Effects on preventing mother-to-child transmission of syphilis and associated adverse pregnant outcomes: a longitudinal study from 2001 to 2015 in Shanghai, China

BACKGROUND Maternal syphilis is a health threat to both the pregnant women and the children. This study aimed to delineate the longitudinal trend of maternal syphilis and burden of associated adverse pregnant outcomes (APOs) in Shanghai from 2001 to 2015; and to evaluate the effects of preventing mother-to-child transmission (PMTCT) of syphilis in Shanghai with regard to service coverage and APOs averted. METHODS PMTCT program of syphilis has been implemented since 2001. Municipal and national PMTCT surveillance data were used in analysis. By using WHO estimation model, the burden of associated APOs and APOs averted were estimated. The differences in access to antenatal care and PMTCT services between resident and non-resident pregnant women were analyzed. RESULTS The prevalence of seropositivity for maternal syphilis in Shanghai ranged from 0.20% to 0.38% during 2001-2015. The treatment rate varied from 69.8% to 96.8% and remained 83.6% in 2015. Under the PMTCT program, 2163 APOs had been averted during the 15-year period, including 852(39.4%) early fetal loss/stillbirth, 356(16.4%) neonatal death, 190(8.8%) prematurity or low birth weight, and 765(35.4%) clinical evidence of congenital syphilis. Compared with the residents, the non-resident pregnant women had a higher prevalence of syphilis (1.2‰ vs. 2.5‰) and contributed to 81.7% of the syphilis associated APOs in 2015. CONCLUSION Screening of maternal syphilis has reached a full coverage both in residents and non-residents. Large numbers of APOs has been averted attributing to the PMTCT program. More attentions should be paid to those vulnerable non-resident pregnant women and tailored interventions including health education, PMTCT promotion and point of care should be given to maximize the effects of PMTCT in Shanghai.