An analysis of breastfeeding patterns and menses returning in Chengdu, China

To study the relationship between infant feeding practices and the duration of lactational amenorrhea, WHO conducted a multi-centered prospective study in 7 countries from 1989. This paper reports the preliminary results based on the data collected in Chengdu center in China.

A detailed follow-up survey was conducted among 541 pairs of mothers and infants from delivery to the returning of menses of mothers at the interval of every 2 weeks.

The results showed that the mean number of breastfeeding episodes and mean duration of breastfeeds had little correlation with the time since delivery. Within 6 months since delivery, the percentage of infants' feeds consisting of breastmilk was over 90%, and this percentage dropped to 70% at 1 year's age of infants. The time to the start of regular supplementation was 153 days postpartum. The proportion of women in exclusive breastfeeding at 2 weeks postpartum was 73.4%, and these figures at 3 and 6 months postpartum were about 60% and 40%, respectively. Until 18 months postpartum, nearly 80% mothers were partial breastfeeding their infants. The cumulative probabilities of menses returning were 0.0150, 0.0395, 0.2345 and 0.6820 at 61, 89, 187 and 369 days postpartum respectively. The median duration of lactational amenorrhea was 282 days.

These results indicated that the duration of lactational amenorrhea would be prolonged if the time of exclusive/predominant breastfeed was extended and the supplementary food was introduced later. The paper concluded that the first menses returning was the signal for initiating contraceptive methods for women.