It is an understatement to say that pregnancy does some strange things to women’s bodies, from physical transformation to bizarre cravings for left-field food combinations. But it also provokes significant changes to the immune system that are essential to making sure the foetus isn’t rejected like any other interloper into the body.
This is just one of the reasons why, more than almost any other surgical procedure, caesarean sections can lead to infection: the patient’s natural defences against germs simply aren’t as vigilant as they normally would be.
“A C-section is never really a clean procedure,” says Dr Methodius Tuuli, whose research specialises in women’s reproductive health, particularly as it relates to birth. “Especially if you do it when a woman is already in labour, the risk of infection after caesarean section is higher than any other surgical process. We often simply don’t have the time to do the sterilisation work on the skin that we normally would.”
Bucking tradition
Much of Tuuli’s research is focused on mitigating these risks and bringing down rates of infection. Traditionally, iodine alcohol has been used as an antiseptic solution to prepare the skin for caesarean surgery. But it is not as effective as many might think. In medicine, and especially in obstetrics, Tuuli argues, a lot is done simply out of deference to tradition. Until someone comes along and proves that something else works better, not much changes. With rates of infection often as high as 5%, there is definitely room for improvement.
“It has a high efficiency, of course, compared with not using an antiseptic,” he says. “It played its part and people just kept using it because it was tradition; it is how they were trained and how they have always practised.”
Tuuli and his team thought they should try something new, replacing iodine with chlorhexidine, a common antiseptic and one that is often used in patient care when alternatives are not working as well as they should be. When thinking about what could replace the standard antiseptic, it seemed the obvious choice.
“The thought was that if we optimise the cleanliness of the skin before surgery, that has the potential to reduce infections,” he says. “We looked at the literature; we saw that there wasn’t very much written on the subject.
“So we set up this trial, firstly to get the data that didn’t exist, and secondly to resolve the issue of whether it was the alcohol [in the solutions] or the chlorhexidine that was responsible for any superior effectiveness.”
The trial turned out to be one of the largest ever done on a particular surgical procedure. Between September 2011 and June 2015, 1,147 patients were tested with either iodine or chlorhexidine.
Initially, many tests showed that the difference was negligible: cleaning the skin, from a surgical standpoint, could only reduce the kinds of infections happening at the surface level, not the organ-occupying kinds that often take place during caesarean sections. But, as trials continued, it gradually became clearer which was the more effective antiseptic: out of the 572 patients given the chlorhexidine solution, 23 developed an infection within 30 days. By contrast, of the 572 given the iodine solution, 42 – almost double – suffered an infection.
“We found that the rate of infection in women who were chlorohexidine alcohol skin-prepped was 4%, translating to a risk reduction of 45% when compared with iodine alcohol skin-prepping, and that was statistically significant,” says Tuuli.
Procedure of choice
Across the world, the number of women who are choosing to deliver children via surgery is on the rise. It is not hard to see why, given the choice, they would opt for caesarean section: it reduces the chance of a drawn-out, painful labour; the procedure reduces certain risks that may occur during natural childbirth; and it is often far more comfortable.
Part of the reason is that patients are changing, especially with increasing rates of obese and overweight women giving birth – women who are much more likely to have to undergo caesarean sections because labour tends not to go as smoothly for them. Women who have undergone the procedure in the past, Tuuli points out, are also much more likely to repeat the process for second, third or even fourth pregnancies.
The US’s litigious healthcare system and culture, too, could be playing a role in increasing numbers of surgical births: patients in the US are much more likely to sue their surgeon if there are complications than patients in Europe.
“It is easier to do a C-section,” explains Tuuli. “It takes a lot of skill and patience, and a willingness to take risks, to wait and say ‘we don’t need to do a C-section right now’. That element definitely plays a role for some physicians.”
Practice patterns in the US and the rest of the world help to account for the increasing rates of caesarean section. Physicians simply aren’t waiting as long as they normally would before concluding that labour is not going well and cervical dilation is not proceeding as it should.
Many patients are not even opting in, necessarily, but being given the procedure as a matter of protocol. A report published in the New York Times in January 2016 found that the most likely indicator of whether a person would undergo a caesarean section was the area in which they delivered the child and the progress at which labour is going when they arrive at the hospital.
Take the state of California, where rates of caesarean section in what are deemed ‘low-risk’ births (instances in which the procedure is not medically essential for the mother’s survival) are high, between 11.2% and 68.8%, and often the result of arbitrary rules. For example, some hospitals consider very heavy babies to always be grounds for the procedure, whereas other hospitals do not.
With one in three women in the US undergoing the procedure – a 50% increase over the past 15 years – rates of infection are on the rise. Because caesarean sections are becoming so common, there is a multiplier effect, and it is little surprise that, as with all surgery, things often go wrong.
“So even if the rate is 5%, and you deliver one in three babies with the procedure, that means over 1.3 million a year,” Tuuli explains. “That percentage really translates to a lot.”
Given the far-reaching nature of the findings and the implication for the long-term treatment of women in childbirth, it is not surprising that the findings, published in the New England Journal of Medicine in February 2016, garnered significant press coverage.
“For a new mother who needs to care for her baby – which is stressful even when all things are equal – having an infection can really impair her ability to do that,” says Tuuli. “We are very interested in clarifying the best ways to prevent these infections, reducing the burden on the patients, their infants and the healthcare system as a whole.”
Rethinking standards
As one of the largest such trials – and one with such clear-cut evidence in favour of its hypothesis – it will be impossible for clinicians and obstetricians to ignore Tuuli and his team’s findings. He has already heard from a range of hospitals that have been advising employees to begin using chlorhexidine and that are keen to get his professional advice about the practical issues involved in making the transition.
“They will continue to use iodine alcohol for those who are allergic to [the alternative], but the standard of care really, at least for C-sections, is now chlorhexidine alcohol,” he says. “I suspect that the next editions of guidance from the CDC on what we should be using for skin prep will likely change to say the data is now clearly in favour of providing it.”
Ultimately, Tuuli argues, this research gives clinicians another tool in the fight against infection in hospitals. With the increasing prevalence of superbugs in hospitals, it is more essential than ever for them to be equipped with the most effective antiseptics.
“I have no pretence that just one intervention will wipe out infection; skin prep using chlorhexidine alcohol will be one of several evidence-based interventions we should be looking for,” he says. “As of now, we are undertaking other types of trials to see if these interventions work.”
Part of these new interventions will involve homing in on subgroups of patients who are at a particularly high risk of infection: obese patients and those who undergo caesarean sections once labour has begun. Both groups are known to be particularly prone and would be helped by research focused on their needs. With a grant from the National Institutes of Health (NIH), one of the key funding agencies for healthcare products in the US, Tuuli and his team can begin to home in on these uniquely vulnerable patients.
“They are funding us to test a device which applies negative pressure prophylactically,” he says. “I think that the next steps will be testing, especially in high-risk women, to identify other tools in the fight against infection.”
Tuuli is lucky – this is exactly the kind of research that many researchers and clinicians dream of, one that has a very tangible effect on the lives of patients, and that could make the complex and often difficult process of childbirth that little bit easier for billions of women. And all it takes is a simple change in antiseptic
