FACTS ABOUT GROUP B STREP (GBS)
* Routine screening for GBS on all pregnant women became the standard in 2002.
* There are two types of GBS infection in the newborn – early onset (occurs before 7 days of life), and late onset (occurs after 7 days of life). The rate of each occurring is about 50/50.
* About 25% of women are estimated to be colonized with GBS at some point in their pregnancy according to the March of Dimes – the CDC estimates the figures to be 15-40%
* 99.5% of babies born to mothers who are GBS+ will not become sick from it..
~ Of those babies who DO get sick with EARLY onset of GBS infection…4.7% will die. Early onset GBS has a higher death rate than late onset GBS.
~ Of the babies who get sick with late-onset GBS, 2.8% will die. Of those infected with LATE onset of GBS…50% of those were not infected by their mothers, but by outside sources (according to the CDC)
Here are the risks of GBS if we take the highest risk estimates according to various estimations…
Let’s say that 40% of women have GBS (the highest rate I could find)…and those who have GBS have a 1 in 200 chance (according to the CDC) of having a baby infected with GBS.
If we DON’T screen a woman for GBS…the odds that her baby will be infected is .2%.
Of the babies that are infected (.2%), those infected with early onset (50% of them) brings the total percentage of babies in the general population who, if mom were not screened and no antibiotics were given, that would contract early onset GBS…we’re at .1% of babies who would contract early onset GBS at all.
Understanding that a baby sick with early onset GBS has a 4.7% chance of dying…that means that If we didn’t screen at all, didn’t give antibiotics, did nothing at all…the percentage of babies who would be born, contract early onset group B strep, and would die from this infection….we’re at the last figure of .0047% (or 1 in 21,276 babies in the general public without screening)
I’m going to repeat that figure for emphasis….
if we did not test you for GBS, and did not treat you for GBS, your baby has a 1 in 21,276 chance of getting sick and dying from GBS (.0047%).
Serious complications can result from GBS other than just death – those complications include pneumonia and meningitis which can have life-long effects on the baby.
What increases the risk?
There are certain conditions that we know increase the risk to a baby of a GBS+ mother. Those conditions are…
1. Previous baby colonized with GBS
2. Preterm birth (<37 weeks)
3. Rupture of membranes during labor 18 hours or more before delivery
4. A fever during labor of >100.4
5. Having a UTI caused by GBS
Limitations of the test:
The main limitation of the current GBS screening is this: a woman can test positive one week, then negative the next, then positive again. What we are testing for is the colonization of the bacteria – or for it to be in a high enough number to be considered an “infection”. Let’s compare it to yeast – you have yeast in your vagina, but you don’t have a yeast infection. It’s not until the yeast grow out of control and reaches a certain level, then you are considered to have a “yeast infection”. Just because you don’t have a yeast infection today doesn’t mean you won’t have one next week – and having a yeast infection today does not mean you will have one next week.
The same happens with GBS….as the number of bacteria in your system fluxuate, your GBS status can change. However, it takes 3 days to culture and see your GBS status. Our limitation with regards to screening becomes evident – testing you at 37 weeks does not necessarily tell us your GBS status when you give birth, it’s simply the best we can do.
What is done if I test GBS+?
The current CDC recommendations are that all pregnant women should be routinely screened for GBS between 35-37 weeks of pregnancy, all women who test GBS+ should be given antibiotics during the course of their labor (at least 2 rounds – 4 hours apart), and all women whose GBS status is unknown should be treated with antibiotics only if they develop risk factors that I have listed above.
What are the down sides to antibiotics in labor if I am GBS+?
Antibiotics are not without risks to you or your baby – a good unbiased review of some of the risks can be found at Medscape. I could copy/paste the entire article, but that would be plagiarism and seems silly when you can just go there and read the article.
Even if the antibiotics were without notable risks, there is question over the effectiveness of them during labor for GBS. A very recent study published in the Cochrane Review (2009) concluded, “Intrapartum antibiotic prophylaxis appeared to reduce EOGBSD, but this result may well be a result of bias as we found a high risk of bias for one or more key domains in the study methodology and execution. There is lack of evidence from well designed and conducted trials to recommend IAP to reduce neonatal EOGBSD.”
(EOGBSD= early onset group B strep disease IAP= intrapartum antibiotic prophylaxis)
Are there alternative options?
There are always options. You can…
~ Choose to screen at 35-37 weeks as is recommended by the CDC – or you can choose not to screen at all.
If you test positive, you may…
1. choose IV antibiotics while in labor if you test GBS+
2. choose to refuse antibiotics and accept the risks as they are
3. use Hibiclens (chlorohexadine) as a vaginal rinse while in labor if you are in the higher-risk group.
There have been multiple studies on using chlorohexadine (sold as “hibiclens” – an antibacterial rinse) as a preventative measure for GBS that have shown it to be very effective and without a lot of the risks of IV antibiotics. Here is a good page on Medscape about the possible benefits of chlorohexadine in labor to prevent GBS infection in the newborn.
I’ve tried to make this paper as unbiased and factual as I possibly could…but here are some of my random thoughts on GBS…
We know that GBS risk increases the longer your water is broken – why is it that you can test GBS+, and MOST doctors won’t hesitate to break your water in labor?
Why are there not more studies on the risks of antibiotics compared to the risks of GBS in the newborn? And the mother? Why are we not worried about the number of vaginal exams after her water is broken in a GBS+ mother (since each exam shoves GBS bacteria up towards the baby in the womb)?
And finally, there are no guarantees. You can have a baby that dies from GBS even though you had antibiotics…or that dies from an E-coli infection caused by the antibiotics in labor….or a mother that dies from an anaphylactic reaction to the antibiotics. Life is all about risk assessment and choice, and this is one only you can make.