Questioning induction of labour in older women

As a student midwife, I looked after a few women who were having their first baby near or around the age of 40. As far as I can recall, my mentor midwives had two main concerns. The first was the slight increase in the chance of congenital problems that occurred with each additional year of maternal age, a subject which they raised in a kindly manner before explaining the range of available screening tests, noting the risks of testing, and reassuring women that it was also OK to decide not to have testing. (This was in the days when we had time to talk women through such things and help them make the decisions that were right for them.)

The second thing of concern to some of my mentors was whether those older-than-average women would have a good labour, given that these midwives had a theory – based purely on their own observations, I should add – that women who were older tended to have read more and to take longer to get ‘out of their heads and into their bodies’ when they were in labour. I’m not sharing that because I think it’s true, but as a reflection on how times have changed.

 

How times change

Nowadays, midwives have another topic to discuss with older women: the question of early induction. Some midwives are feeling they need to raise this topic early on, even if just to warn older women to be aware that their 39th week of pregnancy may be interrupted by someone wanting to schedule an induction date out of the blue. Older women may also be told they need more monitoring or intervention, whether or not their labour is induced. But, as the early induction recommendation seems to be taking hold around the country, I keep wondering whether the negative bias towards older mothers is justified and whether the evidence really supports the recommendation to induce labour early?

 

Note: This is a 2016 article. I have an updated blog post on this topic here.

 

I can’t possibly do justice to such an enormous question in a couple of pages, but I would like to share a few thoughts and look at some of the issues that aren’t getting quite as much press. One of these is the excellent point made by Rosemary Mander about the way we view pregnancy, birth and motherhood in older woman:

‘Research reports and recommendations ‘ tend to ignore the positive aspects of advancing maternal age. These include the likelihood that psychological and social strengths, such as increased confidence, may more than compensate for any biological problems with which advanced age may be associated’ (Mander 2013: 49).

 

Will we just increase intervention?

Rosemary was responding to a discussion paper published by the Royal College of Obstetricians and Gynaecologists (RCOG) (2013) which suggested that induction should be routinely offered to women aged 40 years or more at 39-40 weeks gestation, in the hope of reducing the rate of stillborn babies. (In practice, induction is now being offered to even younger women, but I’ll come back to that in part two of this article.)

One problem is that the data that we have in this area are equivocal and often lacking, and there is more than one way of responding to such uncertainty. While bodies such as the RCOG (2013) err on the side of recommending intervention, it is also possible that a policy of advising older women to have their labour induced will increase the problems and intervention experienced by this group of women and babies without making a significant difference to the stillbirth rate. When we have areas in which differences between different courses of action are marginal and the size of any potential benefit or loss is unknown, shouldn’t women be told about both sides of the debate and supported in making the decision that is right for them and their family?

 

That lumping problem again

While research has suggested that there may be an association between increased maternal age and a higher chance of certain types of complication, this finding is not straightforward. For instance, Huang et al (2008) carried out a meta-analysis which showed that older women may be more likely to have a stillbirth than younger women, and yet the researchers themselves noted that the magnitude and mechanisms of this increased risk weren’t clear and that further research was needed.

This doesn’t stop people quoting the Huang et al finding in support of routine induction, and yet Huang et al‘s point about the magnitude of any increased risk being unknown is vitally important. It is possible that the size of this increased risk varies so much between the included studies because the included studies themselves were really varied. Some studies were recent and some were 20 years old. Some included healthy women and some included women with illnesses or problems. There was no consensus as to what the cut-off point for ‘advanced maternal age’ was, and the studies also defined stillbirth itself differently, in that they used different cut-off gestational points.

 

How can we individualise?

As has been the case with other research into induction (Wickham 2014), this lumping together of such a variety of studies can be really problematic. It also raises an important question for women: if the data influencing practice are generated from studies which pool large numbers of very different women, then how can individual women hope to be able to get information specific to their situation? If you are a healthy woman, then surely you want to know what a healthy woman’s chances are and not what the data are for the whole population, which includes women with problems or medical conditions that might in themselves increase their chance of problems?

The RCOG are aware of this issue and sought out studies which controlled for some of these factors, but the only studies left then include data from women who gave birth 30 or more years ago, when midwifery and obstetric practice was (as I mentioned above) rather different. Women’s lives may be very different too, in all manner of ways.

It’s just so hard to find good data and, no matter which studies I look at, I haven’t found evidence that convinces me that routine induction of labour in older women is justified. But a recent randomised controlled trial set out to look at this area and its results have further ignited discussion.

 

The admirable goal of stillbirth reduction

It is vital that we consider whether and how we can prevent or reduce stillbirth. But history teaches us that ill thought-out prevention efforts can sometimes backfire and cause knock-on poblems without having the intended positive effect. It is because of this that we should always ask whether it is rational to implement a particular policy, and part of our decision should include consideration of whether the proposed change is supported by robust evidence. We have been implementing intervention without robust evidence of benefit for far too long and I would argue that this is one of the underlying causes of the muddle that modern maternity services are in. This muddle includes high intervention rates, a generation of women who have been taught to distrust their bodies and professionals who are tired, de-skilled and frustrated by the gap between what they know and what they’re forced to do.

I find it difficult to understand how policymakers can justify the introduction of practices which they claim are designed to reduce stillbirth and yet which are based on expert opinion or on just one perspective rather than on careful consideration of the evidence and the wider issues. Such changes are particularly galling when we look back at the history of evidence-based practice and see that the forefathers of this ideology were trying to move away from the situation where doctors were reliant on guesswork because robust evidence wasn’t available. We now also have considerable knowledge from the fields of ethics, social science and human rights law about how people should be treated, and yet practice is still often rooted in a fear-based, adversarial and risk-focused approach.

 

The 35/39 trial

Researchers have recently published the first paper from a randomised controlled trial that set out to evaluate the effect of early induction of labour (at 39 weeks) in older women (Walker et al 2016). This study has been termed the 35/39 trial, because it defined older women as those aged 35 and above. Although many people thought that this study was going to compare stillbirth rates between the two groups, this was actually not the aim. Instead, the authors were trying to determine whether early induction led to an increased chance of caesarean section.

The study experienced really low recruitment levels when 86 per cent of the women who were asked to be in the study declined to participate. This might be because many women aren’t enamoured with the notion that they should undergo early induction of labour simply because of their age. Or perhaps they aren’t happy with the idea that the mode of onset of their labour should be randomly determined. In the end, only 619 women were randomised into the study. There were no maternal or neonatal deaths in either group and no significant differences in the women’s experiences or in the frequency of adverse outcomes. Given that the study included only a small fraction of the women who were invited to participate and that those who took part didn’t mind whether their labour was induced or began spontaneously, it may be prudent to take the lack of difference in women’s experiences between the two groups with a pinch of salt. The 86 per cent of women who didn’t want to be in the trial may have felt very differently from those who were OK with the notions of intervention and randomisation.

 

No differences, but does that mean anything?

As with some other induction studies, the data showed no difference in caesarean section rates between the two groups, but even the Royal College of Obstetricians and Gynaecologists (RCOG) (2013) paper acknowledges that professional decision-making features prominently in determining this outcome, as I have discussed elsewhere (Wickham 2014). Research by Wang et al (2011) and Carolan et al (2011) has also confirmed that there is a lower threshold for caesareans in older women. When caregivers become worried that being older is a risk factor, they tend to suggest intervention sooner. The intervention itself can cause more problems, such as increased bleeding, and a self-fulfilling prophecy is created.

 

Will this change practice?

When areas of practice are as complex and uncertain as this one is, it seems prudent to take a wider view on the subject and try to increase our understanding before we wade in with significant policy changes.

This, however, doesn’t seem to be happening. I am hearing from colleagues in different areas that older women are being told they are at risk and that early induction is being recommended on the basis of this study and before further research is undertaken. Yet the study showed no benefit to induction, it was underpowered to compare outcomes and its authors state that this wasn’t its intention anyway. Few people are looking deeply at the issues or paying attention to the voices of the 86 per cent of women who said no to being in this study, or to others like them.

It’s clear that some women who are older experience more problems and that we need to continue to explore this area, ideally with better-quality research than we currently have. But this is a complicated issue, and there are many other facets to health than age alone. Having looked at some of the evidence on this topic, it’s even clearer to me that there is not a straightforward solution to this in the form of a routine recommendation for early induction of labour. If only more people could take a wider view, we might begin to get some better and more woman-centred answers.

 

References

Carolan M, Davey MA, Biro MA et al (2011). ‘Older maternal age and intervention in labor: a population-based study comparing older and younger first-time mothers in Victoria, Australia’. Birth, 38(1): 24–29.

Huang L, Sauve R, Birkett D et al (2008). ‘Maternal age and risk of stillbirth: a systematic review’. Canadian Medical Association Journal, 178(2): 165-172.

Mander R (2013). ‘Induction of labour for advancing maternal age’. EM, 4(8): 46-49.

RCOG (2013). Induction of labour at term in older mothers, London: RCOG.

Walker KF, Bugg GJ, Macpherson M et al (2016). ‘Randomized trial of labor induction in women 35 years of age or older’. New England Journal of Medicine, 374(9): 813-822.

Wang Y, Tanbo T, Abyholm T et al (2011). ‘The impact of advanced maternal age and parity on obstetric and perinatal outcomes in singleton gestations’. Archives of Gynecology and Obstetrics, 284(1): 31–37.

Wickham S (2014). ‘Does induction really reduce the likelihood of caesarean section?’ TPM, 17(8): 39-40.

 

This article was originally published as Wickham S (2016). Questioning induction of labour in older women. TPM 19(7):36-37 and  TPM 19(8).

 

photo credit: Leo Reynolds Puffy Sticker Punctuation question mark via photopin (license)

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