Treatment of maternal syphilis for preventing congenital syphilis: an observational study of adherence to treatment recommendation in Suzhou, China, 2019-2021.

Background: China is one of the countries that set the goal to eliminate mother-to-child transmission (EMTCT) of syphilis by a target date. Active screening for syphilis among pregnant women, followed by effective treatment of maternal syphilis, is critical for achieving the goal. The China health authority issued national implementation protocols to guide EMTCT practice in health facilities.

Methods: Within a cohort of infants born to mothers infected with syphilis, we obtained the data of regimens used for treatment of maternal syphilis from the National Information System of Prevention of Mother-to-Child Transmission of HIV, Syphilis and Hepatitis B, and analysed the physician's treatment behaviour and its associated factors in a public hospital in Suzhou of China.

Results: A total of 450 pregnant women who were positive for treponemal or non-treponemal antibody, or had previous infection with syphilis were included into the study for analysis. Of them, 260 (57.8%) were positive for both treponemal and non-treponemal antibodies (syphilis seropositivity), and 353 (78.4%) were treated for syphilis according to the protocol in which 123 (34.8%) were treated with two courses. Non-adherence to treatment recommended by the protocol for maternal syphilis was significantly associated with antenatal visits in the third trimester (AOR 6.65, 95% CI 2.20-20.07, P =0.001), being positive only for a treponemal test (AOR 5.34, 95% CI 3.07-9.29, P <0.001) or having a syphilis infection before the pregnancy (AOR 2.05, 95% CI 1.14-3.69, P =0.017), whereas the uptake of treatment for two treatment courses was associated with attending antenatal care in 2020 or before (AOR 3.49, 95% CI 1.89-6.42, P <0.001), being positive for treponemal and non-treponemal tests (AOR 5.28, 95% CI 2.78-10.06, P <0.001) or having non-treponemal antibody titre of ≥1:8 (AOR 3.71, 95% CI 1.77-7.78, P =0.001).

Conclusions: Implementation of the current recommendation to offer a universal treatment for syphilis among all pregnant women who are shown to be positive for a treponemal test alone is challenging in some clinical settings in China.