Intra-Couple Discordance Supporting Preconception Syphilis Screening for Both Spouses: A National and Population-Based Survey in China between 2013-2018

Abstract

Background: Antenatal screening strategy remains inadequate for eliminating congenital syphilis. To further eliminate maternal-fetal transmission, preconception syphilis screening is considered as an option. In this study, we investigated syphilis sero-positivity and intra-couple discordance among married couples planning a pregnancy in China, to provide essential baseline evidence for preconception syphilis screening. Methods: This national population-based survey enrolled married Chinese couples planning conception within 6 months between 2013 and 2018. Syphilis was screened using rapid plasma reagin (RPR) test; socio-demographic characteristics were collected through questionnaire and medical records. R software (v3.2.2) and ArcGIS (v10.2) were applied for statistical analyses and geographic mapping. Findings: Among 31,955,041 couples, 29,737,172 (93.06%) had complete RPR results for both spouses; of those, 0.62% (186,100) were sero-positive, with a dramatic intra-couple discordance: 0.33% positivity in wives, 0.24% in husbands, and 0.05% in both spouses. Across time, sero-positivity and intra-couple discordance were stable. Regional sero-positivity was significantly different, and provincial rates varied geographically from Tibet (0.8%) to Hebei (0.2%) (P < 0.05). Economic level was an independent factor for this regional variation, with sero-positivity increasing as gross domestic product income decreased (P < 0.05). Interpretation: Intra-couple discordance is notable among couples, with a considerable rate of pre-existing syphilis before pregnancy. Thus, screening both spouses during integrated preconception health care is recommended for further eliminating maternal-fetal transmission. Funding Statement: Database reported in this publication was supported by Chinese government, a national nonprofit project which benefits rural reproductive aged population. This study was supported by the National Key Research and Development Program of China (grant no. 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.