Relapsing fever risk factors

Risk Factors
TBRF in pregnancy

TBRF contacted during pregnancy can cause spontaneous abortion, premature birth, and neonatal death (Melkert and Stel 1991). The maternal-fetal transmission of Borrelia is believed to occur either transplacentally (Steenbarger 1982) or while traversing the [[birth canal.  In one study, perinatal infection with TBRF was shown to lead to lower birth weights, younger gestational age, and higher perinatal mortality (Jongen, van Roosmalen et al. 1997).

In general, pregnant women have higher spirochete loads and more severe symptoms than nonpregnant women. Higher spirochete loads have not, however, been found to correlate with fetal outcome.

Immunity

Although there is limited information on the immunity of TBRF, there have been patients who developed the disease more than once.