Behaviour of the Cervix and the Presenting Vertex in Labour in Blacks and Indians of Natal
The mean durations of the first stage of labour for Black and Indian primiparas and multiparas have been ascertained. These figures are similar to those which have been reported. The upper limits of normal for the duration of the first stage :of labour for primiparas and multiparas have baen ascertained· These figures differ from those which have
been reported in that the duration is much shorter. Interpolated time- and cervix-based graphs showing the rate of cervical dilatation have been constructed. The curves obtained differ from those reported in that they
are not sigmoid in shape and have no distinct phases. Interpolated time-based graphs depicting the rate of descent of the presenting vertex have been constructed. The graphs constructed show the upper and lower limits of normal. They can be used to detect any deviation from normal very early on. The graphs and figures obtained confirm the reliability
of Crichton's principles which have been used as a guide in our unit for the past 15 years in assessing the progress of labour; but recordings of the rate of cervical dilatation, descent of the head, and fetal heart rate, on
a graph, so as to compare these with the established norm in each case, is likely to be advantageous.
S. Afr. Med. J., 48, 791 (1974).