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The debate on Group B Streptococci (GBS): Screening and Antibiotics in Labour

I had a recent experience where I transfered a woman during labour to hospital and she was going to be treated with intravenous antibiotics for unknown GBS as she did not have the GBS screening done as part of her routine pregnancy care. I was shocked about this aggressive approach to an unknown GBS status and thought this is a great opportunity to have a look at the evidence.


What is GBS and why are women screened for GBS?

streptokokkenmGroup B Streptococci or GBS is a common organism that lives in the gut, bladder and vagina. 10 to 30% of women are colonised with GBS. Carrying GBS is benign in adults and not a cause of concern but it can potentially be very problematic for the newborn baby due to the risk of GBS transmission to the baby in labour. There is a 40-50% chance of the baby becoming colonised with GBS during labour and birth however it does not necessarily cause GBS disease. Once the baby is colonized the risk of GBS disease is 1-2%, so overall 15-30 babies per 100.000 births will have a serious outcome. GBS causes Sepsis, Pneumonia and Meningitis in the newborn and does have a 5-10% mortality rate. Babies diagnosed with GBS disease are treated with antibiotics and will be admitted to the special care unit. Because of this GBS screening is done to prevent GBS disease in the newborn. Screening for GBS involves collecting a vaginal swab. As the GBS organism ‘comes and goes’ it is recommended for the swab to be obtained around the time of birth (35 to 37 weeks of pregnancy) to get an accurate estimate of GBS presence in the vaginal flora.


How do the Melbourne Hospitals approach GBS screening?

Some hospitals take the universal approach, which involves taking a vaginal swab on every pregnant woman around 35-37 weeks of pregnancy. Other hospitals have decided to work with a risk-based approach, meaning that the swab is only taken after identifying certain risk factors that increase the risk of GBS disease in the newborn:

  • Preterm labour (before 37 weeks of pregnancy)
  • Women whose waters have been broken for more than 18 hours
  • A fever in labour (greater than 38C)
  • A previous GBS affected baby
  • GBS urinary tract infection in pregnancy.

The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) have recommended either a risk-based or screening approach to identify pregnant woman for antibiotic prophylaxis during labour. In the UK The Royal College of Obstetricians and Gynaecologists (RCOG) do not recommend universal screening for GBS.

In my own practice I adapted the risk-based approach. I do not routinely screen for GBS during pregnancy unless the pregnant woman presents with risk factors.


What interventions during labour can increase the rates of GBS infection in the newborn?

  • Membrane Sweeping ‘Stretch & Sweep’
  • Vaginal Exams
  • Breaking waters artificially, having intact waters is protective!
  • Applying an electrode to the baby’s head to monitor the baby’s heart rate in labour


What is the consequence of a positive GBS result?

If the vaginal swab returns positive for GBS or if the woman has risk factors then the hospital protocols state that the woman will be given 4 hourly intravenous antibiotics once in labour. In Melbourne the hospitals have different guidelines on the prophylactic antibiotic cover and doses.

To prevent 1 neonatal death from GBS disease, 24.000 women would need to get screened for GBS and 7000 women would need treatment with antibiotics in labour. If a woman that is GBS positive has no risk factors and no treatment the chance that her baby is being affected by GBS is 1 in 500, which is a low risk.


What does it mean to give 7000 women antibiotics to prevent 1 baby from dying?

3908781655Babies are born sterile and during the first contact the baby gets all the bacterial flora from the mother. The baby swallows the mother’s healthy bowel flora during a vaginal birth and the baby’s gut gets coated with healthy bacteria.

The antibiotics given to the woman in labour will have an impact on the woman’s own flora that she passes on to her baby at the time of birth. If antibiotics are given to the woman in labour there is a delay in newborn gut colonisation. The antibiotics that the woman receives in labour will partially pass to the baby at the first moment of gut colonisation, interfere with the baby’s development of a healthy gut flora and potentially allow dangerous penicillin-resistant bacteria to become established.

This first opportunity of developing or not developing a healthy gut flora does have life long consequences. According to Bedford Russell (2006) “There is rapidly increasing evidence from experimental studies that the initial colonisation of the intestine is a moment of pivotal importance in long-term health, playing a profound role in imprinting of immune and systemic homeostasis.” The gut flora is the largest part of the immune system and an abnormal gut flora has been implicated in asthma, autoimmune diseases, diabetes, cancers and obesity.

Women who receive antibiotics in labour have a 10% chance of getting nipple thrush within 1 month after birth. Nipple thrush is very painful and can be a reason for women to stop breastfeeding, which is a significant public health concern.

There is also a possibility of allergic reactions and anaphylaxis that can potentially lead to death. Another big concern is antibiotic resistances. Penicillin is currently effective for treating GBS disease in newborns. One of the serious ramifications of the mass antibiotic cover for women whose babies were at risk of GBS disease is that ever since antibiotics have been introduced to treat large amounts of women, the rate of E.coli infections in premature babies has more than doubled. In one study 85% of the E.coli infections showed resistance to the antibiotics prescribed to treat GBS.


Does giving antibiotics actually make a difference?

abb-04-07A Cochrane review looked at trials comparing women who had received antibiotics with women who had no antibiotics. Antibiotics did reduce the incidence of GBS infection in newborns but there was no significant difference in the number of babies that died. Cochrane concluded that “Very few of the women in labour who are GBS positive give birth to babies who are infected with GBS and antibiotics can have harmful effects such as severe maternal allergic reaction, increase in drug-resistant organisms and exposure of newborn infants to resistant bacteria, and postnatal maternal and neonatal yeast infections. Giving antibiotics is not supported by conclusive evidence” (2009).


This article has 8 comments

  1. I have personal experience with an early onset gbs baby, from a c-section, without prolonged labor. Although I can agree to the reasoning behind not administering antibiotics durning labor, I can not condone the risk based assessment, which I was subject to. My baby nearly died because if the risk based approach. It sickens me now that gbs is not universally screened for with a swab test, to at least ensure that the maternity staff and the parents have a ‘heads up’ to closely monitor the baby for the first few hours and days of life. 

    • Thank you for engaging in the GBS discussion.

      Having had the frightening experience of giving birth to a baby affected by early onset GBS disease makes it completely understandable that you are questioning the risk based screening approach.

      It is great that we live in a country with easy access to medical treatment, including antibiotics that can treat illnesses very effectively.

      Unfortunately in the case of early onset GBS disease, the other side of the token is that methods such as universal screening expose many women to get overtreated with prophylactic antibiotics due to a positive swab result.

      Firstly, even if a swab result returns positive at 36 weeks, that does not mean that the vagina is still colonised with GBS by the time you go into labour and vice versa. And secondly, research has shown that whilst the antibiotics might be effective in most cases, they do not 100% prevent early onset GBS disease.

      The decision to administer antibiotics for prophylactic reasons should be carefully considered and weight up against risks versus benefits.

      Giving antibiotics does have long-term health implications for the baby due to interfering with the initiation of the baby’s microbiome, whilst the risk of GBS disease is very low in the absence of any risk factors for GBS.

      But irrespectively of knowing or not knowing the woman’s GBS status, if any risk factors present during labour the medical staff would recommend antibiotics there and then and the baby would get closely observed straight away after birth, including paediatric referral.

      Specifically to your situation I would be very interested to know a few more details about your labour and birth, such as how long were your waters broken, was your baby born premature, did you have a fever, did your baby’s heart rate pattern shown any distress during labour and have you given birth previously to a GBS affected baby? And if so, were you commenced on antibiotics during labour? How closely was your baby monitored after birth before it was picked up that your baby was unwell?

      All babies, born in the hospital or at home, get closely monitored after birth (hourly for the first 4 hours after birth, then 4 hourly for the next 24 to 48 hours depending on the presence of risk factors), irrespectively of GBS status. As soon as any abnormality is noticed, such as an increased breathing rate or temperature instability the baby gets referred to a paediatrician straight away and blood tests for inflammatory markers will get taken. If they are elevated, then the baby will go to the Special Care Nursery for antibiotic treatment without any delays.

      Again, I am unsure what the circumstance were for your baby after birth and how early the GBS disease was diagnosed and appropriate treatment initiated. Of course, a delay in diagnosis of early onset GBS disease can have a futile oucome.

      Ten Moons

    • Its been a few years… I was not screened, to answer your other questions it was my first child, and the only risk factor was that I was running a slight fever (only 1 risk factor, must meet 2 to be of concern) in hindsight, my failure to progress in labor even while being induced should have alerted the maternity staff that there were risks in my pregnancy/birth but it was overlooked, even my emergency cesarian was delayed twice because the doctor felt the situation had improved.  My child was not monitored closely after birth and after 24 hours of life, when she was exibiting signs of sepsis and has started having seizures, running a slight fever, lethargic, irritable and not interested in feeds it was dismissed as ‘just a cesarian’ baby, and treatment was drastically delayed. If I had of been screened and tested positive to GBS, it is most likely my child would have been more closely monitored and treated in a more timely manner rather than being left with permanent severe brain damage and significant disability. It is too easy for medical staff to overlook early signs and symptoms of GBS in babies. Routine swab test screening rather than the risk based assessment would at least alert medical staff to babies who need closer monitoring and are at risk, and would surely reduce the risk of babies dying or being left disabled. 

      The risk based approach does not cover first time mothers adequately enough to alert medical practitioners of GBS risk. 

  2. My son was born in 2004. I was not screened during pregnancy. I was told during an induced labour at 40 weeks that I had strep and would be given penicillian introveneously. My son did not receive my good gut flora. I also fed him colostrum immediately after birth for his immunity. None of the good bacteria would have been passed on due to the penicillian. He has brain fog, anxiety, autism, constipation and bloating, asthma, allergies, ADHD and specific food obsessions. He is medicated but I see an improvement
    with zinc, vitamin c and probiotics in high doses.

  3. I am very interested to read your stories about your babies born with GBS. My 13month old was born by emergency Caesarian and was born with an APGAR of 1. He was quickly revived and early tests revealed he had Group B Strep.  I had a positive screening for GBS and so had antibiotics intravenously on arrival at hospital. There were clear signs of distress in son (meconium in my waters and fast heartbeat) so he was born by Caesar.
    Thankfully he responded quickly from antibiotics and I was able to feed him without complication when he was 1 day old.
    I’m interested in the discussion about the change in gut flora that he would likely have given his birth experience and consumption of antibiotics for the first week of his life.  We have not observed any obvious complications for his dramatic birth although he has had a few recurring eczema outbreaks and we think is sensitive to Salicylates.
    I’m interested to hear stories of other GBS babies and any similar experiences with eczema/allergies?

  4. I forgot to say, our hospital never made any conclusions (to my knowledge) of how he contracted the GBS. On reflection I believe my waters may have slightly broken about 30 hours before he was born thus allowing the infection to transfer to him. Within 24hours my instincts told me there was something wrong so I was on alert and we went to hospital when my waters were green…
    He was full term at birth.


    • Hi, My Name is Alisha. I am a Registered Nurse in Australia with some experience in a Level II Special Care Nursery. I have cared for babies that have been colonized with GBS under antibiotic treatment so I can understand the concern that families have with its effect from a clinical standpoint. As a mother I also understand the fear and weighted decision about being colonized with GBS and choice of treatment for my baby.

      I think it is awesome that you are looking into reasoning’s behind your child’s struggles with Eczema and Allergies. As an asthma, eczema and multiple allergy sufferer myself with a very devoted mother who tried everything under the sun to heal me- I can seethe passion in your search for some answers also. 

      If you have not already seen it, there is a stimulating documentary called “Microbirth” which may give you some insight into current research in relation to gut flora and the use of antibiotics. It also will give you a wealth of information on the links between the use of antibiotics in birth and allergic diseases. Essentially, if we strip a newborn of any beneficial flora during birth, we are altering the naturally occurring microbiome. We commonly see Asthma and Eczema occurring together as they are both brought on by an allergic reaction to environmental stimuli.  

      An abstract from a 2015 article by Riiser explains the microbiome really well:

      The human microbiome can be defined as the microorganisms that reside within and on our bodies and how they interact with the environment. Recent research suggests that numerous mutually beneficial interactions occur between a human and their microbiome, including those that are essential for good health. Modern microbiological detection techniques have contributed to new knowledge about microorganisms in their human environment. These findings reveal that the microbiomes of the lung and gut contribute to the pathogenesis of asthma and allergy. For example, evidence indicates that the microbiome of the gut regulates the activities of helper Tcell subsets (Th1 and Th2) that affect the development of immune tolerance. Moreover, recent studies demonstrate differences between the lung microbiomes of healthy and asthmatic subjects. The hygiene and biodiversity hypotheses explain how exposure to microorganisms is associated with asthma and allergy. Although those living in developed countries are exposed to fewer and less diverse microorganisms compared with the inhabitants of developing countries, they are experiencing an increase in the incidence of asthma and allergies. Detailed analyses of the human microbiome, as are being conducted under theauspices of the Human Microbiome Project initiated in 2007, promise to contribute insights into the mechanisms and factors that cause asthma and allergy that may lead to the development of strategies to prevent and treat these diseases.  

      Although antibiotics are called for in some circumstances there is concern arising as to the prophylactic use of them during labor and birth in every woman colonized with GBS. I will attach some current research that I have on the topic of gut flora and also any links with allergies and eczema so you can make your own conclusions. We are seeing a rise in many inflammatory and autoimmune disorders such as celiac disease, asthma and eczema. Some believe it may be due to how we grow and produce our food, and others believe early use of antibiotics may also have an impact. As far as I have found, the research is still somewhat primitive in the direct correlation between GBS Bacteria, use of Antibiotics and Allergies/Eczema. This doesn’t mean there isn’t a link…it isjust hard to pinpoint due to many contributing factors. 

      Research also indicates that it is not only the use of antibiotics that is contributing to depletion of beneficial flora at birth, but it is also immediately after birth and early parenting methods. When you thinkabout it- as we see a rise in the number of cesarean section, we see babies being removed from their mothers, wiped down, dressed up- with no skin to skin benefit. What people do not realize also is that there is continuous transmission of beneficial flora from the skin of their family (mother and father). Early (within the first hour) and sustained breastfeeding also colonizes the gut with beneficial flora. In hospitals sometimes there are many hours and even days before mother and baby get to be together. I am not sure what your C-Section experience and first few days were like, but I would often see mothers and babies separated for a long period of time without any skin to skin connection. 

      My daughter Norah may have been exposed to GBS during her birth due to me being colonized vaginally. The likelihood of transmission was minimized due to my water being intact until 3 hours before her birth, and her being delivered in water. She was born on my chest out of the water and didn’t move for several hours while I breastfed her. She also had some skin to skin time with her daddy.  I also believe that some of the homeopathic interventions I invested in also may have decreased her likelihood of transmission or even increased her body’s own fighting ability. This was done by increasing her opportunity to be colonized with good bacteria at birth (I have included some research on the use of probiotics; although I don’t believe just taking probiotics is enough). Norah has had a few dry patches when we started to introduce some foods, but quickly discovered that they were a couple of food that I was allergic to. We stopped giving them and her skin is clear, potentially as she is still breastfeeding my antigens in the milk may be the cause of the reaction. She is a perfectly healthy 8 month old with no other issues thus far. We also have chosen not to give her vaccinations. 

      Your suspicions are probably correct with your son in that women colonized with GBS often have a higher chance of prolonged ruptured membranes (like you were saying- waters breaking greater than 12 hours). Once your waters break- there is no longer any protection surrounding baby, and this is increases the opportunity for the bacteria to become harmful. My midwife was always very clear in her desired approach with my birth of Norah, which was to monitor for any signs of infection, and to offer antibiotics at home if my water had broken for a significant amount of time. We were very fortunate that I gave birth shortly after my water broke. I believe that the strength in my membranes was due to the probiotic and homeopathic interventions. I believe this because as I tested further along in my pregnancy, I saw a decreasing number of present bacteria, and I eliminated it from my urine (when seen in the urine usually means you are heavily colonized). I don’t believe that the bacteria had the opportunity to weaken my membranes therefore they held up really well. 

      In regards to the research the use of antibiotics in labor due to GBS colonization you might be interested in reading the latest systematic review. Systematic reviews are heavily weighted in evidence base, so I have included the most recent Cochrane Review on GBS for you to read. Inother words….it is the cream of the crop when looking at evidence. In it you will see that they found very few colonized women actually gave birth to babies infected with GBS, and they found that the use of antibiotics had potentially more harmful risk. They found that the use of antibiotics during labor was not supported by conclusive evidence. Unfortunately there has been widespread hospitals antibiotic protocols put in place albeit the evidence to the contrary. This is bad news for women who want hospital birth but have previously tested positive for GBS and wish to take a more preventative and watch and wait approach. 

      I am not sure if you are planning to have any more children, but as you search for answers in the cause of your son’s allergies/eczema- I’m sure you will find that what you read will impact how you would like to influence the experience of your future children. I encourage you to explore your options for VBAC, or Microbirthing if you require another cesarean. 

      I hope that some of this has answered your questions, and stimulated some thought in regards to the birth of your son. 

      I wish you all the best. 

      Link for Cochrane Review – Having antibiotics in labour if you are GBS positive (best available evidence)

      Clinical Trials: 
      Preliminary Trial Release- Midwifery Clinic in Arizona USA- 

      If you haven’t seen this Documentary, it is also worth a watch. I think it is incredibly empowering on the topic of choices in birthing. 
      The Face of Birth 
      The Face of Birth official teaser: a film about the importance of choice in pregnancy and childbirth 

      Home – Microbirth 
      Home – MicrobirthDocumentary film revealing the microscopic events during childbirth that could hold the key to the future of humanity

  5. Wow Alisha, thank you for investing so much time and thought into your reply. There is a lot to get my head around and I appreciate all the links that I will start having a look at. 
    I have three beautiful boys and don’t plan on any more. Leading up to my third sons birth, it never occurred to me to question/challenge my GBS ‘status’ and the consequences.  If only I knew then what I know now!  But such is life and I’m grateful to be on a path to learning how I can help his gut bounce back.
    My doctor has had him on probiotics since birth and more recently on zinc and NAC also.
    Thanks again Alisha for inspiring me to learn more.

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