How accurate is EFW?

How accurate is EFW?

In accordance with numerous other studies, our results confirmed that the ultrasound-derived EFW during labor at term is an appropriate diagnostic tool, with an average accuracy of 70% within a relative difference of ±10% to the real birth weight [9,10,11,12,13].

How is EFW calculated?

log10(Fetal weight) = 1.3596 – (0.00386 * AC * FL) + (0.0064 * HC) + (0.00061 * BPD * AC) + (0.0424 * AC) + (0.174 * FL) , where: Fetal weight is given in grams (g); AC means the Abdominal Circumference and is given in centimeters (cm);

What is Johnson’s formula?

Johnson’s formula for estimation of foetal weight in vertex presentation is as follows: Foetal weight (g)=fH (cm)n × 155. fH=fundal height and n=12 if vertex is above ischial spine or 11 if vertex is below ischial spine. If a patient weighs more than 91 kg, 1 cm is subtracted from the fundal height.

What should be EFW at 33 weeks?

Your baby’s actual size by week (in length and weight) may vary substantially….Fetal growth chart.

Can EFW be wrong?

It’s important to know there is a recognised 15% error in ultrasound fetal weight estimation. This means your baby can be either 15% smaller or 15% larger than the estimated weight given at your ultrasound. Ultrasound scans are generally more accurate for assessing your baby’s size during the first half of pregnancy.

How far off can a dating ultrasound be?

Between 18 and 28 weeks of gestation, the margin of error increases to plus or minus two weeks. After 28 weeks, the ultrasound may be off by three weeks or more in predicting a due date.

How can I estimate my birth weight?

For those of you who have a thing for math, here’s the equation: Birth weight (g) = gestational age (days) x (9.38 + 0.264 x fetal sex + 0.000233 x maternal height [cm] x maternal weight at 26.0 weeks [kg] + 4.62 x 3rd-trimester maternal weight gain rate [kg/d]] x [number of previous births + 1]).

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