| Abstract|| |
Objective: To evaluate the role of Color Doppler in predicting the fetal outcome in cases of pregnancy induced hypertension (PIH).
Materials & Methods: A total of 100 cases of PIH between 28 - 36 wks of gestation were studied over a period of 2 years. A color doppler scanner with a 3 - 5 MHz curvilinear probe was used for studying uterine, umbilical & fetal middle cerebral arteries. We used only S/D ratio as the indicator to evaluate perinatal outcome. The results of first doppler examination were taken into consideration for the study. Follow up study was done whenever required. S/D ratio of more than 3 in umbilical artery & more than 2.6 in uterine artery was considered abnormal. The results were correlated with parameters of fetal outcome.
Results: In our study of 100 hypertensive cases 56% had abnormal S/D ratio in umbilical artery and/or uterine artery. 60% of these patients delivered IUGR babies. In patients with absent end diastolic velocity (AEDV) & reversed end diastolic velocity (REDV) perinatal mortality was 50% & 50% had IUGR babies. The fetuses with compromised circulation showed increased diastolic flow in fetal MCA suggestive of brain sparing effect. The results of abnormal umbilical artery were more significant than uterine artery in predicting perinatal outcome. The patients who had follow up studies, the improving S/D ratio suggested good fetal outcome whereas increasing S/D ratio showed poor fetal outcome.
Conclusion: Color Doppler is an excellent tool for non-invasive hemodynamic monitoring of PIH patients. It helps to identify the fetuses at risk & predict perinatal morbidity & mortality. Doppler velocimetry can guide us in the treatment of these pregnancies & prevention of high mortality & morbidity in hypertensive patients
Keywords: Color Doppler, Pregnancy induced hypertension & IUGR.
|How to cite this article:|
Bhatt C J, Arora J, Shah M S. Role of color doppler in pregnancy induced hypertension (a study of 100 cases). Indian J Radiol Imaging 2003;13:417-20
|How to cite this URL:|
Bhatt C J, Arora J, Shah M S. Role of color doppler in pregnancy induced hypertension (a study of 100 cases). Indian J Radiol Imaging [serial online] 2003 [cited 2014 Sep 3];13:417-20. Available from: http://www.ijri.org/text.asp?2003/13/4/417/28724
| Introduction|| |
The main goals of prenatal testing is to identify fetuses at increased risk for perinatal morbidity & mortality. In general population two large prospective studies failed to show significant improvement in neonatal performance associated with doppler technology . Among high risk patients several studies suggested a significant decrease in neonatal morbidity & mortality when doppler evaluation was a part of fetal survellian .
Hypertensive disorder of pregnancy is one of the most common complication that effects human pregnancy. It is one of the leading cause of maternal & fetal mortality & morbidity .
The purpose of our study was to evaluate the role of doppler in predicting fetal outcome in patients with PIH.
| Materials & Methods|| |
Hundred patients of diagnosed PIH with gestational age between 28-36 weeks were studied by color doppler over a period of 2 years. The findings at the time of first examination were taken into consideration. Repetitive doppler studies were performed whenever required. Doppler velocity waveform analysis of umbilical, uterine & fetal MCA were obtained using 3-5 MHz curvilinear transducer on AU3 partner machine.
The uterine artery was studied by first identifying the placental site. If the placenta was unilateral, uterine artery of that side was studied. In case of central placenta, both uterine arteries were evaluated. Free-floating loop of umbilical cord was examined to evaluate umbilical artery. The flow velocity waveforms were computed automatically, the average value of three such recording was obtained. A patient with rise of at least 30 mm of Hg & 15 mm of Hg in systolic and diastolic pressure respectively over previous known blood pressure was diagnosed to have PIH. If previously BP was not known than BP of at least 140/90 mm of Hg was considered abnormal. The data regarding perinatal outcome was collected which included birth weight (using New ballard Scoring System in our hospital) , no. of fetal & perinatal deaths, admission to NICU & number of days in NICU and mode of delivery. S/ D ratio of greater than 3 & 2.6 in umbilical & uterine arteries respectively were considered abnormal. Absent end diastolic velocity (AEDV), Reversed end diastolic velocity (REDV), & persistent early diastolic notch in uterine artery were considered abnormal. Increased in diastolic flow in fetal MCA suggested brain sparing effect seen in asymmetric IUGR.
| Results|| |
The results have been compiled in the form of tables.
Raised S/D ratio is the commonest abnormal finding in cases of IUGR. In cases of AEDV & REDV there is 50% perinatal mortality.
| Discussion|| |
Pregnancy induced hypertension (PIH) & small for gestation age are both pathological conditions strongly related to development & function of utero placental & feto placental circulations. This results in improper blood flow in uterine & umbilical arteries. An adequate fetal circulation is necessary for normal fetal growth. To facilitate this remarkable maternal & placental vasculature changes occur.
Hemodynamic changes occurring on the maternal side of placenta is reflected in uterine artery by 20 weeks of gestation. Trophoblastic cells penetrate the maternal spiral artery within inner 1/3rd of myometrium disintegrating the internal elastic lamina of spiral arteries by 25 weeks. This results in maximum dilatation & minimum vascular resistance in the vessels  [Figure - 1]. In PIH there ;Is inadequate invasion leading to increased resistance in spiral arteries. This leads to impedance of blood flow in uterine arteries . The S/D ratio in uterine artery greater than 2.6 is considered abnormal. [Figure - 2]. The presence of early diastolic notch is normal phenomenon upto 26 . weeks of gestation. Presence of notch after 26 weeks is I a bad indicator suggesting increased impedance of blood flow  [Figure - 2]. The difference between S/D ratio greater than 1 in right & left uterine arteries suggests higher incidence of poor fetal outcome.
Umbilical artery: - Umbilical artery velocimetry correlates with hemodynamic changes in the fetoplacental circulation. With increase in number of tertiary stem villi & arterial channels, fetoplacental compartment develops & the impedance in the umbilical artery decreases. From 15 weeks of gestation umbilical artery resistance declines & the diastolic component appears in the waveform during early second trimester . S/D ratio of less than or equal to 3 is considered normal [Figure - 3].
Fetal MCA : In normal fetus, there is little diastolic flow in MCA & S/D ratio is greater than 4 [Figure - 4]. In asymmetric IUGR there is increased diastolic flow, a pattern believed to reflect brain sparing phenomena described in experimental models of fetal hypoxia [Figure - 5].
In our study of 100 hypertensive patients, 44% had normal doppler velocimetry whereas 56% had abnormal S/D ratio in umbilical and/or uterine arteries. 60% of these hypertensive patients with abnormal velocimetry delivered growth retarded babies. In fleschier et.al study 67% of hypertensive patients had IUGR babies .
In patients with AEDV & REDV perinatal mortality was 50% [Figure - 6] & [Figure - 7]. The same was observed by Battaglia et. al in their studies . The rest 50% had IUGR babies. The patients with AEDV in umbilical artery should undergo intensive surveillance & REDV represents a pre-terminal fetal state . Patient with AEDV & REDV has gravest outcome as shown by MC Parland .
As shown by Fleischer et al about 40% of hypertensive pregnancies have increased resistance in the umbilical artery which is significantly associated with IUGR & perinatal mortality & morbidity . In our study 46% of hypertensive patients had raised S/D ratio (greater than 3) in umbilical artery [Figure - 8] 11 % had associated uterine artery abnormal ratio. Only 2% had normal S/D ratio in umbilical artery but raised S/D ratio in uterine artery & in these patients fetal outcome was good. This suggests umbilical artery is good predicator of fetal outcome as compared to uterine artery. The persistence of early diastolic notch was seen in 6 patients with raised S/D ratio in uterine artery. Specificity of doppler examination was 100% when abnormality was seen in both umbilical & uterine arteries.
The changes of raised S/D ratio reverted to normal on follow up study after bed rest & properly controlled hypertension in 35% of patients. These patients had mild PIH & the perinatal outcome was good. Sengupta S. et al found that 50% of their patients reverted to normal S/D ratio after bed rest in a study of 128 patients.
In patients with normal first doppler examination findings, 18% delivered IUGR babies. However follow up studies in these patients showed increased S/D ratio in umbilical artery stressing the importance of follow up doppler examination in PIH patients.
| Conclusion|| |
Thus we conclude that the doppler velocimetry is primary tool for fetomaternal surveillance in hypertensive pregnancies because the changes in umbilical & uterine circulation strongly correlates with pregnancy outcome. It helps us to take timely action, plan the treatment & also counsel the patients in their future pregnancies. We strongly recommend the use of Color Doppler examination in all cases of PIH.
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C J Bhatt
A/28, Ashok Tenements, Opposite Cadilla, Ghodasar, Ahmedabad - 380 050
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8]
[Table - 1], [Table - 2]