Situation: A 25-year-old woman, gravida 2 para 1, comes to the Barangay Health Station (BHS) for her first prenatal visit at 8 weeks' gestation. Her first pregnancy 2 years ago was uncomplicated, and her child is healthy. She reports no danger signs. The nurse gives her iron–folic acid tablets under the DOH program. Which instruction about taking the tablet is BEST?

Iron is absorbed better with vitamin C and poorly with milk, calcium, tea, coffee, and antacids. The DOH gives 60 mg elemental iron plus 400 mcg folic acid daily for about 180 days, so she should also expect dark stools and keep taking the tablets.

Absorption mechanics of oral iron
Oral iron is absorbed primarily in the duodenum and proximal jejunum, and its bioavailability is highly sensitive to what is co-ingested. Ferrous iron crosses the enterocyte membrane most efficiently in an acidic, reducing environment. Ascorbic acid (vitamin C) reduces ferric iron (Fe³⁺) to the more soluble ferrous form (Fe²⁺) and forms a chelate that remains absorbable at the higher pH of the small intestine, which is why orange juice improves uptake. In contrast, milk and calcium salts compete with iron for the same divalent metal transporter, while tannins in tea and coffee, phytates, and antacids that raise gastric pH all impair absorption ^[1][2].

Watch out! The instruction “take with milk to protect the stomach” is a common distractor. Milk does not protect the stomach from iron’s gastrointestinal irritation; it reduces the amount of iron actually absorbed, which undermines the entire purpose of supplementation.

DOH program dosing and expected effects
Under the Philippine DOH prenatal package, the standard regimen is 60 mg of elemental iron plus 400 mcg of folic acid daily for approximately 180 days. Darkening of the stool is an expected, harmless effect of unabsorbed iron in the gut, not a sign of bleeding or toxicity. Discontinuing iron because of dark stools would interrupt protection against maternal anemia and is never indicated when the color change is isolated.

Why compliance matters in the community setting
Community-based studies in Ethiopia and Senegal show that even when iron–folate supplements are provided free of charge, actual daily intake remains low, and anemia persists in a large proportion of pregnant women ^[1][2]. In one Nigerian cohort, 96.77% of women who had been on supplemental oral iron and folic acid since early pregnancy still showed absent stainable iron in the bone marrow later in pregnancy, suggesting that either the dose, absorption conditions, or adherence were insufficient ^[4]. These findings reinforce that correct administration timing and avoidance of absorption blockers are as important as the prescription itself.

Key point! The best instruction is to pair the tablet with a vitamin C source such as orange juice and to separate it from tea, coffee, milk, and antacids. This maximizes the fraction of the 60 mg dose that actually enters the circulation.

Co-ingested substance	Effect on iron absorption	Mechanism
Orange juice / vitamin C	Increases	Reduces Fe³⁺ to Fe²⁺ and chelates iron to keep it soluble
Milk / calcium	Decreases	Competes for the divalent metal transporter in enterocytes
Tea / coffee	Decreases	Tannins and polyphenols bind iron into nonabsorbable complexes
Antacids	Decreases	Raise gastric pH, reducing iron solubility and reduction
Dark stools	No change needed	Expected effect of unabsorbed iron; continue the supplement

In a first-trimester visit with no danger signs, the nursing priority is to establish a sustainable daily habit. Advising the client to take the tablet with orange juice and away from tea or coffee addresses the most modifiable dietary factor affecting iron bioavailability, while also preparing her for the expected dark stools so that she does not stop the regimen prematurely ^[1].