Abstract: The rising incidence of premarital pregnancy is largely an indication of the rapid change of the attitudes and practices about sex and marriage in China．Pregnancies ended with abortion also imply new threats to women’ s health and development．Based on discussing the data bias and theoretical shortages in past research，we propose new frames to measure and analyze this problem．Using data from the 2013 National Floating Population Dynamic Monitoring Survey we examine age，peri- od，and cohort trends in premarital pregnancy，and test hypotheses about the effect of migration．Re- sults show that younger cohorts have higher incidence of premarital pregnancy promoted by migration， especially for the rural migrants and those with lower education．We suggest to collect more data on premarital sex behavior and pregnancy，and to offer family planning services for the youth and adults who have not yet married．

Keywords:  Premarital Pregnancy, Migration, Floating Population, Cohabitation

摘要： 未婚先孕和婚前流产不仅反映中国青年婚姻和性相关的观念、实践的变化，也意味着潜在的健康威胁与公共服务需求。文章针对既有研究的数据偏差和理论不足提出改进的数据采集方案与解释框架，利用 2013 年“流动人口动态监测调查”数据的生育史信息，对流动人口未婚先孕水平和模式进行探索，并采用竞争性风险事件史模型验证了婚前流动对未婚先孕的影响及其异质性。结果表明，流动妇女中有 20% ～25%会经历以生育结束的未婚先孕，加上以流产结束的部分，未婚先孕 发生率会更高; 婚前流动会显著提高未婚先孕几率; 初次外出时年龄越小，流出时间越长，未婚先孕几率越高; 婚前流动经历对农业户籍、教育水平较低的流动妇女发生未婚先孕的影响更大。

关键词: 流动人口, 流动, 未婚先孕, 未婚同居