[The status of postpartum weight retention and its associated factors among Chinese lactating women in 2013].

Objective: To analyze the status of postpartum weight retention and its associated factors among Chinese lactating women in 2013. Methods: This study was based on the databank of Chinese National Nutrition and Health Surveillance in 2013. Using the multi-stage stratified cluster sampling method, we enrolled 12 514 women, at 0-24 months postpartum, from 55 sites in 30 provinces of China (excluding the Tibet Autonomous Region). Questionnaires were used to collect data on basic characteristics, physical activity, lifestyle, food intake, pre-pregnancy weight, weight before delivery, disease history during pregnancy, delivery date, delivery mode, parity and breastfeeding information. Current body weight and height of each subject were measured. Postpartum weight retention in each subject was calculated as the difference between pre-pregnancy and current weights. High postpartum weight retention was defined as ≥5 kg. Survey sample weights were calculated according to the sampling design and number of children under 2 years old from 2010 population census data of China. Associated factors of high postpartum weight retention were identified by multiple logistic regression analysis. Results: A total of 9 972 women were included in this study. P50 (P25-P75) of weight retention for participants was 3.6 (0.2-7.3) kg and high weight retention accounted for 41.5% of the subjects (4 134/9 972). The weighted means (SE) of weight retention was 3.5 (0.1) kg, and it was at 0 to <3, 3 to <6, 6 to <9, 9 to <12, 12 to <18 and 18 to <24 months postpartum were 5.3 (0.2), 4.5 (0.2), 3.8 (0.2), 3.1 (0.2), 2.8 (0.2) and 3.0 (0.2) kg, respectively. The weighted proportion of high postpartum weight retention was 37.4% (95%CI: 36.0%-38.9%). Compared with women aged under 25 years old, the odds ratio of high postpartum weight retention was 1.31 for women over 30 years old. Compared with women at 18 to <24 months postpartum, the odds ratio of high postpartum weight retention was 2.67, 1.61 and 1.31 for women at 0 to <3, 3 to <6 and 6 to <9 months postpartum, respectively. Compared with women having a pre-pregnant BMI from 18.5 to <25.0 kg/m2, the odds ratio of high postpartum weight retention was 1.30 and 0.67 for women having pre-pregnant BMI <18.5 kg/m2 and ≥25.0 kg/m2, respectively. Compared with women having appropriate gestational weight gain, the odds ratio of high postpartum weight retention was 0.47 and 2.24 for women having low and excessive gestational weight gains, respectively. Compared with farmers, the odds ratio of high postpartum weight retention was 1.44 for housewives. (P<0.05 for all comparisons). Conclusion: Postpartum weight retention in Chinese lactating women is at an intermediate level. High postpartum weight retention is primarily associated with age, postpartum period, pre-pregnant BMI, gestational weight gain and career. The key control factor for weight retention is gestational weight gain, and 1 year postpartum is critical period for weight recovery.