Syphilis and Pregnancy: What You Need to Know

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Even though syphilis is a treatable and curable sexually transmitted infection (STI), rates of congenital syphilis, or babies being born with the disease, have skyrocketed in recent years. The Centers for Disease Control and Prevention (CDC) report a nationwide 254% increase in cases since 2016.

The good news: Despite these increases and the serious complications congenital syphilis can cause, it's completely preventable. Here's what you need to know when it comes to syphilis and pregnancy.

What Is Syphilis?

Syphilis is a curable STI. “It is caused by a bacteria called treponema pallidum,” explains OB/GYN and reproductive health specialist Kelly Culwell, MD, aka Dr. Lady Doctor. It can be spread through direct contact with another person during vaginal, anal, or oral sex.

Syphilis Symptoms

There are four stages of syphilis, each of which can come with different symptoms, notes Dr. Culwell. “Primary syphilis usually presents as a single painless skin lesion, often on the genitals. These lesions often heal within a few weeks without treatment, so they may not be noticed.” Since this sore typically goes away on its own, primary stage syphilis can be difficult to catch without regular STI testing.

The secondary stage of syphilis, which typically happens while your primary sore is healing or several weeks later, usually starts with a rough, red rash on one or more areas of the body. But again, the rash often does not itch and can be very faint, so it may be unnoticeable. Other symptoms
at this stage may include fever, swollen lymph glands, sore throat, hair loss, headaches, muscle aches, and fatigue.

The next phase is the latent stage, which is when there are no visible signs or symptoms. Without treatment, syphilis can remain in your body for years without causing any issues.

Between 15% and 30% of people who have syphilis will go on to develop the final stage, which is known as tertiary syphilis. This can appear 10-30 years after the initial infection and can be fatal. In this stage, the infection can damage any number of organ systems, including the brain, heart, blood vessels and bones.

During any of these stages, syphilis can also invade the nervous system (neurosyphilis), visual system (ocular syphilis) and auditory system (otosyphilis), causing symptoms associated with those bodily systems.

Syphilis Diagnosis and Treatment

Syphilis is diagnosed using a blood test that detects antibodies related to the treponema bacteria that causes the infection. If this test is positive, a second blood test is used to confirm the diagnosis, since someone with syphilis may continue to have a positive result on the first test even after successful treatment. This second confirmation test is very important both because someone with a history of syphilis may continue to have a positive result on the first test even after successful treatment, and because certain other conditions may result in a false initial test including Lyme disease, lupus, or other autoimmune conditions—and sometimes even pregnancy itself.

Once the infection is confirmed, it's treated with antibiotics (primarily penicillin) to prevent it from progressing any further. Dosages and preparations vary based on the stage of syphilis that is present.

Syphilis and Pregnancy

Syphilis can be dangerous for both a pregnant person and their growing baby. “Syphilis in pregnancy is no different for the pregnant person than it would be for non-pregnant people,” notes Dr. Culwell. This means that a pregnant person is at risk for all of the above symptoms, depending on the stage of their disease.  

“If a pregnant woman is infected with syphilis, the harmful bacteria can cross through the placenta and infect the growing baby,” says Sherry Ross, MD, women’s sexual health expert and author of She-ology and The She-quel. This is how congenital syphilis develops, and the effects can be dire. “Potential complications include miscarriage, prematurity, stillbirth, and death to the baby once delivered,” Dr. Ross says.

How to Prevent Syphilis

Pregnant or not, syphilis can be prevented by ensuring that both or all sexual partners have been recently tested. If a partner does have syphilis, condoms can prevent physical contact with a sore that could spread the infection. If you and a partner decide you want to try to become pregnant and have previously been using condoms during sex, it’s smart to get tested before you stop using them.

Syphilis in a pregnant person and congenital syphilis in their baby can be prevented with frequent testing. “Getting a blood test for syphilis should be performed when a woman is trying to conceive and during the first trimester of pregnancy,” notes Dr. Ross. If someone is at risk for getting syphilis during pregnancy, or they began prenatal care in the second trimester or later, they are often tested again during the third trimester and at delivery.

“If detected prior to conception, or during the first trimester of pregnancy, syphilis can be successfully treated and the harmful complications can be prevented,” Dr. Ross says.

Indeed, even if syphilis is discovered during pregnancy, a pregnant person can receive the full treatment regimen. Since penicillin is considered safe during pregnancy, an additional dose is sometimes given to prevent congenital syphilis. This applies to people diagnosed at any stage of
pregnancy, though people diagnosed and treated during the second half of pregnancy are at an increased risk for premature labor or fetal distress.

A Word From Verywell

Despite the fact that congenital syphilis cases are on the rise in the United States, syphilis is preventable with frequent testing and safe sex practices, and it can be curable with timely treatment.

For people who are thinking about becoming pregnant and are concerned about syphilis, Dr. Culwell urges them to schedule a chat with a healthcare provider. “It is always a good idea to see a healthcare provider when you are considering trying to become pregnant," she says. "They can recommend tests you may need based on your personal situation and medical history.”

4 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2020.

  2. Centers for Disease Control and Prevention. Syphilis - CDC Detailed Fact Sheet.

  3. Mayo Clinic. "Syphilis."

  4. Centers for Disease Control and Prevention. Syphilis During Pregnancy.

By Alyssa Sybertz
Alyssa has been writing about health and wellness since 2013. Her work has appeared in print in publications like FIRST for Women, Woman's World, and Closer Weekly and online at places like,, and She is the author of The OMAD Diet and has served as editor-in-chief for two magazines about intermittent fasting.