ACOG Publishes Guidelines on Hemoglobinopathies in Pregnancy

The American College of Obstetricians and Gynecologists (ACOG) estimates that more than 270 million persons worldwide are heterozygous carriers of hereditary disorders of hemoglobin (Hb), and at least 300,000 affected homozygotes or compound heterozygotes are born every year. To address this, ACOG has released recommendations for screening and clinical management of hemoglobinopathies during pregnancy.

Genetic screening can help physicians identify couples at risk of having children with hemoglobinopathies and counsel them about reproduction and prenatal diagnosis. DNA analysis of cultured amniocytes or chorionic villi is preferred for prenatal diagnosis of hemoglobinopathies. Persons of northern European, Japanese, Native American, Inuit, or Korean descent are considered to be at low risk of hemoglobinopathies. Those of southeast Asian, African, or Mediterranean descent are at higher risk of being carriers of hemoglobinopathies, and ACOG recommends that physicians offer these patients carrier screening. However, ethnicity is not always a good predictor of risk because patients from high-risk groups may marry outside of their ethnic group.

Evaluation for Hematologic Assessment

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Figure 1.

Specialized antepartum evaluation for hematologic assessment of patients of African, southeast Asian, or Mediterranean descent. Patients of southeast Asian or Mediterranean descent should undergo electrophoresis if their blood test results reveal anemia. (Hb = hemoglobin.)

Adapted with permission from the American College of Obstetricians and Gynecologists. Hemoglobinopathies in pregnancy. ACOG Practice Bulletin No. 78, January 2007. Obstet Gynecol 2007;109:232.

A complete blood count should be obtained to ensure that Hb is accurately identified for patients of non-African descent. For patients of African descent, ACOG recommends performing Hb electrophoresis in addition to obtaining a complete blood count (Figure 1). Solubility testing for Hb S (Sickledex), high-performance liquid chromatography, and isoelectric focusing have been used for primary screening; however, solubility tests alone often fail to identify transmissible Hb gene abnormalities that could affect fetal outcomes. Additionally, many persons with these genotypes (e.g., Hb C, beta thalassemia, Hb E, Hb B, Hb D) are asymptomatic. If their partners have the sickle cell trait or another hemoglobinopathy, they could have offspring with more serious hemoglobinopathies. Therefore, solubility testing could be valuable for rapid screening for sickling when the information is crucial to immediate patient care.

Women with sickle cell disease who are pregnant are at increased risk of morbidity and mortality because of the combination of underlying hemolytic anemia and multiorgan dysfunction associated with this disorder. These patients need increased prenatal folic acid supplementation. However, the standard of 1 mg of folate in prenatal vitamins is not adequate for patients with hemoglobinopathies; instead, 4 mg per day of folic acid is recommended.

Women with sickle cell disease who are pregnant also are at increased risk of spontaneous abortion, stillbirth, and preterm labor. Therefore, ACOG recommends that serial ultrasonography and antepartum fetal testing be performed. Most of these patients require narcotics for pain control, so physicians should interpret the results of abnormal antepartum testing with caution. Cesarean delivery is not recommended in women with sickle cell disease, and it should be performed only for obstetric indications. Epidural analgesia is usually well tolerated as long as hypotension and hypoxemia are avoided. Ideally, however, pregnant women with sickle cell disease should receive care at institutions that can manage complications of the disease and high-risk pregnancies.

AAP Releases Guidelines on Treatment of Anaphylaxis

Epinephrine is an effective treatment option for anaphylaxis if it is injected into the lateral leg immediately. Delayed injection is associated with poor outcomes and may cause death. Persons who require additional care after the administration of epinephrine should seek immediate medical attention.

The American Academy of Pediatrics (AAP) recommends a lateral thigh epinephrine injection of 0.01 mg per kg, but no more than 0.30 mg, for children with anaphylaxis. [corrected] Administering the epinephrine intravenously increases the risk of dosing and dilution errors, and it also can increase the patient's risk of cardiac dysrhythmia.

Compared with other methods (e.g., syringe/needle/ampule), autoinjectors of epinephrine are preferred because they are easier to use. However, autoinjectors are available in only two doses (0.15 mg and 0.30 mg). Despite this potential problem, the AAP recommends that physicians prescribe an adequate autoinjector dose for children at risk of anaphylaxis. On the basis of limited data, children who are healthy and weigh 22 to 55 lb (10 to 25 kg) can be given 0.15 mg of epinephrine, and those who weigh 55 lb or more can receive 0.30 mg of epinephrine. For healthy children who weigh less than 22 lb, physicians should consider the health needs of the child and the risks of delaying the dose when a syringe/ampule/needle is used instead of an autoinjector.

The AAP recommends that children who have had a previous episode of anaphylaxis be given epinephrine because anaphylaxis is likely to occur again. In some instances, self-injection of epinephrine should be prescribed for patients who are at an increased risk of anaphylaxis (e.g., patients with asthma) but who have not yet had an episode.

Physicians should always prescribe epinephrine if there is an emergency involving an individual at risk of anaphylaxis. A comprehensive management approach should be used for children at risk of anaphylaxis, and patients and their families should be shown how to use epinephrine autoinjectors. Physicians also should explain the warning signs and symptoms of anaphylaxis and instruct patients to call for emergency help if anaphylaxis occurs.

It is also important to instruct patients and their families to avoid allergens. If possible, a subspecialist should evaluate children at increased risk to confirm allergic triggers, educate the patient on how to avoid them, and provide specific preventive treatment.

To provide a safe and secure environment for children at risk of anaphylaxis, the AAP recommends that patients and their families construct emergency action plans and give them to other persons responsible for the child's care at home as well as outside of the home.