Anemia is a condition characterized by a decrease in the concentration of red blood cells or hemoglobin below normal values. In pregnancy, due to some physiological changes, the hemoglobin and hematocrit cut-off points are different compared to the non-pregnant population. (1) There is an increase in plasma volume of 40-50% in singleton pregnancies, which is more evident in the second trimester, which makes at this point, the cut-off point 10.5 g/dL, instead 11 g/dL, which is the cut-off point in the first and third trimester. (2)
It is the most frequent medical condition in pregnancy; in fact, in a study in the United States, it was determined that there is a prevalence of 21.55 per 1,000 women, (3) and in other regions such as Latin America and the Caribbean, the prevalence is much higher, being a public health problem. (4)According to the World Bank, the prevalence of anemia in Latin American countries in 2019 was: Venezuela (26.4%), Ecuador (22.3%), Peru (27.1%), Argentina (20.6%), Colombia (21.8%) and Mexico (20.2%). (5)
Anemia can have various origins: decreased production of red blood cells, increased destruction and blood loss. During pregnancy, and in general population, the most frequent cause of anemia is iron deficiency, which results in a decrease in the production of erythrocytes with the consequent decrease in hemoglobin and hematocrit values. (6)
As expected, the diagnosis of anemia is based on the measurement of serum hemoglobin concentration or hematocrit, however, it can be suspected by history and physical examination; tiredness, palpitations, weakness, headache, dizziness, paleness, tachycardia, are some frequent findings in anemia.
Identification of anemia in pregnant women is important, since it is an important cause of multiple complications during pregnancy (preterm delivery, low birth weight and perinatal death), so it is recommended to all pregnant women, in the first prenatal visit and at 28 weeks of gestation, the measurement of serum concentrations of hemoglobin and hematocrit as a screening test for anemia. However, with this practice it is not possible to identify iron deficiency anemia (which is the most common), because it is a non-specific test, unlike serum ferritin levels, which has high sensitivity and specificity for the diagnosis of iron deficiency anemia. (4)
In practice, the diagnosis of mild to moderate anemia is often presumptive, and treatment with iron is usually started without waiting for iron-related laboratory results, and prompt further investigation should be done when a satisfactory response to treatment is not obtained.
CDC recommends that all pregnant women receive low-dose iron supplementation from their first prenatal visit to prevent anemia during the third trimester, in addition to the rest of the prenatal vitamins, (2) and thus avoid multiple complications.
A balanced diet is vital to ensure that pregnant women receive sufficient amounts of iron. Most of the easily absorbed iron comes from red meat, fish, liver, fortified cereals, grains etc., as well as orange juice, strawberries, grapes, and broccoli, which increase iron absorption.
In conclusion, adequate iron intake is crucial for maintaining a healthy pregnancy, so all women should receive nutritional counseling, as well as iron and folic acid supplements during the first prenatal consultation. (7)
Blog and photo by Dr. Nestor Ferrer, Venezuela
WHO. Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. Vitamin and Mineral Nutrition Information System. Geneva, World Health Organization, 2011 (WHO/NMH/NHD/MNM/11.1)
Recommendations to prevent and control iron deficiency in the United States. Centers for Disease Control and Prevention. MMWR Recomm Rep 1998;47:1–29.
Adebisi OY, Strayhorn G. Anemia in pregnancy and race in the United States: blacks at risk. Fam Med 2005;37:655–62
Gandra, Y. La anemia ferropénica en la población de América Latina y El Caribe. 1970. Boletín De La Oficina Sanitaria Panamericana. pp.375-385.
The World Bank. Prevalence of anemia among pregnant women (%) - Latin America & Caribbean. Available on: https://data.worldbank.org/indicator/SH.PRG.ANEM?locations=ZJ&view=map
American College of Obstetricians and Gynecologists' Committee on Practice Bulletins—Obstetrics. Anemia in Pregnancy: ACOG Practice Bulletin, Number 233. Obstet Gynecol. 2021;138(2):e55-e64. doi:10.1097/AOG.0000000000004477
Abu-Ouf, N. M., & Jan, M. M. (2015). The impact of maternal iron deficiency and iron deficiency anemia on child's health. Saudi medical journal, 36(2), 146–149. https://doi.org/10.15537/smj.2015.2.10289
Prenatal assessment seeks to identify, through clinical history, sociodemographic characteristics, mean blood pressure, Doppler of the uterine arteries and biochemical markers such as pregnancy-associated plasma protein A (PAPP-A) and placental growth factor (PlGF), those women who are at high risk of developing preeclampsia in order to take appropriate measures. that can help reduce that risk.