From the Guidelines
When a patient comes in labor, blood tests such as maternal syphilis, hepatitis B surface antigen, and HIV status should be ordered, along with umbilical cord or newborn blood type and direct Coombs test result, if clinically indicated, to ensure maternal and fetal wellbeing. These tests are essential to assess the risk of maternal and fetal complications, and to guide decisions about management and interventions during labor and delivery. The most recent and highest quality study, 1, recommends that maternal and infant laboratory tests, including maternal syphilis, hepatitis B surface antigen, and HIV status, should be available and reviewed. Additionally, umbilical cord or newborn blood type and direct Coombs test result should be ordered if clinically indicated. Other tests, such as complete blood count (CBC), blood type and antibody screen, basic metabolic panel, and blood glucose testing, may also be necessary depending on the patient's individual risk factors and medical history. However, the primary focus should be on ordering the tests that are most critical for ensuring maternal and fetal wellbeing, as recommended by the most recent and highest quality study, 1. Key considerations include:
- Maternal syphilis, hepatitis B surface antigen, and HIV status to assess the risk of maternal and fetal complications
- Umbilical cord or newborn blood type and direct Coombs test result to identify potential Rh incompatibility issues
- Other tests, such as CBC, blood type and antibody screen, and basic metabolic panel, as needed based on individual patient risk factors and medical history. It is also important to note that the evidence quality of the recommendations may vary, with some studies providing stronger evidence than others, such as 1, which recommends a direct antibody test, blood type, and an Rh (D) type on the infant’s (cord) blood if a mother has not had prenatal blood grouping or is Rh-negative. However, the most recent and highest quality study, 1, should take precedence in guiding clinical decision-making.
From the Research
Blood Tests for Patients in Labor
- A complete blood count (CBC) is a crucial test for patients in labor, as it helps identify anemia and other hematologic abnormalities 2, 3, 4
- The American College of Obstetricians and Gynecologists recommends screening for anemia with a CBC in the first trimester and again at 24 0/7 to 28 6/7 weeks of gestation 2
- For patients in labor, a CBC can help estimate blood loss during delivery and identify those who may need blood transfusions 5, 6
- However, routine postpartum CBC may not be necessary for all patients, and a selective approach based on risk factors and clinical symptoms may be more appropriate 5, 6
Specific Blood Tests
- Hemoglobin concentration is an essential component of the CBC, and a level of less than 11.0 g/dL in the first trimester and less than 10.5 or 11.0 g/dL in the second or third trimester is considered anemia 2
- Mean corpuscular volume (MCV) is also an important parameter, as it helps differentiate between iron deficiency anemia and other types of anemia 2
- Reticulocyte count, white blood cell count, and platelet count are other components of the CBC that can provide valuable information about the patient's hematologic status 3, 4