restricted fetuses. The study population consisted of 38 growth-restricted fetuses at 26-37 weeks' gestation from pregnancies with abnormal uterine and/or umbilical artery Doppler velocimetry. The 1-hour FHR tracing was analyzed by computer within 4 hours of cesarean birth before the onset of labor. Umbilical artery cord blood was collected at birth, and pH was determined within 5 minutes of collection. On linear regression, the duration of episodes of low variation in minutes (r = -0.77, r2 = 0.59) and short-term (r = 0.72, r2 = 0.52) and long-term (r = 0.69, r2 = 0.47) variation in milliseconds were significantly related to umbilical artery pH at birth, and more so than the number of accelerations of ten (r = 0.57, r2 = 0.32) and 15 (r = 0.38, r2 = 0.14) beats per minute. There were significant differences in computer measurements of FHR accelerations and variation between the umbilical artery pH categories of acidemia (pH less than 7.20), preacidemia (7.20-7.25), and nonacidemia (greater than 7.25). Stepwise regression revealed that episodes of low variation best described the model for predicting umbilical artery pH at birth (P < .001), with no improvement provided by the addition of other computer-analyzed FHR characteristics. In this population of growth-restricted fetuses delivered by elective cesarean, the computer indices of duration of episodes of low variation and short-term and long-term variation were significantly associated with umbilical artery pH and predicted umbilical artery acidemia at birth.

Intrauterine growth restriction prior to 24 weeks of gestation associated with abnormal uterine and umbilical artery doppler velocimetry.

Intrauterine growth restriction prior to 24 weeks of gestation associated with abnormal uterine and umbilical artery doppler velocimetry.

Uterine artery Doppler velocimetry in the detection of adverse obstetric outcomes in women with unexplained elevated maternal serum α-fetoprotein levels

OBJECTIVE: We hypothesized that in pregnancies complicated by unexplained elevations of maternal serum α-fetoprotein, second-trimester uterine artery Doppler findings would detect adverse obstetric outcomes. STUDY DESIGN: One hundred three subjects with unexplained elevations of maternal serum α-fetoprotein had uterine artery Doppler velocimetry studies performed at the time of targeted ultrasonographic examination (17 to 22 weeks). A resistance index >95th percentile or the presence of a uterine notch was considered abnormal. Adverse outcomes included preeclampsia, preterm birth, low birth weight, intrauterine growth restriction, abruptio placentae, and fetal death. Statistical analysis was performed by Student t test, χ 2 analysis, and stepwise logistic regression analysis. RESULTS: An elevated uterine resistance index was associated with an increased relative risk for both preeclampsia (relative risk 41.82, 95% confidence interval 5.36 to 326.13) and low birth weight (relative risk 4.65, 95% confidence interval 1.90 to 11.39). A uterine artery notch was associated with an increased risk of preeclampsia (relative risk 52.22, 95% confidence interval 6.82 to 399.70), preterm birth (relative risk 3.21, 95% confidence interval 1.32 to 7.81), and a low birth weight (relative risk 4.18, 95% confidence interval 1.64 to 10.66). when the presence of a uterine notch, vaginal bleeding, and level of maternal serum AFP were analyzed, by stepwise logistic regression, the presence of a notch was found to be the only significant factor (odds ratio 6.95, 95% confidence interval 1.24 to 39.10) for the development of an adverse outcome. CONCLUSIONS: Abnormal uterine artery Doppler findings are associated with an increased frequency of adverse obstetric outcomes in women with unexplained elevated maternal serum AFP levels. Abnormal Doppler findings demonstrated high sensitivity for the development of preeclampsia but were less sensitive in predicting other outcomes. the presence of a uterine artery notch is a better independent predictor of adverse outcome than are early vaginal bleeding or maternal serum AFP level.

Attenuation of ischaemia reperfusion injury by human thioredoxin.

Active oxygen species are thought to play a part in ischaemia reperfusion injury. The ability of a novel agent, human thioredoxin (hTRX), to attenuate lung damage has been examined in a rat model of ischaemia reperfusion injury. Twenty eight animals were studied. At thoracotomy the left main bronchus and the left main pulmonary artery were clamped for 75 minutes and the lung was then reperfused for 20 minutes. Phosphate buffered saline was administered intravenously to nine control animals and hTRX (30 micrograms/g body weight) was given intravenously to another group of nine animals. Two experiments were carried out. The first (Exp 1) was a time matched pair experiment (five treated, five controls), and the second (Exp 2) was performed under controlled conditions (four treated, four controls; temperature 25 degrees C, humidity 65%). In another 10 nonischaemic rats and those in Exp 1 biochemical measurements of lipid peroxide, superoxide dismutase, and glutathione peroxide levels were performed. In both experiments rats perfused with hTRX survived longer than controls. In Exp 1 the arterial oxygen tension (PaO2) on air in the hTRX group was higher at 20 minutes than at one minute after reperfusion. In Exp 2 PaO2 at 20 minutes was higher in the hTRX group than in the controls. Lipid peroxide, superoxide dismutase, and glutathione peroxide levels in the control group were higher than in the hTRX group and in the non-ischaemic groups. Histological examination showed less thickening and oedema of the alveolar walls in the hTRX group than in controls. These results suggest that hTRX is effective as a radical scavenger and can limit the extent of ischaemia reperfusion injury of the lungs of experimental animals.

Abnormal uterine artery doppler velocimetry predicts adverse obstetric outcome in women with elevated maternal serum alphafetoprotein (MSAFP): [formula omitted]∗, I.M. Bernstein, E.L. Capeless, Dept. Ob/Gyn, Univ. of VT., Burl., VT

Abnormal uterine artery doppler velocimetry predicts adverse obstetric outcome in women with elevated maternal serum alphafetoprotein (MSAFP): [formula omitted]∗, I.M. Bernstein, E.L. Capeless, Dept. Ob/Gyn, Univ. of VT., Burl., VT