It starts with a simple enough question: What should women’s ferritin levels be in pregnancy? But the answer will surprise many. There are in fact two. The first reflects the practice guidelines for GPs and obstetricians in most western countries regardless of trimester and then there’s another, that is arguably more evidence based, accounts for the essentiality of physiological anaemia in pregnancy & is also, sensibly, trimester specific. To challenge the ‘noise’ and have the confidence that ‘normal’ is ‘enough’, we need to better understand the mother’s protective physiological adaptation of iron regulation and the intricate systems the foetus has to ensure its needs are met. This of course is not without limit, so we need to also be clear about the maternal serum ferritin threshold for negative impact on the foetus and newborn. Getting the balance or iron right in pregnancy for both mother and baby, is perhaps easier than we have been led to believe.