The association between lactating behaviours and postpartum weight retention during the 'Zuòyuèzi' period in China: a multicentre mother-infant cohort study.

Background: Few studies have examined the association between lactating behaviors and postpartum weight retention (PPWR) during the 'Zuòyuèzi' period, a traditional Chinese postpartum confinement practice that typically occurs within the first month after delivery. This study aimed to examine the association between breastfeeding practices (exclusive vs. mixed feeding) and PPWR during the Zuòyuèzi period; and to explore the feasibility of the new latent category variable derived from latent class analysis (LCA) reflecting lactating experience and quality.

Methods: Multiple linear and logistic regressions were used to examine the associations among 749 mothers from the Phoenix Multicentre Mother-Infant Cohort Study in China. The new independent variable was generated using the best-fit model in LCA.

Results: Women with a higher pre-pregnancy body mass index (BMI), who were not obese, had gestational diabetes mellitus during pregnancy and were living in coastal areas retained less weight. Multiple linear analysis showed that PPWR was partly affected by the type of breastfeeding as early as 1 month after delivery. The mixed-feeding group had a greater trend towards PPWR in comparison to the exclusive breastfeeding group (β = 0.694, P = 0.029). After adjusting for pre-pregnancy BMI and physical activity level through multiple regression analysis, exclusive breastfeeding reduced the risk of substantial PPWR by 26.3% (OR = 0.737; 95%CI, 0.543-0.999). There were distinctive differences in baseline information between the two independent latent category groups (Low/High Experience & Incentives). However, there was no significant association with the PPWR at 1 month after delivery.

Conclusion: Exclusive breastfeeding can lower the PPWR during the 'Zuòyuèzi' period in China.