GBS - the Constant Conundrum

This week I have been in contact with the hospital system and had extensive discussions about GBS. Group B Strep is a bacteria that can live in your vagina. It is transient - it comes and goes- 15 to 30% of us have it at one time. This is only a potential problem if you happen to be pregnant.

Strep B also known as GBS
There is a lot of scare mongering about GBS and it's implications, so what is the real deal?

Well first of all should you get the test? In the UK where screening isn't part of the antenatal testing circus this is what they have to say:

Estimated effects of bacteriological screening. Approximately 25% of mothers in the UK are likely to be GBS carriers. This estimate is based on a single study performed in the 1980s and it is possible that this study does not reflect the current picture. With the addition of women who present with other clinical risk factors for GBS disease, such as preterm labour, around 30% of all pregnant women would receive intrapartum antibiotic prophylaxis if a bacteriological screening programme were to be introduced in the UK (this is approximately 204,000 women per annum).

In Australia GBS testing is routine at about 36 weeks. If this is positive, you are assumed to be positive at the time of birth. The standard hospital treatment for this is antibiotics when in labour. Just because you have gbs in your vagina doesn't mean you have an infection it means you have the risk of an infection. Just because you had gbs at 36 weeks doesn't mean you have it at term as it grows in cycles.

Antibotics are promoted as a preventative measure, which isn't true. Antibiotics are not there to prevent infection but to cure it. As shown in the studies here, most people with gbs will give birth and their baby will either not be colonised by gbs or the baby will be colonised but suffer no ill effects. Antibiotics are inconsequential to those people, but there is a minute part of the population who's baby will be colonised and become extremely ill from gbs. The Medical fraternity feel that antibiotics will cure any disease and have insignificant effects to those who have taken it unnecessarily.

The cochrane data base also says that although antibiotics reduces the rate of infection it hasn't been shown to alter the the rate of death.
This is how most of the medical interventions occur, better to do something rather than just wait.

Antibiotics - When in doubt, give them out!

Taking unncessary antibiotics also carries a risk.

• 1 in 10 chance of an allergic reaction.


• 1 in 10,000 chance of a severe allergic reaction like anaphylaxis.


• 1 in 100,000 chance of death from taking antibiotics.

There is also a chance that the antibiotics affect the baby by restricting growth of natural flora which affects immune development.

Remember , this may all be worth it if you have an infection but having a positive swab doesn't mean you have the infection but the risk of infection as listed below.

So what is the risk of GBS incidence? The biggest results are from the UK. It is difficult to be totally country specific. The only thing they really know is the incidence in the UK is much smaller than the incidence in America.

The current incidence of early-onset GBS disease in the UK and the Republic of Ireland is 0.50/1,000 births,which is equivalent to approximately 340 babies per annum. If we estimate that intrapartum antibiotic prophylaxis is 80% effective at preventing early-onset GBS disease, then this will decrease the number of affected babies to 68. Therefore each year in the UK 204,000 women will be treated to prevent 272 babies developing early-onset GBS disease. For every 1,000 women treated with antibiotic prophylaxis, 1.4 cases of disease may be pevented. However,the numbers of women treated to prevent one case may be higher, as this estimate assumes that antenatal swabs identify all GBS carriers, which is not the case. Also, when applied in practice, 65 to 70% may be a more reasonable approximation of the effectiveness of intrapartum antibiotic prophylaxis. Both of these factors will increase the numbers of women who are treated to prevent one neonatal infection. It is also true that the rate varies within the UK (0.21/1000 births in Scotland, 0.73/1000 births in Northern Ireland). Where local figures are known, the number needed to treat (NNT) should be adjusted appropriately. The mortality from early-onset GBS disease in the UK is 6% in term infants and 18% in preterm infants.

Intrapartum antibiotic prophylaxis will not prevent all deaths. Even when treated appropriately some infants will still die of early-onset disease, particularly when the disease is well established prior to birth. If one makes the assumption that the effect of antibiotic prophylaxis on neonatal death from GBS is equivalent to its effect on GBS disease, then to prevent one neonatal death from GBS would require at least 7000 colonised women to be given intrapartum antibiotic prophylaxis, which would require at least 24,000 women to be screened.

Estimated effects of risk based Screening

Information about the UK prevalence of the antenatal risk factors for early-onset GBS disease and data from the cases of early-onset disease in the UK surveillance study can be used to estimate the risk of the disease developing in the presence of each antenatal risk factor with and without antibiotic prophylaxis. The combined risk factor approach recommended by CDC may also be analysed in the same day.

Approximately 15% of all UK pregnancies have one or more of the following risk factors: intrapartum fever, prolonged rupture of membranes (PROM) greater than 18 hours, prematurity less than 37 weeks, previous infant with GBS. Approximately 60% of UK early-onset GBS cases have such risk factors. Thus, two cases of disease and 0.21 deaths from GBS disease occur for every 1,000 pregnancies with one or more of these factors. Approximately 625 women with one or more of these risk factors need to be treated to prevent one case of disease and 5,882 women need to be treated to prevent one death. This can be compared with prophylactic corticosteroids given prior to preterm birth when the number of women needed to treat to prevent one neonatal death is 23.

It seems that getting tested and treated isn't as straight forward as it seems.

This article by Sara Wickham is another look at the figures.


What happens at home?

Unless requested, my clients do not have the test for GBS. We use a watch and wait policy which is advocated by RCOG and any clinical signs are immediately referred for the appropriate collaboration.

If a client has SRM there is no VE as this can aid ascending infection, extra vit C, B6 and garlic taken and there are lots of other natural remedies that can work including acidophilus and grape seed extract.

If you have had a positive swab I would recommend the natural course of action and retesting weekly to see if the GBS has gone and keep up the treatment until birth.

You can always choose the medical model of treatment at any time you feel uncomfortable and have weighed up all the pros and cons.

There has also some evidence that garlic pessaries can be useful.