Most pregnant women and women of childbearing age are worried about the Zika virus this summer, but they also face another serious concern — a shortage of Bicillin L-A to treat syphilis.

Caused by the spirochete bacterium Treponema pallidum, syphilis was once on the verge of elimination but re-emerged as a health threat in 2001. The only recommended treatment for syphilis in pregnant women, Bicillin L-A, is now on back order due to a manufacturing delay.

Pfizer Pharmaceuticals is the only company to offer Bicillin L-A, which is the brand name for penicillin G benzathine preparation. The pharmaceutical giant sent a letter on April 27, telling customers they would continue to ship about 30 percent of the normal monthly demand into the supply chain. Pfizer also recommended wholesalers and distributors place Bicillin L-A on allocation in order to serve as many customers as possible until the supply chain resumes its normal operations.

The Centers for Disease Control and Prevention (CDC) has reported a sharp increase in the number of babies born in the United States with syphilis in recent years. Reported cases of congenital syphilis declined between 2008 and 2012, dropping from 10.5 to 8.4 cases per 100,000 live births. The rates increased suddenly between 2012 and 2014, jumping from 8.4 to 11.6 cases for every 100,000 births to reach the highest rate of congenital syphilis since 2001.

The increase in congenital syphilis is associated with an overall nationwide increase in syphilis. The CDC reports that the primary and secondary syphilis rates have increased by 15.1 percent since 2013. Primary and secondary syphilis are the most infectious stages of the disease.

A mother with untreated syphilis can pass the infection to her child during pregnancy to cause congenital syphilis. Untreated syphilis in the mother may result in miscarriage, stillbirth or death after birth. Up to 40 percent of babies born to untreated mothers may be stillborn or succumb to Treponema pallidum infection sometime after birth, according to the CDC.

The effects of untreated syphilis on a baby's health depend largely on how long the mother has the infection and when she received treatment, if at all. Children with congenital syphilis can suffer a variety of health problems, including:

  • Musculoskeletal deformity
  • Anemia
  • Enlarged liver and spleen
  • Jaundice
  • Auditory nerve disease and other neurological conditions
  • Meningitis
  • Skin rashes and/or mucous membrane lesions

Pfizer Pharmaceuticals expects supplies to resume in July. The CDC suggests practitioners refrain from prescribing Bicillin L-A for streptococcal pharyngitis and other infectious diseases when other antimicrobials are available.

The government health organization instructs prescribers to adhere to the recommended dosing regimen of 2.4 million units of penicillin G benzathine IM when treating primary, secondary or early latent syphilis. The CDC also reminds clinicians that additional doses of penicillin G benzathine do not enhance the antimicrobial's efficacy, even in patients with HIV.

For current information on the availability of Bicillin L-A, check the FDA website, which is updated and verified regularly.