Pre-Existing Syphilis Prevalence, Its Intra-Couple Discordance and Infection Awareness as an Essential Evidence for Preconception Screening: A National and Population-Based Survey Among 29 Million Married Couples Planning a Pregnancy in China During 2013-18

Background: The preventive strategy based on antenatal syphilis screening has greatly progressed for reducing mother-to-child transmission, however, it is still regarded inadequate for eliminating congenital syphilis. In order to explore potential risks for maternal transmission, including pre-existing syphilis sero-positivity, intra-couple discordance and infection awareness, we investigated the prevalence among married couples planning a pregnancy in China, and their temporal and regional characteristics as well. Methods: A national and population-based survey was conducted for married couples intending to conceive within 6 months during 2013-1 in mainland China8. Syphilis screening was performed using rapid plasma reagin (RPR) test; information on infection awareness and socio-demographic characteristics were also collected based on questionnaire and medical records, respectively. R software (version 3.2.2) and ArcGIS (version 10.2) was applied for statistical analyses and geographic mapping. Results: Among enrolled 31955041 married couples planning a pregnancy, 29901308 (93·57%) couples had complete RPR results for both husband and wife. 0·62% (186853/29901308) couples were identified as syphilis sero-positivity with a dramatic intra-couple discordance: 0·32% of only wife positivity, 0.25% of only husband positivity and only 0·05% of both positivity. According to temporal trend, sero-positivity and intra-couple discordance was stable by year (P>0·05), together with continuously increased infection awareness (P 0.05). Economic level was an independent risk factor for regional variation by the increased sero-positivity along with lower GDP income (P