Ferritin and fertility: When does iron deficiency prevent pregnancy?

Medical issues are rarely simple, and fertility challenges sit at the more complex end of healthcare. It would certainly be reassuring if a single, easily correctable factor could significantly improve the chances of pregnancy. In recent years, ferritin and iron levels have received increasing attention in discussions around fertility.

But what does science actually tell us about ferritin, iron, and reproductive health? And when is it relevant to investigate iron levels as part of fertility planning?

What is ferritin and why does iron matter?

Iron is essential for the body’s ability to transport oxygen. Hemoglobin in red blood cells binds oxygen and each hemoglobin molecule requires iron to function. Approximately 60–70% of the body’s iron is found in red blood cells, making iron a tightly regulated and limited resource.

Ferritin is a protein that reflects the body’s stored iron. A low serum ferritin level often appears before hemoglobin levels fall, which is why ferritin can be a sensitive marker of early iron deficiency.

It is important to note, however, that ferritin is also an acute phase reactant. Levels can increase in response to inflammation, infection, or chronic disease even when the body’s usable iron stores are not elevated. For this reason, ferritin values should always be interpreted in clinical context.

The impact of iron on fertility

Iron deficiency is the most common nutritional deficiency worldwide, particularly among women of reproductive age. Adequate iron stores are important when planning pregnancy, as pregnancy itself significantly increases iron demands to support fetal growth and maternal blood volume.

Severe iron deficiency may negatively affect fertility on its own, particularly if it leads to:

• Anemia

• Fatigue

• Ovulatory disturbances

At the same time, iron balance is delicate. Excess iron can be harmful, as it promotes oxidative stress through the formation of oxygen radicals, which can damage cells and DNA.

Studies suggest that both very low ferritin levels (typically below 12 µg/l) and high ferritin levels (above approximately 60 µg/l) have been associated with adverse pregnancy outcomes, such as lower birth weight. Certain reproductive conditions also show altered iron regulation. For example, endometriosis is associated with local iron accumulation in the pelvic cavity, and people with PCOS may have higher ferritin levels compared to control groups, possibly due to metabolic or inflammatory factors.

These findings underline the importance of balance: iron deficiency should be corrected when clinically relevant, but unnecessary supplementation should be avoided.

Ferritin reference values and target levels

The typical laboratory reference range for serum ferritin in women is approximately 13–150 µg/l, although exact ranges vary slightly between laboratories.

In a Finnish population study, the average ferritin level among women was around 28 µg/l, and values below 12 µg/l—consistent with iron deficiency—were found in roughly one in ten women. Reference ranges are broad by design, and values within them are generally considered physiologically acceptable when hemoglobin levels are normal and symptoms are absent.

Take your next step at Ovumia

If you have concerns about your iron levels, ovulation, or your overall chances of becoming pregnant, you don’t have to navigate these questions alone. A consultation with one of Ovumia’s reproductive medicine specialists can help clarify what matters in your individual situation and support you in planning the next steps toward parenthood.