国家卫生健康委科学技术研究所

Objective:To analyze the trend of the body mass index（BMI） value of women during the preparing pregnancy after the implementation of the two-child policy.Methods:A total of 33 335 352 Han Chinese women who wanted pregnancy and had participated in the National Free Pre-pregnancy Health Checkup Program in 2013-2019 were included in this study.The average BMI value,the overweight rate,and the obesity rate of the women were calculated monthly.The primiparae in these women were included in control group,and the pluriparae in these women were included in study group.A controlled interruption time series analysis was conducted to obtain the trend of the BMI value of women before and after the implementation of the two-child policy.Results:Compared with those of the women in the control group,the mean monthly BMI value change of the women in the study group was 10.01 × 10 -2 kg/m~2（95%CI-0.07-19.94,P=0.05）,and the change of the overweight/obesity rate of the women in the study group was 1.36%（95 % CI 0.36 %-2.35 %,P＜0.01）.The results of subgroup analysis showed that the change of overweight rate of the women with age≥35 years old,less than high school education level,or the farmer occupation in the study group was significantly higher than that of the women in the control group（P＜0.05）,and the obesity rate of the women with age≥35 years old,and the average GPT of 40 000-50 000 Yuan,or reside in the first-tier city in the study group had significantly different from that of the women in the control group.In the trend change,the trend change of obesity rate of the women with the aged of 30-35 years old,the per capita GPT 50 000-70 000 Yuan or≥70 000 Yuan,or reside in the second,the fourth,or the fifth tier cities had increased significantly（P＜0.05）,the trend change of overweight rate of the women with the aged of 30-50 years old,or reside in the third-tier city had increased significantly（P＜0.05）,and the trend change of overweight/obesity rate of the women with high school or above education level,vocational workers,or reside in the first or the third tier cities had decreased significantly（P＜0.05）.Conclusion:After the implementation of the universal two-child policy,there is little change in the overall trend of the BMI value among the women who are ready for pregnancy,and there are differences in the different social demographic characteristics and the different social development degree.The weight management of the women with planned pregnancy should be carried out to improve the health of the women of childbearing age.

Objective:To study the trend of menarche age in Han and Mongolian women born from 1951 to 2005 in Mongolian region.Methods:A cross-sectional cluster sampling survey method was adopted, From 2003 to 2019, a retrospective survey was carried out in three banners/counties in Tongliao region on the female population of Han and Mongols nationalities aged 16 to 46 and conducted under standardized survey procedures and quality control standards. The basic data of menarche age of women born between 1951 and 2005 were obtained. The changes and rules were analyzed by taking 1 year, 5 years and 10 years as nodes.Results:Totally 46 and conducted under standardized survey procedures and quality control standards 928 pepole (24 450 Han and 22 478 Mongolian) were recruited, the survey response rate was 96.09% (46 928/48 836). In one-year-period analysis, the menarche age gradually decreased from 1951 to 2005. The mean menarche age of Han and Mongolian women changed from (16.22±0.52) years and (15.86±1.24) years in 1951 to (12.37±1.15) years and (12.33±0.98) years in 2005, respectively. The mean menarche age of Han and Mongolian women decreased 3.85 years and 3.54 years. The trend of the mean menarche age's change showed a significant negative correlation with the years (all P<0.000 1). In five-year-period analysis, the mean menarche age of Han and Mongolian women changed from (15.54±1.45) years and (15.53±1.48) years from 1951 to 1955 to (12.41±0.97) years and (12.47±0.96) years from 2001 to 2005, the mean menarche age decreased 3.13 years (3.41 months ahead of schedule every 5 years on average) and 3.06 years (3.34 months ahead of schedule every 5 years on average) in Han and Mongolian women respectively. In ten-year-period analysis, the mean menarche age of Han and Mongolian women changed from (15.79±0.95) years and (15.53±1.33) years from 1951 to 1960 to (12.41±0.97) years and (12.47±0.96) years from 2001 to 2005, the mean menarche age decreased 3.38 years (6.76 months ahead of schedule every 10 years on average) and 3.06 years (6.12 months ahead of schedule every 10 years on average) in Han and Mongolian women respectively. During the 15 years from 1951 to 1965, 1966 to 1970, 1971 to 1990, and 1991 to 2000, they were concentrated at the ages of 15-16, 14-15, 13-14, and 12-13, respectively. The proportion of women at 11 years, 12 years and 13 years menarche age were 26.79% (457/1 706), 73.27% (1 250/1 706), and 92.85% (1 584/1 706) during 2001—2005 in Han women, while the proportion were 23.25% (653/2 809), 62.01% (1 742/2 809), and 90.14% (2 532/2 809) in Mongolian women. Conclusion:The menarche age decreased in Han and Mongolian women from 1951 to 2005, and the ethnic groups tended to be the same. It is recommended to start adolescent education at the age of 8-9 years and pay attention to the changing pattern of early onset of menarche.