Pregnancy and sexually transmitted infection

Pregnancy is a time of joy and anticipation – but also a phase in which the health of the expectant mother and the unborn child must be especially protected. Sexually transmitted infections (STIs) play a central role in this: they can go unnoticed and have serious consequences for both mother and child. In this article, you will learn which STIs can occur during pregnancy, what risks they pose, and how you can effectively protect yourself.

The WHO estimates that in 2022, approximately 1.1 million pregnant women worldwide were infected with the sexually transmitted infection syphilis, leading to more than 390,000 stillbirths (WHO, 2024).

Table of Contents

• Can STIs be transmitted to the baby during pregnancy?
• Which STIs can occur during pregnancy?
• How can STIs affect pregnancy and the unborn child?
• What are the symptoms of an STI during pregnancy?
• Which STIs are tested for during pregnancy?
• How are STIs diagnosed during pregnancy?
• What treatment options are available for STIs during pregnancy?
• How can you protect yourself from STIs during pregnancy?
• Frequently asked questions
• Summary

Can STIs be transmitted to the baby during pregnancy?

Yes, certain STIs can be transmitted to the baby during pregnancy, childbirth, or breastfeeding and can lead to severe complications such as developmental disorders, malformations, or even stillbirths. Below is a table of some STIs and their transmission routes:

Source: Irshad, U. et al., 2023; NIH, 2019; CDC, 2024; CDC, 2020; LaCour, D. E., & Trimble, C., 2012.

Which STIs can occur during pregnancy?

The sexually transmitted infections (STIs) that can occur during pregnancy do not differ from those affecting non-pregnant women. These include chlamydia, gonorrhea, syphilis, HIV, genital herpes, trichomoniasis, hepatitis B, hepatitis C, and human papillomavirus (HPV). What makes them particularly concerning is that these infections can have especially serious consequences for the health of the mother and the unborn child during pregnancy (CDC, 2024).

How can STIs affect pregnancy and the unborn child?

Infections with STIs during pregnancy can have significant effects on the health of both mother and child. Depending on the timing and type of infection, they can lead to a range of complications for the unborn child:

• Low birth weight (less than 5 pounds)
• Eye infection
• Pneumonia
• Infection in the baby’s blood
• Brain damage
• Poor coordination of body movements
• Blindness
• Deafness
• Acute hepatitis
• Meningitis
• Chronic liver disease, which can lead to liver scarring (cirrhosis)
• Stillbirth

Source: NIH, 2019

What are the symptoms of an STI during pregnancy?

During pregnancy, STIs can cause symptoms similar to those in non-pregnant women, such as:

• Unusual-smelling vaginal discharge
• Burning during urination
• Lower abdominal pain
• Itching or redness
• Irregular bleeding

However, many infections remain asymptomatic, making regular screenings essential to protect the health of both mother and child (Mayo Clinic, 2023).

Which STIs are tested for during pregnancy?

It is recommended that pregnant women are routinely screened for certain STIs to reduce risks for both mother and child. The list of recommended tests includes:

• Chlamydia and gonorrhea: Routine testing, especially for young women and those at higher risk; repeat testing in the third trimester if necessary.

• HIV: Testing at the beginning of pregnancy, and repeat testing in the third trimester if needed.

• Syphilis: Testing at the beginning of pregnancy and repeat testing if indicated.

• Hepatitis B: Testing at the beginning of pregnancy.

• HPV: Pregnant women should be screened at the same intervals as non-pregnant women.

Quelle: Bundesministerium für Gesundheit, 2024; Deutsche Apotheker Zeitung, 2024; CDC, 2024.

How are STIs diagnosed during pregnancy?

STIs during pregnancy are diagnosed using specific tests. These include blood tests (e.g., for HIV, syphilis, and hepatitis B), cervical or vaginal swabs (e.g., for chlamydia and gonorrhea), and urine tests (e.g., for trichomoniasis). These tests are part of prenatal care and enable early treatment (MedlinePlus, 2024).

Discreet home tests such as the Basic 4 STI Test, the Chlamydia and Gonorrhea Test, or the STI Test Plus from Homed-IQ offer a convenient way to detect infections early. These tests can be easily performed at home and support timely treatment.

What treatment options are available for STIs during pregnancy?

Treatment during pregnancy depends on the STI. Some can be safely treated with antibiotics, while others may require antiviral medication or other measures to reduce transmission to the baby. Speak with your healthcare provider about the safest treatment option during pregnancy (CDC, 2025). 

Doxycycline is a commonly used broad-spectrum antibiotic for various bacterial infections, including several sexually transmitted infections. However, its use is generally contraindicated during pregnancy and breastfeeding (ECDC, 2026). 

How can you protect yourself from STIs during pregnancy?

During pregnancy, protecting your health and that of your unborn child is a top priority. With simple yet effective measures, you can significantly reduce the risk of sexually transmitted infections:

• Use condoms: A reliable form of protection that significantly lowers the risk of infection.
• Attend regular prenatal checkups: Early detection and treatment of infections protect both mother and child.
• Get tested for STIs before or at the beginning of pregnancy: For a safe start to this special time.
• Commitment and trust in your relationship: Reduces the risk of new infections and strengthens your bond.
• Vaccinations before pregnancy: Vaccinations (for example against HPV) provide preventive protection against specific pathogens.
• Open communication: Share your concerns and questions with your partner – together you can ensure your sexual health.

These measures support you in having a healthy pregnancy and giving your child the best possible start in life.

Frequently asked questions

How do STIs affect fertility, and what are the risks of untreated infections?

Untreated STIs can affect fertility in the long term by causing inflammation and permanent damage to the reproductive organs. The most common STIs are chlamydia and gonorrhea, which can lead to pelvic inflammatory disease (PID) and scarring of the fallopian tubes, increasing the risk of infertility and ectopic pregnancies. Other sexually transmitted diseases like Mycoplasma genitalium or HIV can also cause reproductive complications and infertility (CDC, 2024; Fertility Society of Australia, 2021).

Can I breastfeed my baby if I have an STI?

Whether breastfeeding is possible with an STI depends on the type of infection. Always consult your doctor to find the best solution for your individual situation.

• STIs where breastfeeding is possible:
  With infections like chlamydia, gonorrhea, and HPV, breastfeeding is considered safe because they are not transmitted through breast milk. Breastfeeding is also safe with hepatitis B if the baby is vaccinated immediately after birth.
• STIs where breastfeeding is not recommended:
  In the case of HIV, active syphilis, or herpes lesions on the breast, breastfeeding is not advised due to the potential risk of transmission. Breastfeeding is only possible if the baby does not come into contact with a lesion.

Sources: NIH, 2019; HIV.gov, 2023; CDC, 2024; CDC, 2023.

Summary

Sexually transmitted infections during pregnancy can endanger both the mother and the unborn child and may lead to miscarriage, developmental disorders, and birth complications. Routine testing and early treatment are essential to minimize these risks. Protective measures such as condom use, regular checkups, and open communication allow expectant parents to actively contribute to their sexual health.