IV Iron vs. Oral Iron for Pregnancy Anemia

randomized-controlled-trial PMID: 34839481

Quick Summary: A study found that giving iron directly into a vein (IV iron) was more effective at reducing anemia in pregnant women compared to taking iron pills.

What The Research Found

This research looked at how well different types of iron treatments worked for pregnant women with iron-deficiency anemia (IDA). The study compared giving iron through an IV (intravenous) to taking iron pills. The main finding was that IV iron was better at raising the mother's iron levels and reducing anemia right before delivery.

Study Details

Who was studied: 23 pregnant women between 24 and 34 weeks of pregnancy who had iron-deficiency anemia.

How long: The study was cut short due to logistical issues, but followed women until they delivered their babies.

What they took:

IV Iron Group: Received a single dose of iron directly into their vein.
Oral Iron Group: Took iron pills twice a day.

What This Means For You

If you're pregnant and have anemia, this study suggests that IV iron might be a faster way to improve your iron levels than taking pills. However, this was a small study. Talk to your doctor about the best treatment for you. They can consider your specific situation and help you decide if IV iron is a good option.

Study Limitations

The study was small, so the results might not apply to everyone.

The study wasn't "blinded," meaning both the patients and doctors knew which treatment was being given. This could have affected the results.

Some women in the study switched treatments, which could have impacted the findings.

The study was stopped early, so the results are preliminary.

Key Findings

IV iron (1,000 mg single dose) significantly reduced maternal anemia at delivery (40% vs. 85% for oral iron, p=0.03).
No significant differences in adverse reactions (mild/moderate or severe) between groups.
IV iron led to greater increases in maternal hemoglobin (+1.3 g/dL vs. +0.5 g/dL for oral iron) and ferritin (+14.5 ng/mL vs. +10.2 ng/mL), though ferritin differences were not statistically significant.
High crossover rates (5/10 oral group patients received IV iron post-randomization) and early trial cessation due to logistical challenges.
Conclusion: IV iron shows promise for treating pregnancy-related IDA but highlights barriers to adherence and the need for larger, blinded trials.

Study Design

Type: Open-label, randomized controlled trial (RCT) registered as NCT03438227.
Population: 23 pregnant women (24–34 weeks gestation) with IDA (hemoglobin <10 g/dL, ferritin <30 ng/mL).
Randomization: 1:1 to IV iron (n=10) or oral iron (n=13).
Duration: Conducted until logistical issues halted enrollment; follow-up until delivery.
Analysis: Per-protocol (excluding 15 patients who withdrew or crossed over).

Dosage & Administration

IV iron: Single 1,000 mg dose of low-molecular-weight iron dextran infused over 1 hour.
Oral iron: 325 mg ferrous sulfate twice daily (standard regimen).
Administration: IV given in one session; oral self-administered daily until delivery.

Results & Efficacy

Primary outcome: Maternal anemia at delivery (hemoglobin <11 g/dL) occurred in 40% (4/10) of IV recipients vs. 85% (11/13) of oral recipients (p=0.03).
Hemoglobin increase: IV group showed greater mean improvement (+1.3 g/dL vs. +0.5 g/dL for oral).
Ferritin: IV group had higher ferritin at delivery (+14.5 ng/mL vs. +10.2 ng/mL for oral), but difference was not statistically significant.
Neonatal outcomes: No significant differences in birth weight, gestational age, or neonatal hemoglobin/ferritin levels.

Limitations

Small sample size (n=23) due to early cessation, limiting statistical power and generalizability.
Open-label design introduced potential bias, with 38% of enrolled patients (15/38) withdrawing or crossing over to alternate therapy.
Selection bias: Results may not reflect broader populations due to strict inclusion criteria and high attrition.
Underpowered for safety: Adverse reaction rates could not be reliably compared due to low event numbers.
Short follow-up: Outcomes assessed only until delivery, with no long-term maternal/neonatal data.

Clinical Relevance

IV iron may offer a faster, more effective solution for correcting IDA in late pregnancy compared to oral iron, particularly for patients with poor adherence or intolerance to oral supplements.
High crossover rates suggest patient preferences and clinician practices significantly influence treatment adherence, necessitating strategies to address these barriers in future trials.
The study supports the feasibility of a larger RCT but underscores the need for double-blinding and streamlined administration protocols to ensure robust evidence.
For pregnant women with IDA, IV iron could be a viable alternative if oral therapy fails, though current results require validation in larger, well-controlled studies.

This preliminary trial highlights IV iron’s potential to improve perinatal outcomes but emphasizes logistical and methodological challenges that must be resolved before widespread adoption.