Does a once daily 120mg dose of elemental iron produce comparable improvement in hemoglobin levels to a twice daily 60mg dose among pregnant mothers with iron deficiency anemia?

The study will be carried out at the antenatal clinic of the German Sri Lanka Friendship Hospital for Women (Teaching Hospital Mahamodara).

Participants will be allocated to one of two treatment groups using a simple randomization method facilitated by a computer-generated randomization sequence. To ensure allocation concealment, the randomization sequence will be prepared in advance by a research assistant not involved in the study. The allocation process will be implemented as follows: Sealed, Opaque, and Sequentially Numbered Envelopes, Each envelope will be numbered sequentially and contain the assigned group (Group A: elemental iron 120mg once daily or Group B: elemental iron 60mg twice daily). Envelopes will be opaque to prevent any possibility of seeing the allocation through the envelope. Randomization Procedure: Upon enrollment, a research assistant (not involved in outcome assessment) will open the next envelope in the sequence to assign the participant to their group. This process ensures that the assignment is both concealed and unbiased. This randomization process will continue until adequate study participants are recruited.

Blood samples will be collected at initiation evaluation to assess hemoglobin level, blood picture, and serum ferritin. Following a careful assessment of inclusion and exclusion criteria, all the eligible participants will be instructed to take the iron tablets one hour before meals with vitamin C tablets and not to take them with calcium tablets, tea, coffee, or milk (Routine instructions given at the clinic). Group A (elemental iron 120mg) will be advised to take the tablets at one time per day, whereas group B (elemental iron 60mg) will be instructed to take the medication twice a day.

The investigators will briefly lecture on iron preparations' most common unwanted effects and how to minimize those. This will include nausea, vomiting, bowel disturbances, burning epigastric pain, bad taste, foul odor, constipation, and loss of appetite. They were instructed to report any severe intolerance preventing them from taking the supplements. We will assess patient-reported side effects following the initiation of iron treatment during antenatal clinic follow-ups and will record them in the part III of the questionnaire.

We will assess the serum hemoglobin level of each participant at two weeks from starting the iron supplement . Those who could not achieve a hemoglobin rise of 0.8-1 g/dL at the end of 2 weeks following the initiation of treatment will be subjected to further investigations to exclude hemoglobinopathies as institution management warrants. All participants diagnosed with hemoglobinopathies following HPLC will be excluded from the study All participants will receive standard antenatal care and dietary advice.

The duration of the study intervention and assessment period will be three months. However, iron supplementation will be continued beyond this period as part of routine antenatal and postpartum care, based on clinical indications and standard hospital guidelines.

Outcome assessors and investigators will be blinded.

• Pregnant mothers aged 18–40 years attending the antenatal clinic at German Sri Lanka Friendship Hospital for Women

• Gestational age < 27 weeks

• Singleton pregnancy

• Hemoglobin < 11 g/dL in first trimester and < 10.5 g/dL in second trimester

• Serum ferritin < 30 ng/mL

• Known hemoglobinopathies (thalassemia, sickle cell disease)
• Chronic medical disorders affecting anemia management (e.g. chronic kidney disease, chronic liver disease, inflammatory disorders)
• Recent blood transfusion within the last 3 months
• Multiple pregnancy
• History of severe intolerance to oral iron
• Ongoing significant bleeding disorders
• Pregnant mothers who decline consent