Answers to the questions we're most frequently asked 

Group B Streptococcus (GBS) is a common bacterium normally carried in 20-40% of adults in the UK and 25% of pregnant women carry GBS in their vagina. GBS carriage seldom causes any symptoms and is not an STD although it can be passed from person to person through sexual or skin contact.

Group Strep B infection is a leading cause of early-onset neonatal infection, resulting in sepsis, pneumonia and meningitis. Early onset Group B Strep (EOGBS) currently affects 1 in 1750 babies and 1 in 400 if the mother is carrying group B strep. EOGBS can be life threatening, unfortunately there is no way to tell which baby will be affected.

Carrying Group Strep B is asymptomatic, meaning there are no symptoms associated with Group Strep B. The only way to find out whether you are carrying it is through a Group Strep B test.

Unfortunately routine screening for GBS is not currently available on the NHS although many other countries routinely screen for GBS and have seen a significant reduction in GBS infections such as: Australia, Argentina, Belgium, Bulgaria, Canada, Chile, Czech Republic, Dubai, France, Germany, Hong Kong, Hungary, Italy, Japan, Lithuania, New Zealand, Norway, Oman, Poland, Singapore, Spain, Slovenia, Switzerland, Taiwan and the USA.

A Group B Strep test is the only way to identify whether or not you are carrying GBS. If GBS is detected during pregnancy steps can be taken to minimise the risk of your newborn developing the GBS infection.

It is advised to test between 35-37 weeks as our test has a high predictive indicator of whether you will be carrying GBS in the next 5 weeks which is the time you are more likely to go into labour.

GBS carriage can come and go, however GBS status does not come and go daily. Studies show that the result from a GBS test is very unlikely to change over the next 5 weeks which is why it is advisable to test from 35- 37 weeks in pregnancy. This gives you the best chance of knowing what your GBS status is when you go into labour.

No. Testing before or after 35-37 weeks of pregnancy will show whether or not you are carrying GBS when the test was taken. GBS carriage can come and go, though the result from a Strepelle test is highly predictive for the next 4-5 weeks. If the test is taken before 5 weeks before birth, your GBS carriage status may have changed by the time of delivery. If the test is taken after 37 weeks it will still give you a good indication whether you are carrying GBS for the next 5 weeks, but the results may not come back in time so you could go into labour without knowing your GBS status. Testing between 35-37 weeks is the best way to predict if you will be carrying GBS when you are most likely to go into labour- the next 5 weeks.

Yes you can. Testing after 37 weeks will still give you a result that is highly predictive of your GBS status for the next 5 weeks, However there is a risk that you could deliver your baby before you receive your results.


Taking the test is simple, and involves collecting samples with 2 swabs one from the vagina and one from the rectum. Clear detailed instructions are provided in the kit. Post your samples on the day that you take them, in time to catch the post. We advise that you collect your samples at a suitable time for posting back to us on Monday to Thursday. This is to avoid sample strength deterioration in the postal system over the weekend.

Yes, if you are or have recently been taking antibiotics, this may affect the result of a test for Group B Strep carriage. Ideally there should be a gap of at least 7-10 days between finishing a course of antibiotics and taking the test.

Strepelle uses the most accurate test currently on the market designed specifically to detect Group B Strep carriage. It is a home to laboratory test, which means that you are getting access to the accuracy and reliability of a professional test from the convenience of your own home. Once you have purchased Strepelle your test will arrive in the post. The test is quick and easy to conduct and all you need to do is collect two swab samples. Everything is included in the kit and simple step-by-step instructions will guide you through the process. The Freepost envelope will allow you to post the samples back to our laboratory.

Your results will be sent to you by email.

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If your sample is received by our laboratory before 11.00 AM, you will receive the results the same day. If received later than 11.00 AM, your results will be sent to you the following day.

Whatever the test result, it’s good news – if negative for GBS carriage, that’s great- the chance of you becoming positive in the next 5 weeks is very small. If positive, it’s also a good thing as the level of risk is then known. This allows you to contact your healthcare professionals so that you can be offered intravenous antibiotics in labour. These are very effective at preventing GBS infection in the newborn during the vital first days of life. If your result is positive you should contact your midwife or healthcare provider as soon as possible.

Whilst we understand a positive result may be concerning to you, the good news is that you can help protect your baby. The first step is to provide your Strepelle results email to your Midwife or health care provider who will ensure you will be offered intravenous antibiotics when you are in labour.

If GBS is detected during pregnancy, you should be offered intravenous antibiotics at the onset of labour and usually at 4-hourly intervals until your baby is born. This will significantly reduce the risk of your baby developing early onset GBS infection by 85/90% cutting the risk from 1 in 400 to 1 in 4,000.

Whilst it is good to receive antibiotics to reduce the risk of your baby developing GBS infection the decision to have antibiotics in labour is your choice. If you decide not to have antibiotics inform your health professionals who will be able to monitor your baby to watch for any signs of infection, particularly in the first 12-24 hours after birth.

There is a very small risk of developing severe allergic reaction (anaphylaxis) after receiving antibiotics. some authorities quote: • 1 in 10,000 of the mother developing a severe allergic reaction (anaphylaxis) and. • 1 in 100,000 of the mother developing fatal anaphylaxis, resulting in her death. Studies from both the UK and USA show that in fact the above statistics are likely to be significantly over-estimated. As you will be in hospital when you are having the intravenous antibiotics, you will be closely  monitored and your health professionals will be able to provide treatment to reverse anaphylaxis were it to occur. There have been studies that suggest an effect on the baby’s microbiome, but these findings have not been consistent and are likely to be temporary in most cases. The long term effect, if any, of these changes is currently unclear but is likely to be very small compared with the harms from early onset GBS infection.

It is still valuable to test for GBS. Although a C-section reduces the risk of GBS infection it does not eliminate it completely as rarely GBS can cross intact amniotic membranes to cause infection in the baby. More importantly, if you carry GBS and your labour starts or waters break before you have your c-section, you should be offered the intravenous antibiotics as soon as possible,and have them repeated at regulat intervals (4 hourly for penicillin) until delivery.

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If you would like more information please email us through our email or visit the Group B Strep Support charity’s website GBSS