Group B Strep


Lets talk Group B Strep (GBS)

This is one of those areas of maternity care which gets a lot of media attention. And often because the effects of GBS can be devastating for those parents affected by babies who become severely unwell with GBS. But what are the risks and should I be screened?

What is Group B strep?

Group B strep is a naturally occurring bacteria, that between 20-40% of women carry (around 150-200000 women each year having babies), however rates vary between ethnicities and countries. There is often no harm to women who have group B strep, and it can be present one day and gone the next. Very occasionally if a woman has Group B strep in her urine it can cause urinary tract infection (UTI) symptoms which require treatment with oral antibiotics in pregnancy. UTI’s can trigger pre term labour and birth. The first urine sample you provide to your midwives is sent off to the labs to be tested for a variety of bacteria’s which include Group B strep. The biggest problem with GBS is that it can affect some babies quite severely, causing sepsis, long term health problems and even death in rare circumstances.

GBS affects around 1 in 1750 babies in the UK. On average this is around 43 babies developing early onset GBS every month (516 a year). It is fatal in around 1:35000 babies (2 per month in the UK). The UK has chosen not to screen all women for several reasons, partly because of the low prevalence, partly because there would be a lot of antibiotics given to women and babies unnecessarily (which can cause other problems with the gut microbiome and increase allergies), but also because the testing is not accurate at this moment in time (because the bacteria can come and go, so swabbing at 35-37 weeks could mean you would have a different result at the time of the baby being born and that either you didn’t receive antibiotics OR you received them unnecessarily. Lin et al 2011 found 10% of women with negative screening were positive at the time of birth and 50% of women who screened positive were negative at the time of birth (Pg 30 Sara Wickham).  There are studies looking at same day testing ongoing to improve the accuracy.

Because the UK maternity system does not routinely test or screen women for GBS Intravenous (medications into your veins) antibiotics are offered to women who have other risk factors; this includes waters ‘gone’ for longer than 18-24 hours, birth before 37 weeks and any mum who has a fever of >38degrees in labour as the research studies which have been done show these factors all increase the risks significantly of a baby being affected with group B strep. If you have had a previous baby with group B strep you are more likely to have GBS again in any future pregnancies, although the research which exists in this area is very small, further research is needed to confirm this ‘risk factor’. With any of these risk factors being present, routine baby observations will be recommended when your baby is born to check for any symptoms of infection and if there are symptoms you will be advised to remain in the unit and for your baby to receive IV antibiotics. With babies who show any signs of infection (regardless of risk factors or test results) it is important to begin antibiotics sooner rather than later because they have very little immunity and early antibiotic treatment does save babies lives.

Will having IV antibiotics in labour mean my baby won’t be affected by early onset GBS?

Not necessarily (See pages 79-83 in Sara Wickham’s book for much firther details). To Briefly summarise, the Cochrane collaboration included three trials in their review between 1986-2002 which included 500 women.  Ohlsson and Shah (2014) concluded that antibiotics in labour reduced the incidence slightly compared to no treatment BUT that the antibiotics made no difference to the amount of deaths caused by early onset GBS or other infections. Some other pieces of research (retrospective – looking back at cases) mention by screening everyone and giving more women antibiotics the rates of early onset GBS infection in babies dropped. This is mentioned in much more detail in Sara Wickham’s book for you to make your own decisions.

What is also difficult is different antibiotics are used by different units. Benzlypenicillin is given four hourly in most units if you do not have a penicillin allergy; those who have a mild allergy should have a cephalosporin antibiotics (because of effectiveness in treatment, but some people who react to penicillin react to cephalosporins) and those with severe allergy should have vancomycin. No clinical randomised trials have been undertaken to assess how effective these antibiotics are in preventing GBS.

Your baby may still develop signs and symptoms of GBS and in which case IV antibiotics and observation for your baby may be recommended. Having IV antibiotics may also limit your birth place options as IV antibiotics will be given in delivery suite environments, meaning a home birth may not be as much of an option if you choose to have IV antibiotics. Some midwife led units also don’t recommend women with GBS choosing to birth in their centres because of the IV access, IV medication and risk of anaphylaxis (allergic reaction). There is no reason why if you only have GBS you shouldn’t be able to use the water pools for labour, birth and you don’t need a CTG either to monitor your baby as the risks to your baby are after birth, not during the birth.

Is there anything else which might reduce my chances of my baby developing early onset GBS?

There are some on going studies looking into vaginal douching during labour or before vaginal examinations (VE’s) and GBS prevalence in the UK at the moment. We are awaiting the outcomes. Minimising VE’s during labour has been shown to reduce the infection rate to women overall, these are often recommended every 4 hours in labour but it’s something to discuss with your midwives especially if your waters have already ‘gone’. Breastmilk is also being studied at the moment as there have been sugars found in breastmilk which may protect newborns against group B strep bacteria in early research trials.

So how do I know whether to get a private swab or not?

That is up to you what you would like to do. I would highly recommend that you read Sara Wickham’s GBS book for further information, you have a look on the GBS support website and then use your BRAINS to decide what is right for you. There is no right answer with paying privately for the screening test or not, to have antibiotics in labour or not. It is your choice, your pregnancy, your birth and your baby.

I would also highly recommend following Sara Wickham on insta or facebook as her publications, research and messages to women are amazing – she is a brilliant Midwife.

There is also two amazing birth stories from first time mum’s who were both found to be GBS positive on routine swabs taken during pregnancy (for suspected infections/thrush) and both who decided that having antibiotics IV in labour was the right choice for them. Take a look at them on my website/instagrams.

RCOG guidance:

GBS support:

Sara Wickham:, her books are available to buy and I highly recommend all of them.

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