Sexually transmitted diseases (STDs), also called sexually transmitted infections (STIs), are common during pregnancy and should be aggressively sought and treated (Coonrad and colleagues, 2008). Importantly, education, screening, treatment, and prevention are essential components of prenatal care (Piper and colleagues, 2003). STDs that affect pregnant women and potentially affect the fetus include syphilis, gonorrhea, trichomoniasis, and chlamydial, hepatitis B, human immunodeficiency virus (HIV), herpes simplex virus–1 and -2 (HSV-1, -2), and human papillomavirus (HPV) infections. Recommended treatment protocols for most adhere to the frequently updated guidelines provided by the Centers for Disease Control and Prevention (2006b). Treatment of most STDs is clearly associated with improved pregnancy outcome and prevention of perinatal mortality (Goldenberg and associates, 2003, 2009; Gray and co-workers, 2001).
Despite the availability of adequate therapy for more than 60 years, syphilis remains a major issue for both mother and fetus. Syphilis rates reached an all time low in 2000, but from 2001 through 2006 for the United States, there has been a steady increase in primary and secondary syphilis rates (Centers for Disease Control and Prevention, 2006b). The rate of syphilis in 2006 among both sexes was 3.3 cases per 100,000 individuals, a 13.8-percent increase from the year prior. Among women for the same year, the rate of primary and secondary syphilis was 1.0 case per 100,000 population. Congenital syphilis rates were 8.5 per 100,000 live births.
Pathogenesis and Transmission
The causative agent for syphilis is Treponema pallidum. Minute abrasions on the vaginal mucosa provide a portal of entry for the spirochete. Cervical eversion, hyperemia, and friability increase the risk for transmission. Spirochetes replicate and then disseminate through lymphatic channels within hours to days. The incubation period averages 3 weeks—3 to 90 days—depending on host factors and inoculum size. The early stages of syphilis include primary, secondary, and early latent syphilis. These are associated with the highest spirochete loads and transmission rates of up to 30 to 50 percent. Transmission rates in late-stage disease are much lower because of smaller inoculum sizes.
The fetus acquires syphilis by several routes. Spirochetes readily cross the placenta to cause congenital infection. Because of fetal immunocompetence prior to approximately 18 weeks, the fetus generally does not manifest the immunological inflammatory response characteristic of clinical disease before this time (Silverstein, 1962). Although transplacental transmission is the most common route, neonatal infection may follow after contact with spirochetes through lesions at delivery or across the membranes.
Increased rates of maternal syphilis have been linked to substance abuse, especially crack cocaine; to inadequate prenatal care; and to inadequate screening (Johnson, 2007; Lago, 2004; Trepka, 2006; Warner, 2001; Wilson, 2007, and all their colleagues). In a study of prenatal syphilis during four decades, Klass and associates (1994) concluded that the continued prevalence of prenatal syphilis was associated with substance abuse, HIV ...