🤍 STI and Pregnancy — What You Need to Know Before Planning

Planning a pregnancy involves a lot of conversations — about timing, about health, about readiness. STI screening is rarely the first thing that comes to mind in those conversations. But it belongs there — and understanding why can make a meaningful difference to both the pregnancy and the health of the baby.

Here’s what the evidence shows, and what it means for anyone planning to conceive.

Why STI screening matters before pregnancy

STIs that are undetected and untreated during pregnancy can have serious consequences — for the pregnancy itself, for the birthing parent, and for the baby. Many of these consequences are entirely preventable with early detection and treatment.

The key word is early. Most of the complications associated with STIs in pregnancy are significantly more manageable — or entirely avoidable — when infections are identified and treated before conception or in the early stages of pregnancy.

This is one of the strongest arguments for proactive testing rather than reactive testing. Knowing your status before pregnancy — rather than discovering an infection after conception — gives the most options and the most time to act.

The specific infections — what to know

Chlamydia

Chlamydia is the most commonly reported STI globally and is frequently asymptomatic. During pregnancy, untreated chlamydia is associated with preterm labour, premature rupture of membranes, and low birth weight. It can also be transmitted to the baby during delivery, causing neonatal conjunctivitis and, in some cases, pneumonia.

The good news — chlamydia is curable with antibiotics. Treatment during pregnancy is safe and effective. The key is knowing it’s there.

Gonorrhea

Gonorrhea shares many characteristics with chlamydia — frequently asymptomatic, transmissible to the baby during delivery, and associated with pregnancy complications including preterm labour and premature rupture of membranes. Neonatal gonorrhea can cause serious eye infections that, if untreated, can lead to blindness.

Like chlamydia, gonorrhea is curable with antibiotics — though treatment has become more specific due to antibiotic resistance. Testing and treatment before or early in pregnancy are straightforward and effective.

Syphilis

Syphilis is the STI with perhaps the most serious consequences in pregnancy — and one of the most important reasons for preconception testing.

Congenital syphilis — when syphilis is transmitted from parent to baby during pregnancy or delivery — can cause miscarriage, stillbirth, premature birth, and severe neonatal illness. The consequences can be devastating.

The critical point is that congenital syphilis is almost entirely preventable. Screening and treatment before or early in pregnancy effectively eliminates the risk. Many countries have seen a resurgence of syphilis rates in recent years, making preconception testing particularly important.

HIV

HIV transmission from parent to baby — known as vertical transmission — can occur during pregnancy, labour, delivery, or breastfeeding. Without intervention, vertical transmission rates range from 15–45%. With effective antiretroviral treatment, that rate can be reduced to below 1%.

People living with HIV who are on effective treatment and have an undetectable viral load have very low to zero risk of transmitting HIV to their baby. This makes knowing your HIV status before pregnancy — and accessing treatment if needed — one of the most important preconception steps available.

Testing for HIV before pregnancy allows for the earliest possible engagement with treatment, and the most time to achieve viral suppression before conception and delivery.

Herpes (HSV)

Neonatal herpes — when herpes is transmitted to a baby during delivery — is rare but serious. The greatest risk occurs when a primary herpes infection happens in late pregnancy, because the birthing parent hasn’t yet developed antibodies that would provide some protection to the baby.

For people with established herpes who are pregnant, antiviral suppressive therapy in the final weeks of pregnancy reduces the risk of an outbreak during delivery — and with it, the risk of transmission. A planned caesarean delivery may be recommended if active lesions are present at the time of labour.

Knowing your herpes status before pregnancy allows for appropriate planning and management.

Hepatitis B

Hepatitis B can be transmitted to the baby during delivery. Babies born to people with hepatitis B are at high risk of developing chronic hepatitis B — with serious long-term consequences for liver health.

The intervention is effective — babies born to hepatitis B positive parents can receive hepatitis B vaccine and immunoglobulin at birth, significantly reducing the risk of transmission. But this intervention requires knowing the parent’s hepatitis B status in advance.

Hepatitis C

Hepatitis C can be transmitted vertically during pregnancy — at a rate of approximately 5–6%. There is currently no intervention that reduces this risk during pregnancy, but identifying hepatitis C status before pregnancy allows for consideration of treatment before conception, since effective hepatitis C treatment (which can cure the infection) is not typically given during pregnancy.

Preconception testing — what to ask for

For anyone planning a pregnancy, a preconception sexual health screen should include HIV, chlamydia, gonorrhea, syphilis, hepatitis B, and hepatitis C. This covers the infections most likely to affect pregnancy outcomes and for which early detection makes a meaningful difference.

Standard prenatal screening — typically offered at the first antenatal appointment — includes tests for some of these infections. But waiting until the first prenatal appointment means testing after conception has already occurred. Preconception testing — before trying to conceive — gives more time to treat any infection found and reduces the window during which an untreated infection might affect the pregnancy.

For LGBTQ+ individuals planning pregnancy

For same-sex couples, trans individuals, and non-binary people planning pregnancy — the same preconception STI screening applies, with anatomy-based considerations.

For couples using donor sperm or eggs, the screening of donors is part of the process through regulated fertility services — but this doesn’t replace screening of the person who will be pregnant.

For trans men who are pregnant or planning pregnancy while retaining a uterus and ovaries — the same STI screening recommendations apply. The intersection of gender-affirming care and pregnancy care benefits from providers who understand both.

Where CLEAR fits in

CLEAR’s at-home Ship Kit covers HIV, chlamydia, gonorrhea, syphilis, and hepatitis B and C — the core infections relevant to preconception screening — using PCR-based analysis in a certified medical laboratory. Results are delivered privately to your CLEAR account within 48 hours.

For anyone in the planning stage of pregnancy who wants a comprehensive picture of their sexual health status — privately, without a clinic visit — CLEAR provides a practical starting point. Any positive results should be followed up with a healthcare provider for treatment before proceeding with conception. 🤍

🔗 Learn more via the link in Bio.

Bottom line

STI screening before pregnancy is one of the most practical and highest-impact preconception health steps available. The infections most likely to affect pregnancy outcomes are largely detectable, treatable, and manageable — when identified early. The consequences of leaving them undetected are significantly more serious.

Test before you plan. Know before you conceive. The information you get is the foundation for the healthiest possible start. 🤍

The information in this article is intended for general educational purposes only and does not constitute medical advice. Please consult a qualified healthcare professional for personal medical guidance.