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what is congenital syphilis

By: Karen Terry

September 5, 2022

What Is Congenital Syphilis: Everything You Need to Know

In recent years, the number of congenital syphilis cases in the United States increased significantly. According to the Centers for Disease Control, there were more than 2,000 cases of this infectious disease in 2020 alone.

Syphilis during pregnancy can have severe and debilitating implications for child health. However, with rapid STD testing, early diagnosis, and sufficient prenatal care, effective treatment is possible.

What is congenital syphilis, and how does the transmission of this multisystem infection occur? In this guide, the team at Rapid STD Testing discusses congenital syphilis and the diagnosis and treatment of this infectious disease.

Congenital Syphilis Symptoms

Syphilis is a chronic disease resulting from an infection of the bacterium treponema pallidum. This sexually transmitted disease (STI) can transmit from one person to another via physical contact with a syphilitic sore, usually during sexual contact.

What Is Congenital Syphilis?

When a pregnant mother passes syphilis to her baby in the womb, the infection is called congenital syphilis. This transmission is transplacental, which means the mother transmits the bacteria to her baby via the placenta.

Pregnant women can transmit a congenital infection to their babies regardless of whether they acquired the disease during or before pregnancy. However, the longer the infection period before the pregnancy, the lower the baby's risk of contracting the infection.

On the other hand, if the mother acquired the infection during pregnancy, her infant has a higher risk of contracting the infection in the womb. The baby's risk of encountering severe health complications is also higher.

The mother's risk factors for contracting syphilis in pregnancy include:

  • Multiple sexual partners
  • Transactional sexual contact
  • Lack of access to sufficient prenatal care
  • Incarceration of the pregnant mother or her partner
  • Heroin or methamphetamine use
  • Homelessness or housing issues

How Can Syphilis Affect Pregnancy?

A pregnant woman with syphilis might also experience intrauterine stress, which causes pregnancy complications. These issues can include a significant estrogen reduction, along with an increase in serum progesterone, possibly resulting in:

  • A miscarriage: the loss of an infant before the 20th week of pregnancy
  • A stillbirth: the loss of an infant after 20 weeks of pregnancy
  • A premature birth:  A birth that occurs before the 37th week of pregnancy

In some cases, newborns with maternal syphilis die shortly after birth.

In the case of premature birth, babies have a higher risk of chronic health issues and are more prone to asthma, feeding issues, and infections. Learn whether newborns can have STDs and how to protect babies in the womb from STDs.

Understanding Newborn Syphilis

The overall risk of a mother with syphilis transmitting the infection to the baby via the placenta ranges from 60% to 80%. A mother with primary or secondary syphilis is more likely to pass the infection on to her baby. The risk of latent transmission (transmitting a syphilis infection with no symptoms) to a baby is generally lower.

The symptoms of congenital syphilis in babies can present as early as three weeks of age. However, in some cases, children only start developing symptoms between the ages of two and five.

During Pregnancy

The symptoms of syphilis in pregnant mothers depend on their infection duration and the treatment they receive. During the primary stage of syphilis, one or more small sores develop in the genital area. Pregnant mothers with secondary syphilis might experience any of the following symptoms:

  • Fever, headaches, or a sore throat
  • Weight loss
  • Hair loss
  • Swollen lymph nodes
  • Muscle aches and pains
  • Fatigue

In the case of latent syphilis, the mother experiences no symptoms, but the infection is still present in the body. Same-day STD testing can detect this infection, allowing patients to seek treatment.

After Birth: The Symptoms of a Baby Born with Syphilis

Congenital syphilis in babies can result in clinical manifestations within the first three months of life. These symptoms of early congenital syphilis include umbilical cord hardening and inflammation. The baby can also experience:

  • Enlargement of the liver and spleen
  • Skin shedding and rashes around the palms and soles
  • Bone inflammation, or periostitis
  • A low birth weight
  • A rash around the mouth, nose, and diaper area
  • Stuffy nose with a blood-stained nasal discharge that is infectious
  • Inflammation of the brain

The symptoms of late congenital syphilis can start presenting after the age of two years and include:

  • Gummatous ulcers affecting the septum, nose, periosteal lesions, and hard palate
  • Retinitis pigmentosa, a severe eye condition
  • Interstitial keratitis resulting in blurred vision, eye pain, and light sensitivity
  • Neurosyphilis, the increase of leukocyte and protein levels in the cerebrospinal fluid
  • Oral and anal fissuring

In many cases, patients only receive a diagnosis of late-onset congenital syphilis in adulthood.

Exams and Tests to Determine the Presence of Congenital Syphilis

Some babies don't present any symptoms of congenital syphilis at birth, and testing might be necessary to make a diagnosis.

Determining if a baby has congenital syphilis involves:

  • Testing the mother for syphilis
  • Determining if the mother received treatment for syphilis
  • Evaluating the effectiveness of the mother's treatment for syphilis
  • Examining the baby for symptoms like enlarged liver or bone inflammation
  • Performing a blood test, x-ray, or spinal tap on the baby

Blood tests can confirm whether the mother or baby has syphilis.

The blood tests for syphilis include treponemal tests and nontreponemal tests. Treponemal tests detect antibodies against treponema pallidum proteins. These tests include:

  • Microhemagglutination assays for treponema pallidum
  • Treponema pallidum particle agglutinations
  • Treponema pallidum hemagglutination assays
  • Fluorescent treponemal antibody absorbed (FTA-ABS) tests
  • Chemoluminescence immunoassays
  • Enzyme immunoassays for the detection of treponemal antibodies

A 10-panel test is a plasma screening for syphilis with an incubation period of up to 90 days.

Nontreponemal tests detect antibodies against damaged host cells and lipoidal antigens. These tests include:

  • Rapid plasma reagin (RPR)
  • Toluidine red unheated serum test
  • Venereal Disease Research Laboratory (VDRL) test

Suppose a mother has positive blood test results indicating a syphilis infection. In this case, her newborn baby should undergo evaluation with the same blood test the mother underwent. Doctors test the baby's blood from the heel because testing the umbilical cord blood can result in a false positive due to maternal blood contamination.

The transfer of immunoglobulin G antibodies can occur via the placenta. This antibody transfer can make it challenging to interpret the test results on babies younger than 30 days. Consequently, infants only undergo nontreponemal testing and not treponemal testing.

Diagnosis and Treatment of Congenital Syphilis in a Baby

The delay in diagnosing congenital syphilis is often due to late-onset symptoms. However, untreated syphilis can result in severe health complications or even death. As a result, the baby of a mother with evidence of syphilis must undergo further evaluation and testing to determine if early syphilis is present.

The diagnosis of late congenital syphilis involves a physical examination, blood tests, and an evaluation of the child's clinical history.

Maternal testing and treatment are crucial in preventing congenital syphilis. But what is congenital syphilis treatment? Benzathine penicillin is often the treatment doctors recommend for pregnant women in the early stages of syphilis.

However, if a pregnant woman is in the later stages of syphilis or if she has neurosyphilis, the suitable regimen might be the same as for patients who are not pregnant. A pregnant mother who is allergic to penicillin might need to undergo desensitization before receiving penicillin treatment.

The recommended treatment for a newborn with a confirmed diagnosis of congenital syphilis typically involves the administration of aqueous crystalline penicillin or procaine penicillin. These treatments might also be suitable for an infant who doesn't have a confirmed diagnosis but whose mother has positive test results and:

  • Did not receive treatment for syphilis during pregnancy
  • Started receiving treatment less than four weeks before delivery
  • Received insufficient treatment, for example, a non-penicillin regimen

If a mother shows signs of reinfection or relapse, or if her treatment status is unavailable, the newborn may also receive the penicillin treatment.

The recommended treatment for a child with late congenital syphilis includes the administration of aqueous crystalline penicillin or benzathine penicillin.

Treating Syphilis with Complications

The mother may also receive treatments for health complications resulting from congenital syphilis.

For example, a doctor may prescribe atropine drops and a corticosteroid when treating interstitial keratitis. This treatment typically occurs in consultation with an ophthalmologist. A corticosteroid and penicillin treatment can relieve hearing loss due to inner ear or nerve damage.

STDs such as syphilis can potentially have a debilitating effect on a child's health. Consulting with a doctor is critical to seeking effective treatments and mitigating health risks.

Fortunately, modern medicine can be effective in reducing the effects of syphilis. Learn about STDs in ancient times.

Testing Is Your First Defense Against Syphilis

What is congenital syphilis? Hopefully, after reading this guide, you have a clearer understanding of this condition, how it spreads, its symptoms, and the available treatments.

If you suspect that you have syphilis or any other STD, you need to undergo a rapid STD test, seek early treatment, and protect your sexual health. At Rapid STD Testing, we offer secure and confidential STD testing solutions, and all our tests are FDA-approved.

Our RapidSTD Basic Panel, Test Panel, and Test Panel Plus packages are all suitable options for syphilis testing. Visit one of our STD testing centers near you today.


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By: Karen Terry
September 5, 2022

With a profound passion for making intricate medical information accessible to all, John possesses a unique ability to simplify complex concepts without sacrificing accuracy or depth. Armed with a comprehensive understanding of various healthcare fields, John is well-versed in the latest research and advancements. However, what truly sets him apart is his remarkable talent for distilling this wealth of knowledge into engaging, reader-friendly content.