The short answer: Iron tablets often cause nausea, stomach pain and constipation, so many women quietly stop. In India, only 44% of pregnant women take iron for the full 100 days. Timing, food and a gentler iron form can help, but never change a prescribed dose without your doctor.
Why is everyone talking about iron tablets right now?
You were handed a strip of iron tablets. Maybe at your first pregnancy check-up, maybe after a blood test. A week later, your stomach hurt and you felt sick. So the strip went into a drawer.
If that sounds familiar, you are in very large company. A July 2026 study in BMC Pregnancy and Childbirth looked at 174,947 Indian women [1]. All of them got iron and folic acid (IFA) tablets during pregnancy [1]. It used data from the National Family Health Survey, NFHS-5 (2019-21).
The paper notes that more than 85% of women who gave birth were given or bought IFA tablets [1]. But only 44% took them for the recommended 100 days or more [1]. Medical Dialogues covered the study on 6 October 2026, which is why it is in the news now [2].
This matters because anaemia is so common here. NFHS-5 found that 57% of Indian women aged 15 to 49 are anaemic [10].
Why do so many women stop taking iron tablets?
The study authors list the reasons other research has found again and again [1]. The most common ones are:
- Simply forgetting, day after day.
- Side effects from the tablets.
- The size and taste of the tablets.
- Not knowing how long, or how, to take them.
Money and support also played a part. The poorest women had 1.6 times the odds of not reaching 100 days, compared with the richest [1]. Women with fewer check-ups, or whose husbands never came to a visit, were also more likely to stop [1].
So stopping is not a personal failure. It is a pattern, and it has fixable causes.
Are iron tablet side effects real, or is it in your head?
They are real. A 2015 review pooled 43 trials with 6,831 adults [3]. It looked at ferrous sulfate, the classic, cheap iron salt found in many tablets.
People taking ferrous sulfate had 2.32 times the odds of stomach and gut side effects, compared with people on a dummy pill, a placebo [3]. In plain words, the tablets roughly double your chances of tummy trouble. The same review did not find a clear link between dose and side effects [3].
The UK's National Health Service (NHS) lists the common ones [4]:
- Feeling or being sick.
- Stomach discomfort or heartburn.
- Losing your appetite.
- Constipation, or sometimes diarrhoea.
- Darker than usual poo.
Is black poo from iron tablets normal?
Darker poo is common on iron and is usually nothing to worry about, says the NHS [4]. Still, it is one of the things that scares many women into stopping.
But there is a line you should know. Call a doctor straight away if your poo is black and tar-like, red, or has blood in it [4]. The same applies if you also feel unwell in any other way [4]. Tar-like stool is sticky and shiny, not just dark.
How can you make iron tablets easier on your stomach?
Here is the honest trade-off. The NHS says ferrous sulfate works best on an empty stomach, 30 minutes before food or 2 hours after [5]. But if it upsets your stomach, you can take it with or after food [5].
A tablet you actually take beats a "perfect" tablet sitting in a drawer. Talk to your doctor about which timing suits you.
A few other things that the NHS and research support:
- Keep chai away from your iron. The NHS says to leave a 2-hour gap between iron and tea, coffee, eggs or dairy [5]. A classic study found black tea with a meal cut iron absorption by 79 to 94% [8].
- Even a 1-hour gap helps. In a small 2017 trial of 12 women, drinking tea 1 hour after the meal roughly halved tea's blocking effect [9].
- Ask about vitamin C. A doctor may suggest taking iron with orange juice or vitamin C, which is believed to help absorption [5].
- Fight constipation with food. More fibre from fruit, vegetables and whole grains, plenty of water and a daily walk can help [4].
- Use a reminder. If you often forget, set a phone alarm, the NHS suggests [5]. If you miss a dose, do not take two together [5].
Is iron bisglycinate gentler than regular iron tablets?
Iron bisglycinate is iron bound to glycine, a small amino acid. Think of it as iron wrapped in a protective coat.
A 2023 review in Nutrition Reviews pooled 17 trials comparing it with other iron forms [6]. In pregnant women, 4 to 20 weeks of iron bisglycinate gave higher haemoglobin, the iron-carrying protein in red blood cells [6]. It also came with about a third as many gut side effects [6].
That is promising, but notice the fine print. The clear benefit was found in pregnant women. In children, the review found no difference [6].
Can you just switch to a gentler iron at a lower dose?
Not on your own. A 2023 trial in 480 non-pregnant women in Cambodia tested exactly this idea [7]. One group took 18 mg of iron as bisglycinate. Another took 60 mg as ferrous sulfate. A third took a placebo.
After 12 weeks, ferritin, the protein that stores iron in your body, was 99 in the sulfate group [7]. It was 84 in the bisglycinate group and 78 on placebo [7]. The lower bisglycinate dose was not as effective [7].
So a gentler form is not a shortcut around the dose. If your doctor has prescribed IFA, especially in pregnancy, keep taking it as advised. If side effects are stopping you, tell your doctor. Ask about timing, a different form, or other options. Do not quietly swap or stop.
What this means if you...
...are pregnant and have stopped your IFA tablets
You are not alone, and it is not too late to talk about it. Tell your doctor or ANM what happened, in plain words. "The tablets made me vomit" is useful information. They can suggest a different timing or another option. Please do not restart, double up or switch on your own.
...are not pregnant but were told your iron is low
Ask what your ferritin number is, not just your haemoglobin. Ask how long you should take iron and when to re-test. The NHS notes that iron is often continued for 3 to 6 months after levels improve, to refill your stores [5].
...take iron, then chai, every morning
Move one of them. Even a 1-hour gap between your iron and your tea helped in the 2017 trial [9]. The NHS suggests 2 hours [5]. Your morning chai can stay. It just needs its own time slot.
Where AIM stands
We are building FORGE, launching soon. It is a daily sachet with 9 mg of elemental iron as iron bisglycinate and 80 mg of vitamin C. It also has 5 g of creatine monohydrate and BioPerine. We chose bisglycinate because the evidence on gut comfort is encouraging, mainly in pregnant women. But 9 mg is a daily-top-up amount. It is not a replacement for iron your doctor has prescribed for anaemia or pregnancy, and we will never say it is.
Frequently asked questions
Why do iron tablets make me feel sick?
Iron salts like ferrous sulfate irritate the stomach and gut in many people. A 2015 review of 43 trials found ferrous sulfate roughly doubled the odds of gut side effects compared with a placebo. The NHS says taking it with or just after food can ease nausea, though absorption is best on an empty stomach.
Is it normal to get constipation from iron tablets?
Yes, constipation is one of the common side effects listed by the NHS. More fibre from fruit, vegetables and whole grains, plenty of water and a daily walk can help. If it does not settle, speak to your doctor or pharmacist rather than stopping your iron on your own.
How many days should pregnant women take iron and folic acid tablets?
Indian research measures adherence against at least 100 days, and also 180 days, of IFA during pregnancy. A 2026 study of NFHS-5 data found only 44% of pregnant women reached 100 days. Your doctor will tell you the exact plan for your pregnancy, so follow their advice.
Can I drink tea after taking an iron tablet?
Yes, but leave a gap. Black tea taken with a meal cut iron absorption by 79 to 94% in one classic study. The NHS suggests a 2-hour gap between iron and tea, coffee, eggs or dairy. A small 2017 trial found even a 1-hour gap roughly halved tea's effect.
Is iron bisglycinate better than ferrous sulfate?
For gut comfort, the evidence is encouraging. A 2023 review found it gave higher haemoglobin and about a third as many gut side effects in pregnant women. But a lower dose of it raised ferritin less than standard ferrous sulfate in a 2023 trial. Form helps tolerance, it does not replace the right dose.
Sources
- Sengupta A, Prakash M, Dutta T. Non-adherence to iron and folic acid consumption among Indian pregnant women: evidences from national family health survey-5 data (2019-21). BMC Pregnancy and Childbirth, 2026, 26:1089. doi.org/10.1186/s12884-026-09639-4
- Dr Pooja N. New Data Uncover Alarming Drop in Iron and Folic Acid Use Among Indian Pregnant Women: Study. Medical Dialogues, 6 October 2026. medicaldialogues.in
- Tolkien Z, Stecher L, Mander AP, Pereira DI, Powell JJ. Ferrous sulfate supplementation causes significant gastrointestinal side-effects in adults: a systematic review and meta-analysis. PLoS One, 2015. doi.org/10.1371/journal.pone.0117383
- NHS. Side effects of ferrous sulfate. nhs.uk
- NHS. How and when to take ferrous sulfate. nhs.uk
- Fischer JAJ, Cherian AM, Bone JN, Karakochuk CD. The effects of oral ferrous bisglycinate supplementation on hemoglobin and ferritin concentrations in adults and children: a systematic review and meta-analysis of randomized controlled trials. Nutrition Reviews, 2023, 81(8):904-920. doi.org/10.1093/nutrit/nuac106 (PMID 36728680)
- Fischer JAJ, Pei LX, Elango R, Hou K, Goldfarb DM, Karakochuk CD. Is a lower dose of more bioavailable iron (18-mg ferrous bisglycinate) noninferior to 60-mg ferrous sulfate in increasing ferritin concentrations? A randomized controlled noninferiority trial. Journal of Nutrition, 2023, 153(8):2453-2462. doi.org/10.1016/j.tjnut.2023.05.029 (PMID 37271416)
- Hurrell RF, Reddy M, Cook JD. Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages. British Journal of Nutrition, 1999, 81:289-295. doi.org/10.1017/S0007114599000537
- Ahmad Fuzi SF, Koller D, Bruggraber S, Pereira DI, Dainty JR, Mushtaq S. A 1-h time interval between a meal containing iron and consumption of tea attenuates the inhibitory effects on iron absorption. American Journal of Clinical Nutrition, 2017, 106:1413-1421. doi.org/10.3945/ajcn.117.161364
- Press Information Bureau, Ministry of Health and Family Welfare. Anaemia Mukt Bharat (NFHS-5 anaemia data). 4 February 2022. pib.gov.in
This article is for education only and is not medical advice. Supplements are not a substitute for a varied diet or for treatment from a qualified doctor. If you are pregnant, breastfeeding, on medication, or have a medical condition, talk to your doctor before starting any supplement. Individual results vary.
Photo: William Fortunato via Pexels.