Iron deficiency (ID) affects approximately 18% of pregnant individuals in the United States, and the estimated prevalence of iron deficiency anemia (IDA) is 5% in this population.1 Numerous intersecting disparities based on race, socioeconomic status, and other factors affect prevalence rates of ID and IDA and related issues across different populations.1,2
Compared to Hispanic and non-Hispanic White women, studies have found that Black women have a higher risk for ID and IDA and associated complications in pregnancy and are less likely to be screened for these conditions by clinicians, according to a paper published in JAMA Network.3 In addition, pregnant Black individuals have a 2-fold greater risk for requiring blood transfusions and up to a 5-fold higher risk of death due to postpartum hemorrhage.3
Untreated ID and IDA in pregnancy have been linked to an array of maternal and fetal risks such as pre-eclampsia and preterm birth as well as impaired development in affected children.4 Observational findings have demonstrated improvement in these outcomes following iron supplementation, underscoring the need for timely screening and treatment in pregnant individuals when indicated.1
However, the lack of consensus regarding recommendations both for screening for ID and IDA and for iron supplementation in asymptomatic pregnant people represents a key barrier to addressing these conditions and related disparities.
Hematology Advisor discussed these issues and potential solutions in interviews with the following experts:
- American Society of Hematology (ASH) spokesperson Margaret Ragni, MD, MPH, professor of medicine and clinical and translational research in the division of hematology/oncology at the University of Pittsburgh School of Medicine and director of the Hemophilia Center of Western Pennsylvania
- Ashley Benson, MD, MA, MS, assistant professor of obstetrics and gynecology at the Oregon Health and Science University School of Medicine in Portland, Oregon
What are some of the common causes and risk factors for IDA in pregnancy?
Dr Ragni: Causes of ID or IDA in pregnancy include increased demands due to the growing fetus, pregnancy, and lactation; ID or IDA preceding pregnancy — for example, from heavy menstrual bleeding (HMB); increased plasma volume in pregnancy, causing dilutional anemia; and increased red blood cell mass in pregnancy.4
Risk factors for ID in pregnancy include the increased demands noted above as well as low socioeconomic status, low access to healthcare, and issues related to nutritional status, such as dietary deficiency due to a vegan diet, lack of iron-rich food, or food insecurity.1
Additional risk factors include chronic blood loss from previous HMB, bleeding or platelet disorders with low levels at the start of pregnancy, and impaired absorption in the gastrointestinal (GI) tract due to GI disorders such as celiac disease, Crohn’s disease, a duodenal ulcer, or medications such as blood thinners or aspirin.1,4
Dr Benson: Common causes for IDA in pregnancy include increased iron utilization, insufficient dietary intake, impaired iron absorption, and blood loss. Iron utilization increases in pregnancy due in part to increased red blood cell mass and fetal iron loading via placental iron transfer.
There are many causes of impaired iron absorption that can affect pregnant individuals, such as celiac disease, inflammatory bowel disease, or a history of bariatric surgery.5 Other dietary factors may inhibit iron absorption, including high intake of calcium or phytate, which is found in many grains and legumes.
Pregnant-capable individuals are also very likely to experience blood loss preconceptionally due to HMB or antepartum due to hemorrhoids.
What are the current recommendations regarding prevention and treatment of ID and IDA in pregnant patients with IDA?
Dr Ragni: The US Preventive Services Task Force (USPSTF) has stated there is insufficient evidence to recommend screening for ID or IDA or to determine whether treatment with iron supplements is helpful in prevention of poor maternal and fetal health outcomes.1
Overall, there is a lack of consensus on the routine use of screening for ID in pregnancy and which diagnostic thresholds to use for diagnosis of ID in pregnancy.3 For example:
- The American College of Obstetricians and Gynecologists (ACOG) uses ferritin <30 ng/mL.
- The World Health Organization (WHO) suggests ferritin <15 ng/mL.
- A 2017 systematic review found that two-thirds of studies used ferritin 12-15 ng/mL.
- Others have used ferritin <50 ng/mL.
Dr Benson: For treating pregnant individuals with IDA, both oral iron and IV iron are acceptable, although IV iron is generally avoided in the first trimester due to a lack of safety data. I recommend IV iron in the following circumstances:
- Intolerance or unresponsiveness to oral iron
- Second trimester if Hb<10 g/dl
- Third trimester
- After bariatric surgery
- History of abnormal uterine bleeding
- Presence of inflammatory bowel disease or other active inflammatory conditions
Regarding prevention, there are not high-quality studies to inform us, but recent studies indicate that a preconception ferritin in the range of 70 ng/mL may be sufficient to prevent ID or IDA from developing throughout pregnancy.6
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Addressing inequities in IDA among Black women in pregnancy requires targeted research, improved screening protocols, and equitable treatment strategies.
Dr Benson, in a recent editorial, you and your colleagues noted that Black women in the US have a higher risk of ID and IDA, along with a greater risk of complications associated with IDA in pregnancy.3 What measures are needed to address these inequities?
Dr Benson: Targeted resources and funding are needed to adequately answer this question. Addressing inequities in IDA among Black women in pregnancy requires targeted research, improved screening protocols, and equitable treatment strategies. Studies should focus on understanding the specific social, biological, and environmental factors contributing to higher IDA rates and complications in this population.
Studies should specifically address whether routine and early screening for IDA may mitigate these effects. Treatment guidelines should prioritize timely iron therapy and follow-up care. Provider training to address implicit bias and standardized care protocols are also critical to ensure that Black women receive consistent, effective treatment for IDA during pregnancy.
What additional efforts are warranted to address the reported high rates of ID and IDA in pregnancy in general?
Dr Ragni: ID and IDA in pregnancy are public health problems associated with disparities in care. To address these disparities and help identify patients at risk for ID and IDA, test cutoffs to diagnose ID and IDA, and screening recommendations based on cutoffs, need to be defined. In addition, current supplement, oral vs IV, and prevention vs treatment need to be defined.
Dr Benson: FIGO recently published a statement that addresses this question quite nicely.7 The FIGO statement identifies several remaining needs regarding ID and IDA in women and girls. More research is required to understand the long-term health impacts, especially in adolescents and pregnant or postpartum women.
There is also a need for enhanced education and training for health professionals to improve early detection, treatment, and counseling on this issue. Public health efforts should focus on increasing access to iron-rich foods and supplements and promoting awareness through targeted campaigns.
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