## How to measure fundal height using the ﬁnger method

If the top of the uterus is *below* the bellybutton, measure how many fingers *below* the bellybutton it is. If the top of the uterus is *above* the bellybutton, measure how many fingers *above* the bellybutton it is.

Look carefully at Figure 10.2. If the baby is growing normally, by how many finger-widths should the uterus rise in the **second trimester** (3-6 months of pregnancy, or 15-27 completed weeks of gestation)?

How many fingers above the bellybutton should the top of the uterus be at 7 months' gestation?

How do you explain the position of the dotted line at 9 months in Figure 10.2, which is below the line showing fundal height at 81/2 to 9 months?

Look at the diagrams in Figure 10.4 (a) and (b). How many weeks pregnant is the woman in each case, based on the finger method of measuring fundal height shown in Figure 10.2?

When you measure fundal height at every antenatal visit, write down the number of fingers you used to measure the height of the uterus on the woman's antenatal record card. Put a '+' (plus) sign in front of the number if the top of the uterus is *above* the bellybutton. Put a '-' (minus) sign in front of the number if the top of the uterus is *below* the bellybutton.

How would you record the measurements shown in Figure 10.4(a) and (b)?

## Limitations of the finger method

You need to be aware that the finger method for estimating **gestational age** (the number of weeks/months of pregnancy) has some limitations that affect its accuracy.

Look at your own hands. Can you suggest why the finger method might give a different estimate of gestational age if two different health workers used this method to measure the *same* woman's fundal height?

Even if the *same* health worker measures the fundal height of the *same *woman several times on the *same* day, the answer may be different each time, because the finger method is not very precise. (This is known as 'intra-observer variation', i.e. variation by a single observer at different times.)

Finally, you might have realised that the distance between the symphysis pubis (pubic bone) and the umbilicus (bellybutton) varies between women when they are *not* pregnant, and this variation affects the accuracy of the fundal height measurement using the finger method. For example, it assumes that the distance between the pubic symphysis and the umbilicus is 20 cm at 20 weeks' gestation, but it can be as long as 30 cm and as short as 14 cm.

To overcome these limitations, it is recommended that you measure fundal height using a soft tape measure if you have one, as described next.