Swabs in Pregnancy: What They Test For
A swab in pregnancy is a quick, simple test where a small sample is taken using a soft cotton bud, either from the vagina or sometimes by you yourself. Swabs are used to check for infections that could affect your comfort, your pregnancy, or your baby around the time of birth. Most are nothing to worry about, and many are easily treated if anything is found.
What Swabs Test For
Swabs in pregnancy may check for:
- Group B Streptococcus (GBS) — a common bacterium that lives harmlessly in the body for many people, but which can occasionally be passed to a baby during birth. If GBS is found, you may be offered antibiotics during labour.
- Bacterial vaginosis (BV) — an imbalance of the normal bacteria in the vagina, which can cause discharge and is treatable.
- Thrush — a common yeast infection causing itching and discharge, which is uncomfortable but harmless and easily treated.
- Sexually transmitted infections such as chlamydia and gonorrhoea, which can be screened for and treated to protect both you and your baby.
Some swabs are offered routinely; others are taken only if you have symptoms such as unusual discharge, itching, soreness, or a smell.
When Are Swabs Taken and What to Expect
You may be offered some screening at your booking appointment early in pregnancy. Symptom-based swabs can be taken at any point if you have concerns. In the UK, routine testing for GBS is not offered to everyone, but if it is checked, it's usually done in the later weeks of pregnancy. If you've had GBS in a previous pregnancy, tell your midwife.
The swab itself is quick and usually painless. It may feel slightly odd or cause brief mild pressure, but it should not hurt. Sometimes you'll be shown how to take a low vaginal swab yourself, which many people find more comfortable. Results are explained by your midwife or GP, along with any treatment if needed.
What Is Normal and When to Seek Help
It's completely normal to be offered swabs, and a positive result for something like thrush, BV, or GBS does not mean you've done anything wrong. Contact your midwife or GP if you have symptoms such as itching, soreness, a change in discharge, or pain when passing urine, as these can be checked easily. Seek urgent advice from your midwife, maternity unit, or NHS 111 if you have a high temperature, feel generally unwell, or have any bleeding alongside these symptoms.
Frequently Asked Questions
Are swabs in pregnancy painful?
No, a swab is generally quick and painless. You might feel a little pressure or find it slightly uncomfortable for a moment, but it should not be sore. Tell your midwife if you feel anxious and they can talk you through it.
Do I have to have a swab?
Swabs are offered, not forced. Routine screening is recommended to protect you and your baby, and symptom-based swabs help find the cause of any discomfort. You can always ask why a swab is being suggested and what it will check for.
Will an infection harm my baby?
Many infections found on swabs are easily treated and cause no harm once managed. Some, such as GBS, are simply monitored and treated around birth if needed. Your midwife will explain what any result means for you and your baby.
Always speak to your midwife or GP for advice tailored to your pregnancy.
This article is for informational purposes only and does not constitute medical advice.
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