Many pregnant women miss iron level screenings despite deficiency being ‘very common’
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Ferritin testing needs to be a routine part of maternal care and pregnancy health screenings, according to the authors of a study published in Blood Advances.
The authors noted that low iron levels were found among half of the pregnant women who had a simple blood test to check their iron stores. One in four of these women had a severe iron deficiency.
However, 40% of the pregnant women overall in the large regional study never had their iron levels checked, and women who were from lower socioeconomic backgrounds were less likely to get tested.
“Despite the very high prevalence of iron deficiency in pregnancy, and how easy it is to treat, we are not doing a very good job of checking for it,” author Jennifer Teichman, MD, of the University of Toronto, said in a press release.
The study was conducted at St. Michael’s University/Unity Health Toronto, which is affiliated with the University of Toronto.
“It’s not top of mind, in part, because of inconsistent recommendations for ferritin testing across clinical guidelines,” Teichman said.
The developing fetus, the growing placenta and the increased blood supply needed to sustain the pregnancy all have high iron requirements, and this demand increases as the pregnancy continues.
As the most common cause of anemia during pregnancy, iron deficiency has been linked to poorer outcomes for mother and baby alike, including a higher risk for premature delivery, low birth weight, postpartum depression and maternal death.
Anemia during the early stages of pregnancy has also been associated with neurodevelopmental delays in the offspring, even as the child approaches school age and later, pointing to potentially long-lasting effects, the researchers said.
Low levels of iron can cause fatigue, weakness and brain fog among pregnant women as well, Teichman said.
The study included 44,552 pregnant women receiving prenatal testing at community laboratories in Ontario between 2013 and 2018 to determine the frequency of ferritin testing. Also, the study examined the prevalence and severity of iron deficiency among pregnant women and aimed to identify whether certain clinical or demographic factors influenced whether they received a ferritin test.
General practitioners ordered 48% of tests, and obstetricians and gynecologists ordered 32%. Also, 71% of ferritin tests occurred at or around the time of the first prenatal visit, when the risk for iron deficiency is lowest. Often, the researchers continued, iron levels only were checked once during the pregnancy.
“Iron deficiency becomes more common as women progress through pregnancy,” said Teichman. “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.”
The women in the study received care in Canada’s publicly funded health care system, so they did not have to pay for the ferritin testing themselves. Yet women of lower socioeconomic status were less likely to be tested for iron deficiency anyway, further underscoring differences in access to care and how clinicians may treat these patients differently, the researchers said.
The researchers also urge women who plan to become pregnant or who are pregnant to ask about their iron levels before and during their pregnancy.
“Iron deficiency is very common, and there can be poor outcomes for both mom and baby if it isn’t identified and treated,” said Teichman. “The good news is that it’s easily found with a simple blood test and completely correctable with iron supplements.”
Standard prenatal vitamins alone cannot treat iron deficiency, Teichman said.
“Prenatal vitamins contain only a sprinkling of iron and many combine iron with calcium, which can inhibit the absorption of iron,” said Teichman. “The way to address the problem is by identifying iron deficiency early on and then supplementing women with therapeutic doses of iron, which has 10 times the amount found in most prenatal vitamins.”
Additionally, guidelines will need to be revised to ensure that women are appropriately screened as well, Teichman said.
In 2015, the U.S. Preventative Services Task Force said there was not enough evidence to recommend for or against screening for iron deficiency anemia in pregnant women.
But sufficient data now show the harms of iron deficiency and anemia in pregnancy, and it would be unethical to conduct a study in which iron-deficient women do not receive supplementation, Teichman said. Iron screenings present no conceivable harms, she added.
The researchers noted that the study was limited to the Ontario region and that it did not include women who may have had a miscarriage, who received fragmented care or who were referred to a hospital-based obstetric practice. Data pertaining to ethnicity and education levels were unavailable as well.
Reference:
Teichman J, et al. Blood Adv. 2021;doi:10.1182/bloodadvances.2021004352.