Objective  To examine the prevalence and influencing factors of weight retention measured 6 months after childbirth among the women in southeastern Shanxi province and to provide evidences for formulating measures to improve the condition.

  Methods  We enrolled 635 local pregnant women to be delivered between July 2015 and June 2017 for a prospective cohort study. Follow-up surveys were performed at one month and 6 months postpartum. The observation items included general conditions, weight before pregnancy, weight gain during pregnancy, and 6 months postpartum weight.

  Results  Of all the participants, 495 were followed up till 6 months postpartum, with a response rate of 77.95%. For the women completing the following up, the average prenatal body mass index (BMI) was 20.27 ± 2.28 and that at 6 months postpartum was 23.12 ± 2.74; the average body weight retention was 2.68 ± 2.48 kg. The ratio of overweight and obesity increased from 16.36% during pregnancy to 24.65% at 6 months postpartum. A total of 295 participants (59.6%) had the weight increment at least 1 kg exceeding the United States Institute of Medicine (IOM) recommendation and 104 (21.01%) exceeded the standard of 5 kg. The results of multivariate linear regression revealed that gestational weight gain, postpartum depression, and pre-pregnancy BMI were influencing factors of body weight retention at 6 months postpartum.

  Conclusion  Weight management and mental health interventions are needed during pregnancy and within 6 months postpartum to reduce the incidence of obesity and obesity-related diseases.