Syphilis Screening During Pregnancy: Why It Matters
The short answer
Syphilis screening during pregnancy is critically important because congenital syphilis (transmitted from parent to baby) has increased dramatically in the US, rising over 900% from 2012 to 2022. Untreated syphilis during pregnancy can cause miscarriage, stillbirth, preterm birth, and serious complications in the newborn. The good news is that syphilis is completely treatable with penicillin, and treatment during pregnancy prevents transmission to the baby in almost all cases. All pregnant individuals should be screened, with repeat screening recommended in high-prevalence areas.
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By Age
What to expect by age
First trimester
All pregnant individuals should be screened for syphilis at the first prenatal visit, ideally in the first trimester. This is a standard part of prenatal care in the United States. The test is a simple blood draw. If the test is positive, treatment with penicillin should begin immediately. Early treatment (before the third trimester) is most effective at preventing transmission to the baby. If you are at higher risk (live in a high-prevalence area, have a new sexual partner, or have other STI risk factors), your provider may recommend additional screening later in pregnancy.
Third trimester
Many states now require repeat syphilis screening in the third trimester (around 28-32 weeks) and again at delivery, particularly in regions with high syphilis rates. New infections acquired during pregnancy are just as dangerous to the baby as pre-existing infections. If you are diagnosed with syphilis during pregnancy, your baby will need to be evaluated at birth and may require treatment. Treatment during pregnancy with penicillin is safe and highly effective. Partners should also be tested and treated to prevent reinfection.
At delivery
Some states require syphilis testing at delivery to catch cases that may have been missed or acquired late in pregnancy. If a pregnant person has untreated syphilis at delivery, the baby is at high risk for congenital syphilis, which can affect the bones, liver, skin, brain, and other organs. Newborns born to mothers with syphilis will receive blood tests and physical examination, and may require antibiotic treatment regardless of whether they show symptoms, because some signs of congenital syphilis do not appear until weeks or months later.
What Should You Do?
When to take action
- Being screened for syphilis as part of routine prenatal blood work
- Being tested again in the third trimester in high-prevalence areas
- Your screening test is negative
- You have questions about your syphilis screening results
- You have a new sexual partner during pregnancy or think you may have been exposed to an STI
- You were not screened for syphilis during prenatal care
- You or your partner have been diagnosed with syphilis and you have questions about treatment
- You have a positive syphilis test during pregnancy and have not yet received treatment
- You develop signs of syphilis during pregnancy: painless genital sore, body rash, or flu-like symptoms
- Your newborn has signs of congenital syphilis: rash, runny nose (snuffles), enlarged liver or spleen, or poor feeding
Sources
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Trust your instincts. If something feels wrong, reach out to your pediatrician.
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Related Maternal Concerns
Signs That Labor Is Starting
True labor is characterized by regular contractions that increase in frequency, duration, and intensity over time, and do not stop with rest, hydration, or position changes. Other signs that labor may be approaching include loss of the mucus plug (bloody show), water breaking (rupture of membranes), persistent lower back pain, and a feeling of increased pelvic pressure. First-time parents are generally advised to head to the hospital when contractions are about 5 minutes apart, lasting 1 minute each, for at least 1 hour (the 5-1-1 rule).
Preeclampsia Warning Signs in the Third Trimester
Preeclampsia is a serious pregnancy complication characterized by high blood pressure and signs of organ damage, typically occurring after 20 weeks of pregnancy. It affects 5-8% of pregnancies and can progress rapidly. Warning signs include persistent severe headache, vision changes (blurring, spots, light sensitivity), sudden severe swelling (especially face and hands), upper abdominal pain (especially right side), nausea or vomiting in the second half of pregnancy, and sudden weight gain from fluid retention. These symptoms require immediate medical evaluation.
Dealing with Abnormal Prenatal Screening Results
An abnormal prenatal screening result can be terrifying, but it is important to understand that screening tests are designed to cast a wide net and have significant false-positive rates. Most people with abnormal screening results go on to have healthy babies after further testing confirms the baby is fine. An abnormal screening is a reason for more information, not a diagnosis.
Pregnancy Over 35 (Advanced Maternal Age)
While pregnancy after 35 carries some increased risks (including chromosomal abnormalities, gestational diabetes, and hypertension), the vast majority of people over 35 have healthy pregnancies and healthy babies. The term "geriatric pregnancy" is outdated and does not reflect reality. With appropriate prenatal care and monitoring, outcomes are excellent.
Amniocentesis Questions and Fears
Amniocentesis is a diagnostic test performed between 15-20 weeks that analyzes amniotic fluid to detect chromosomal conditions and genetic disorders with over 99% accuracy. The risk of pregnancy loss from the procedure is approximately 1 in 500-1,000 when performed by an experienced provider. Understanding the actual risks can help you make an informed decision.
20-Week Anatomy Scan Unexpected Findings
The 20-week anatomy scan checks your baby's major organs, structures, and growth. Most scans are completely normal. When unexpected findings are identified, they range from minor variants that resolve on their own to conditions that need further evaluation. Many findings require nothing more than a follow-up ultrasound to confirm the baby is developing well.