My midwife has given me quite a bit of information on this. I'm still not sure what I'm going to do, as I want to talk to her a bit about it first.
Either way, I thought it might help if I posted some quotes from the information she gave me:
Group Beta Strep Colonization in Women, and GBS disease in the Newborn
6% to 25% of women are colonized with GBS.
GBS disease of the newborn is a very serious infection. GBS disease usually develops in the first few hours after bith, although symptoms sometimes take a week to appear. GBS disease often results in sepsis (an overwhelming infection), pneumonia (a lung infection), and meningitis (a brain infection).
Babies who develop signs of GBS disease can be treated with antibiotics (usually Penicillin), but treatment does not always prevent damage or death from the disease.
Six percent of babies with GBS diease will die and 20% of those who survive will have some kind of permanent disability such as hearing and vision loss or brain damage.
GBS disease occurs in 2 out of every 1000 newborn babies.
Detecting Group Beta Strep Colonization in Pregnant Women
Is is possible to do a simple vaginal/rectal swab at 35-37 weeks of pregnancy to test for the presence of GBS in the mother. Unfortunately, because of the nature of the GBS bacteria, cultures are not always accurate in assessing colonization.
It is possible for a colonized woman to have a positive culture one day and a negative culture the next. Some of this is due to difficulties with the culture itself, and some of it seems to relate to variations in the number of bacteria present at any specific time.
Cultures done at 35-37 weeks will detect 85% of colonized mothers. Unfortunately, that means that 15% of women tested will believe they are not at risk, when they actually are colonized with GBS, but the test did not detect it. Therefore, it is possible for a baby to contract GBS disease without the mother testing positive for GBS.
Remember also that testing positive for GBS colonization does not mean that your baby will get GBS disease. Only 2% of babies of colonized mothers will develop GBS disease.
Preventing GBS disease
Because treatment of newborns with GBS disease after they are born is often not enough to prevent major complications, pediatricians and obstetricians have collaborated to study ways to prevent as many cases of GBS disease as possible.
Possible treatment strategies that have been explored include simply treating all newborns or all newborns of colonized mothers with one dose of antibiotics (a shot of penicillin) shortly after birth. Because the disease usually develops in the first 12-24 hours of life, it was hoped that the disease could be prevented by pre-treating newborns at risk. Unfortunately, this treatment was not shown to prevent GBS disease.
The idea of treating all pregnant women who are colonized with GBS during the pregnancy has also been explored. Women who tested positive by culture for GBS were treated and most of them were positive again three weeks later. There does not seem to be a way to eradicate GBS bacteria from women's bodies.
Treating women during pregnancy did not reduce the rate of GBS disease in their babies.
Treating women during labor with IV antibiotics has been shown to prevent GBS disease in the newborn. The antibiotic must be given at least four hours prior to the birth to allow the antibiotic to pass into the amniotic fluid and treat the baby. If colonized women are given antibiotics during labor, 90% of newborn GBS disease is prevented.
Antibiotic Treatment to Prevent GBS Disease
If treating mothers during labor will prevent 90% of GBS disease, then why don't we simply give all laboring women antibiotics?
The answer is threefold. Some people are allergic to penicillin and will have a reaction to the treatment that could be worse than the disease, giving antibiotics to all (or most) pregnant women will lead to the growth of bacteria that are resistant to antibiotic treatment, and treatment is expensive and logistically difficult to give to all laboring women.
Prenatal Testing Strategy
If all pregnant women are tested for GBS and those who are positive are given antibiotics during labor, 27% of all laboring women in this country will get antibiotics. This will prevent 90% of GBS disease.
Using this strategy, all women will be tested during pregnancy and those with positive cultures will be recommended to have IV antibiotic treatment during labor.