How Does Iron Deficiency Affect Pregnant Women with Sickle Cell Disease?

Desmond Aroke, MD

A review of the literature to ascertain the prevalence, determinants and maternal/fetal outcomes of iron deficiency anemia in pregnancy with sickle cell disease was conducted to inform decisions on iron supplementation for this population.

Desmond Aroke, MD, Health and Human Development Research Network, Douala, Cameroon and colleagues pointed out that although iron deficiency anemia in pregnancy is a known significant contributor to maternal morbidity and mortality, individuals with sickle cell disease (SCD) are at risk for iron overload from the frequent transfusions required in treating the disease.

"The risk of iron overload amongst SCD patients and risk of iron deficiency in pregnancy makes supplementation of iron in pregnant women with SCD a difficult decision," they indicate.

In an earlier published opinion, Aroke and colleagues suggested that the risk of iron overload could actually be smaller than generally assumed, most likely occurring when multiple transfusions are administered for hemolytic crisis.

They recommended exchange transfusion rather than normal transfusions for indications other than anemia; and, except when there have been multiple transfusions, that iron supplements be provided in pregnancy when microcytosis indicates deficiency.

"Clients with no history of transfusions or with ≤5 units of blood transfusion should be routinely supplemented with iron in pregnancy," they opined.

In their current publication, Aroke and colleagues indicated that although decisions on supplementation can be based on the individual's iron status, their interest is in compiling data to support "a global consensus."

"Daily iron supplementation in pregnancy is recommended by the World Health Organization (WHO) as a proactive measure to reduce anemia and its associated complications in pregnancy," they explained. "However, there are no clear guidelines on iron supplementation (for) the pregnant women with SCD subpopulation."

To address this, Aroke and colleagues undertook a systematic review and meta-analysis. Out of a total of 710 reports identified, however, only 5 met quality standards for inclusion, and 4 of those were observational studies of "fair" quality. The single randomized controlled trial (RCT) was assessed to have "unclear" quality. All had been conducted in the 1990s or before.

The 5 studies comprised 67 participants, with a prevalence of iron deficiency anemia among pregnant women with SCD ranging from 6.67 to 83.33%.The studies varied by design and diagnostic methods, and none provided evidence on factors associated with the condition. Further, the one RCT found no difference in outcomes between groups that did, or did not receive iron supplementation.

"The review has shown that evidence is lacking and there is urgent need for studies with better study designs and larger sample sizes to be carried out," Aroke and colleagues remarked.

The reviewers called for research to identify which biomarkers better quantify iron deficiency anemia in this population; determine fetal and maternal outcomes during iron deficiency; and ascertain whether iron supplementation would curb this burden.

"We advocate for more studies with larger sample size, using robust study designs such as case control studies, prospective cohort studies and randomized clinical trials to evaluate iron stores in pregnant women at various trimesters," Aroke and colleagues declared.

The review, "Iron stores in pregnant women with sickle cell disease: a systematic review," was published online in BMC Pregnancy and Childbirth.