Current methods for the assessment of fetal well-being and detection of compromised fetus in the routine antenatal care include: symphysis fundal height measurement from the 24th week ( Neilson 1998a NICE 2008), fetal movements charts ( Mangesi 2007) and antenatal cardiotocography ( Pattison 1999). Initial Doppler studies have been restricted to the umbilical artery, but other fetal vessels have recently become a focus of interest including middle cerebral artery and ductus venosus.Īlthough stillbirths and fetal complications related to placental problems are rare in uncomplicated pregnancy, the impact is devastating. In extreme circumstance the blood flow at the end of diastole may be absent or even reversed (Figure 2 - we plan to insert a scan picture in a final version). A high ratio in umbilical artery indicates a high vascular impedance and possible feto-placental compromise. These indices reflect the down stream vascular resistance by quantifying the differences between the peak systolic and the enddiastolic velocity within blood vessels of interest in each cardiac cycle. Flow of the umbilical and fetal arteries is most often quantified either by pulsatility index or resistant index ( Burns 1993 Nelson 1988). Different Doppler methods are used in obstetrics: continuous-wave, pulsed-wave, colour and power Doppler flow ( Eik-Nes 1980 Mires 2000).ĭoppler ultrasound examination can be performed as a part of a more detailed ultrasound assessment that includes fetal biometry and anatomical survey or as a separate ultrasound examination. red cell) ( Campbell 1983 Fitzgerald 1977 Nelson 1988 Owen 2001). Early antenatal detection, treatment where appropriate, and timely delivery could minimise the risks significantly.ĭoppler ultrasound technology is based on the Doppler shift, a physical principle of the change of ultrasound frequency when aimed at the moving object (e.g. The serious morbidity includes intraventricular haemorrhage, bronchopulmonary dysplasia, necrotising enterocolitis, infection, pulmonary haemorrhage, hypothermia and hypoglycaemia ( Fisk 2001). Growth restricted fetuses are at increased risk of mortality and morbidity ( Bernstein 2000 Fisk 2001). Inability to distinguish easily between small but healthy fetuses and those who are failing to reach their growth potential has hampered attempts to find appropriate treatment for growth restriction ( Soothill 1993). Some fetuses are constitutionally small and they do not have increased perinatal mortality or morbidity. It is important to highlight that the fetal growth restriction is often confused with the concept of being small-for-gestational age. Two recent studies identified the fetal growth restriction in 43% ( Gardosi 2005) and 52% ( Froen 2004) of unexplained stillbirth respectively, concluding that the IUGR was the strongest risk factor for an unexplained intrauterine death. Unrecognised IUGR remains the main cause of unexplained stillbirths in otherwise uncomplicated pregnancy. The rate of unexplained fetal deaths decreased from 3. In majority of cases the fetal death can be attributed to a ‘known’ cause such as maternal disorder (hypertension, diabetes and others), fetal pathology (congenital abnormalities, intrauterine growth restrictions (IUGR)), placental pathologies or intrapartum complications. The routine use of a screening test should be based on proven clinical effectiveness, to avoid subjecting a large group of normal women to anxiety and inappropriate intervention with subsequent risk of iatrogenic morbidity and mortality. One of the main aims of routine antenatal care is to identify the ‘at risk’ fetus in order to apply clinical interventions which could result in reduced perinatal morbidity and mortality ( RCOG 1997).
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