Increase in Congenital Syphilis in Maricopa County, Physicians Reminded Of Testing Requirements

Congenital Syphilis is a condition in which a pregnant woman with syphilis transmits the infection to her baby. Syphilis is connected to numerous adverse outcomes and often goes unnoticed or misdiagnosed due to vague symptomology.  

Testing Requirements

  • Arizona law requires syphilis testing (e.g. RPR reflex to TPPA) during the first prenatal visit or first medical visit during pregnancy, which may include urgent care or emergency department settings.
  • As a high morbidity county, ALL pregnant women should have repeated syphilis screening early during the third trimester and at delivery.
  • Infants should not be discharged from hospitals until the syphilis serologic status of the mother is known. Infants born to women with reactive RPRs must have RPR tests themselves. 
  • New syphilis infections are indicated by one of the following

Treatment Guidelines

Timing and accuracy of proper treatment is critical. See CDC links:

Documentation and Reporting

  • All syphilis test results and treatment should be thoroughly documented in the medical records of both mother and baby.
  • Reactive syphilis tests must be reported to public health within 24 hours. Maricopa County maintains as up to date records of syphilis tests as possible with these reports, which is an ideal resource for providers serving new patients. Health Advisors are ready to assist you at 
    602-506-5435 or 602-506-6205.


  • Anemia
  • Jaundice
  • Hepatosplenomegaly
  • Long bone deformities
  • Skin lesions
  • Skin rash
  • Skin peeling
  • Primary sore
  • Mucous membrane lesions

Supplemental Labs

  • Reactive CSF VDRL
  • Elevated CSF protein
  • Elevated CSF WBC

Maricopa County Congenital Syphilis Rates Have Doubled Since 2016

congenital syphilis frequency and rates locally vs national average

National & County Statistics:

  • From 2014 to 2018, Maricopa County congenital syphilis cases nearly tripled with a 50% increase from 2017 to 2018 alone.
  • Between 2016 and 2018, the proportion of syphilis cases among females rose from 17% to 25%.  In the same time frame, total female syphilis cases more than doubled.
  • In 2018, 5 of 30 congenital syphilis cases in Maricopa County resulted in fetal demise of the infant either by stillbirth or infant death shortly after delivery.

Syphilis Serologic Tests for Screening and Diagnosis

Screening Nontreponemal Tests – Become negative following treatment.

Detect both IgM and IgG antibodies (detectable as early as 6 days postinfection).

  • Rapid plasma reagin (RPR) – best screening test for blood
    • Detects and measures Treponema pallidum antibodies in blood
    • Repeat RPR used to monitor treatment effectiveness following antibiotics
    • Titers should drop  following treatment; unchanged or rising levels could indicate reinfection or treatment failure.
  • Venereal disease research laboratory test (VDRL) 
    • Should only be used for cerebrospinal fluid (CSF)
    • Detects and measures Treponema pallidum antibodies in blood or CSF

Confirmatory Treponemal Tests – (In order of preference) - Remain positive regardless of treatment

  • Treponema pallidum particle agglutination assay (TP-PA) – blood only
    • Detects Treponema pallidum antibodies
    • Used to confirm syphilis after positive screening test above
    • CANNOT be performed on CSF
  • Fluorescent treponemal antibody absorbed test (FTA-ABS)
    • Detects Treponema pallidum antibodies
    • Cannot be used in the first 3 to 4 weeks after exposure.
    • Can be performed on blood or CSF

“Gold Standard”

Darkfield microscopy – used to diagnose PRIMARY Syphilis

  • Identifies spirochetes in a fluid or tissue sample from an open sore.
  • Used to diagnose early stage syphilis before antibodies are detectable



  • Patient with no History of Syphilis
    • Nontreponemal and Treponemal Test reactive
      • Treat according to stage
    • Nontreponemal test reactive Treponemal test non-reactive
      • Not a case, no treatment needed
  • Patient with History of Syphilis 
    • Nontreponemal and Treponemal Test both reactive
      • Compare current RPR titer with most recent RPR titer, if 4-fold or greater increase (ie. 1:4 to 1:16 or greater) then treat according to stage
  • Treatment by Stage:
    • Early Stage (infected <1 year): Benzathine penicillin G 2.4 million units IM x 1
      • Asymptomatic patients with a negative test within one year or asymptomatic patient with a history of syphilis and a lower titer RPR within one year
      • Patient with primary or secondary symptoms of syphilis
    • Late Stage (infected >1 year) or Unknown Duration: Benzathine penicillin G 2.4 million units IM x 3 doses 1 week apart
      • Asymptomatic patients with last negative test more than one year ago
      • Asymptomatic patients with no syphilis testing history

**Please note, patients can also be staged based on their sexual history with a known early case, however this is typically not information a provider has available.