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

Abstract

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<0·05). Conclusions: Pre-existing syphilis sero-positivity among Chinese married couples planning a pregnancy are considerable and intra-couple discordance are higher than expected. Health promotion to raise infection awareness is indicated. Preconception syphilis screening for couples could be an optional recommendation for further eliminating the potential risk of mother-to-child syphilis transmission. Funding Statement: This study was supported by the National Key Research and Development Program of China (grant no. 103 2016YFC1000307). Declaration of Interests: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. MS Ma reports National Free Preconception Health Examination Project (NFPHEP) supported by Chinese government, a national nonprofit project which benefits rural reproductive aged population. No other disclosures were reported. Ethics Approval Statement: The Institutional Review Board of Chinese Association of Maternal and Child Health Studies approved the project (IRB201001), and written informed consent was obtained from each participant before enrollment.