The Comparison Of Birth Interval And Their Influencing Factors Between Rural-to-urban Migrants And Resident Population In China

The birth interval can reduce the total fertility rate and affect the fertility level of the population by adjusting the fertility density of the population.China's family planning policy has forcedly controlled the the birth interval,which has changed the distribution of women's reproductive age and the structure of population,and effectively controlled the rapid population growth.In addition,the birth interval is related to maternal and infant health.The too short or too long birth interval can cause maternal and infant unhealthy outcomes.The reproductive behaviors of the rural-to-urban migrants has became the focus of social attention,due to the sharp increase in the number of young migrants,as the main members of the migrants.Therefore,the study of the status,changing trend and the influencing factors of the birth interval of the migrants and resident population is not only helpful to explore the reproductive behavior of this special group of migrants,but also to provide the basic data for the birth interval in order to increase the accuracy of the forecast of the new born population.At the same time,it can provide empirical evidence to improve the maternal and child health of migrants and resident population.This paper utilizes Migrants Population Dynamic Monitoring Survey Data 2015 to explore the status and trend of birth interval by descriptive statistic method,and to plot the survival curve by Kaplan-Meier method.And the Cox proportional hazards model and Cox mixture cure model to explore the influencing factors of first birth interval and second birth interval respectively.The results show that in our country,almost half of families would choose to have their first child within 2 years,while the second birth interval is at least 5 years for more than half of migrants.In 2015,the median of first birth interval is 17 months and 30 months for migrants and resident population respectively,and the median of second birth interval is about 5.1 years and 6.4 years,suggesting that longer birth interval is fairly common.Both the first birth interval and second birth interval have shown an increasing trend in this century for the two groups of people,while the migrants have shorter birth interval than the resident population,including first birth interval and second birth interval.Ethnic,household,education level,age at marriage and marriage time all have influence on the first birth interval,in which the effect of marriage time is most obvious.The family planning policy has a greater impact on the second birth interval.Moreover,the family demographic characteristics and the marital and obstetric history can also influence the second birth interval in migrants,while women' marital and obstetric history has obvious effect in resident population.In conclusion,we believe that under the absence of fertility policy constraints,the birth interval is likely to increase further,with the increase of women' education and pressure on life,which will continue to aggravate the decline in fertility.Meanwhile,the proportion of migrants with long second birth interval may increase,and those with extra-long second birth interval will exist for a time among resident population.So,the relevant health authorities need to pay attention to the phenomenon of long birth interval,and to strengthen propaganda education of the importance of birth interval to health.Besides,it's necessary to ensure maternal and child health services for people with longer birth interval.