Postpartum Anemia: A Complication of Labor and Delivery

Doctors diagnose postpartum anemia when the concentration of hemoglobin in the mother’s blood drops below 100 g/L (10 g/dL) in the postpartum period, the period after delivery. Anemia is common after delivery on account of substantial blood loss. This is because most women giving birth lose some blood during delivery of the baby. This blood loss comes when many pregnant women are already hovering on the border of anemia. During pregnancy, the volume of blood within your body increases by up to 50 percent by term. This causes decreasing concentration in red blood cells (RBCs), causing a drop in the RBC count when your blood is tested, along with a drop in hemoglobin. In many cases, these changes are accompanied by changes in various other measurements in the blood that doctors use to determine if you are iron deficient. The body begins compensating for the dilution of RBCs by increasing RBC production. In some women, this acceleration in RBC production returns the RBC count and hemoglobin to normal, or close to normal by delivery, but often the RBC count remains low. This expansion of the blood volume compensates for your growing uterus, which requires a great deal of blood flow, for blood loss during delivery, and for expansion of blood vessels throughout the body to allow for blood to flow with decreased resistance (called a decrease in systemic vascular resistance). Consequently, losing a substantial amount of blood during delivery brings you easily into the realm of anemia. But blood loss lowers the already low concentrations of RBCs, hemoglobin, and iron, thus producing anemia.

In cases of complicated delivery, such as cesarean section and postpartum hemorrhage, the mother can lose more than 1.5 liters of blood. For this reason, doctors need to look out for postpartum anemia and manage it, but also need to keep an eye on various lab values, including hemoglobin levels and iron stores, prior to labor and delivery. Assessing for anemia involves doing a complete blood count (CBC) on the mother’s blood. This is particularly important, if the mother has suffered postpartum hemorrhage amounting to more than 500 mL, or if the mother has symptoms and signs of anemia, such as fatigue, pallor, dyspnea (shortness of breath), heart palpitations, chest pain, lightheadedness or dizziness, or cold extremities.

Treatment of postpartum anemia depends on the particulars of the case. In women with a hemoglobin of less than 10 g/dL, doctors will begin oral iron ferrous sulfate, meaning iron supplement pills. Usually, this will be 200 mg three times daily for three months when your hemoglobin of less than 9 g/dL. In some cases, doctors may need to administer iron as an infusion. One reason for this could be that the patient does not adhere to the oral treatment, or she cannot tolerate the oral treatment on account of side effects. Such side effects include dark colored stools and constipation. Oral iron also may not be useful when you cannot absorb it, due to inflammatory bowel disease, or if the product produces an allergic reaction. Also, if you are suffering from an active infection, doctors will withhold iron infusion, since many infectious agents feed on iron, meaning that iron can worsening the infection. Consequently, doctors must treat any infection prior to beginning intravenous iron therapy.

If your hemoglobin falls very low, generally below 7 g/dL, the medical team will consider transfusion of blood products. These blood products include packed red blood cells as well as plasma and certain clotting proteins. Doctors also may administer drugs, such as oxytocin, misoprostol, and anti-fibrinolytic agents. The latter group of medications work against the enzymes that normally break down a clotting protein called fibrin, also called clotting factor XIII. Consequently, fibrin lasts longer in the blood, so the blood clots more easily. The most used anti-fibrinolytic agent is called tranexamic acid (TXA). For a few years, there has been some talk about TXA raising the risk for formation of blood clots. This is a hypothetical risk, based on the TXA’s mechanism of action, but generally it is thought that such a risk is outweighed by the advantage of TXA stopping the bleeding. The fact that TXA is given for a short time further adds to the rationale of using it. It’s also worth noting that there is some concern about TXA getting into breast milk, but it’s not a major concern. Studies show that only small amounts will get into your milk, so if you really need this agent, most doctors will not use it as a reason for you to avoid breastfeeding.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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