Background: In 2017, China proposed to achieve the goal that 50% of infants aged 0-6 months should be exclusively breastfed by 2025 proposed by the World Health Assembly in 2012. However, delayed onset lactogenesis II has adverse effects on breastfeeding and thus on neonatal health. There has been no meta-analysis of the prevalence and risk factors of delayed onset lactogenesis II among parturient women in China. To provide best practices, updated evidence-based evidence is needed to supplement reviews on this topic.
Objective: The purpose of this systematic review and meta-analysis was to quantitatively analyze the prevalence and risk factors of delayed onset lactogenesis II in China.
Methods: We identified relevant studies by searching literature published prior to October 2022 in PubMed, Web of Science, China National Knowledge Infrastructure, Wanfang, and VIP databases for all available observational studies. Stata 16.0 were used for performing the systematic review and meta-analysis.
Results: The researchers examined data from 14 observational studies involving 17610 females. The prevalence of delayed onset lactogenesis II from these studies was 31% (95% CI = 25.0%-38.0%, p < .001), and the prevalence showed a significant increasing trend in China over the past decade. The frequency of breastfeeding was >2 times per day at 24-48 h after delivery was one protective factor against delayed onset lactogenesis II (OR = 0.41). The significant risk factors for delayed onset lactogenesis II were breastfeeding initiation > 30min after birth (OR = 1.31), maternal age > 35 years (OR = 2.19), primiparous women (OR = 2.38), maternal overweight/obesity (OR = 2.22), cesarean section (OR = 1.33), anxiety (OR = 3.23), depression (OR = 3.21) and gestational hypertension (OR = 3.43).
Conclusions: There is a high incidence of delayed onset lactogenesis II in Chinese parturient women. We identified eight risk factors and one protective factor for DOL II. These findings suggest health care professionals should pay attention to these risk parturients so as to better provide early preventive interventions to increase the breastfeeding rate.
Keywords: breast feeding; lactogenesis II; meta-analysis; prolonged lactations.