You will need
  • Protocol ultrasound studies.
The basic Protocol includes ultrasound study of the situation and presentation of the fetus, heart rate, location of the placenta, umbilical cord, internal organs, possible malformations. Made measurements of head, abdomen, chest, bones, heart, brain, and then the data is checked for compliance with the term of the pregnancy.
The body weight of the child is not required for diagnosis, but as a rule, the doctor calculates it and logs. This indicator is important in deciding prenatal care. In particular, if a woman has a narrow pelvis, and the baby is large, perhaps this fact will be regarded as an indication for caesarean section.
The software of ultrasound scanners contains various formulas of calculation of estimated weightand fetal (Hadlock, Merz, Shepard, Warsof, etc.), so the diagnosis is not difficult to calculate it. But if the doctor has not determined the body weight of the child, you can do it yourself.
Depending on the chosen formula, you will need the following measurements, which are necessarily conducted on each study during pregnancy:- biparietal head size (BPD – Biparietal Diameter); circumference of the head (HC – Head Circumference); the abdominal circumference (AC – Abdominal Circumference); length of femur (FL – Femur Length).
Calculate the weight of the baby on any of the formulas:- Hadlock: log(10)W=1,3596+0,0064(HC)+0,0424(AC)+0,174(FL)+0,00061(BPD)(AC)-0,00386(AC)(FL);- Merz: W=0,1(AC^3) or W=-3200,40479+157,07186(AC)+15,90391(BPD^2);- Shepard: log(10)W=-1,7492+0,166(BPD)+0,046(AC)-(2,646(AC+BPD))/1000;- Warsof: log(10)W=-1,599+0,144(BPD)+0,032(AC)-0,111(BPD^2(AC))/1000.Legend:^ - degree;log(10) logarithm;W – Weight – weight.
Keep in mind that any method of estimating the body mass of the fetus has some error. Considered the most accurate formula of Hadlock and Shepard, although they deviate in the range of 200-300 grams.