Mild iron deficiency anemia seldom leads to complications. Left untreated, iron deficiency anemia can become severe and lead to health problems which can be fatal. Below are some examples of possible health complications of iron deficiency anemia if it is left untreated.
Heart Problems
In patients with iron deficiency anemia, the hearts pump more blood to compensate for the lack of oxygen carried in the blood. This can cause a rapid or irregular heartbeat which may result in a cardiomegaly or congestive heart failure. If the anemia is severe, hypoxemia can occur, and the risk of coronary insufficiency and myocardia ischemia are increased significantly. Likewise, it can worsen the pulmonary status of patients with chronic pulmonary disease.
Premature Births
In pregnant women, severe iron deficiency anemia has been associated with premature births and low birth weight babies. This condition can be prevented if pregnant women with iron deficiency receive iron supplements as part of their prenatal care.
Brittle Fingernails & Glossy Tongue
Prolonged iron deficiency anemia can cause defects in structure and function of epithelial tissues. Fingernails may become brittle or longitudinally ridged, with the development of koilonychia (spoon-shaped nails). The tongue may show atrophy of the lingual papillae and develop a glossy appearance.
Cold Intolerance
One fifth of patients with chronic iron deficiency anemia develops cold intolerance, vasomotor disturbances, neurologic pain, or numbness and tingling on the extremities.
Diminished Work Performance
Iron deficiency anemia diminishes work performance by forcing muscles to depend on anaerobic metabolism to a greater extent than they do in healthy individuals. This change is believed to be attributable to deficiency in iron-containing respiratory enzymes rather than to anemia.
ADHD Like Symptoms in Children
Children with iron deficiency may exhibit behavioral disturbances which could manifest as an attention deficit disorder. Severe iron deficiency that leads to anemia has shown to delay their growth and neurologic development. The neurologic damage to an iron-deficient fetus results in permanent neurologic injury and typically does not resolve on its own. Iron repletion stabilizes the patient so that his or her status does not further decline.
You may also want to read:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4212392/ https://www.mayoclinic.org/diseases-conditions/iron-deficiency-anemia/symptoms-causes/syc-20355034 https://www.uptodate.com/contents/approach-to-the-adult-with-anemia?search=anemia&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1