Breastfeeding

Patterns for the two continents contrast markedly for both the last closed birth interval and the open interval. The median duration of breastfeeding is generally 1-2 years in Asia and 6 months in Latin America (except for Peru). Surprisingly, breastfeeding duration did not differ according to the child"s sex even in countries where male children are preferred. The survey partially solves the complex problem of linking breastfeeding with mortality by restricting some analyses to surviving children. Much more work is needed in this area, however. The data"s doubtful reliability, e.g., as evident in the different biases obtained for the open and closed intervals, makes it difficult to analyze breastfeeding trends in detail, as does restricting analysis to demographic variables. Also discussed is a method employing data on the current breastfeeding status of children born in the recent past, including the open, the last closed, and even prior intervals. Disadvantages of this method include the inaccurate imputation of children"s birth dates; the use of the child as the unit of analysis, causing duplicate representation of most fertile women; and heightened sampling variability. Other complications, specific to the closed interval analysis, include the unexplained longer duration of breastfeeding for older women. Future needs include developing techniques to identify and measure phenomena more precisely and conducting comparative analysis of the impact of breastfeeding duration on birth intervals -- a question which survey data from 20 additional countries should help clarify. Further study is also needed on the impact on birth intervals of related factors, e.g., contraception and post partum amenorrhoea. The authors note that changes in fertility levels and patterns necessarily include changes in intermediate variables and so recommend that population programs examine the only partially understood biological and sociological factors underlying observed fertility behavior. Numerous figures and charts are included.