Short answer: Iron is needed to form red blood cells and transport oxygen, and women of childbearing age lose iron during menstruation. An observational study has linked iron supplements to a lower risk of ovulatory infertility, but the evidence is limited and not unequivocal. Replenishing a confirmed iron deficiency is reasonable – but more iron than you need is unlikely to provide any additional benefit.
Why iron is important for women of childbearing age
Iron is a building block in hemoglobin, the protein that transports oxygen in the blood. During menstruation, iron is regularly lost, and the need also increases during pregnancy as the body needs to cover both the mother's and the fetus's needs. According to 1177 Vårdguiden, a significant proportion of women of childbearing age have low iron levels, and common symptoms of iron deficiency can include fatigue, difficulty concentrating, dizziness, and shortness of breath. However, the symptoms can be vague, meaning that deficiency is sometimes overlooked.
What research says about iron and fertility
The evidence is limited and largely based on observational studies, which can show correlations but not necessarily cause and effect. In a large American cohort study (Nurses' Health Study II), women who used iron supplements had a lower risk of ovulatory infertility compared to those who did not. The association primarily applied to so-called non-heme iron, which is found in supplements and plant-based foods, while heme iron from meat did not show the same connection. However, newer studies on couples planning pregnancy have not been able to confirm such a clear association, suggesting that the picture is more complex than it first seemed.
Diet or supplements – what is reasonable?
The Swedish Food Agency recommends a daily iron intake of approximately 15 mg for women of childbearing age, partly to compensate for menstrual losses. Iron is found in both animal sources (such as meat and blood products) and plant-based sources (such as legumes, whole grains, and green leafy vegetables), and the absorption of non-heme iron increases if you also consume vitamin C. For many, a varied diet is sufficient, but in cases of confirmed deficiency, supplements may be needed. Extra iron beyond what is needed is unlikely to provide any additional fertility benefits and can cause side effects in high doses.
When it might be worth checking your iron levels
If you recognize symptoms such as persistent fatigue, shortness of breath, or dizziness – or have heavy periods – it may be worth talking to a healthcare professional about a blood test to measure your iron status. Taking iron supplements on your own without a confirmed deficiency is rarely justified, as the body has a limited ability to get rid of excess. Individual advice from healthcare professionals takes into account your own values and situation.
Frequently asked questions
Can iron supplements make me get pregnant faster?
There is limited evidence suggesting a link between iron supplements and a lower risk of ovulatory infertility, but it has not been shown that iron itself makes you get pregnant faster. Primarily address a confirmed deficiency rather than taking iron preventively without a deficiency.
Should I take iron even if I don't have a deficiency?
Probably not without reason. Extra iron beyond what is needed does not seem to provide any fertility benefits, and high doses can cause side effects such as stomach upset. A blood test through healthcare can show if you actually need supplements.
Which form of iron is best absorbed?
The absorption of non-heme iron from plants and supplements improves if you combine it with vitamin C, while coffee and tea near meals can reduce absorption. Heme iron from animal sources is generally absorbed more efficiently, but the need and suitable form differ from person to person.
This text is general information and not medical advice. Always consult healthcare professionals before starting supplements or if you have symptoms or questions about your fertility or health.