Optimising perinatal outcome in fetal growth restriction using doppler velocimetry

Sunitha, Soundarapandian (2007) Optimising perinatal outcome in fetal growth restriction using doppler velocimetry. Masters thesis, Madras Medical College, Chennai.


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INTRODUCTION: Ante partum fetal surveillance is the corner stone of preventive obstetric management aimed at reducing maternal and perinatal mortality and morbidity. Ante partum detection of fetus at risk of death or compromise in utero remains the major challenge in modern obstetrics. Specific and accurate methods for detection of fetus at risk can result in early appropriate intervention and hence reduce fetal loss. Diagnostic ultrasound is the main stay in the evaluation and management of obstetric patients. Antenatal test of fetal well being depends indirectly on changes in fetal physiology, an aspect of fetus, which until recently, has been relatively inaccessible to study. There has been a paucity of techniques to measure the placental function - the critical organ through which the transfer of nutrients occur. Fetal growth and development rely on normal uteroplacental and fetoplacental circulation to supply oxygen and nutrients from the maternal circulation. New technologies have now become available in the clinical assessment of placental function. Doppler ultrasound offers a non - invasive evaluation of the feto-placental circulation and can identify placental circulatory failure. There are specific abnormalities in Doppler parameters in asymmetric intrauterine growth retardation, which occurs as a result of utero - placental insufficiency . Hence doppler ultrasound plays a key role in antenatal fetal surveillance of high risk pregnancies like evaluation of growth restricted fetuses. AIMS AND OBJECTIVES: 1. To detect any abnormalities in fetoplacental unit and fetal circulation in IUGR. 2. To identify the hypoxemic fetus & time the delivery before the occurrence of acidemia. 3. To correlate the occurrence of adverse perinatal outcome with degree of abnormality in doppler indices. MATERIALS AND METHODS This study was conducted jointly at the Institute of Obstetrics and Gynecology and Barnard Institute of Radiology, Chennai both coming under the Madras Medical College, Chennai. Two hundred documented IUGR cases confirmed by clinical evaluation and serial ultrasound biometry were selected for the study and it was done on singleton pregnant women with welldocumented period of gestation beyond 34 weeks. Known congenital anomalies were excluded from the study. The machine used for Doppler was an Aloka 3500 color Doppler machine with a 3.5 to 5 MHz curvilinear probe. Name, Age, Unit, Registration number and Address of the patients were noted. Detailed obstetric history including the history of pregnancy induced hypertension; gestational diabetes and chronic hypertension were obtained. History of previous pregnancies including birth weight of previous babies, perinatal deaths, and mode of delivery were elicited. Details of present pregnancy were asked, including the date of last menstrual period, details of scan in the first trimester and clinical examination noting, if available, were scrutinized. SUMMARY: Diagnosis of IUGR was done by clinical assessment and serial sonography. • The routine use of SFH measurement together with the use of serial ultrasound examinations in the 3rd trimester of high risk pregnancies detected majority of IUGR cases. • With the use of Doppler of umbilical and middle cerebral arteries, it is possible to predict that an IUGR fetus is not hypoxic. • With ductus venosus alteration, detection of fetal acidemia is possible. • Negative predictive value of normal Doppler is 100%. It means that if the Doppler is normal in an IUGR fetus the possibility of an abnormal perinatal outcome is very rare. So, unnecessary intervention can be reduced in those pregnancies with normal Doppler and normal amniotic fluid volume. • There is a strict co-relation between abnormal umbilical Doppler velocimetry and an increased incidence of perinatal complications in an IUGR fetus. • Incidence of perinatal mortality and morbidity are increased with the worsening of Doppler velocimetry. • In cases with absent and reversed diastolic flow in umbilical artery the perinatal morbidity is nearly100%. • The perinatal mortality in cases of ductus venosus alteration is 100%. • In cases with differential shunting of blood flow to the fetal brain, frequent monitoring and early delivery should be done. • The Doppler ultrasound finding of increased resistance of umbilical artery and decreased resistance of middle cerebral artery, detects the fetus at risk of complications 2 weeks earlier than the conventional methods like NST. • After identifying those fetuses at risk of complications, close monitoring is done by non stress test and bio-physical scoring for planning the delivery so as to improve the perinatal outcome. • Since ductus venosus has been shown to cause irreversible fetal compromise and inevitably leads to fetal demise, close monitoring should be done so as to deliver before the fetus becomes acidotic which is shown by the increase in ductus PI values. CONCLUSIONS: The diagnosis of utero-placental insufficiency causing fetal growth restriction identifies a group of fetuses who are prone for perinatal complications. • Many fetuses with FGR are hypoxemic and some are acidemic even prior to the onset of labor. • The role of antenatal surveillance is identification of the hyproxemic fetus, since the sequelae of hypoxemia can only be altered by iatrogenic intervention. Delivery is timed to precede acidemia. • Doppler ultrasound velocimetry is a noninvasive, repeatable and simple method for antepartum fetal surveillance which holds great promise in this area. • There is a strong correlation between fetal hypoxemia and Doppler measured flow indices of the fetal arterial and venous circulations. • Grading of the Doppler abnormalities can accurately predict the perinatal outcome of the potentially compromised FGR baby much earlier than NST and thus it can be used as a prognostic tool as proved in our study. • So, Doppler ultrasound should be used in all patients with fetal growth restriction, to identify impending hypoxia, to optimise the time of delivery, and hence to optimise the perinatal outcome in these patients.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Optimising perinatal outcome ; fetal growth restriction ; doppler velocimetry.
Subjects: MEDICAL > Obstetrics and Gynaecology
Depositing User: Subramani R
Date Deposited: 03 Dec 2017 11:20
Last Modified: 09 Dec 2017 02:11
URI: http://repository-tnmgrmu.ac.in/id/eprint/4170

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