Exploring management of antenatally diagnosed fetal syphilis infection

The incidence of syphilis among Canadian women of childbearing age has risen dramatically in the past decade, with a resurgence of infants born with congenital syphilis. While guidelines exist to guide maternal infection during pregnancy, there is little evidence available to guide management in situations where the developing fetus is found to be severely affected.

Our patient presented in the second trimester of her pregnancy as syphilis contact. Positive serologic tests (venereal disease research laboratory titre of 1:64) and a chancre suggested primary infection. Ultrasound demonstrated a fetus at 19+3 weeks gestation with hydrops fetalis and a markedly abnormal brain. Amniocentesis confirmed congenital syphilis infection on polymerase chain reaction testing. After nine days of intravenous penicillin G, the fetal status had worsened, and the family ultimately chose a medical termination of the pregnancy.

Evolving ultrasound technology has allowed us to identify severely affected fetuses, who may historically have been delivered stillborn. Following routine syphiliotherapy with benzathine penicillin, these abnormal ultrasound features may take weeks or months to reverse, which poses a challenge in prognostication and counselling. Case reports data suggests intensive treatment with intravenous penicillin may be effective in severe cases where fetal hydrops is present.

This case highlights the potential morbidity of fetal syphilis infection and underscores the paucity of current literature. Information sharing will be essential to build a modern knowledge base on treating this ancient disease.