- What is GBS & Why Is it Important?
- Impact of GBS in Pregnancy
- Risks of Baby Developing GBS Infection at Birth
- Who “Gets” GBS? & Which Babies Get GBS Infection?
- Is GBS Testing Recommended and Reliable?
- Can’t I Just Skip the Test to Avoid Antibiotics in Labor?
- What if I Test Positive But a Later Test is Negative?
- What's the Treatment & Is It Recommended for Me?
- How Effective is Antibiotic Prophylaxis in Labor?
- Will Antibiotics in Labor Harm My Baby’s Microbiome
- Are There Other Risks to Antibiotics in Labor I Should Be Aware Of?
- Can I Decline Antibiotics & What are the Risks?
- If I Don’t Accept Antibiotics, Does My Baby Need Special Testing or Observation?
- Are Alternatives to Antibiotics in Labor Reliable?
- Can GBS Colonization be Reduced or Prevented?
- A Healthy Microbiome: A Natural Defense Against GBS?
- If You Need/Choose an Antibiotic in Labor, It’s Okay!
This article was first published online in October 2015, originally excerpted from my textbook, Botanical Medicine for Women’s Health (Elsevier, 2009), now in its second edition (Elsevier, 2017), This article was updated in July 2020,
It’s practically impossible to pick up a newspaper or magazine, or browse the internet these days, without coming across an article on the importance of a healthy microbiome for our overall health. If you’ve been educating yourself about the microbiome, you’ve probably learned that antibiotics are one of the things that can have a negative impact on it. You may also have heard that when young babies are exposed to antibiotics, it can increase their risk for eczema, allergies, and asthma in childhood, and even obesity and diabetes later in life, an issue that has gotten significant attention because of its relationship to birth by cesarean section, which keeps baby from being exposed to the mom’s vaginal flora during birth. So it’s understandable that pregnant moms, and even some health care professionals, are concerned about antibiotic overuse, particularly during pregnancy, labor, and for babies in the newborn period or early childhood.
So what do you do if testing shows you have Group B Strep (GBS) in pregnancy and are facing the decision about using antibiotics in labor (intrapartum antibiotic prophylaxis, or IAP) as preventative treatment. Many women are unsure which is the greater risk – take the chance on your baby developing a GBS infection if you don't do the antibiotics, or take an antibiotic that can impact your baby's microbiome.
This article answers the numerous questions mommas have sent to me, explains what Group B Strep is, reviews the risks to baby if untreated, and will discuss the validity and safety of some of the common GBS testing “hacks” being used in pregnancy, as well as alternative methods of preventing/reducing GBS colonization to achieve a negative prenatal test.
GBS is a complex issue, and while I can’t give you “the answer to what you should do,” because in truth there is no one right answer, and much of what we know about the impact of antibiotics on the infant microbiome is still emerging, my hope is to give you enough information (this is a comprehensive blog!) to make the most educated decision possible that is also within your comfort zone.
What is GBS & Why Is it Important?
Group B Streptococcus, specifically, Streptococcus agalactiae, also known as Group B Strep or GBS for short, is one of the trillions of organisms that normally inhabit the human intestinal tract. Via migration from the intestines, it also colonizes the rectum, bladder, and vaginal tracts of many women. At any given time, worldwide, as many as 35% of people are colonized with this bacteria. While it can cause infection in people of any age, GBS doesn’t seem to play a particularly beneficial role in human health, nor, when kept in check by healthy gut, vaginal, or bladder flora, does it usually cause harm to adults who are colonized with it, and in fact, most people colonized with it will never develop infection – that is, illness caused by it.
So what's the fuss?
In the 1970s, GBS was recognized as a leading cause of serious infection in newborns and infants. Two well-established syndromes exist for GBS disease
- Early-onset disease (GBS EOD), which occurs when baby is less than 7 days old, and
- Late-onset disease (GBS LOD), which occurs when baby is between 7-90 days old.
Either can cause pneumonia, sepsis, and meningitis, though meningitis is more common with late onset disease (7% of cases of EOD, 25-30% of LOD.
Early onset disease is the one that can be transmitted vertically, that is, from mother to baby during labor and birth, and is responsible for potentially serious adverse events in the baby, most commonly sepsis, pneumonia, and less often meningitis, which is more typically associated with late onset disease.
Late-onset disease develops through contact other than via vertical transmission – for example, it can occur as a result of transmission from a member of the hospital team, for example, nursery personnel, or a member of your community who has contact with the baby. Up to 45% of health care workers may carry the bacteria on their skin and may transmit the infection to newborns. Other sources can include members of your community who have contact with baby. Meticulous hand-washing practices in the hospital are essential for prevention of infection transmission, and for anyone who is going to hold and care for the baby after birth, including friends, family members, nannies, etc.
A third category of GBS infection has now been postulated: Prenatal Onset of GBS (POGBS). Currently, babies who are born already infected with group B strep are classified as “early-onset” regardless of when the infection began. However, according to a 2012 study, it was hypothesized that “data support the concept that early-onset GBS represents a spectrum of infection that often precedes birth.” According to the CDC 2010 MMWR, “The burden of prenatal-onset GBS disease has not been assessed adequately and no effective prevention tools have been identified before the intrapartum period.” A 2015 systematic review suggested that Group B Streptococcus causes up to 12.1% of stillbirths, but that more research is needed. While I don't mean to be scary, this infection can be asymptomatic and still lead to stillbirth. Unless you have a GBS positive urine result, you're unlikely to know you have GBS until 35 week's gestation, and no treatment is offered for earlier GBS colonization unless it causes a UTI. That's why further research on GBS colonization prevention is so important, and why, as I discuss later in this article, I recommend pregnant women take probiotics to at least try to minimize colonization.
Impact of GBS in Pregnancy
GBS in pregnancy can also cause bladder and uterine infections, miscarriage, and it increases the risk of premature labor and premature rupture of membranes (PROM) and stillbirth. This is important as the early-onset prevention strategy of using antibiotics in labor doesn't prevent GBS infections beginning before a woman's labor starts or her water breaks, and don't prevent these problems prenatally.
What are the Risks of Baby Developing GBS Infection at Birth – and How Serious Is It?
When a baby is exposed to GBS in labor or during the birth, he or she has a 50% chance of becoming colonized with GBS. Most healthy, full-term babies will just develop their own colonization of the skin and gut as a result, without developing infection – in other words, they don’t get sick.
However, a small percentage who get exposed will become infected – meaning they get sick. The risk of a baby developing a serious, life-threatening GBS infection, according to the Centers for Disease Control and Prevention (CDC), is 1 to 2%. GBS infection in the newborn can lead to very long stays in the NICU (Neonatal Intensive Care Unit), and up to 44% of infants who survive GBS meningitis (infection in the brain and spinal cord) end up with long-term health problems, including developmental disabilities, paralysis, seizure disorders, hearing loss, and vision loss – though again, this complication is more common with late onset disease.
The mortality rate (number of babies that die) among babies with GBS EOD is 2 to 3% for full-term infants (I know that sounds low, but as I always tell my patients, it’s 100% if it’s your baby). For premature newborns (born before 33 weeks gestation), it’s as high as 18-35% with an average of 21.6%. A quick look at CDC's GBS page says an infection rate of 0.22 per 1000. With approximately 4 million births in the US last year, we'd expect <1000 infections per year, and with a case fatality rate (CFR) or about 2-3%, we'd expect about 25 deaths/year, despite antibiotic prophylaxis in labor. This is in part due to false negative results that occur with testing, leading some women who are GBS positive to be untreated in labor, and in part because IAP isn't 100% effective.
IAP given to the mother during labor is used to prevent early-onset infection – I'll discuss its effectiveness below.
Who “Gets” GBS? & Which Babies Get GBS Infection?
While anyone can be colonized with GBS, and again, up to 30% of people are, the following factors are associated with a higher likelihood of a positive GBS test:
- Women under 20 years old
- Women with multiple sexual partners
- More likely to have been exposed to antibiotics prior to labor/birth
- More likely to have chronic hypertension or pre-existing diabetes
- Regular tampon users
- Prior tobacco use
- Frequent sex, or sex close to the time you get tested
- Oral sex (receiving, not giving it)
- Infrequent hand washing
While any baby can develop GBS infection if the mother is colonized, the following factors increase a baby’s risk:
- Birth prior to 37 weeks
- Very low birth weight
- High temperature in the mom during labor,
- Rupture of membranes before entering labor (prom)
- A prolonged time between membrane rupture and birth,
- Chorioamnionitis (infection of the membranous sac surrounding the baby)
- Intrauterine monitoring in labor (fetal scalp monitor, intrauterine pressure monitor)
- African-American descent
Most bacterial transmission to the newborn occurs during birth via passage of the baby through the birth canal, or through bacteria that ascend the birth canal when the membranes have ruptured (broken “bag of waters”). In one large study of 148,000 infants born between 2000 and 2008, nearly all of the 94 infants who developed early GBS infection were diagnosed within an hour after birth – suggesting that early onset GBS infection probably begins even before birth.
The increased risk for Black mothers and babies is likely in large part due to inherent systemic racism leading to overall higher maternal and infant mortality for black mothers and babies, less access to prenatal testing, and greater likelihood, again based on factors due to systemic racism, to have preexiting diabets or hypertension – or both.
There is also some epidemiological evidence that while Lactobacillus is considered the most predominant and protective genus of vaginal flora in women, this is a bias, as this is true in white women, but not necessarily in Black women who may have different and equally healthy predominant species but that perhaps are less protective against GBS. This has not been elucidated in the medical literature and should be studied.
While there have been conflicting results when studies looking at the impact of frequent vaginal exams on GBS EOD have been evaluated, with no impact shown from three or more vaginal examinations, some studies have shown an increased risk as the number of vaginal exams goes up, particularly if the mother does not receive IAP. In any case, vaginal exams should not be performed unnecessarily, and should be minimized to the extent possible in women with GBS or ruptured membranes.
Artificial Rupture of Membranes (AROM) is usually performed to augment (speed labor) up. It can be effective for prolonged labor, modestly reducing the need for cesarean section, but like so many other procedures in labor, is over performed, isn’t always effective, and can increase a mother’s and baby’s risk of infection, which may include GBS. If AROM is recommended to augment labor in a GBS positive mother, it’s optimal, whenever possible, to postpone doing it until antibiotic prophylaxis has been given, with ideally 4 hours of time before baby is born, to reduce the risk of GBS EOD.
Is GBS Testing Recommended and Reliable?
GBS testing was first initiated in the early 1990s, and from 2002 through early 2020, it's been recommended that pregnant women be tested for GBS between 35 and 37 weeks of pregnancy. As of 2020, the American College of Obstetricians and Gynecologists (ACOG) now states that the best time to test for GBS presence is between the 36th and 37th weeks of pregnancy. Testing at this time is thought to provide coverage for women who don’t go into labor until in their 41st week. The test consists of obtaining a bacterial culture of a sample collected from a simultaneous vaginal and rectal swab. This is usually done by your obstetrician, family doctor, or midwife, however, a recent study shows that women can self-test equally as effectively with a little bit of instruction. so if you’re not comfortable having your provider do the swab, you can request instruction on doing it yourself.
Studies suggest that GBS positive cultures have a high degree of accuracy in predicting GBS colonization status at birth if cultures are collected within 5 weeks of birth and test results are positive. A negative test, however, does not mean you do not have the infection; it could be what is called a “false negative” meaning that the test missed the infection. In fact, 2/3 of cases of GBS EOD are now the result of false negative testing in pregnancy. You can also become colonized after the test was done, so while your test could have been negative in pregnancy, you could in fact be positive at the time of labor. As a result, a substantial number of women who are ultimately GBS positive at the time of birth will not receive IAP because the presence of the bacteria was missed in pregnancy.
An FDA approved rapid test can diagnose GBS in pregnant women in about an hour. It is currently used only in labor when a woman’s GBS status is unknown and testing needs to be done rapidly for medical reasons such as premature rupture of membranes (PROM). Some studies have shown the test to be up to 91% sensitive, even more so than the 36-37 week culture, which catches about 69% of cases. More research on the pros and cons of switching to rapid testing is needed, as this could potentially be a shift in current practice to a new best practice.
GBS is also found in the urine of 2%-7% of pregnant women. A positive urine test for GBS is considered a marker of heavy rectal and vaginal colonization in the mother, and is a risk factor for GBS EOD in the newborn. Thus it is considered an indication for antibiotic use in labor, and precludes the need for testing at 36-37 weeks pregnancy. Antibiotic treatment of GBS bacteriuria during pregnancy does not eliminate GBS from the genitourinary and gastrointestinal tracts, and recolonization after a course of antibiotics is typical, so this does not offset the recommendation that pregnant women with GBS in their urine receive antibiotics in labor.
Because GBS resistance to specific antibiotics has developed, especially to those used for penicillin-allergic women, culture and sensitivity testing is recommended as part of the testing process.
Can’t I Just Skip the Test to Avoid Antibiotics in Labor?
Skipping the test to avoid a positive result is one strategy many women ask me about, and it’s certainly within your legal right to do so. But here’s the thing: if you don’t know whether you are positive and you're having your baby in the hospital, or have to transport from a home birth to the hospital with any risk factors for GBS including early broken waters, prolonged broken waters (> 18 hours), or an elevated temperature, you’re still going to be prescribed the antibiotic. On the other hand, if you've been tested and have had a negative test result, then the antibiotic isn’t indicated and you're sort of in the clear from the decision. Having a negative test result can actually be an advantage and can put your mind at ease if you're worried about being GBS positive.
Further, if you are positive and know it, you can get educated about your decision and will likely be more mindful of signs of possible GBS infection in your baby, should you choose to forego the antibiotic. So while I am not saying everyone should get testing, simply declining the test to avoid knowing the results isn’t necessarily more effective for avoiding the antibiotic in labor. It’s sort of the same with gaming the test by using natural treatments for the few weeks before the test to achieve a negative test result – you might have just reduced the colonization so that it was low enough to give you a negative, but you might still be colonized at the time of birth and not know it.
Some women have raised the fact that not all countries test routinely, and that is true. The United Kingdom National Screening Committee, for example, states that pregnant people in the UK should not be screened for GBS. But the UK follows the risk-based approach; this includes giving antibiotics in-labor to all women who have fever, prolonged rupture of membranes >18 hours, GBS in urine at any time during pregnancy, preterm labor, or a prior infant with GBS. At the end of the day, the data shows that about the same number of women (about 30% of all laboring women) will receive antibiotics either way.
What if I Test Positive But a Later Test is Negative?
When it comes to GBS infection in pregnancy, once you test positive, even if you test negative later in the same pregnancy, you are still considered to be positive and antibiotic treatment is recommended by the CDC (note if you are negative in this pregnancy, but were positive in a previous pregnancy, you do not require antibiotics unless your previous baby developed GBS infection, in which case IAP is considered appropriate).
What's the Treatment & Is It Recommended for Me?
Universal prophylaxis with IV antibiotics (usually penicillin or ampicillin, or an alternative for penicillin-allergic women) is recommended if you meet any of the following criteria:
- If you test positive for GBS in your urine during this pregnancy
- If you previously had a baby who had GBS infection
- If your vaginal-rectal cultures at 36 0/7-37 6/7 weeks of gestation are positive for GBS, unless a cesarean is performed before you go into labor, and your bag of waters was intact (no ruptured membranes) at the time of the cesarean.
It’s recommended that women receive antibiotics at least 4 hours before baby is born for maximum effectiveness in preventing infection in baby, however recent studies have shown that antibiotics given at least two hours before birth has been shown to reduce GBS vaginal colony counts and decrease the frequency of neonatal sepsis.Since the time of birth can't be predicted, it's recommended that antibiotics be started when you arrive at the hospital, and given every four hours until baby is born.
IAP is also recommended if your prenatal GBS culture result is unknown when labor starts, but you have risk factors for GBS EOD including:
- Preterm birth
- Preterm prelabor rupture of membranes (PPROM)
- Rupture of membranes for 18 or more hours at term
- You have a fever in labor (temperature 100.4°F [38°C] or higher)
- GBS colonization in a previous pregnancy
If you have a positive prenatal GBS culture, but have a cesarean before you go into labor, with intact membranes at the start of the cesarean, you do not require GBS antibiotic prophylaxis.
How Effective is Antibiotic Prophylaxis in Labor?
Overall, IAP has been highly effective for reducing the numbers of newborns that develop GBS EOD. If a GBS positive woman is treated with antibiotics during labor, her infant’s risk of developing early onset GBS infection decreases by about 80%.
For example, the risk could drop from 1% down to to 0.2%. As a result of routine testing in pregnancy, and treatment protocols using antibiotics given to positive moms during labor that began in 2002, the rate of early-onset infection decreased from 1.7 cases per 1,000 live births (1993) to 0.22 cases per 1,000 live births (2016).
This has not been without some controversy, though. An excellent review of this controversy was done by Dekker at Evidence Based Birth.
Will Antibiotics in Labor Harm My Baby’s Microbiome
There is evidence from a number of studies demonstrating that use of antibiotics during pregnancy and delivery can affect the microbiome of your baby, for example in one study of 52 newborns, half of whose mothers received IAP for GBS in labor and half didn’t (this group of mothers was negative for GBS), there were decreased in the beneficial bacteria Bifidobacterium in the antibiotic group. But how this links to long-term health impacts is still not well understood. Some studies show that the newborn microbiome changes resolve within two months.
Evidence to date suggests that the use of antibiotics for less than 24 hours during labor is not a source of long-term microbiome damage, nor risk of later eczema. Studies also suggest that any short-term damage can be mitigated by breastfeeding and possibly the use of probiotics given to the newborn. One study of over 4800 Canadian women found no association between childhood obesity and GBS antibiotic exposure during delivery. However, greater than 24 hours of antibiotic exposure in labor was associated with an increase in eczema at 2 years of age.
One study by Azad et al. done in 2016, found that while yes, at 3 months old, there were differences between the microbiomes of babies who had versus had not been exposed to antibiotics, breastfeeding was an important factor – babies exposed to antibiotics and who were exclusively breastfed for at least 3 months had more similar microbiomes to those not exposed to antibiotics than babies who had been exposed but were not exclusively breastfed. Some babies did have persistent changes even at 1 year after birth, after which the microbiomes of babies tend to become similar regardless of type of birth or whether antibiotics were used. While this is overall reassuring, it does not take into account the impact of microbiome alterations in the first year of life on the development of the immune, digestive or nervous systems, thus much more research is needed to be able to compare the long-term health effects of these early microbiome perturbations.
Overall, my review of the literature suggests that antibiotics used IV during labor by the mother can impact the baby's microbiome unfavorably, however it appears that if antibiotics are used for less than 24 hours the risk is short-term. If baby is breastfed for ideally about 6 months, the risk is mitigated, and it's also possible to give baby an infant probiotic that might also prevent some of the potential impact of microbiome disruption, for example, eczema, allergies, and asthma that have been associated with antibiotic use in pregnancy. Cesarean birth seems to compound the risk of antibiotics used during labor, as baby is not receiving exposure to the immune enhancing flora that would naturally occur during vaginal birth. In these babies not only are there deficits in healthy microbial species and diversity, but overgrowth of pathogenic organisms including Clostridium Enterococcus, and Streptococcus have been measured in their stool.
In babies born by cesarean, where there is also antibiotic exposure through mom, a probiotic given to baby has been shown in some studies to prevent atopic conditions, and is something I also recommend in my medical practice when mothers had antibiotics in labor for GBS.
Bottom line: At this time, I consider the typically recommended use of IAP for GBS to be low risk for the baby's longterm microbiome health as long as the baby is breastfed.
Are There Other Risks to Antibiotics in Labor I Should Be Aware Of?
Adverse events from IAP are thought to be poorly documented. All medications carry risks of adverse events; the greatest risks with GBS prophylaxis are an antibiotic reaction and potential to develop a yeast infection after birth (vaginal yeast infection and nipple infections – or thrush in your newborn – sometimes occur) which can cause nipple pain, cracking, and bleeding, having a harmful effect on your breastfeeding experience.
Allergic reactions can generally be prevented by making sure you're getting the appropriate antibiotic for you – particularly if you have a penicillin allergy or have had a prior reaction to any antibiotics. Taking a probiotic starting in pregnancy, or if you have not, immediately postpartum to support your gut health, and vaginal and skin (nipple) flora, may prevent thrush and other yeast infections, which, according to one study, occur in 15% of women receiving GBS antibiotic prophylaxis, more than double the rate of women who don't.
While many women are concerned about having to be immobilized during labor to receive the antibiotics, in fact they can be delivered over about 30 minutes via IV, and only need to be repeated at 4 hour intervals throughout labor. You can move around while receiving the IV, and have the IV drip disconnected between doses, the IV port saline or heparin locked so you can move about and do your thing.
Can I Decline Antibiotics & What are the Risks?
First of all, for women choosing to birth at home, the use of IV antibiotics in labor may not be a realistic option because in many states, home birth midwives do not administer IV medications. Home birth midwives in this situation, therefore, often use a risk-assessment model, transporting to the hospital for IV antibiotics should indications arise, including rupture of membranes longer than 18-24 hours (length of time varies with the protocol of different medical and midwifery communities) or any signs of infection.
If you're having your baby in the hospital, you do have the right to decline antibiotic prophylaxis in labor, and you should not be bullied, harassed, or coerced, including with the threat of social services being called on you. The right to informed refusal is codified in the ACOG Refusal of Medically Recommended Treatment During Pregnancy.
If you decline, while there is an overall very low likelihood (1-2% chance) that your baby will develop early onset GBS infection it’s important to know that the risk is about 5 times higher than if you did accept the antibiotic.
I have also seen a few situations get legally complicated, including social work being called to assess for negligence and child abuse, when parents declined antibiotic prophylaxis in labor, and one case where the parents were forced to let the baby be given the antibiotic after birth, since mom had declined to receive the antibiotic in labor, even though the baby had no signs of infection. While hopefully you’d not be met by that vitriolic response by your care provider or hospital risk management team, having the discussion with your obstetrician, family doctor, or midwife at the time of the positive test result, rather than during labor, is strongly advised so you don’t face any surprises.
It's important to be fully aware of the risks of GBS before choosing to pass on the antibiotic prophylaxis. There is also no natural substitute for antibiotics in women who are GBS positive, with signs of infection and prolonged rupture of membranes (>24 hours rupture) – and all newborns exhibiting signs of GBS infection must receive immediate antibiotic therapy.
If I Don’t Accept Antibiotics, Does My Baby Need Special Testing or Observation?
If your baby is otherwise healthy and full-term, no additional or special monitoring aside from the usual care and attention given to a newborn is usually needed, whether or not you accept routine IAP. However, I do recommend paying close attention during the first 48 hours; remember, from the study above, though, most babies who developed GBS EOD were diagnosed within the hour after birth.
Signs of sepsis are nonspecific and include irritability, lethargy, respiratory symptoms (eg, tachypnea, grunting, hypoxia), temperature instability, poor perfusion, and hypotension. Baby may or may not have fever. Should baby develop any unusual symptoms it's important to get immediate medical care as baby can become compromised very quickly. Let any care providers know that you tested GBS positive in pregnancy, and if you did not accept antibiotics, let them know so they know how to best evaluate and treat your baby should a workup or medical care be indicated.
Are Alternatives to Antibiotics in Labor Reliable?
An alternative treatment to IV antibiotics that has been investigated in Europe and is used in resource challenged countries, but is not employed in the United States other than by some homebirth midwives, is the use of chlorhexidine, a topical antiseptic solution that kills GBS. While some studies have shown that chlorhexidine does reduce colonization and infection compared with conventional antibiotic treatment, other studies have shown only a reduction in colonization but not in the rates of GBS EOD. The most recent review by the Cochrane Database in 2014 concludes that there is no difference in rates of GBS infection with chlorhexadine use compared to non-use. The only possible effective protocol, which should be reserved for use in resource limited countries only, is a combination of vaginal chlorhexadine washes with newborn chlorhexadine skin wiping. It is unlikely to help in the prevention of infection when there is prolonged rupture of membranes, as it can’t keep bacteria from ascending. Hibiclens, which contains chlorhexidine, is the form that is typically used by midwives in the US.
Keep in mind that Hibiclens and chlorhexidine will also wipe out healthy vaginal flora, likely for many hours after each application, and not just selectively eliminate the GBS, so while you might avoid the antibiotic, you may be defeating the purpose of avoiding it without a better outcome, which is keeping the vaginal flora healthy so baby gets optimally colonized with mom’s flora at birth.
Can GBS Colonization be Reduced or Prevented?
Really common questions I receive are ‘Are there natural things I can do to test negative for GBS during pregnancy?' or ‘Can GBS colonization be prevented & treated naturally?' The answer is, yes, there do seem to be some things you can do based on the research evidence, and there are definitely things my clients/patients have done over the years!
A Healthy Microbiome: A Natural Defense Against GBS?
New research is regularly being published on the role of a healthy vaginal and gut microbiome in preventing vaginal infection in general, and that the presence – or absence – of certain vaginal microorganisms may prevent or contribute to the likelihood of GBS colonization.
A healthy microbiome has also been found to mitigate risk of miscarriage, preterm labor, vaginal, and bladder infections during labor, so addressing vaginal microbiome health during pregnancy has been a part of my prenatal protocols for the past 10 or so years. When my textbook, Botanical Medicine for Women's Health, was originally published in 2010, the research was nearly absent – and talking about the microbiome was fringe! The evidence to support this approach now continues to grow, but more research is absolutely warranted.
Steps I recommend to support a healthy microbiome include:
- Eliminate processed sugar and junk foods from the diet, as these have been shown to disrupt the gut microbiome
- Increase leafy greens, and other fruits and vegetables to ensure 8 servings, day, to get adequate fiber which is beneficial for gut health
- Take a prenatal vitamin to insure that you are getting all the nutrients you need, especially zinc, vitamin D, vitamin A, and vitamin C, to keep your immunity boosted
- Reduce stress through meditation, journaling, getting massage, and other relaxing activities – high stress impairs immunity, gut health, and the microbiome
- Eat lacto-fermented foods (sauerkraut, yogurt if you tolerate dairy) daily
- Use of oral and vaginal probiotics throughout pregnancy for women at higher risk – GBS colonization in a prior pregnancy, frequent UTIs or vaginal infections for example yeast or Bacterial vaginosis, history of preterm labor, or early rupture of membranes
If you meet criteria for an antibiotic in labor, this does not change your status; however, it may have a protective effect against GBS-related prenatal complications that are not prevented by in-labor antibiotics, and if you have never tested positive before, or have never had a baby with GBS EOD, this may prevent GBS colonization and the need for antibiotic prophylaxis.
Probiotics Prenatally: Why & How
Many species of Lactobacillus have been shown to be beneficial to the vaginal flora; Lactobacillus reuteri and Lactobacillus rhamnosis are species known to be especially helpful for supporting healthy vaginal (and bladder) flora, while these and others, including L crispatus and L. salivarius strains, have been shown to to inhibit the growth of vaginal pathogens including Gardnerella vaginalis and Candida albicans, and also reducing the frequency of bladder infections in addition to vaginal infection. The reduction in yeast infections is important; a 2020 study found that the presence of Candida albicans vaginally promotes bladder colonization of Group B Streptococcus, which, if you recall, is considered an indication for treatment with IAP.
While not all studies have shown conclusively positive effects in reducing GBS colonization in pregnancy, some have been shown specifically to inhibit GBS through a variety of mechanisms including reducing the numbers of GBS by changing the vaginal pH to one that is inhospitable to that bacteria, and reducing the ability of GBS to adhere to the vaginal lining.
In one study, 110 pregnant women at 35-37 weeks of gestation who were diagnosed by GBS culture as being GBS positive for both vaginal and rectal GBS colonization were randomly assigned to be orally treated with two placebo capsules or two probiotic capsules (containing L. rhamnosus and L. reuteri ) before bedtime until delivery. All women were tested for vaginal and rectal GBS colonization again by GBS culture on admission for delivery. Of the 99 who completed the study (49 in the probiotic group and 50 in the placebo group), the GBS colonization results changed from positive to negative in 21 women in the probiotic group (42.9%) and in nine women in the placebo group (18.0%) during this period. The researchers concluded that an oral probiotic containing L. rhamnosus and L. reuteri could reduce the vaginal and rectal GBS colonization rate in pregnant women.
In another study involving 57 healthy pregnant women, L. salivarus was taken daily by the 25 GBS positive women in the group from weeks 26 to 38 of pregnancy. At the end of the trial (week 38), 72% and 68% of the women were GBS-negative in the rectal and vaginal samples, respectively. The researchers concluded that this seemed to be an efficient method to reduce the number of GBS-positive women during pregnancy, decreasing the number of women receiving antibiotic treatment during labor and birth.
In another small clinical trial, researchers randomly assigned healthy, fertile, non-pregnant women to wear panty liners that were impregnated with a probiotic with the species L. plantarum, or to wear placebo panty liners. The results showed that it is possible to transfer probiotics to the labial folds and vagina using panty liners. The researchers also found that people who had higher levels of Lactobacilli in the vagina had lower levels of GBS. They concluded that high numbers of Lactobacilli may contribute to a low vaginal pH and seem to have a negative influence on Group B streptococci.
Further, antibiotics in labor can't prevent prenatal risks, for example, it does not prevent GBS-related miscarriages, stillbirths and preterm births. And even though the risks seem tolerable and microbiome disruption in the newborn short term, both do occur. So overall, given the potentially beneficial and protective effects of probiotics against UTI, preterm labor, and also protection of the baby's microbiome when taken by the pregnant mother, it seems reasonable to include a probiotic starting in the first or second trimester in any woman who has tested positive for GBS in previous pregnancies, who has had a history of urinary tract infections, miscarriage, or other problems that may be reduced by probiotic use, and for prevention of GBS colonization in the mother and need for antibiotics in labor.
How to Use Probiotics
A typical dose is 1 to 2 capsules of a probiotic containing at least 10 billion CFUs, to be taken orally, daily during pregnancy, and especially in the 3rd trimester, not just to help prevent GBS, but also because it has been shown to reduce the risk of atopic conditions in kids (allergies, eczema, asthma) when taken by mom in the last third of the pregnancy. In addition, a capsule can be inserted vaginally, nightly before bed, starting at the onset of the the 3rd trimester and continuing until just prior to GBS testing.
Are Probiotics Safe in Pregnancy?
One of the most important criteria for using any supplements in pregnancy is safety; these and other strains of probiotics have been consistently found to be safe and well-tolerated, including in the limited number of studies done for use during pregnancy.
What about Using Garlic or Essential Oils Vaginally
Garlic has been used as an antimicrobial for millennia and research does support its antibiotic and anti-fungal effects. There's much debate over the effectiveness and even safety of using garlic as a vaginal suppository for the treatment of vaginal yeast infection, and also for GBS prevention; on her website, one childbirth educator posits a risk of rupture of membranes from its use. However, to my knowledge and research, including as the author of the primary textbook available on women's herbal medicine, I was able to find no evidence of harm; there is significant evidence of empirical use by midwives around the US, for decades. That said, there is no evidence of safety or efficacy either, so it is a personal decision as to whether this is something you would consider. One small study of questionable quality, reported that for yeast infection, a vaginal cream containing garlic and thyme was as effective as much as clotrimazole vaginal cream for the treatment.
The traditional use is to insert a single clove (not a bulb, just a clove!) of carefully peeled, un-nicked garlic into the vagina each night, using your finger to push it in about 2-3 inches. It can be dipped in a small amount of olive oil to coat it prior to insertion. You then remove with your finger the next day. It's typically recommended for a few weeks prior to GBS testing. One risk that one has to consider is that you temporarily reduce colonization and are able to achieve a negative test, but it is possible that bacterial levels will creep back up and then you wouldn't know whether you were GBS colonized. In contrast, the use of probiotics does improve the vaginal flora over time, in a way that can abate or may eliminate GBS colonization.
Essential oils also have a long history of use for treating bacterial infections, as well as vaginal infections. Herbal suppositories may be beneficial – clinically I have found them to be – but while the suppositories themselves are safe and the herbs have shown in vivo effectiveness against many organisms, including GBS, there is again, no western scientific evidence supporting their effectiveness or safety in pregnancy, other than empirical evidence. in the human body
- Melt ¼ cup of coconut oil and ¼ cup of cocoa butter in a small saucepan
- Turn off the heat and add:
- 2 Tbsp. of calendula oil
- 1/4 tsp. of thyme or oregano essential oil
- Optional 1 tsp each myrrh and goldenseal powders
- Optionally, 2 Tbsp. of probiotic powder containing some combination of L reuteri, L rhamnosus, L. plantarum, L crispatus, and L salivarius
Pour the warm, slightly thick liquid into a suppository mold (you can order affordable silicon ones online). Put the whole mold into the fridge and let the suppositories harden for about an hour, then pop them out of the mold and store in the fridge in a container. Suppository molds can easily be prepared at home by using aluminum foil that has been folded several times lengthwise, and then widthwise, to form a trough approximately 8 inches in length and 1/2 inch in width. This mixture is then poured into the mold, refrigerated to harden, cut into pieces the size of the patient's pinky finger, and inserted as needed.
Wear a light menstrual pad each night to protect underwear and bedding, as the oil can stain as the suppository melts. These herbal products can be purchased from Mountain Rose Herbs online.
Of course, discuss use of any of these alternative approaches, including probiotics, with your midwife or physician, prior to use.
Why I Strongly Advise Against Colloidal Silver
One popular remedy, called colloidal silver, recommended in this case for topical vaginal use, is imbued with many claims about its ability to prevent and cure all manner of infections, but colloidal silver has not been proven safe and effective, and taken orally can cause toxic effects. Vaginal mucosa is highly absorptive, so I really recommend against it, even though I know it is popular amongst midwives. The FDA also warned in 1999 that colloidal silver isn’t safe or effective for treating any disease or condition, and it can cause argyria, a bluish-gray discoloration of the skin, which is usually permanent.
If You Need/Choose an Antibiotic in Labor, It’s Okay!
While we do need to be concerned about the health of our babies' microbiomes, and it's not ideal to give our babies an antibiotic as part of their welcome to the world, antibiotics do play a role in preventing serious infections, and prevention in this case can mean preventing drastic consequences. Further, it does appear possible to mitigate the impact of antibiotics both by breastfeeding and possibly also by giving baby a probiotic daily for the first 6 months after birth.
It's important to make the decision that you are most comfortable living with and that is best for your baby, and not feel swayed by any pressure to avoid an antibiotic because of the desire to go “all natural.” There's an appropriate time and place for most things, and while right now the jury is still out on the severity of the implications of giving antibiotics to newborns via mom, or directly, it would not be an inappropriate choice at all to decide to use an antibiotic in labor.
If you'd like to listen to my podcast Protecting Baby's Microbiome: Right From the Start on Natural MD Radio on this topic, click here.
Wishing you a healthy pregnancy, birth, and baby, with peace of mind about your decisions.
ACOG Committee Opinion; Prevention of Group B Streptococcal Early-Onset Disease in Newborns. Obstetrics & Gynecology. February 2020 – Volume 135 – Issue 2 – p e51-e72.
ACOG Committee Opinion; Prevention of early-onset group B streptococcal disease in newborns. Int J Gyn. 54(2):197-205, 1996.
Adair, C. E., L. Kowalsky, et al. Risk factors for early-onset group B streptococcal disease in neonates: a population-based case- control study. CMAJ 169(3):2003;198-203.
Aloisio, I. et al. Influence of intrapartum antibiotic prophylaxis against group B Streptococcus on the early newborn gut composition and evaluation of the anti-Streptococcus activity of Bifidobacterium strains. Appl Microbiol Biotechnol 98, 6051–6060 (2014).
American Academy of Pediatrics: Committee on Fetus and Newborn: Revised guidelines for prevention of early-onset group B streptococcal (GBS) infection, Pediatrics. 99:1997; 489–496.
Azad, MD et al. Impact of maternal intrapartum antibiotics, method of birth and breastfeeding on gut microbiota during the first year of life: a prospective cohort study. BJOG. 2015.
Aziz N et al. Evaluation of probiotic oral supplementation effects on group B streptococcus rectovaginal colonization in pregnant women: a randomized double-blind placebo-controlled trial.
Bahadoran P. et al. Investigating the therapeutic effect of vaginal cream containing garlic and thyme compared to clotrimazole cream for the treatment of mycotic vaginitis. Iran J Nurs Midwifery Res. 2010 Dec; 15(Suppl1): 343–349.
Bayó, M, et al. Vaginal microbiota in healthy pregnant women and prenatal screening of group B streptococci (GBS). Int Microbiol 5, 87–90 (2002).
Berardi, A. et al.Group B Streptococcus Late-Onset Disease: 2003-2010. Pediatrics. 2013 Feb;131(2):e361-8.
Burman L, Christensen P and Christensen K, et al.Prevention of excess neonatal morbidity associated with group B streptococci by vaginal chlorhexidine disinfection during labor, Lancet. 340(8811):1992; 65–69.
Centers for Disease Control and Prevention. Prevention of perinatal group b streptococcal disease. MMWR:2010;59: 1-32.
Christensen K, Christensen P and Dykes A, et al.:Chlorhexidine for prevention of neonatal colonization with group B streptococci, Eur J Obstet Gynecol Reprod Biol. 19(4):1985; 231–236.
Cohain. Long-term symptomatic group B streptococcal vulvovaginitis: eight cases resolved with freshly cut garlic. European Journal of Obstetrics & Gynecology and Reproductive Biology 146(1):2009; 110-111.
Crombleholme W: Obstetrics, In (Tierney L, McPhee S and Papadakis M eds.) Current Medical Diagnosis and Treatment. 2007; New York: McGraw-Hill.
Dinsmoor N et al.Use of intrapartum antibiotics and the incidence of postnatal maternal and neonatal yeast infections. Obstet Gynecol. 2005 Jul;106(1):19-22.
Dekker, R. Group B Strep in Pregnancy: Evidence for Antibiotics and Alternatives. 2017.
Edwards J et al. Group B Streptococcus (GBS) Colonization and Disease among Pregnant Women: A Historical Cohort Study. Infectious Disease in Obstetrics and Gynecology. Volume 2019 |Article ID 5430493. 6 pages
Facchinetti F, et al. S: Chlorhexidine vaginal flushings vs. systemic ampicillin in the prevention of vertical transmission of neonatal group B streptococcus, at term, J Matern Fetal Neonatal Med. 11(2):2002; 84–88.
Fairlie, T, et al. Effectiveness of intrapartum antibiotic prophylaxis for prevention of early-onset group b streptococcal disease. Obstetrics and Gynecology 121(3): 2013; 570-577.
Seedat F et al. Adverse events in women and children who have received intrapartum antibiotic prophylaxis treatment: a systematic review. BMC Pregnancy Childbirth. 2017 Jul 26;17(1):247.
Goldenberg, RL, et al. Use of vaginally administered chlorhexidine during labor to improve pregnancy outcomes. Obstetrics and Gynecology 107(5): 2006; 1139-1146.
Håkansson S, et al. Group B Streptococcal carriage in Sweden: a national study on risk factors for mother and infant colonisation. Acta obstetricia et gynecologica scandinavica. 2008;87(1):50–58..
Hicks P, Diaz-Perez MJ. Patient self-collection of group B streptococcal specimens during pregnancy. J Am Board Fam Med 2009;22:136–40.
Ho M. et al. Oral Lactobacillus rhamnosus Gr-1 and Lactobacillus reuteri Rc-14 to reduce Group B Streptococcus colonization in pregnant women: a randomized controlled trial. Taiwan J Obstet Gynecol. 2016 Aug;55(4):515-8.
Johri, AK, et al. Group B Streptococcus: global incidence and vaccine development. Nat Rev Microbiol 4(12): 2006; 932-942.
Kubec R, et al. Isolation of S-n-butyl cysteine sulfoxide and six n-butyl-containing thiosulfinates from Allium spiculum, J Nat Prod. 65(7):2002; 960–964.
Libster, R.,et al. Long-term outcomes of group B streptococcal meningitis. Pediatrics 130(1): 2012; e8-15.
Martin V. et al. Rectal and Vaginal Eradication of Streptococcus agalactiae (GBS) in Pregnant Women by Using Lactobacillus salivarius CECT 9145, A Target-specific Probiotic Strain. Nutrients. 2019 Apr 10;11(4):810.
Metz T. et al. Exposure to group B Streptococcal antibiotic prophylaxis and early childhood body mass index in a vaginal birth cohort. J Matern Fetal Neonatal Med. 2019 Feb 7;1-6.Meyn, L et al. Rectal colonization by group B Streptococcus as a predictor of vaginal colonization. American Journal of Obstetrics and Gynecology. Volume 201, Issue 1, July 2009, Pages 76.e1-76.e7C Nan. Maternal group B Streptococcus-related stillbirth: a systematic review. BJOG. 2015 Oct;122(11):1437-45.
Nanduri S, et al. Epidemiology of invasive early-onset and late-onset group b streptococcal disease in the United States, 2006 to 2015 multistate laboratory and population-based surveillance. JAMA Pediatr. 2019;173(3):224-233.
Ohlsson, A. and V. S. Shah . Intrapartum antibiotics for known maternal Group B streptococcal colonization. Cochrane Database Syst Rev 1: CD007467, 2013.
Ohlsson A, et al. Vaginal chlorhexidine during labour to prevent early-onset neonatal group B streptococcal infection. Cochrane Database of Systematic Reviews 2014, Issue 12. Art. No.: CD003520.
Price D, et al. Self-sampling for group B streptococcus in women 35 to 37 weeks pregnant is accurate and acceptable: a randomized cross-over trial. J Obstet Gynaecol Can 2006;28:1083–8.
Ronnqvist, P.D., et al. Lactobacilli in the female genital tract in relation to other genital microbes and vaginal pH. Acta Obstet Gynecol Scand 85(6):2006; 726-735.
Schrag S, Zell E and Lynfield R: A population-based comparison of strategies to prevent early-onset group B streptococcal disease in neonates, NEJM. 347; 2002; 233-239.
Shing SR, et al. The Fungal Pathogen Candida albicans Promotes Bladder Colonization of Group B Streptococcus. Front. Cell. Infect. Microbiol., 10 January 2020
Stade, B., V. Shah, et al. Vaginal chlorhexidine during labour to prevent early-onset neonatal group B streptococcal infection. Cochrane Database Syst Rev(3): CD003520, 2004.
Stray-Pedersen B and Bergan T: Vaginal disinfection with chlorhexidine during childbirth, Int J Antimicrob Agents. 12(3):1999; 245–251.
Taha T, , et al. Effect of cleansing the birth canal with antiseptic solution on maternal and newborn morbidity and mortality in Malawi: clinical trial, BMJ. 315(7102):1997; 216–219.
Tudela, CM.et al. Intrapartum evidence of early-onset group B streptococcus. Obstetrics and Gynecology 119(3): 2012; 626-629.
Wohl DL, et al. Intrapartum antibiotics and childhood atopic dermatitis. J Am Board Fam Med. Jan-Feb 2015;28(1):82-9..
Zarate, G. and Nader-Macias, M. E.. Influence of probiotic vaginal lactobacilli on in vitro adhesion of urogenital pathogens to vaginal epithelial cells. Lett Appl Microbiol 43(2):2006; 174-178.