Obstetric cholestasis – who is really at risk?

A recent systematic review and meta-analysis has such positive implications for a particular group of women that I made it my study of the month in our March 2019 Birth Information Update and, for anyone who isn’t yet on our newsletter list, I wanted to share it here too.

The paper, by Ovadia et al (2019) was published in The Lancet and it is open access. It is about women who are diagnosed with obstetric cholestasis (which is also known as intrahepatic cholestasis of pregnancy). We have long known that these women have a higher chance of adverse outcomes, including preterm birth and possibly stillbirth (Ovadia et al 2019). However, although it has long been suspected that the outcomes worsen with the severity of the condition, we did not have good evidence about this and about exactly which women had a higher chance of having a problem. As a result, many women with this condition have been advised to have intervention, including early induction of labour, but without good evidence about whether or not this would make a difference.

But a systematic review and meta-analysis by Ovadia et al (2019), which also includes unpublished data from two UK hospitals has now greatly added to our knowledge, and the key finding will make things a lot clearer for women who develop this condition. Here it is:

“The risk of stillbirth is increased in women with intrahepatic cholestasis of pregnancy and singleton pregnancies when serum bile acids concentrations are of 100 μmol/L or more. Because most women with intrahepatic cholestasis of pregnancy have bile acids below this concentration, they can probably be reassured that the risk of stillbirth is similar to that of pregnant women in the general population, provided repeat bile acid testing is done until delivery.” (Ovadia et al 2019).

I have looked after several women with ICP over the years whose serum bile acids were considerably lower than this cut-off point but who were offered early induction of labour because, at the time, we didn’t have better data. These findings mean that we can now focus on the very small number of women whose babies may genuinely be at greater risk. And, as with everything, we can still only talk about risks and relative chances, and I’m not suggesting that every woman whose serum bile acid levels are above this will want intervention when they weigh up the pros and cons in relation to their individual circumstances, but this is a great example of a paper which is really going to help us to determine which women and babies may truly benefit from intervention and which will not.

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Ovadia C, Seed PT, Sklavounos A et al (2019). Association of adverse perinatal outcomes of intrahepatic cholestasis of pregnancy with biochemical markers: results of aggregate and individual patient data meta-analyses. The Lancet 393(10174): 899-909. March 2, 2019.