Wednesday, August 16, 2006

Group B strep test

Most of this post is copied and pasted from other places. I've put all my comments in italics. I'm still undecided whether I will have the test or not.

About 40% of adults are carriers of Group B Streptococcum (GBS) in their genital or intestinal tracts. Usually, GBS doesn't cause problems. In fact, in most healthy adults it is considered a "normal" organism, and treatment with antibiotics is not given. It does have significance for the pregnant woman, however. GBS, which can be passed from mother to baby during childbirth, is the leading cause of newborn sepsis--serious infection throughout the baby's body soon after birth.
A specific combination of factors seems to be at work in babies who develop GBS disease. It is most likely to develop in babies whose mothers are carriers of GBS and who have one or more clinical risk factors. In these babies, who are at the highest possible risk for GBS disease, about five out of 100 will develop it. Babies whose mothers are GBS carriers but have no clinical risk factors are less likely to develop GBS disease: about one in 200 babies will get GBS disease. Those whose mothers have clinical risk factors but test negative for GBS are even less likely to develop GBS disease--about 1 in 1000--and those whose mothers have neither risk factors nor a positive GBS culture have a very small chance of getting GBS disease--about 1 in 3000.
Clinical Risk Factors for Developing GBS Disease:Prenatal risk factors: Previous baby with GBS disease; urinary tract infection with GBS at any time during this pregnancyLabor-related risk factors: Onset of labor before 37 weeks, rupture of membranes before 37 weeks; rupture of membranes more than 18 hours before birth; fever over 100.4 degrees during labor.
Researchers conducted a review of infants who had early-onset group B streptococcal (EOGBS) infections and were born in Southern California Kaiser Permanente Hospitals from 1988 through 1996. To summarize:
*319 infants with EOGBS sepsis, bacteremia, or clinically suspected infection were identified from a population of 277,912 live births (approximately 1 in every 870 births).*Of the 172 term infants with culture-positive infection who had clinical signs of infection, 95% exhibited them in the first 24 hours of life.*All of the infants exposed to antibiotics during birth became ill within the first 24 hours of life.
Researchers concluded that "exposure to antibiotics during labor did not change the clinical spectrum of disease or the onset of clinical signs of infection within 24 hours of birth for term infants with EOGBS infection."
(from )

Because women who carry GBS but do not develop any of these three complications have a relatively low risk of delivering an infant with GBS disease, the decision to take antibiotics during labor should balance risks and benefits. Penicillin is very effective at preventing GBS disease in the newborn and is generally safe. A GBS carrier with none of the conditions above has the following risks:
* 1 in 200 chance of delivering a baby with GBS disease if antibiotics are not given
* 1 in 4000 chance of delivering a baby with GBS disease if antibiotics are given
* 1 in 10 chance, or lower, of experiencing a mild allergic reaction to penicillin (such as rash)
* 1 in 10, 000 chance of developing a severe allergic reaction--anaphylaxis--to penicillin. Anaphylaxis requires emergency treatment and can be life-threatening.

the bacteria can come and go, so the test isn't always a reliable indicator of who will have GBS on delivery day. And since results aren't available for a few days, testing during labor isn't possible. (*Why do it if you are not sure if the results will still be acurate?)
Some doctors only screen patients who have a history of urinary tract infections, a fever near delivery time, or who have had a GBS baby. (*I have none of these things*)
GBS is easily treated with antibiotics, so call your doctor if your baby has symptoms such as uncontrollable crying, poor feeding, fever, grunting, or blue skin. (Late-onset GBS, which develops after the first week, may also cause vomiting.)

Apparently you can test positive, but then do it again later and be negative. I don't think the test is very reliable. However, I don't want anything to happen to the poor innocent raisin either.

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