True about antenatal doppler analysis is all except
C i.e. In normal gestation placental resistance is high Doppler ultrasound analysis in pregnancy The routine use of doppler in pregnancy is constroversialQ. TVS (transvaginal sonography) is method of choice for monitoring infeility disorders, diagnosis of ectopic pregnancy & differentiating abnormal & normal 1st trimester pregnancy. The advantages of TVS is that it can be performed in empty bladder and its ability to use higher frequency trandsducer nearer the organs of interst thus providing higher resolution of uterus, ovaries, cul de sac & adnexa. - Doppler may prove valuable in assessment of pregnancy complications & at risk factusQ. Both fetoplacental & uteroplacental circulations can be assessed. As normal pregnancy progresses, placental blood flow increases d/t reduction in placental vascular resistanceQ. - Increased placental resistance results in reduced blood flow, manifesting as decreased or absent end diastolic flow. Systolic diastolic (S/D) ratio, resistive & pulsatility indices are used to quantify these changes. Increased values of S/D ratio & R-P indices and reduction in end diastolic flow are associated with IUGR & poor fetal outcomeQ. (d/t fetoplacental insufficiency). Other associations include pregnancy induced hypeension, oligohydramnios, & cesarian section for fetal distress. Doppler USG is either continuous wave or duplex (pulsed) wave. The duplex wave from uterine & umblical aeries is useful in assessment of IUGR whereas colour & power doppler are invaluable in assessment of fetal hea & outflow tracts and other fetal vessels such as intracerebral & renal aeries. Although, predictive value of continuous wave doppler for IUGR is relatively low, reversed diastolic flow indicates severely hypoxic fetus. In head spared IUGR, diastolic flow to brain (cerebra aery obtained by colour doppler) is increased, an indication that the head is spared from the diminished flow to the body.
Reduction in end diastolic flow is associated with poor out come
Reduction in EDF is associated with IUGR
In normal gestation placental resistance is high
S/D ratio is high in IUGR