Iron deficiency anemia affects over half of girls and young women with heavy periods and is the most common cause of anemia worldwide. Most girls with heavy periods who also have iron deficiency anemia are prescribed iron to take by mouth every day by their doctor. There are some studies showing that taking iron every other day may actually help the iron be absorbed into the bloodstream better. This study is trying to compare how taking iron every other day compares to taking iron daily for treatment of anemia.

The goal of this clinical research study is to learn which of the two methods of care will be the best way for girls and young women with iron deficiency anemia to take iron supplementation.

The research will be conducted at the following location(s):

Baylor College of Medicine, TCH: Texas Children's Hospital, and TCH: Texas Children's Hospital Clinic.

If patient appears to qualify for the study they will sign and date this consent form, and the doctor will confirm that they are eligible for the study. The patient will complete the following procedures:

• Medical history including prior hospitalizations, lab results, medications, diet, social and family history
• Physical Examination
• Blood samples: The patient will not have any extra blood draws (pokes) for this study. However, we will ask to take about 1/2 (0.5) teaspoons (3 mL) of extra blood for an extra research test when you have follow up blood test(s) in one month.

Patient will be on the study for 24 weeks (6 months),and will receive an information sheet about how to take iron to help it absorb in the stomach and on iron-rich foods.

There are 2 different treatments in this study. If a patient enrolls, they cannot choose which treatment to receive. Instead, they will be randomly assigned to one of the two treatments. That means there is a fifty percent chance they will receive iron medicine to take every day and a fifty percent chance they will receive iron medicine to take every other day.

Inclusion Criteria:

1. Age 9 years or greater and less than age 22 years
2. Heavy menstrual bleeding, defined as a Pictorial Blood Assessment Chart (PBAC) Score >100
3. Iron deficiency anemia, defined as both hemoglobin <12 g/dL and ferritin <15 ng/mL within 7 days of enrollment.

Exclusion Criteria:

1. non-uterine cause of vaginal bleeding
2. pregnancy
3. chronic kidney disease
4. serology confirmed celiac disease
5. active gastrointestinal blood loss
6. active malignancy
7. inability to follow-up at Texas Children's Hospital
8. receipt of intravenous iron within 30 days prior to enrollment
9. allergy or known inability to tolerate oral iron

Must be born a female.

Twelve weeks

All-Cause Mortality, Serious Adverse Events, and Other (Gastrointestinal) Adverse Events were collected at the 12 week visit.