title: The patterns and causes of fertility differentials in the Sudan (with reference to nomadic and settled populations).
abstract: Abstract   A demographic survey was undertaken in the Sudan for the purpose of studying fertility differentials between the nomadic and settled populations. In a previous publication the magnitude of these differentials was examined. The present paper examines the nature of the differentials and possible causes are then assessed. These causes are divided into two categories: those arising from the differential marriage patterns and those which are broadly termed 'medical and physiological'. Under the former heading it was found that larger proportions of nomadic women were still single, while those who had married had tended to do so at later ages, more had experienced broken marriages, and more were in polygamous marriages. Under the latter heading it was found that the nomadic women had experienced higher rates of pregnancy loss, appeared to show a high incidence of venereal disease and malaria, and tended to breast-feed their children for periods two to three times as long as the women in agricultural communities. Nutritional standards among the nomads were also substantially lower, and may well have affected fecundity.
authors.forename: R A
authors.initials: RA
authors.lastname: Henin