Lactation and fertility.

During the last decade there have been many reports indicating a decline in breast feeding practices in the urban areas of developing countries. This decline might have adverse effects on maternal and child health. A study of 1079 urban hospital attending women was undertaken to evaluate their breast feeding practices. Prolonged (mean duration of lactation 19.8 months) and successful lactation (failure of lactation occurred in only 3.5%) was common among this group. But a trend toward shorter duration of breast feeding was found among educationally and economically better off segment. There was very good correlation between mean duration of lactation, lactational amenorrhea, and interpregnancy interval. Therefore, it is possible that decrease in duration of lactation might result in shorter interpregnancy interval. The duration of lactation appeared to be "fixed" for each individual irrespective of age and parity. This in turn resulted in "fixed" duration of lactational amenorrhea and interpregnancy interval under conditions of unhindered lactation and uncontrolled fertility. Conception during lactational amenorrhea was low (7.7%) but once periods were reestablished lactation offered very little protection against conception.