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STI Screening in Pregnancy: What to Know

Contributor: Sophia DeLevie-Orey, CNM, MSN
6 minute read
Pregnant woman discusses with practitioner in an exam room

Rates of sexually transmitted infections (STIs) have increased significantly nationwide in recent years. Because STIs can lead to pregnancy complications and have serious effects on your baby’s health, it’s now even more critical to get tested.

“It’s super important to detect these diseases because there is something you can do about it,” says Sophia DeLevie-Orey, CNM, MSN, a certified nurse midwife at Mass General Brigham. “STIs can cause premature birth, can be passed on to your baby, and can make you and your baby sick. But the good news is that these diseases can be mitigated by early detection and treatment, sometimes to the point that they’ll have absolutely no effect on the pregnancy. The sooner we identify an STI, the better we can manage it.”

Screening tests are simple and painless, she adds, and they can be integrated into your regular prenatal care. And all of these diseases have treatment options that are safe in pregnancy and can prevent harm.

Screening for STIs in pregnancy

The STIs of major concern in pregnancy are chlamydia, gonorrhea, syphilis, HIV, and hepatitis B. DeLevie-Orey sees patients at Massachusetts General Hospital, where providers screen all pregnant patients for those five infections in the first or second prenatal care visit. All people should have repeat screening for syphilis in the third trimester. Depending on risk factors such as age (under 25) or history of STIs, some should also have repeat screening for other STIs.

For gonorrhea and chlamydia, the test involves a painless swab of the vagina, which patients can do themselves if they prefer. The screening test for the other three infections is a blood test. Providers can collect a blood sample at the same time as other routine blood tests.

DeLevie-Orey recommends that all pregnant people actively seek care that involves these convenient and relatively pain-free tests. It can be the first step in avoiding harmful effects for the pregnant patient and baby.


Chlamydia is the most common STI, but it is also the least dangerous in pregnancy and very easy to treat, DeLevie-Orey says. “But if it goes untreated, there are absolutely risks that are concerning,” she adds.

Chlamydia can be transmitted from pregnant patient to baby during vaginal birth when the baby passes through a cervix infected with chlamydia. The most common chlamydia-related health problems for infants are conjunctivitis (pink eye) and pneumonia (a respiratory infection). More rarely, this STI can cause babies to be born prematurely and with low birthweight (less than 5 pounds, 8 ounces). But prompt treatment with oral antibiotics can cure the infection in the pregnant patient and prevent transmission to baby.


Like chlamydia, gonorrhea can be transmitted through vaginal birth. If it’s not detected and treated early, gonorrhea can lead to more severe conjunctivitis. This can cause serious vision problems if untreated.

“In rare cases, a newborn can actually develop widespread infections, which can lead to sepsis. So gonorrhea can be quite dangerous,” DeLevie-Orey says. This STI also can cause an infection of the amniotic fluid, premature birth, low birthweight, and (rarely) miscarriage. However, antibiotic treatment can be curative and protect both pregnant person and baby.


“Syphilis is especially concerning because it can spread directly from the pregnant person to the baby. The risk is higher with early-stage syphilis in the pregnant patient, and that risk increases later in pregnancy,” DeLevie-Orey says. “So if you were to become infected, for example, during the third trimester, the risk to the baby is greater.”

A baby with syphilis can experience complications such as:

  • Anemia
  • Blindness or deafness
  • Bone damage
  • Enlarged liver and spleen, or jaundice (yellowing of the skin or eyes)
  • Meningitis
  • Premature birth
  • Skin rashes
  • Stillbirth

Syphilis during pregnancy also can be treated with a simple antibiotic regimen.

HIV and hepatitis B

Both HIV and hepatitis B are linked to possible pregnancy complications if the diseases are not properly managed. But the biggest concern is that they can spread directly to your infant during pregnancy.

Fortunately, early treatment with proper medication regimens significantly reduces a pregnant patient’s viral load (the amount of virus circulating in the bloodstream). A lower viral load reduces the likelihood of transmission and harm to the baby, DeLevie-Orey explains.

Antiretroviral medications are recommended for all pregnant patients with HIV. For people with hepatitis B, antiviral treatment depends on viral load, which is monitored throughout pregnancy.

For both diseases, the care team is prepared to administer medication to the baby after birth to further reduce risk of transmission.

We try to destigmatize this. There’s no judgment. We’re here to keep you and your baby as healthy as possible.

Sophia DeLevie-Orey, CNM, MSN
Certified Nurse Midwife
Mass General Brigham

Judgment-free screening for sexually transmitted infections during prenatal care

DeLevie-Orey encourages pregnant people not to delay screening for STIs in pregnancy. The infections often cause no symptoms, so screening may be the only way to identify the issue.

If a test comes back positive, she facilitates prompt treatment for the patient. If the patient has chlamydia , DeLevie-Orey also may offer automatic treatment to the patient’s sexual partners through a process known as expedited partner treatment. The team helps coordinate convenient partner screening tests.

She emphasizes that Mass General Brigham is a safe space to have STI discussions and tests. “These diseases get passed along, just like people pass along diseases by sneezing on each other and coughing on each other,” she says. “We try to destigmatize this. There’s no judgment. We’re here to keep you and your baby as healthy as possible.”

Headshot of Sophia DeLevie-Orey, CNM, MSN


Certified Nurse Midwife