Iron deficiency and the resulting anemia is widely prevalent in India, especially among pregnant women, the incidence being approximately 50%. This is a significant cause for maternal morbidity and mortality. Estimation of ferritin will help diagnose iron deficiency early before it develops into significant iron deficiency anaemia and iron supplements can be started early. However, there is a cost factor as well as nonavailability of the test everywhere, which may pose a problem.

A new study from Canada published in the journal Blood Advances^1,2 has studied in detail the frequency of ferritin testing in pregnancy as well as the incidence of anemia and the impact of testing for ferritin in pregnancy.The retrospective study involved 44,552 pregnant women who underwent antenatal tests at community laboratories in Ontario, Canada, over a five-year period (between 2013 and 2018). The study aimed to evaluate the frequency of ferritin testing during the antenatal care.

The prevalence and severity of iron deficiency was also determined.Results showed that 59.4% % of the study participants had been tested for ferritin levels during pregnancy; 52.8% of the pregnant women had iron deficiency (≤29 µg/L) at least once in pregnancy, 25.2% had iron insufficiency (30-44 µg/L), while 8.3% had anemia with hemoglobin (Hb) levels <105 g/L (10.5g/dL).Sixty-two percent of patients had been tested only once for ferritin and 71% of these tests were done during the first trimester of pregnancy.Of the 44,552 pregnant women included in the study, a baseline Hb level was measured within 4 weeks of the index date in 33,446 (75.1%) women; 23,752 (71.0%) had at least one subsequent Hb check following the baseline test.

Among the 34,034 patients who had their Hb tested at least once in pregnancy, 2835 (8.3%) were anemic at least once; of these, 774 (27.3%) had a subsequent ferritin test ordered in that pregnancy (up to 32 weeks following the index date). The number of women with anemia who underwent a subsequent ferritin test increased with worsening severity of anemia, ranging from 22% to 67% of patients in the lowest and highest anemia severity categories, respectively.Women with lower annual household income were less likely to be tested for ferritin. Most tests were ordered by general practitioners (48%) and obstetricians-gynecologists (32%).This study highlights that just about 60% of pregnant women were tested for ferritin levels despite the fact that almost half of the study population was found to have iron deficiency. And, most were tested in the first trimester, where the risk of iron deficiency is lowest.Ferritin being a more expensive test, clinicians mainly rely on Hb to detect anemia, but it is not exactly indicative of the iron stores in the body.Canadian guidelines recommend therapeutic iron doses if the ferritin is less than 30ug/L, but do not recommend routinely testing ferritin in pregnancy.

The United States Preventive Services Task Force (USPSTF) does not recommend universal screening for iron deficiency in pregnancy, citing the evidence as “insufficient to assess the balance of benefits and harms of screening for iron deficiency anemia in pregnant women.” The American College of Obstetricians and Gynecologists (ACOG) recommends complete blood count (CBC) to screen all pregnant women for anemia in the first trimester and again between 24 and 28 weeks of pregnancy.³ 

The British Blood Transfusion Society recommends CBC to screen for anemia at presentation and at 28 weeks, as well as at any time during pregnancy if symptoms of anemia are present. And, it recommends a trial of oral iron or serum ferritin measurement in women with microcytic or normocytic anemia to confirm iron deficiency.⁴ 

FOGSI recommends serum ferritin as a direct measurement of iron stores and start treatment when the levels fall below 30μg/L.⁵Based on their findings, the study authors suggest that ferritin testing should be a routine practice in antenatal care. It should be done at the first antenatal visit and also during the subsequent antenatal visits as iron requirements increase during pregnancy.

Early detection of iron deficiency allows early initiation of oral iron supplementation to build up the iron stores and reduce the morbidity and mortality associated with iron deficiency anemia during pregnancy. Detection of deficient iron stores later on in pregnancy may require intravenous iron replacement.“If we don’t re-evaluate iron stores later in pregnancy, we miss a lot of women who are becoming iron deficient in later trimesters,” said Jennifer Teichman, MD, of the University of Toronto, Canada and its affiliated hospitals including St. Michael’s Hospital/Unity Health Toronto and lead author of the study.

References

1.  Teichman J, et al. Suboptimal iron deficiency screening in pregnancy and the impact of socioeconomic status in a high-resource setting. Blood Adv. 2021 Aug 30;bloodadvances.2021004352. doi: 10.1182/bloodadvances.2021004352.
2. American Society of Hematology Press Release, August 30, 2021.
3. James, Andra H. MD, MPH Iron Deficiency Anemia in Pregnancy, Obstetrics & Gynecology: September 9, 2021 - Volume - Issue - 10.1097/AOG.0000000000004559 doi: 10.1097/AOG.0000000000004559
4. Juul SE, et al. Perinatal iron deficiency: implications for mothers and infants. Neonatology. 2019;115(3):269-274.
5. FOGSI General Clinical Practice Recommendations Management of Iron Deficiency Anemia in Pregnancy. 2016