In pregnancy, a ferritin below 30 micrograms per litre is treated as iron deficiency, and that’s true whether or not you are anaemic.
That threshold is higher than the lower limit printed on most pathology reports, which is why you can be told your iron is normal while your stores are low. If you are still planning a pregnancy, the same logic applies earlier and we cover it in ferritin before pregnancy.
What is a normal ferritin level in pregnancy?
A ferritin above 30 micrograms per litre is considered adequate in pregnancy, and a ferritin below 30 is diagnostic of iron deficiency.¹˒²
The South Australian perinatal guideline states it plainly: in pregnant women, a serum ferritin of less than 30 is diagnostic of iron deficiency.¹ The British Society for Haematology guideline, which Australian maternity services draw on heavily, uses the same cut-off and adds a second one: below 15 micrograms per litre indicates established deficiency with stores essentially empty.²
The guidelines don’t define an optimal number above 30. There is no evidence-based target of 50, or 70, or 100 in pregnancy, despite how often those figures circulate. 30 is a diagnostic threshold, not a goal.
Ferritin measures stored iron. That is the point of testing it, because it falls before your haemoglobin does, so it tells you about a problem while it is still easy to fix.
Why does a low ferritin come back marked normal?
Because the reference interval on your pathology report is not a pregnancy range. It describes the spread of results in a general adult population and the lower limit within the at-risk range sits well below 30.³
So a ferritin of 22 can be printed without a flag beside it and a clinician scanning the page for asterisks sees nothing to act on. The number is not wrong. It is being compared against the wrong benchmark.
This is the single most common reason women are told their iron is fine when a maternity guideline would classify the same result as iron deficiency requiring treatment.¹˒²
The questions that you should ask at each stage of your pregnancy are found in the first trimester checklist. Not “are my bloods okay”, but “what was my ferritin number, and is it above 30”?
Does the threshold change across your pregnancy?
No. The ferritin threshold of 30 micrograms per litre applies at all stages of pregnancy.²
What does change is the haemoglobin cut-off for anaemia, and the two are often confused. Anaemia is defined as a haemoglobin below 110 g/L in the first trimester, below 105 g/L in the second and third trimesters and below 100 g/L after birth.¹˒²
Those haemoglobin thresholds drop because your blood volume expands faster than your red cell mass, which dilutes the concentration. That dilution is normal and expected.
Your iron stores are a different question. They are being drawn down steadily to build your baby’s blood supply, so ferritin tends to fall as pregnancy progresses rather than hold steady. A result of 35 at 10 weeks and a result of 35 at 30 weeks do not carry the same reassurance, because the second one has further to fall.
Can your ferritin look normal when your iron is low?
Yes. Ferritin is an acute phase reactant, which means it rises when there is infection or inflammation anywhere in your body.¹˒²
So an infection, a flare of an inflammatory condition, or recent illness can lift your ferritin into the normal range while your stores are genuinely depleted. Both the Australian and the British guidelines flag this, and the British guideline suggests measuring C-reactive protein, a general marker of inflammation, alongside ferritin to help interpret a result that looks higher than expected.²
This is why clinical context matters more than the number alone. If your ferritin is 40 but you are exhausted, breathless on the stairs and were unwell the week of the blood test, that is a reasonable conversation to have rather than a closed case.
The reverse is also true. A low ferritin is almost always real, because nothing in pregnancy pushes it falsely down.
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Will your ferritin even be tested?
Not necessarily, and this is where Australian guidance genuinely disagrees with itself.
RANZCOG’s routine antenatal assessment guideline recommends a full blood count at your first visit and a repeat haemoglobin and platelet count at 28 weeks. It does not recommend routine ferritin, and names it only as a test to request when your mean cell volume is low.⁴
State maternity guidelines go further. The South Australian perinatal guideline recommends serum ferritin for all pregnant women at the booking visit and again at 28 weeks, with an extra test at 36 weeks for Aboriginal and Torres Strait Islander women.¹
So whether your ferritin gets checked can depend on where you give birth and who orders your bloods. Practice is patchier still. A retrospective audit of 150 births at a regional New South Wales hospital found only 5.3% of women completed the full screening the guidelines recommend, and haemoglobin-only testing was the most common pattern in every trimester.⁵ That was a single-site audit with incomplete records, so it describes one hospital rather than the country.
What happens if your ferritin is below 30?
A trial of oral iron is the usual first step, with intravenous iron considered if oral iron does not work, is not tolerated, or cannot be absorbed.¹
The Australian guideline positions intravenous iron from the second trimester onward for inadequate response to tablets.¹ That is a conversation with your doctor or midwife rather than a given, and it depends on how far along you are, how low your stores are, and how you are coping with tablets.
Oral iron is harder to take than it sounds. Stomach upset and constipation are common, the dose and the schedule both matter for how much you absorb, and taking more is not always the same as absorbing more. We go into getting the most out of tablets, and into infusions, in the iron and ferritin guide.
What this means for you
Ask for the number. “Was my ferritin tested, and what was the result” is a more useful question than asking whether your bloods were normal, because the answer you want is a figure you can compare against 30.
If your ferritin has not been tested and you are tired beyond what you expected, it is reasonable to ask for it, and reasonable to ask again at 28 weeks. If it is between 30 and 50 early in pregnancy, ask whether it should be rechecked later, since stores fall as pregnancy progresses.
If it is below 30, that is iron deficiency by guideline definition and worth treating properly, not watching. Your GP, midwife or obstetrician can work out which form of iron makes sense for you.
References
- SA Health. Perinatal anaemia and iron infusion. South Australian Perinatal Practice Guideline PPG018, version 1. Adelaide: Government of South Australia; 2022.
- Pavord S, Daru J, Prasannan N, et al. UK guidelines on the management of iron deficiency in pregnancy. Br J Haematol. 2020 Mar;188(6):819-30.
- [Verify before publishing: confirm the lower reference limit for serum ferritin printed by the pathology provider most of your readers use, then cite that provider's published reference interval or the RCPA manual here.]
- Royal Australian and New Zealand College of Obstetricians and Gynaecologists. Routine antenatal assessment in the absence of pregnancy complications (C-Obs 3b). Version 12.1. Melbourne: RANZCOG; 2022.
- Ebrahim M, Vadive PD, Dutton T, et al. Retrospective audit compares screening and treatment of pregnancy-related anaemia in regional New South Wales with Australian guidelines. BMC Pregnancy Childbirth. 2024;24:457.
Written by Bella · BBiomedSc, MEpi · Clinical epidemiologist
I read pregnancy research so you do not have to. More about me
Published: 12th October 2026 · Last reviewed: 12th October 2026
How I review research: Editorial policy
Educational only, not medical advice. Full disclaimer
This article is for educational purposes only and does not constitute medical advice. Research findings describe patterns across populations and may not apply to you. Always discuss your own situation with your GP, midwife or obstetrician.
