Maternal Syphilis Leading to High Efficiency In Utero Transmission of Antiretroviral Resistant HIV: Intersection of Two Pandemics.

Background: Testing for syphilis and HIV is indicated in prenatal care in the United States. Effective antiretroviral therapy during pregnancy reduces mother-to-child HIV transmission (MTCT) to less than 1%. Syphilis infection in pregnant women with unsuppressed HIV increases the risk of MTCT, usually in utero. The incidences of syphilis in women of childbearing age and corresponding congenital syphilis are increasing in the United States.

Methods: We report 3 cases of in utero HIV transmission associated with maternal syphilis that occurred during the ongoing syphilis epidemic.

Results: All 3 women had untreated HIV infection and active syphilis with placentitis during late pregnancy. Their newborns were found to have symptomatic congenital syphilis and HIV infection from in utero transmission. The babies' antiretroviral resistance patterns were nearly identical to their mothers'.

Conclusions: When untreated syphilis and uncontrolled HIV coincide in pregnancy, there is a high likelihood of in utero mother-to-child HIV transmission. The current syphilis epidemic in the United States may lead to an increase in MTCT.