Epidural Fever

Epidural fever is the colloquial term used to describe a side effect thought to be associated with epidural analgesia: an increase in the maternal and neonatal temperature and pulse.

We have known about this possible side effect for at least a couple of decades, and there’s no easy answer to the problem it causes, wherein lots of women and babies end up with unnecessary testing (known in some areas as a septic work-up) and/or antibiotics as a result of having epidurals.

Having a raised temperature and pulse is also a sign of infection, and infection in childbearing women and babies is not something to take lightly.

We can’t dismiss a raised temperature in a woman or baby who have been exposed to epidural analgesia just because it’s a known side effect, because a proportion of those women and babies will actually have an infection.

But, as I first wrote some time back in an article called Epidural Fever, “surely we need to find some way of ensuring that women who have epidurals are not automatically signing themselves and their babies up for antibiotics, longer hospital stays and the potential impact these things may have on their first days together.”

This blog post contains the original article that I wrote on this in 2002, along with a few later pieces of research which added to our knowledge.

Here’s a clinical mystery…

On one postnatal ward in a fairly average hospital at the beginning of this year, almost a third of the women were being given antibiotics. Several of these women’s babies were also receiving antibiotics. In all of these cases, the antibiotics were being given prophylactically in response to symptoms of pyrexia and / or tachycardia following labour and birth while clinical staff awaited the results of swab tests. Yet by the time the swab cultures came back showing nothing abnormal had grown and all of the women’s and babies’ symptoms had resolved.

This is one of my older articles; first published in 2002. This is still an issue in some areas, though not in others. I’ve added some more recent studies below.

This could be the bare bones of a plot line for a Robin Cook novel; what caused these women and babies to show symptoms of infection, where no infection could later be found? Have we discovered a new and insidious wonder bug that causes people’s temperature and pulse to become raised without appearing on lab slides?

The truth of this scenario is less of a mystery than it might sound if one considers one other piece of information. All of the women on this postnatal ward who were being given prophylactic antibiotics (or whose babies were having these) had an epidural during labour. It seems the answer to this might be found in epidemiology rather than science fiction.

Since 1989, if not before, we have known that epidural analgesia increases maternal and neonatal temperature and pulse and that this should be noted as a potential side effect for women who have used this in labour. In one study (Fusi et al 1989), where a group of women who had epidural were compared to women having pethidine, the mean temperature of the women having an epidural had risen within six hours of its administration. This rise was not related to any clinical evidence of infection. The women and babies who experienced epidural-induced pyrexia were also more likely to experience tachycardia.

These findings are supported by other studies. One showed that nearly a third of babies whose mothers had epidurals became pyrexic during labour itself, with five percent of babies reaching a temperature of over 40°c; the point at which the authors felt neurological injury could be sustained (Macaulay et al 1992). Research carried out by paediatricians highlighted the problems with the over prescription of antibiotics to neonates whose mothers had had epidurals, estimating that babies whose mothers had received an epidural were four times as likely to be treated with antibiotics (Lieberman et al 1997). The studies showed that this is not simply an occasional side effect, but something which affected the majority of women who have an epidural.

If antibiotics were completely safe and no knock-on effects ensued from the practice of treating pyrexia, guidelines suggesting prophylactic treatment of signs of infection might not be so problematic. Unfortunately, some of the other aspects of this scenario caused real problems to the affected women. Women were prevented from going home when they would have liked to because their babies were receiving intravenous antibiotics. Others suffered from the effect that antibiotics can have on the immune systems of women and babies, including iatrogenic thrush.

There are lots of risks which women should know about before deciding on an epidural. Increased likelihood of systemic infection is not usually cited as one of them. However, perhaps the increased likelihood of women and babies being treated for the symptoms of an infection which may not exist is something that women should be told about? This might be one way to solve the problem, as there is reason to suppose that a great many practitioners are not aware of this. While in some units practitioners are aware that this is a common finding in women who have had epidurals, others – as in the example above – either remain unaware, or unable to do anything about it because of rigid policies regarding the prophylactic administration of antibiotics in the presence of fever.

Another way of dealing with this situation is to use the knowledge that these symptoms can be caused by epidural to make individual clinical decisions with women who experience these symptoms. Of course, this will not sit well with those who like to err on the side of caution and risk, and who are more comfortable with the idea of acting on a particular symptom in a prescribed way. Some people would argue that a proportion of these women and babies may actually have infections for which they should be offered antibiotics. It would be no more helpful to suggest never offering antibiotics to women and babies with signs of infection than the current situation is some areas where women and babies with signs of infection where this might be caused by epidural are always offered antibiotics.

It is well understood that infection, particularly in babies, can be potentially dangerous. But in my own practice, I have rarely seen a baby with an infection whose only symptom was pyrexia; generally they tend to show one or more other symptoms, such as breathing anomalies, being unresponsive, floppy or jittery, not feeding well or seeming generally unsettled. In fact, one text on neonatal care (Kelner et al 1995) suggests that fever should not be considered essential for the diagnosis of neonatal infection. The authors argue that the first signs of infection tend to be non-specific and behavioural, and that waiting for any concern to be confirmed by a raise in temperature can lead to a delay in treating the infection.

Similarly, it is relatively simple to explore other signs of infection with women, by looking at what happened during their birth, the condition of the placenta, and whether they are experiencing any discomfort or other symptoms. They can then make an informed choice about whether they would like antibiotics ‘just in case’, or whether they would prefer to wait a few hours to see if their temperature returns to normal.

However we do it, surely we need to find some way of ensuring that women who have epidurals are not automatically signing themselves and their babies up for antibiotics, longer hospital stays and the potential impact these things may have on their first days together.

Fusi L, Steer PJ, Maresh MJA, Beard RW (1989). Maternal pyrexia associated with the use of epidural analgesia in labour. Lancet 1989: 1:1250-52.

Kelnar CJH, Harvey D, Simpson C (1995) The sick newborn baby 3^rd ed. Bailliere Tindall, London.

Lieberman E, Lang JM, Frigoletto F et al (1997). Epidurals, maternal fever, and neonatal sepsis evaluation. Pediatrics 99:415-19.

Macaulay JH, Bond K and Steer PJ (1992) . Epidural analgesia in labor and fetal hyperthermia. Obstetrics and Gynecology 80(4):665-69.

More recent research

A few papers have been published since I wrote the article which I think are worth looking at if you’re interested in this area. Each of them (and especially the last one) have decent reference lists which will allow you to look into this further if you wanted to do that.

Agakidis et al (2011) undertook a retrospective observational study of 480 babies and showed that epidural analgesia was an independent risk factor for neonatal pyrexia even after controlling for intrapartum pyrexia and other potentially confounding factors. In their study, babies born to women who had epidurals were five times more likely to have a sepsis work-up than babies born to women who did not have epidurals. They concluded that “epidural analgesia in labor is an independent risk factor for pyrexia in term neonates. It is unnecessary to investigate febrile offspring of mothers who have had epidurals unless pyrexia persists for longer than 5h or other signs or risk factors for neonatal sepsis are present.”

Heesen at al (2012) published a review of five studies (including two RCTs and three observational studies) reporting the outcomes of 4667 women, concluding that “Our data suggest that EDA-related maternal hyperthermia results in an increased likelihood of sepsis workup and antibiotic treatment of the infant. A crucial question is whether EDA-related maternal hyperthermia is truly infectious. If not, administration of antibiotics would not be justified and may be dangerous.”

A 2013 review of this topic by Arendt and Segal showed that this area was not quite as straightforward as we originally thought. While they did not go so far as to refute this association, they describe it as complex and controversial, and highlight a number of concerns with some of the studies, including the suggestion that women who have longer labours are more likely to get an infection (and therefore a fever) and are more likely to request an epidural. They also point out that the studies of this area have tended to compare women who had epidurals to women who had opiod or other analgesia, and it is well understood that some (non-epidural) analgesics have an antipyretic (temperature-reducing) effect. As Arendt and Segal (2013) suggest, we really need to compare women who had epidurals to women who were unmedicated.

They conclude that, “With the current popularity of epidural analgesia in labor, it is important that clinicians delineate how epidurals cause maternal fever and how to block the noninfectious inflammatory response that seems to warm a subset of women laboring with epidurals.”

References

Agakidis C, Agakidou E, Thomas SP et al (2011). Labor epidural analgesia is independent risk factor for neonatal pyrexia. Journal of Maternal-Fetal and Neonatal Medicine 24(9):1128-1132.

Arendt KW and Segal BS (2013). The association between epidural labor analgesia and maternal fever. Clinics in Perinatology 40(3): 385-98.

Heesen M, Klohr S, Rossaint R et al (2012). Labour epidural analgesia and anti-infectious management of the neonate: a meta-analysis. Journal of Perinatal Medicine 40(6): 625-630.

Wickham S (2002). Epidural Fever. TPM 5(8):21.