Table 4.

The absolute error of both formulae in the two studied groups

	Engaged head		Non engaged head		P value
	Count	%	Count	%
Absolute error of hadlock
Within 10% of actual birth weight	9	17.6%	51	100.0%	< 0.001
> 10% of actual birth weight	42	82.4%	0	0.0%
Absolute error of isobe
Within 10% of actual birth weight	51	100.0%	23	45.1%	< 0.001
> 10% of actual birth weight	0	0.0%	28	54.9%

Significant P values are given in bold (P < 0.005)