Estimating child mortality in Zimbabwe: results of a pilot study using the preceding births technique.

Using the preceding birth technique, 2,229 mothers were interviewed at four antenatal centres (two of which were urban) over a three month period during a pilot study in Zimbabwe. Results of the study showed that there was a small difference between the under two and under five mortality. The smaller than expected difference could have been due to some degree of urbanisation being experienced at two of the centres, and to a systematic selection bias of the method. Other findings of the study showed that younger mothers (under 20 years of age) and older mothers (over 40 years) experienced higher proportions of mortality, than mothers in the age group between. The higher proportion of male mortality compared to that for females reflected the expected trend, but the size of the difference was somewhat surprising, and could have been due to recall bias. The mean birth interval was 36 months, rather than the expected 30 months, and analysis of mortality in relation to birth interval and maternal age showed that a birth interval of less than 18 months was associated with higher child mortality, significantly so with the second last child, independent of mother's age. Longer birth intervals (more than three years) among older mothers were associated with higher changes of child survival. It is concluded that the Brass-Macrae method is a useful technique to analyse levels and trends of child mortality.