GBS: How Dangerous is it and What Are the Options?

GBS, or Group B Streptococcus (streptococcus agalactiae) is a bacterium found in the intestinal tract of approximately 5-40% of the population. Very rarely does it cause a problem, normally lying dormant and unnoticed by its host. In up to 30% of pregnant women, however, GBS can be found colonized in either the vaginal or rectal area, or both. The outcome of the birth is usually fine even if the mother is colonized in these areas. In approximately 1 in 200 cases of GBS colonization, the baby will become ill, resulting in neonatal death in about 5-15% of those cases. 25% of GBS cases occur in premature infants. Most cases of neonatal GBS are early-onset (within the first week after birth), and because late-onset infection is not usually caused by factors arising during the birth, I will primarily address early-onset GBS.

GBS and VBAC

Some women desiring a VBAC encounter resistance based on their GBS status. There is no evidence to suggest that a woman with previous cesarean(s) is at any higher risk of giving birth to a GBS infected baby. While it's true that cesarean-born babies experience a lower rate of GBS sepsis than their vaginally-born counterparts, encouraging repeat cesarean section for no other reason than GBS colonization makes as much sense as saying all GBS positive mothers should have a cesarean, regardless of whether they've had one in the past. It simply doesn't make sense to raise the risks to mother and baby by delivering through major surgery only to slightly reduce a risk that would have been there anyway even if the woman had not had a previous cesarean. As with any other obstetrical claim or scare-tactic, ask your care provider for medical studies proving his or her position.

Should I be tested?

In 1996 and then again in 2002, the CDC in conjunction with ACOG and other physicians' unions released guidelines for testing and treatment of GBS. One of the changes between the 1996 and 2002 versions of the guidelines was to recommend testing for every pregnant woman between 35 and 37 weeks gestation. Often this is presented as a mandate rather than an option to be discussed between woman and care provider.

With a respectful care provider, testing can be a valuable tool in deciding how to approach potential risk factors that may arise during labor. Unfortunately, in many cases, once a positive GBS test result is recorded in a woman's chart, the pressure to follow established protocol becomes great, regardless of the woman's view of the risks and desire for an alternative course of action. This can complicate the decision whether or not to test, because while ideally that decision should be based solely upon providing the mother with additional information with which to make birth plans, it can become a weapon which might be held over her head in the form of a "dead baby card" if she does not comply with the standard recommendation.

There are certain birth attendants who are less rigid about GBS protocol than others. Homebirth midwives tend to fall into this category, though certainly not all. Most obstetricians follow the current recommended protocol and may not have a positive reaction to a mother who intends to make her own decisions on this issue. Ironically, this can work to your advantage, because if your care provider is hostile to your refusal of GBS testing, you can be reasonably sure she or he will not be friendly to your plans to avoid other pregnancy and birth protocols.

The main options for testing are fairly straightforward:

Opting not to test, instead observing the baby closely in the first 7 days of life

Testing, and treating with antibiotics in the presence of a positive result plus established labor risk factors

Testing, and, given a positive result, treating with antibiotics regardless of risk factors

Testing, and choosing an alternative method of treatment

In the event that a woman chooses not to be tested but changes her mind with the development of a risk factor (prolonged rupture of membranes, fever in labor, or premature delivery), there are rapid tests available that are just as effective as the traditional culture. The Accuprobe produces results within approximately six hours. The other, IDI-Strep B, can produce a result in an hour if the hospital runs a 24 hour laboratory.

Are there alternatives to antibiotics? What are the risks to my baby?

The CDC (Centers for Disease Control and Prevention), currently recommends:

Universal vaginal/rectal GBS testing for all pregnant women at 35-37 weeks

Antibiotic prophylaxis for all women who are colonized, plus any woman who has had a previous baby with GBS sepsis

Risk-based treatment for women with unknown GBS status at time of delivery

According to the CDC, women without certain risk factors (rupture of membranes or labor prior to 37 weeks, membranes ruptured >18 hours, fever in labor >100.4) have the following odds of developing a problem:

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 overall neonatal mortality rate nationwide is approximately 7 deaths per 1000 live births. The fatality rate from GBS sepsis, without antibiotic treatment, is about 3 out of 10,000 babies (many of which may very well be preventable by means other than antibiotic prophylaxis). Viewed in that way, GBS is a very tiny contributor to neonatal mortality.

While most data does show intrapartum antibiotics to be effective in lowering the rate of neonatal GBS sepsis, there is reason to believe it's not that clear cut. The widespread application of prophylactic antibiotics can have ramifications that may reduce, or even nullify, any potential benefits.

One issue of concern in the prevention and treatment of all kinds of neonatal sepsis is the development of antibiotic-resistant strains of bacteria. While one recent study failed to show an increase in non-GBS sepsis pursuant to prophylactic antibiotics during labor, multiple studies have confirmed this problem. One study, at the Illinois Masonic Medical Center, showed a quadrupling of the non-GBS sepsis rate after the introduction of the prophylactic antibiotics protocol, causing the overall neonatal sepsis rate to remain unchanged.

Given the reduction in GBS sepsis concurrent with the institution of widespread antibiotic prophylaxis, it may seem like the obvious course of action. There is more to the issue than meets the eye.

There are many things that can be done to reduce the risk of neonatal GBS infection. Perhaps the single most important phrase that a woman in late pregnancy should learn is "just say no to vaginal exams". Cervical assessment in the third trimester has become so standard that not only do most practitioners vehemently advocate for its use, but many women seem to indeed desire it and look forward to hearing how much they have "progressed". Unfortunately, few care providers bother to inform their clients of some very important facts. Perhaps most significant is the reality that cervical state is not predictive of when the baby will arrive. A woman may walk around for several weeks dilated to 3 centimeters or more, or she could have a closed, unripe cervix and give birth to her baby a few hours later. Regardless of when labor is going to begin, assessing the cervix only sets the care provider as well as the mother up with expectations that may not be realized. The psychological effects of this situation should not be underestimated.

What has cervical assessment got to do with GBS? This is the second piece of the puzzle that is often not disclosed to obstetrical clients - vaginal exams raise the risks of maternal/neonatal infection, including GBS. Performing a vaginal exam can cause bacteria to be pushed up the birth canal to the cervix, whether GBS residing on the perineum, or an external germ carried in on the provider's glove. Given that we know vaginal exams are essentially useless and almost always unnecessary, it seems reckless that care providers would continue to perform them, especially on women known to be colonized with GBS.

Aside from using common sense with regard to cervical exams, there are treatments other than antibiotics that medical research has shown to be effective. Vaginal lavage with chlorhexidine, either prenatally or during labor, has been shown to significantly reduce transmission of microbes to the neonate. Another option is a third trimester injection of benzathine penicillin G, found to be up to 75% effective in eliminating colonization by time of delivery. There are also other, more holistic treatments that may be utilized.

The main advantage of opting against antibiotics is that these alternate treatments can be used without risk of creating super-germs through antibiotic resistance. There are, however, other important factors, such as the risk of yeast infection/thrush that is present with antibiotic use, which can interfere with breastfeeding, putting the baby at a distinct disadvantage health-wise. Another component of antibiotic prophylaxis is the probability of being tied down during labor due to the IV line. This reduces the mother's mobility, thereby reducing the effectiveness of contractions, as well as limiting her options for coping with pain non-pharmacologically, all of which can result in a cascade of interventions and medications, which increase risks to both mother and baby. This problem can sometimes be avoided by requesting a saline lock, which is an IV port that is inserted in the vein but remains capped off except during the administration of the medication every few hours, allowing the mother mobility the rest of the time.

What if I'm planning an out-of-hospital birth?

The first issue to address in talking about home or birth center births, especially for women who have already had a baby, is the fact that GBS colonization can be transient. This means that just because a woman cultured positive in one pregnancy does not mean that she will in subsequent pregnancies. Some providers treat on a "once positive always positive" basis, which is simply not evidence-based, but instead is aimed at protecting their medico-legal concerns. There are several options for women planning to birth outside of a hospital. Many women, particularly those using midwives without physician back-up, choose not to test and instead to watch for risk factors during labor as well as observe the baby in the first week postpartum. If a woman is planning to birth with a CNM (Certified Nurse Midwife) or physician, there is often the option of having IV antibiotics administered at home or in a birth center. Any of the alternative or natural treatments can be used as well. It's important to discuss this issue with your care provider to make sure you are on the same page.

The main thing to keep in mind is that the very choice to have your baby out of the hospital environment, especially at home, significantly reduces the risk of maternal/neonatal infection. It is safe to assume that in most cases, a woman having her baby at the hospital will not likely be able to completely avoid vaginal examination, though she may be able to limit them if well supported emotionally and very firm about her wishes in her interactions with the staff. Having your baby at home means you decide if and how many exams; it also means no internal monitor wires, which can be convenient highways to the uterus for the many germs present in a hospital setting. However the mother chooses to manage GBS colonization in an out-of-hospital setting, her chances of experiencing a problem are much less than the already low rate of occurrence.

An Expert Weighs In

Gloria Lemay, respected Canadian midwife of more than 25 years, remains calm about GBS: "I worked in the birth field before we even knew that GBS existed. All the testing and craziness about GBS was brought about not by the medical professionals but by the parents. Doctors know that it is extremely rare for a baby to get sick from GBS, but the grieving parents of children who have died from this infection have pushed for the universal testing. All that the over-testing has led to is more aggressive obstetrical management of the birth process."

While most information on GBS treatment is widely available, it's a bigger challenge to find sensible advice on managing risk factors in a woman of unknown GBS status during an out-of-hospital birth. Ms. Lemay believes that an individualized approach is best, pointing out "it is more worrisome to have risk factors in a pack a day smoker than in an athlete." According to her vast experience, "it is very rare to have fever in the birth process." She has only witnessed it twice, and both of those women had non-pregnancy related illness at the time. In the case of unexplained fever, Ms. Lemay recommends transporting to the hospital for a white blood cell count in order to assess for uterine infection. However, this is very rare, especially with no pelvic exams.

If the membranes release prior to the onset of labor, Ms. Lemay favors an expectant management approach with emphasis on prevention, including checking temperature every four hours, increasing vitamin C intake, getting plenty of rest, and of course no pelvic exams. While most mothers will deliver spontaneously within 48 hours of the release of membranes, it can be perfectly safe to wait for as long as it takes. One of Ms. Lemay's VBAC clients delivered her baby at home three weeks after the release of membranes. The key to making birth as easy and safe as possible is nearly always to limit intervention and let the body do its job.

Whether a mother chooses to test for GBS colonization or not, to treat or to wait and watch, the most important thing to remember is that these decisions, as with all choices surrounding pregnancy and birth, are ultimately up to the parents. Whether the care provider chooses to remain in the parents' employ when faced with those decisions is up to him or her. Make your choices based on the available evidence and your own instincts, and then, if necessary, find a provider who will support and respect your autonomy. When everyone is on the same team, birth is a much safer and more satisfying experience for all involved.

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