[Prevalence of and risk factors for delayed onset of lactation in Chinese lactating women in 2013].

Objective: To study the prevalence of delayed onset of lactation (later than 3 days) in lactating women in China and to analyze its influencing factors. Methods: Data were extracted from Chinese National Nutrition and Health Surveillance-Mothers, from mothers with children under 2 years of age (in 2013). A total of 11 178 women who were lactating or had lactated were selected from 55 counties of 30 provinces (excluding the Tibet Autonomous Region) in China, using the multi-stage stratified cluster randomization sampling method. Basic information, including onset of lactation, initiation of breastfeeding, breastfeeding difficulties and breastfeeding knowledge were collected using a questionnaire investigation. The prevalence of delayed onset of lactation were analyzed by the weighted processing of complex sampling from the 6th national population census data. A multiple logistic regression was used to analyze the factors associated with delaged onset of lactation. Results: Among 11 178 lactating women, 3 388 had an onset of lactation later than 3 d. The prevalence of delayed onset of lactation was 30.3%. After complex weighting, the prevalence of delayed onset of lactation was 31.2% (95% CI: 25.7%-36.8%) for lactating women in China. Delivery by Caesarean section (OR=1.28, 95%CI: 1.06-1.53) and initiating breastfeeding ≥4 h (OR= 2.34, 95%CI: 1.76-3.11) were the negative factors for delayed onset of lactation. Compared with those living in large cities, lactating women living in medium or small cities (OR=1.39, 95%CI: 1.05-1.84) had a higher risk of delayed onset of lactation. Compared with the lactating women doing housework, the risk of delayed onset of lactation was lower (P<0.05) among those whose occupations were as leaders of Enterprises/Institutions (OR=0.68, 95%CI: 0.47-0.99), in catering and service trades (OR=0.61, 95%CI: 0.43-0.86), in agriculture/forestry/fishery/herdsmen fields (OR=0.65, 95%CI: 0.44-0.96) and who were unemployed (OR= 0.64, 95%CI: 0.46-0.90). Breastfeeding education during pregnancy might lower the risk of delayed onset of lactation (OR=0.78, 95% CI: 0.62-0.98). Conclusion: The prevalence of delayed onset of lactation was relatively high for Chinese lactating mothers. Caesarean section and late initiation of breastfeeding were the primary risk factors. Lactating mothers living in medium or small cities and those doing housework appear to be high-priority groups for intervention. Based on our findings, breastfeeding education during pregnancy is recommended to lower the risk of delayed onset of lactation.