A comparison of manual and ultrasound measurements of fundal height.

BACKGROUND

Uterine fundal height has long been used to assess fetal growth. The common prediction rule states that the distance in centimeters between the pubic symphysis and the top of the fundus equals the gestational age in weeks. The correlation holds best between weeks 18 and 32. This study compares manual and ultrasound measurements of fundal height.

METHODS

We compared palpated and ultrasound symphysis-fundal height. We then compared both measurements with gestational age as determined by usual ultrasound measurements. Patients were statistically separated by weight into two groups: normal and obese. We hypothesized that manual measurements of fundal height would be affected by obesity and race.

RESULTS

Ultrasound fundal height and manual fundal height were equivalent (P < or = .01, R2 = .92). Regression analysis in normal weight and obese patients showed that both methods have the same predictive power in determining fetal age.

CONCLUSION

Manual measurements are still a reliable and inexpensive means of evaluating the course of pregnancy. Ultrasound is needed when there is a size-vs-date discrepancy. Ultrasound is also useful for teaching the measurement of fundal height.