Prema K, Naidu A N, Kumari S N
Am J Clin Nutr. 1979 Jun;32(6):1298-303. doi: 10.1093/ajcn/32.6.1298.
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.
在过去十年里，有许多报告表明发展中国家城市地区的母乳喂养行为呈下降趋势。这种下降可能会对母婴健康产生不利影响。对1079名城市医院就诊女性进行了一项研究，以评估她们的母乳喂养行为。在这组人群中，长时间哺乳（平均哺乳期为19.8个月）且哺乳成功（仅3.5%出现泌乳失败）很常见。但在教育和经济状况较好的人群中发现了母乳喂养时间缩短的趋势。平均哺乳期、哺乳期闭经和两次妊娠间隔之间存在非常好的相关性。因此，哺乳期缩短可能会导致两次妊娠间隔缩短。无论年龄和胎次如何，每个个体的哺乳期似乎都是“固定”的。在不受阻碍的哺乳和不受控制的生育条件下，这反过来又导致了哺乳期闭经和两次妊娠间隔的“固定”时长。哺乳期闭经期间的受孕率较低（7.7%），但一旦月经恢复，哺乳对受孕的保护作用就很小了。
