Group B Strep Colonization and Pregnancy
Hi there Dr. T. I am 36 1/2 weeks and I just found out that I was GBS+ and I am very concerned about my baby. I wonder, why give antibiotics during labor? Why not now? I have also had many problems with yeast infections during my pregnancy and was wondering if that could have caused the GBS? I don't completely understand why I have it and what I did to get it. Is it caused from something, perhaps the heat? Not being clean enough? Please help me!
One of my very first posts here at “Fruit of the Womb” addressed Group B Streptococcus (GBS) infections and pregnancy. The question from today’s reader gives us good reason to revisit this issue since the concerns expressed in the comment are shared by many, many women....
GBS is a bacterium that colonizes the vagina and lower gastrointestinal tract in as many as one-third of all healthy reproductive age women. It is still the leading cause of serious bacterial infection in newborns and most babies contract the organism at the time of delivery. Indeed, 8,000-12,000 babies per year in the U.S. will develop complications related to GBS and approximately 2,000 infants will die from their infections. There are several well-known situations in which babies are at increased risk for developing a serious GBS infection including:
- Premature labor or rupture of membranes before 37 weeks
- Prolonged rupture of membranes (18 hr or longer) before delivery
- Fever in labor (100.4F or higher)
- History of GBS urinary tract infection during the pregnancy (4-fold risk)
- Previous baby affected by GBS disease (increases risk 10-fold!!!)
Some of the dilemmas we face in dealing with GBS in pregnancy are raised by today’s reader. She appears to have had GBS detected at the time of recommended routine screening, 35-37 weeks. She didn’t just “catch it” at this point; it is probably something she has carried with her through most of the pregnancy (and even before conception). We do NOT know why some people carry GBS and others do not, and we are not entirely clear why far more women actually carry the bacterium than are at risk for having a baby with a serious complication related to it, although the maternal immune response to the bacterium probably plays a key role (see below). But, we also know that if you are colonized with GBS and tend to carry it, even if treated, you have a very high risk of being incompletely ‘decolonized’ by treatment and a similarly high risk for becoming ‘recolonized’ in a relatively short period of time for whatever reasons you have it to begin with!
GBS may come and go, but a negative test within 5 weeks of delivery has a ‘negative predictive value’ of about 95%. This implies that only 5% of women who are negative at 35-37 weeks are likely to acquire GBS between the time of screening and delivery. Interestingly, if GBS is detected at routine screening, the ‘positive predictive value’ of the bacteria actually being found at delivery is only about 87%. This means that as many as 13% of women who were positive at the time of screening will not have the bacterium detectable at the time of delivery.
To answer some of our reader’s concerns, these are reasons we do not treat everyone at the time a positive screening test is done unless they themselves have a significant infection (e.g., urinary tract), a previously affected baby, or are in one of the other risk categories noted above. According to the CDC, women who are GBS positive have about a 50% of having a baby who becomes colonized with GBS at delivery and a 1 in 200 chance of having a baby who develops GBS disease if antibiotics are NOT given, but only 1 in 4000 risk if they are given.
There are 5 major serotypes of GBS (Ia, Ib, II, III, and V). All are capable of causing both maternal and neonatal disease. Babies born to women who do not have antibodies to types II and III seem to be at greater risk for complications. Indeed, at some point, this may be one of the primary factors we can use to differentiate pregnancies at risk from those which are less so. About two-thirds of serious GBS infections are apparent at the time of delivery and 90% of babies who will develop complications do so within the first 48 hr after delivery. This is generally referred to as “early-onset” GBS infection and technically is used to define disease occurring in the first week of life. “Late-onset” disease, frequently associated with serotype III, affects another 10% of newborns, often presents as meningitis with septicemia, and rarely occurs after one month of age. Up to one-third of the survivors of GBS meningitis will develop long-term physical and/or neurological handicaps and in 1 of every 8 of these babies, the handicaps will be severe.
Unless you are in one of the high risk groups noted above, the goal of routine prophylactic antibiotic therapy during labor in those who are found to be colonized with GBS during their pregnancies is to deliver antibiotics to the mother early enough in the course of labor that sufficient drug can be transferred across the placenta to achieve protective levels in the baby prior to birth. The goal is not to cure the GBS infection. That means, the antibiotic selected must not only be able to kill GBS, but it must also be able to cross the placenta. Fortunately, GBS has not yet been found to have developed resistance to the antibiotic of choice, penicillin G, and this drug also readily crosses the placenta. It also has a long and proven safety record for the baby. Ideally, antibiotic therapy is begun, intravenously, at least 4 hr prior to delivery so that at least one or two doses can be administered before the baby is born. If a woman has a serious allergy to penicillin, other otions for therapy exist and the risks and benefits of these are discussed in our previous post on this subject.
Anyway, to close this out, I would only like to say to our reader that 1) I doubt the recurrent yeast infections “caused” the GBS, but they might reflect a subtle deficiency in your immune response to other organisms commonly found in the environment. (People with diabetes and autoimmune conditions frequently experience similar problems or, in your case, this may be simply the response your body has to pregnancy; 2) I don’t completely understand why you have it either, but I doubt the “heat” is contributing to the problem and cleanliness is rarely a concern in people who would worry about that to begin with!
The important things are that your doctors did the right thing by screening you, they have identified a potential problem, and there is a well-proven means of significantly reducing the risks from that problem for both you and your baby at the time of your labor and delivery. Thanks for reading and for the good questions. Best wishes for the rest of your pregnancy!
Dr T on Aug 20, 11:32:00 AM 2007
Labels: GBS and pregnancy
7 Comments:
At Sun Oct 14, 02:21:00 PM 2007,
Anonymous said…
Hi Dr. T,
Thanks for an amazingly fascinating blog -- I've been lurking for awhile and enjoying every minute of it.
I had a few followup questions to your GBS post. My daughter was born at term (39+0 weeks) 30 hours post membrane rupture (no meconium or evidence of infection). I was GBS+, afebrile inter- and postpartum, and was administered six intravenous doses of penicillin (one ever 4 hours) while in labor. At birth, my daughter appeared fine (APGARs 8 and 10), but when her blood work showed elevated WBCs (particularly band cells) and CRP a few hours later, she was whisked off to the NICU for prophylactic antibiotics. Nothing grew in any of the cultures (although the Neonatologist mentioned that she could have been fighting an infection but had sterile cultures due to the many penicillin doses she got across the placenta). She never showed any signs of illness and was discharged home after 3 days with four more days of antibiotics by injection from home health. She's done splendidly since.
While my pregnancy was generally uncomplicated, I might have been leaking amniotic fluid at two points during my pregnancy. The first time, at 32 weeks I visited L&D after six hours of intermittent, low-volume fluid leakage became something I could not pretend was my imagination (it was approximately 10-15x the volume of my usual leukorrhea). I had positive nitrazine strip tests, but given the intermittent nature, no positive ferning test. I had no indications for a false-positive nitrazine test (recent intercourse etc.) and the fluid was not urine. It stopped after about 36 hours, and an ultrasound done right around when it stopped showed an AFI of 7.9. A followup ultrasound several days later showed my AFI back up to 14 (where it had been on all previous ultrasounds).
The same thing happened at 35 weeks 5 days -- ~36 hours of intermittent fluid leakage that stopped. I reported it at my OB appointment 2 days later, and my OB initially said oh, just normal discharge, but then followed up after I was measuring two cm smaller than I should have been (no change since two weeks before). The ultrasound showed another low AFI (7.8) that came back up to 14 again when re-checked 5 days later.
I'm a scientist, so I'm comfortable with messy/unclear data, but I am personally convinced that I was leaking amniotic fluid both because of the nitrazine tests and correlation with significantly reduced fluid volume, and from my experience when my membranes did ruptured at term; it began the exact same way, and the characteristics of the fluid matched my previous experiences.
To finally get to the point, I am currently 11 weeks pregnant with my second child. I am 28 years old, healthy, never smoked or used drugs, no chronic medical conditions, no medications. I have these questions:
- does my daughter's NICU admission to rule out GBS sepsis place me in the category of 10-fold increased risk for a serious GBS infection, or is that only for moms with a previous baby with a more definite/serious GBS infection? How does that risk change if I again have term PROM? Or if I don't? Is there anything that can be done to mitigate the 10-fold increased risk?
- if I was indeed leaking amniotic fluid at 32 and 35 weeks, is this current pregnancy at increased risk of PPROM that necessitates a preterm delivery? The only risk factor for PPROM that I had last time was being GBS+; I had no active infections, don't smoke, no surgery or invasive procedures, normal blood pressure, no chronic medical conditions, no history of STIs, no previous miscarriages or abortions, no trauma, generally normal AFIs, normal singleton pregnancy. Those are all still true although my GBS status is unknown at this point since I'm only 11 weeks. If I am at increased risk, is there anything I can do to help prevent it?
- I got PUPPP in the first 24 hours postpartum with my first child. Any idea what the likelihood of this recurring either during or immediately after this pregnancy?
Thanks so much, and thanks again for an interesting and informative blog!
-CS
At Tue Nov 06, 10:34:00 AM 2007,
Anonymous said…
Hi, I am 23 weeks pregnant and currently came down with a slight UTI. When sent for culture, the result came back Streptococcus agalactia serogroup B or in lamens terms Group B Strep. I am a clinical laboratory technologists, so at first I wasn't too worried becaused I know about the bacteria and how common it is among pregnant women. However, once i started to read more and more about the bacteria learning that women who aren't just carriers but have infections such as UTI's caused by the pathogen are at a much higer risk of having babies born with complications from the disease then those who simply are carriers, I began to worry quiet a bit. I am seeking treatment for the UTI right now and will reculture after the round of antibiotics that my doctor prescribed, but still I worry. I have a sever allergy to penicillin and just wonder what options of intravenous therapy I will be able to have that will be affective before I deliver. If anyone has any information that could ease my mind or give me greater knowledge about the issue I would appreciate it very much.
At Tue Nov 06, 12:33:00 PM 2007,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Anonymous Nov 6: It does appear that women who develop GBS urinary tract infections are at greatter risk for complications realted to GBS, but the complication rates are still small. At some point,if you have a severe penicillin allergy, you should probably have antibiotic sensitivities performed on your GBS. If the GBS with which you are colonized is sensitive to clindamycin, that would probably be the best antibiotic to use for prophylaxis at delivery or with any other pregnancy complications such as premature rupture of membranes. The next choice is vancomycin, but the expense and the complication rate for this drug places it far down on my wish list. Hope things go well and thanks for reading! Dr T
At Wed Nov 07, 08:58:00 AM 2007,
Anonymous said…
It is me again from Nov 6, the worried 23 weeker. I had sensitivities perormed on my urine culture and it was resistant to clindamycin. It was suseptible to vancomycin and other drugs that my doctor said pregnant women should't have. I am afraid that they won't be able to find any medication to give me before labor due to all of my medication allergies. All of my life I have taken mostly cephalosporins to treat illnesses. The only cephalosporin that my isolate was suseptible to was rocephin and my OBGYN didn't recomend it. So now I am really scared. I think the only thing that could ease my mind completely would be to have a planned C-section.
At Thu Nov 08, 06:21:00 PM 2007,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Anonymous Nov 7: Great! If you can take cephalosporins and your GBS is sensitive to Rocephin, there is no reason that I am aware of (other than allergic reactions) that it can't be used in pregnancy. We use it all the time. It's sure a lot better than the other alternative -vancomycin- which is VERY expensive and associated with high risk for side-effects (although it's still probably safe for the baby). RELAX GIRL! Things will be fine. Dr T
At Wed Mar 26, 03:40:00 PM 2008,
Anonymous said…
I am currently 36 weeks pregnant and tested negative for gbs. However, I had a first trimester urinary tract infection caused by gbs. What are the chances that I will be gbs+ at birth? Should I be treated for antibiotics? This is my second pregnancy (with the first baby I had a fast labor and was only at the hospital for 5 hours before giving birth)
At Wed Mar 26, 05:15:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous Mar 26: The current recommendations are that any woman who has had a GBS-positive urinary tract infection be TREATED prophylactically at delivery, regardless, of any subsequent cultures. If you labor fast, you should go to the hospital sooner than later and remind your doctor of the GBS UTI. Best wishes. Dr T
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