Adverse pregnancy outcomes following syphilis treatment in pregnancy in the UK

Syphilis infection in pregnancy is known to cause a number of severe adverse pregnancy outcomes, including second-trimester miscarriage, stillbirth, very pre-term delivery and neonatal death, in addition to congenital syphilis. A retrospective review of women with positive syphilis serology and a pregnancy outcome between 2005 and 2012 in Leeds, UK, was performed. In all, 57 cases of positive syphilis serology in pregnancy were identified: 24 with untreated syphilis treated in the current pregnancy (Group 1); seven with reported but unconfirmed prior treatment who were retreated (Group 2); and 26 adequately treated prior to pregnancy (Group 3). The rate of severe adverse pregnancy outcomes in Group 1 at 21% was significantly higher than the 0% outcome of Group 3 (p = 0.02). The severe adverse pregnancy outcomes were two second-trimester miscarriages, two pre-term births at 25 and 28 weeks and one stillbirth at 32 weeks. There were no cases of term congenital syphilis or term neonatal death, but we observed high rates of other adverse pregnancy outcomes despite treatment during pregnancy. Rapid referral for treatment is needed before 18 weeks in order to minimise adverse pregnancy outcomes.