Group B Strep and Chlorhexidine

What are the issues when it comes to group B strep and chlorhexidine?

This is a topic that I have looked at in Group B Strep Explained, and it’s a tricky one. This post offers a fairly brief overview. If you’d like more depth on the evidence relating to GBS and the different options for women found to be carrying this bacteria in pregnancy, see my book.

What is Chlorhexidine?

Chlorhexidine is an antiseptic antibacterial agent in common use in many areas of health care and western medicine.

Chlorhexidine is classified as a medicine and is manufactured by companies in a range of preparations, dosages and forms (including liquid, washes, gels, creams and in pads and dressings). It is sold under a number of different brand names, including Hibiclens®, Hibistat®, Betasept®, Chlorostat®, Dyna-hex® and Stanhexidine®.

It is on the World Health Organisations’ Model List of Essential Medicines, which lists the, “…minimum medicine needs for a basic health care system, listing the most efficacious, safe and cost-effective medicines for priority conditions”. (Although is has been on that list as an antiseptic for some time, it was also added to the section covering neonatal umbilical cord care in 2013, on the basis of the results of research carried out in Bangladesh, Nepal and Pakistan. I’ll come back to that in a bit.)

Chlorhexidine and GBS

Group B Strep Explained; the updated second edition of a popular book which helps parents, professionals and others to understand the issues and the evidence relating to the screening and prophylactic measures offered in the hope of preventing early-onset group B strep (EOGBS) disease.

Chlorhexidine is also sometimes used by pregnant women in a very specific context.

It is sometimes used to flush out the vagina, in the hope of clearing it of group B strep (GBS) bacteria.

In my experience and understanding, there are two reasons why a woman might want to attempt to clear GBS bacteria from her vagina:

1) To reduce the chance that GBS bacteria is passed on to her baby.

2) To reduce the chance of having a positive result to a GBS test which she feels unable to avoid. This might be, for instance, because a negative GBS result is the ‘pass’ that gets her into a particular birth centre, or that enables her to remain in the care of a midwife.

Where it gets tricky…

Both of these reasons sit within incredibly complex and uncertain contexts.

Current evidence (and more on that below) doesn’t show that the practice of douching with chlorhexidine makes any difference to the chances of a baby becoming ill as a result of GBS infection. But some women do it out of desperation, for the second reason above. The fact that some women feel the need to use a home-based intervention as a means of circumventing medical intervention obviously raises myriad issues which are worthy of further and deeper discussion.

Let’s look at the evidence. Again, this blog post is merely a summary and there is far more detail and depth in the book.

A systematic review

In 2018, researchers (Bell et al 2018) reviewed the effectiveness of intrapartum vaginal chlorhexidine in the reduction of maternal and neonatal colonisation and infectious morbidity. Their paper was titled, What is the result of vaginal cleansing with chlorhexidine during labour on maternal and neonatal infections? A systematic review of randomised trials with meta-analysis.

Here are their results:

“Eleven randomised controlled trials (n = 20,101) evaluated intrapartum vaginal chlorhexidine interventions. Meta-analysis found no significant differences between the intervention and control groups for any of the four outcomes: maternal or neonatal colonization or infection. The preferred method for chlorhexidine administration was vaginal irrigation.

Meta-analysis did not demonstrate improved maternal or neonatal outcomes with intrapartum vaginal chlorhexidine cleansing, however this may be due to the limitations of the available studies. A larger, multicentre randomised controlled trial, powered to accurately evaluate the effect of intrapartum vaginal chlorhexidine cleansing on neonatal outcomes may still be informative; the technique of douching may be the most promising.” (Bell et al 2018)

So they did not find any effect, but they did note that this may be due to the limitations of the studies. They suggest that there is ample justification to carry out further research.

The downsides

There are also downsides to using Chlorhexidine as a means of attempting to reduce GBS colonisation.

The first is the concern that chlorhexidine is not safe for newborn skin, especially for babies who were born preterm. This issue has been discussed by several groups of researchers, including Tamma et al (2010), whose survey showed that most of the US neonatal units they surveyed were using chlorhexidine despite safety concerns, and Lashkari et al (2012), who described and photographed a case of a very preterm baby with chlorhexidine-induced burns.

In June 2014, the UK Medicines and Healthcare Products Regulatory Agency released a statement about the risk of chemical burns when chlorhexidine was used on the skin of preterm babies in neonatal intensive care units:

“We have received 14 reports of serious side effects in premature infants who were treated with chlorhexidine solution before central venous catheterisation (umbilical catheterisation or long line insertion). Another 14 cases were identified in the medical literature. The side effects included erythema and chemical burns with and without skin loss. Four of these cases had a fatal outcome, although severe complications of prematurity might have contributed to two of the fatal cases. The chemical injuries occurred in infants of less than 32 weeks gestation and within the first few days of life when alcohol based chlorhexidine solutions (0.5% or 2% in 70% alcohol) or 2% aqueous chlorhexidine solutions were used.” (Full statement here).

Are there better alternatives?

At the time that these risks were being discussed in the literature, a discussion about chlorhexidine and possible alternatives took place in The Lancet.

Maiwald et al (2014) wrote a letter questioning the results of a trial that was originally published more than two decades ago (Maki et al 1991). This trial had evaluated the efficacy of different substances in preventing infection in intravascular devices (central venous and arterial catheters, or tubes which are used to pump fluids into patients’ blood vessels, usually in an intensive care situation). Maki et al (1991) found that, compared to 10% povidone-iodine or 70% alcohol, 2% chlorhexidine substantially reduced the incidence of device-related infection.

Maiwald et al (2014) are clearly concerned about some of the claims of Maki et al’s (2014) research, which they came across ‘while investigating the relevant literature’. Their concern seems to relate to the fact that Maki et al’s (1991) research is one of those studies which has gained prominence in an area and is often cited, despite being potentially flawed. (Those who know me well may now understand why this caught my eye.)

Maiwald et al (2014) go on to point out several methodological issues with Maki et al’s (1991) paper alongside the fact that that earlier research by the lead author “…was supported by a chlorhexidine-producing company”.

Maki et al (2014) understandably responded and defended their paper and position while challenging Maiwald to put his own beliefs on (randomised controlled) trial.

The debate continued, and the entire situation became like a game of research tennis. At this point, the only way to really understand what’s going on it to spend many hours digging into the literature. Even then, we only ever see the things that researchers want to tell us. This is one of many reasons why I talk and write so much about the importance of looking into the issues more deeply, or reading things written by people who have done that.

The bigger picture

There is no doubt that antibacterial drugs and substances such as chlorhexidine can be life-saving when used appropriately. But we must not become so used to the existence of such substances in medical settings that we become complacent about their possible side effects or forget to consider the bigger picture surrounding their use and value.

Right now, we don’t have good answers about the use of Chlorhexidine for GBS. All we can do is to take people through the evidence and information we do have, so that they can make the decisions that are right for them.

And, I hope, continue to talk about how it is disgraceful that some women and families are having to turn to home interventions they don’t really want, just so that they can jump through the hoop that is the gateway to getting the care they need.

References

Bell C, Hughes L, Akister T et al (2018). What is the result of vaginal cleansing with chlorhexidine during labour on maternal and neonatal infections? A systematic review of randomised trials with meta-analysis.BMC Pregnancy and Childbirth 18:139. https://doi.org/10.1186/s12884-018-1754-9

Lashkari HP, Chow P, Godambe S (2012). Aqueous 2% chlorhexidine-induced chemical burns in an extremely premature infant. Arch Dis Child Fetal Neonatal Ed 2012; 97: F64.

Maiwald M, Assam PN, Chan ES-Y et al (2014). Chlorhexidine’s role in skin antisepsis: questioning the evidence. The Lancet, 384(9951): 1344-1345

Maki DG, Alvarado CJ, Ringer M (1991). Prospective randomised trial of povidone-iodine, alcohol, and chlorhexidine for prevention of infection associated with central venous and arterial catheters. The Lancet, 338(8763): Pages 339-343

Maki DG (2014). Chlorhexidine’s role in skin antisepsis: questioning the evidence–Author’s reply. The Lancet. 384(9951): 1345-46. Chlorhexidine solutions: risk of chemical burn injury to skin in premature infants. MHRA Drug Safety Update 7(11):S2.

Tamma PD, Aucott SW, Milstone AM (2010). Chlorhexidine use in the Neonatal Intensive Care Unit: Results from a National Survey. Infect Control Hosp Epidemiol. 31(8): 846–849.

Wickham S (2018). Group B Strep Explained. Avebury: Birthmoon Creations.