Fertility Differentials in Urban Nigeria.

Abstract

This study has examined fertility differentials in Urban Nigeria. Using data from a sample survey conducted in 1973-74, the study has estimated fertility differences in the three urban settings, Ibadan, Benin, Kano, and analyzed the factors which could lead to changes in both the social structure and fertility levels and patterns. Sampling frames were developed from recent aerial photos. The resultant urban samples were multistage, probability cluster samples of households. Within the selected households, all individuals, male or female, aged 15 years and above were interviewed. The total sample size was 1,629 in Ibadan City, 784 in Benin City, and 898 in Kano City. Among these figures, the estimates of women ever married were 1,033, 633, and 800, respectively, in Ibadan, Benin, and Kano Cities. Two methods of analysis have been used: demographic analysis and regression analysis. Demographic analysis allowed us to investigate interrelationships between the variables and to disentangle the various factors of fertility differentials. Under regression analysis, we used prediction analysis which allowed us to estimate the relative contribution of each factor to variations of fertility. In addition, we used path analysis to estimate the direct and indirect influence of each independent variable along each path. Two measures of fertility were used: current fertility (e.g., TFR) and retrospective fertility (i.e., number of children ever born). Using current fertility, we found that each woman in Ibadan, Benin, and Kano Cities would have borne, respectively, an average of 7.8, 8.0, and 4.1 children in the course of her reproductive life. Using retrospective fertility, we found completed family size of 5.0 children per woman ever-married in Ibadan City, 6.0 children per woman ever-married in Benin City, and 3.0 children per woman ever-married in Kano City. Let us single out the variables which seemed the most important in explaining variations in fertility. We found that breastfeeding negatively affected fertility in Ibadan and Kano Cities. The infant-child mortality was positively related to children ever born in all three cities suggesting, first that women tended to replace deceased children by having additional births, and second that they tended to bear more children in anticipation of high infant-child mortality. We also found that age at first marriage explained much of the variation in fertility. Being Muslin was found negatively related to fertility. We were unable to conclude that polygynous women had the lowest fertility, except in Kano City where the data suggested the reducing effect of polygyny by duration of first marriage. We also found that working women had the lowest fertility relative to non-working ones. The women's education had a reducing effect on fertility in all three cities.