Characteristics of study participants.

Abbreviations: IMD = Index of Multiple Deprivation score based on practice post-code (practice level socioeconomic status) or patient post-code (patient level socioeconomic status). The higher the score the greater the deprivation. UTS = up-to-standard (i.e. data meeting GPRD quality standards). ART = assisted reproductive technology.amatching variable.

缩写：IMD = 基于执业地址编码的多重剥夺指数（反映执业层面的社会经济状况）或患者地址编码的多重剥夺指数（反映患者层面的社会经济状况）。指数越高，剥夺程度越严重。UTS = 达标（即符合GPRD质量标准的数据）。ART = 辅助生殖技术，作为匹配变量。