Fertility estimation from retrospective surveys: biases attributable to pregnancy-related movement of mothers.

In a number of developing countries, especially in South Asia, there is a custom for a pregnant woman to go to her mother's home for delivery and remain for some months afterwards. In this context, estimates of various fertility measures, based on data from a sample survey of resident women, will be seriously biased. Inclusion of data for visitors to the sample households does not fully compensate for this bias. The presence and magnitude of the bias is illustrated by the analysis of data from large-scale sample surveys conducted in the state of Orissa in India and by World Fertility Survey data from Bangladesh and Nepal.